Field of the Invention
[0001] This invention relates generally to the generation of neutralizing monoclonal antibodies,
and in particular, to monoclonal antibodies that recognize the Toll-like Receptor
4/MD-2 receptor complex, to monoclonal antibodies that recognize both the Toll-like
Receptor 4/MD-2 receptor complex and Toll-like Receptor 4 when not complexed with
MD-2, and to methods of using the monoclonal antibodies as therapeutics. This invention
also relates to soluble chimeric proteins, methods of expressing and purifying soluble
chimeric proteins, and methods of using soluble chimeric proteins as therapeutics,
in screening assays and in the production of antibodies.
Background of the Invention
[0002] Toll receptors, first discovered in
Drosophila, are type I transmembrane protein having leucine-rich repeats (LRRs) in the extracellular
portion of the protein, and one or two cysteine-rich domains. The mammalian homologs
of the
Drosophilia Toll receptors are known as "Toll-like receptors" (TLRs). TLRs play a role in innate
immunity by recognizing microbial particles and activating immune cells against the
source of these microbial particles.
[0003] Currently, ten types of Toll-like receptors have been identified in humans, TLRs
1-10. These TLRs are characterized by the homology of their intracellular domains
to that of the IL-1 receptor, and by the presence of extracellular leucine-rich repeats.
The different types of TLRs are activated by different types of microbial particles.
For example, TLR4 is primarily activated by lipopolysaccharide (LPS), while TLR2 is
activated by lipoteichoic (LTA), lipoarabinomannan (LAM); lipoprotein (BLP), and peptideglycans
(PGN). Toll receptor homologs, such as RP105, have also been identified.
[0004] Myeloid differentiation protein-2 (MD-2), a TLR4 accessory protein, has been identified
and characterized. This protein has been found to interact directly with TLR4, and
MD-2 has the ability to enable post-translational modifications of TLR4, as well as
facilitate its transport to the cell surface. TLR4 and MD-2 form a complex on the
cell surface.
[0005] Lipopolysaccharide (LPS), a component of gram-negative bacteria, is a microbial particle
capable of strongly activating the innate immune system. LPS delivers signals to immune
cells via its multi-chain receptor, comprising the TLR4/MD-2 complex as the principle
signaling component.
[0006] Accordingly, there exists a need for methods and compositions that modulate signaling
that is mediated by the TLR4/MD-2 complex.
Summary of the Invention
[0007] The invention provides isolated monoclonal antibodies recognizing the TLR4/MD-2 receptor
complex, wherein the monoclonal antibody inhibits at least 50% of lipopolysaccharide
(LPS) - induced IL-8 production in a solution comprising human TLR4/MD-2 transfected
HEK 293 cells when said monoclonal antibody is added to said solution at a concentration
of 10µg/ml, compared to the level of LPS induced IL-8 production in the absence of
said monoclonal antibody. In some cases, the monoclonal antibodies of the invention
also recognize TLR4 when not complexed with D-2 (
e.g., soluble TLR4 proteins, TLR4 expressed on the cell surface). Exemplary monoclonal
antibodies include 18H10, 16G7, 15C1 and 7E3.
[0008] The antibodies of the invention may contain a heavy chain variable region having
the amino acid sequence of SEQ ID NOS: 2, 12, 22 or 32 and a light chain variable
region having the amino acid sequence of SEQ ID NOS: 7,17,27 or 37. Preferably, the
three heavy chain CDRs include an amino acid sequence at least 90%, 92%, 95%, 97%
98%, 99% or more identical a sequence selected from the group consisting of DSYIH
(SEQ ID NO:3); WTDPENVNSIYDPRFQG (SEQ ID NO:4), GYNGVYYAMDY (SEQ ID NO:5); DYWIE (SEQ
ID NO:13); EILPGSGSTNYNEDFKD (SEQ ID NO:14); EERAYYFGY (SEQ ID NO:15); GGYSWH (SEQ
ID NO:23); YIHYSGYTDFNPSLKT (SEQ ID NO:24); KDPSDGFPY (SEQ ID NO:25); TYNIGVG (SEQ
ID NO:33); HIWWNDNIYYNTVLKS (SEQ ID NO:34); and MAEGRYDAMDY (SEQ ID NO:35) and a light
chain with three CDP that include an amino acid sequence at least 90%, 92%, 95%, 97%
98%, 99% or more identical to a sequence selected from the group consisting of the
amino acid sequence of SASSSVIYMH (SEQ ID NO:8); RTYNLAS (SEQ ID NO:9); HQWSSFPYT
(SEQ ID NO:10); RSSQSLENSNGNTYLN (SEQ ID NO:18); RVSNRFS (SEQ ID NO:19); LQVTHWPT
(SEQ ID NO:20); RASQSISDHLH (SEQ ID NO:28); YASHAIS (SEQ ID NO:29); QNGHSFPLT (SEQ
ID NO:30); RASQDITNYLN (SEQ ID NO:38); YTSKLHS (SEQ ID NO:39); and QQGNTFPWT (SEQ
ID NO:40). The antibody binds to the TLR4/MD-2 complex, to TLR4 when not complexed
with MD-2, or to both.
[0009] The present invention also provides the above-described monoclonal antibodies for
use in treating sepsis, ventilator - induced lung injury, acute inflammation, chronic
inflammation, autoimmune disease, osteoarthritis or rheumatoid arthritis.
[0010] The subject to be treated is,
e.g., human. The monoclonal antibody is administered in an amount sufficient to treat,
prevent or alleviate a symptom associated with the pathology. The amount of monoclonal
antibody sufficient to treat or prevent the pathology in the subject is, for example,
an amount that is sufficient to reduce LPS-induced production of IL-8. As used herein,
the term "reduced" refers to a decreased production of IL-8 in the presence of a monoclonal
antibody of the invention, wherein the production is, for example, local IL-8 production
(
e.g., at a site of inflamed tissue) or systemic IL-8 production. LPS-induced production
of IL-8 is decreased when the level of IL-8 production in the presence of a monoclonal
antibody of the invention is greater than or equal to 5%, 10%, 20%, 25%, 30%, 40%,
50%, 60%, 70%, 75%, 80%, 90%, 95%, 99%, or 100% lower than a control level of IL-8
production (
i.e., the level of IL-8 production in the absence of the monoclonal antibody). Level
of IL-8 production is measured,
e.g., using the human whole blood or huTLR4/MD2 transfected HEK293 cellular assays described
herein. Those skilled in the art will appreciate that the level of IL-8 production
can be measured using a variety of assays, including, for example, commercially available
ELISA kits.
[0011] The monoclonal antibodies of the invention are for use in treating a pathology selected
from sepsis, ventilator- induced lung injury, acute inflammation, chronic inflammation
(
e.g., chronic inflammation associated with allergic conditions and asthma), autoimmune
diseases (
e.g., IBD and atherosclerosis) and' disorders induced by endogenous soluble stress factors
(
e.g., Hsp60, fibronectin, heparan sulphate, hyaluronan, gp96, β-Defensin-2 and surfactant
protein A), which disorders induced by endogenous soluble stress factors are osteoarthritis
and rheumatoid arthritis. Pathologies associated with mechanical stress can also occur
in subjects and patients placed on respirators, ventilators and other respiratory-assist
devices. Such pathologies include, for example, ventilator-induced lung injury ("VILI"),
also referred to as ventilation-associated lung injury ("VALI").
[0012] Pharmaceutical compositions according to the invention can include an antibody of
the invention and a carrier. These pharmaceutical compositions can be included in
kits, such as, for example, diagnostic kits.
[0013] We also disclose soluble chimeric toll receptor proteins (also referred to herein
as toll-like receptor proteins), methods for expressing toll receptor proteins, and
methods for purifying such proteins in a soluble form.
[0014] In particular, we disclose chimeric polypeptides in which a toll-like receptor polypeptide,
or a biologically active derivative thereof, is operably linked to an MD accessory
polypeptide, or a biologically active derivative thereof. The toll-like receptor polypeptide
is a polypeptide selected from the group consisting of TLRs 1-10 and RP 105.
[0015] The MD accessory polypeptide is, for example, MD-I or MD-2. The toll-like receptor
polypeptide is, in some instances, operably linked to the MD accessory polypeptide
using a flexible glycine-serine linker, which renders the toll receptor both stable
during expression and soluble during purification. For example, a chimeric polypeptide
of the invention includes the extracellular portion of a toll receptor fused at its
C terminus to the N terminus of a mature MD protein (i.e., MD-I or MD-2) via a flexible
glycine/serine linker.
[0016] We also disclose methods for producing soluble chimeric fusion proteins by coupling
a toll-like receptor polypeptide, or a biologically active derivative thereof, to
an MD accessory polypeptide, or a biologically active derivative thereof. We disclose
methods for producing soluble chimeric fusion proteins by constructing a vector that
includes a nucleic acid sequence encoding a toll-like receptor polypeptide (or a biologically
active derivative thereof) coupled to a nucleic acid sequence encoding an MD accessory
polypeptide (or a biologically active derivative thereof); transfecting a cell with
this vector; culturing the cell under conditions that permit production of a fusion
protein having a toll-like receptor polypeptide coupled to an MD accessory polypeptide;
and isolating that fusion protein. The MD accessory polypeptide is, for example, MD-I
or MD-2, and the toll-like receptor polypeptide can be a polypeptide selected from
the group consisting of TLRs 1-10 and RP105. The toll-like receptor polypeptide is
operably linked to the MD accessory polypeptide by a flexible glycine-serine linker,
which renders the toll receptor both stable during expression and soluble during purification.
[0017] We disclose herein methods of treating or preventing pathologies associated with
aberrant toll-like receptor function, or alleviating a symptom associated with these
pathologies, by administering a soluble chimeric polypeptide of the invention to a
subject in which such treatment or prevention or alleviation is desired in an amount
sufficient to treat or prevent or alleviate the pathology, or a symptom thereof, in
the subject. The subject to be treated is, e.g., human. The amount of soluble chimeric
polypeptide sufficient to treat or prevent the pathology in the subject is an amount
that is sufficient to modulate (e.g., reduce or prevent) the activation of a toll-like
receptor in the subject to be treated. Activation of a toll-receptor is reduced or
decreased when the level of toll-receptor activation in the presence of a chimeric
protein of the invention is greater than or equal to 5%, 10%, 20%, 25%, 30%, 40%,
50%, 60%, 70%, 75%, 80%, 90%, 95%, 99%, or 100% lower than a control level of toll-like
receptor activation (i.e., the level of activation the absence of the chimeric protein).
The level of toll-receptor activation is measured using any of a variety of techniques
known in the art. For example, the level of TLR4 activation can be measured by detecting
the level of LPS-induced IL-8 production. Those skilled in the art will appreciate
that the level of toll-receptor activation can also be measured, for example, by detecting
activation, if any, of NF-kappa B or JNK (c-jun terminal kinase), which initiate the
transcription of genes encoding pro-inflammatory cytokines (e.g., IL1-alpha IL1-beta,
IL6 , and TNF-alpha). Activation of JNK and/or NF-kappa B can be detected by measuring
the levels of one or more pro-inflammatory cytokines.
[0018] The pathology to be treated may be sepsis, acute inflammation, chronic inflammation
or an autoimmune disease. For example, the pathology may be any one of a variety of
types of arthritis.
[0019] We also disclose antibodies that immunospecifically bind to the soluble chimeric
polypeptides of the invention, such as, for example, monoclonal antibodies or humanized
antibodies.
[0020] Pharmaceutical compositions can include a soluble chimeric polypeptide as described
above and a carrier, and/or an antibody of the invention and a carrier. These pharmaceutical
compositions can be included in kits, such as, for example, diagnostic kits.
[0021] We also disclose methods of screening for a ligand that binds a toll- like receptor
and modulates toll-like receptor activity. According to these methods, these ligands
are identified by providing a chimeric polypeptide of the invention that has a property
or function that is ascribable to that polypeptide; contacting the chimeric polypeptide
with a candidate compound; and determining whether the candidate compound alters the
property or function ascribable to the polypeptide, wherein an alteration in the property
or function ascribable to the polypeptide in the presence of the candidate compound
indicates that the candidate compound is a ligand that modulates toll-like receptor
activity.
[0022] One skilled in the art will appreciate that the chimeric polypeptides disclosed herein
and antibodies of the invention have a variety of uses. For example, the chimeric
proteins are used as therapeutic agents to prevent the activation of TLRs in disorders
such as, for example, sepsis, acute inflammation, chronic inflammation, autoimmune
diseases and various forms of arthritis. The chimeric proteins are also used as immunogens
in more efficient methods of generating binding and blocking anti-TLR antibodies,
and/or these chimeric polypeptides can be used as reagents in assays that screen for
small molecular weight binders and blockers of TLRs activity. The chimeric proteins
disclosed herein and/or antibodies of the invention are also used as reagents in diagnostic
kits or as diagnostic tools, or these chimeric proteins and/or antibodies can be used
in competition assays to generate therapeutic reagents.
Brief Description of the Drawings
[0023]
FIG. 1 is a graph depicting the binding of a one monoclonal antibody of the invention,
18H10, to the TLR4/MD-2 complex. Specificity of binding is shown by flow cytometry
using mock transfected or TLR4/MD-2 transfected cells. The results using mock-transfected
cells are shown in the filled graph (left), while the results using TLR4/MD- 2 transfected
cells are shown as in the outline graph (right).
FIG. 2 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the monoclonal antibody 18H10. The cells
were incubated with either mul8H10, HTA 125 (a commercially available anti-human TLR4
non-blocking MAb) or an antibody control at the indicated concentrations and subsequently
incubated with LPS (15 ng/ml). IL-8 levels were assessed 16 hours post LPS treatment.
FIG. 3 is a series of graphs depicting inhibition of LPS-induced IL-8 production in
human whole blood by the monoclonal antibody 18H10. Whole blood was drawn from 3 healthy
volunteers, treated with heparin and diluted 1:4 in RPMI medium. The following antibodies
were added at the concentrations indicated: control monoclonal antibody; HTA125 and
18H10. LPS was subsequently added for a final concentration of 10 ng/ml, and IL-8
levels were measured 6 hours post LPS treatment.
FIG. 4 is a series of graphs depicting the specificity of the 18H10 monoclonal antibody
for MD-2. The specificity of the 18H10 antibody is shown by flow cytometry analysis
of HEK 293 cells transiently transfected with either human TLR4 and human MD-2 (Panels
A, E and 1); rabbit TLR4 and rabbit MD-2 (Panels B, F and J); human TLR4 and rabbit
MD-2 (Panels C, G and K); or rabbit TLR4 and human MD-2 (Panels D, H and L). Cells
were incubated with either α-FLAG™ antibody (to detect TLR4 expression); α-C-myc antibody
(to detect MD-2 expression) or the 18H10 monoclonal antibody, followed by an APC-coupled
α -mouse (H+L) antibody.
FIG. 5A is a graph demonstrating the lack of specificity of 18H10 for recombinant
soluble MD-2 purified from baculovirus-infected insect cell supernatants as determined
by ELISA. Protein was coated directly on 96-well plates (5 µg/ml) followed by purified
MAb at the indicated concentration and anti-mouse IgG (H+L) HRP.
FIG 5B is a graph demonstrating that MD-2 must be associated with TLR4 for the 18H10
antibody to recognize it. Lysates (Panel 1, i.e., upper panel) or supernatants (Panel 2, i.e., lower panel) from HEK 293 cells, transiently transfected as indicated, were incubated
in wells coated with anti-FLAG M2. Binding of a biotinylated form of 18H10 was detected
using streptavidin-HRP. Biotinylated 12D4 (an anti-TLR4 MAb) with streptavidin-HRP
or a polyclonal rabbit Ab raised against soluble MD-2 with an anti rabbit IgG-HRP
controlled the presence of TLR4 and MD-2 respectively. In this experiment, TLR4 had
a FLAG tag at the N-terminus and was expressed using the vector pCNDA3.1 (-)hygro
(Invitrogen). MD-2 had FLAG and 6 x Histidine tags at the C terminus and was expressed
using the vector pCDNA3 (Invitrogen). Mock cells were transfected with empty plasmid.
FIGS. 6A-6F are a series of illustrations depicting the VH nucleotide sequence (SEQ
ID NO:1) (FIG. 6A), the VH amino acid sequence (SEQ ID NO:2) (FIG. 6B), the VL nucleotide
sequence (SEQ ID NO:6) (FIG. 6D), and the VL amino acid sequence (SEQ ID NO:7) for
18H10 (FIG. 6E). The VH complementarity determining regions (CDRs) (SEQ ID NOs:3,
4 and 5) (FIG. 6C) and the VL CDRs (SEQ ID NOs: 8,9 and 10) (FIG. 6F) are highlighted
in the underlined, italic text in FIGS. 6B and 6E.
FIG. 7 is a graph depicting that the VH and VL nucleotide sequence of 18H10 expressed
as a chimeric MAb ("chimeric 18H10") is capable of binding specifically to the human
TLR4/MD-2 complex on the surface of transfected CHO cells. MAb binding to the TLR4/MD-2
transfected CHO cells is shown by flow cytometry using chimeric 18H10 or an isotype
matched control MAb at the concentrations indicated.
FIG. 8 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the chimeric 18H10 MAb. Cells were incubated
with 18H10, or chimeric 18H10 at the indicated concentrations and subsequently incubated
with LPS (15 ng/ml). IL-8 levels were assessed 16 hours post LPS-treatment. Inhibition
of LPS-induced IL-8 production by the chimeric 18H10 was similar to the inhibition
by the 18H10 mouse MAb of the invention.
FIG. 9 is a graph depicting the binding of an monoclonal antibody of the invention,
16G7, to the TLR4/MD-2 complex. Specificity of binding is shown by flow cytometry
using mock-transfected or TLR4/MD-2 transfected cells. The results using mock transfected
cells are shown in the filled graph (left), while the results using TLR4/MD-2 transfected
cells are shown as in the outline graph (right).
FIG. 10 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the monoclonal antibody 16G7. The cells
were incubated with the 16G7 monoclonal antibody, the HTA 125 anti-TLR4 MAb or an
antibody control at the indicated concentrations and subsequently incubated with LPS
(15 ng/ml). IL-8 levels were assessed 16 hours post LPS treatment.
FIG. 11 is a series of graphs depicting inhibition of LPS-induced IL-8 production
in human whole blood by the monoclonal antibody 16G7. Whole blood was drawn from 3
healthy volunteers, treated with heparin and diluted 1:4 in RPMI medium. The following
antibodies were added at the concentrations indicated: Isotype matched control; HTA125
(anti-human TLR4 non-blocking monoclonal antibody); 16G7 and 28C5 (anti-human CD14
blocking monoclonal antibody). LPS was subsequently added for a final concentration
of 10 ng/ml.
FIG. 12 is a series of graphs depicting the specificity of the 16G7 monoclonal antibody
for TLR4. The specificity of the 16G7 antibody is shown by flow cytometry analysis
of HEK 293 cells transiently transfected with either rabbit TLR4 and rabbit MD-2 (Panels
A, E and I); human TLR4 and human MD-2 (Panels B, F and J); rabbit TLR4 and human
MD-2 (Panels C, G and K); or human TLR4 and rabbit MD-2 (Panels D, H and L). Cells
were incubated with either α-FLAG™ antibody (to detect TLR4 expression); α-C-myc antibody
(to detect MD-2 expression) or the 16G7 monoclonal antibody, followed by an APC-coupled
α -mouse (H+L) antibody.
FIGS. 13A-13F are a series of illustrations depicting the VH nucleotide sequence (SEQ
ID NO:11) (FIG. 13A), the VH amino acid sequence (SEQ ID NO:12) (FIG. 13B), the VL
nucleotide sequence (SEQ ID NO:16) (FIG. 13D), and the VL amino acid sequence (SEQ
ID NO:17) (FIG. 13E) for 16G7. The VH complementarity determining regions (CDRs) (SEQ
ID NOs: 13, 14 and 15) (FIG. 13C) and the VL CDRs (SEQ ID NOs: 18, 19 and 20) (FIG.
13F) are highlighted in the underlined, italic text in FIGS. 13B and 13E.
FIG. 14 is a graph depicting the binding of a monoclonal antibody of the invention,
15C1, to the TLR4/MD-2 complex. Specificity of binding is shown by flow cytometry
using mock transfected or TLR4/MD-2 transfected cells. The results using mock-transfected
cells are shown in the filled graph (left), while the results using TLR4/MD-2 transfected
cells are shown as in the outline graph (right).
FIG. 15 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the monoclonal antibody 15C1. The cells
were incubated with the 15C1 monoclonal antibody, HTA 125 (anti-human TLR4 non-blocking
monoclonal antibody) and an isotype-matched control (IgG1) at the indicated concentrations
and subsequently incubated with LPS (15 ng/ml). IL-8 levels were assessed 16 hours
post LPS treatment.
FIG. 16 is a series of graphs depicting inhibition of LPS-induced IL-8 production
in human whole blood by the monoclonal antibody 15C1. Whole blood was drawn from 3
healthy volunteers, treated with heparin and diluted 1:4 in RPMI medium. The following
antibodies were added at the concentrations indicated: Isotype matched control (IgG1);
HTA125 (anti-human TLR4 non-blocking monoclonal antibody); 15C1 and 28C5 (anti-human
CD14 blocking monoclonal antibody). LPS was subsequently added for a final concentration
of 10 ng/ml.
FIG. 17 is a series of graphs depicting the specificity of the 15C1 monoclonal antibody
for TLR4. The specificity of the 15C1 antibody is shown by flow cytometry analysis
of HEK 293 cells transiently transfected with either mock vector, i.e., empty vector (Panel A), human TLR4 (Panel B), human TLR4 and human MD-2 (Panel
C), rabbit TLR4 and rabbit MD-2 (Panel D), human TLR4 and rabbit MD-2 (Panel E), or
rabbit TLR4 and human MD-2 (Panel F). Cells were incubated with the 15C1 monoclonal
antibody (10 µg/ml), followed by an APC-coupled α -mouse (H+L) antibody.
FIGS. 18A-18F are a series of illustrations depicting the VH nucleotide sequence (SEQ
ID NO:21) (FIG. 18A), the VH amino acid sequence (SEQ ID NO:22) (FIG. 18B), the VL
nucleotide sequence (SEQ ID NO:26) (FIG. 18D), and the VL amino acid sequence (SEQ
ID NO:27) (FIG. 18E) for 15C1. The VH complementarity determining regions (CDRs) (SEQ
ID NOs: 23, 24 and 25) (FIG. 18C) and the VL CDRs (SEQ ID NOs: 28, 29 and 30) (FIG.
18F) are highlighted in the underlined, italic text in FIGS. 18B and 18E.
FIG. 19 is a graph depicting that the VH and VL nucleotide sequence of 15C1 expressed
as a chimeric MAb ("chimeric 15C1") is capable of binding specifically to the human
TLR4/MD-2 complex on the surface of transfected CHO cells. MAb binding to the TLR4/MD-2
complex is shown by flow cytometry using chimeric 15C1 or an isotype matched control
monoclonal antibody at the indicated concentration.
FIG. 20 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the chimeric 15C1 MAb. Cells were incubated
with 15C1 or chimerical 15C1 at the concentrations indicated and subsequently incubated
with LPS (15 ng/ml). IL-8 levels were assessed 16 hours post LPS treatment. Inhibition
of LPS-induced IL-8 production by the chimeric 15C1 was similar to the inhibition
by the 15C1 mouse MAb of the invention.
FIG. 21 is a graph depicting the binding of a monoclonal antibody of the invention,
7E3, to the TLR4/MD-2 complex. Specificity of binding is shown by flow cytometry using
mock transfected or TLR4/MD-2 transfected cells. The results using mock-transfected
cells are shown in the filled graph (left), while the results using TLR4/MD-2 transfected
cells are shown as in the outline graph (right).
FIG. 22 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the monoclonal antibody 7E3. The cells were
incubated with the 7E3 monoclonal antibody, HTA 125 (anti-human TLR4 non-blocking
monoclonal antibody) and an isotype-matched control (IgG1) at the indicated concentrations
and subsequently incubated with LPS (15 ng/ml). IL-8 levels were assessed 16 hours
post LPS treatment.
FIG. 23 is a series of graphs depicting inhibition of LPS-induced IL-8 production
in human whole blood by the monoclonal antibody 7E3. Whole blood was drawn from 3
healthy volunteers, treated with heparin and diluted 1:4 in RPMI medium. The following
antibodies were added at the concentrations indicated: Isotype matched control (IgG1);
HTA125 (anti-human TLR4 non-blocking monoclonal antibody); 7E3 and 28C5 (anti-human
CD14 blocking monoclonal antibody). LPS was subsequently added for a final concentration
of 10 ng/ml.
FIG. 24 is a series of graphs depicting the specificity of the 7E3 monoclonal antibody
for the TLR4/MD-2 complex. The specificity of the 7E3 antibody is shown by flow cytometry
analysis of HEK 293 cells transiently transfected with either mock vector (Panel A),
human TLR4 (Panel B), human TLR4 and human MD-2 (Panel C), rabbit TLR4 and rabbit
MD-2 (Panel D), human TLR4 and rabbit MD-2 (Panel E),or rabbit TLR4 and human MD-2
(Panel F). Cells were incubated with the 7E3 monoclonal antibody (10 µg/ml), followed
by an APC-coupled α -mouse (H+L) antibody.
FIGS. 25A-25F are a series of illustrations depicting the VH nucleotide sequence (SEQ
ID NO:31) (FIG. 25A), the VH amino acid sequence (SEQ ID NO:32) (FIG. 25B), the VL
nucleotide sequence (SEQ ID NO:36) (FIG. 25D), and the VL amino acid sequence (SEQ
ID NO:37) (FIG. 25E) for 7E3. The VH complementarity determining regions (CDRs) (SEQ
ID NOs: 33, 34 and 35) (FIG. 25C) and the VL CDRs (SEQ ID NOs: 38, 39 and 40) (FIG.
25F) are highlighted in the underlined italic text in FIGS. 25B and 25E.
FIG. 26 is a graph illustrating that the VH and VL nucleotide sequence of 7E3 expressed
as a chimeric MAb ("chimeric 7E3") is capable of binding specifically to the human
TLR4/MD-2 complex on the surface of transfected CHO cells. Monoclonal antibody binding
toTLR4/MD-2 transfected CHO cells is shown by flow cytometry using chimeric 7E3 or
an isotype matched control MAb at the indicated concentrations.
FIG. 27 is a graph depicting inhibition of lipopolysaccharide (LPS)-induced IL-8 production
in TLR4/MD-2 transfected HEK 293 cells by the chimeric 7E3 MAb. Cells were incubated
with chimeric 7E3 or an isotype matched MAb control at the indicated concentrations
and subsequently incubated with LPS (15 ng/ml). IL-8 levels were assessed 16 hours
post LPS-treatment.
FIG. 28 is an illustration depicting the construction of a TLR4/MD-2 fusion protein
cDNA according to the present invention.
FIG. 29 is an illustration depicting the expression of a TLR4/MD-2 chimeric protein
of the invention in Sf9 cell lysates and supernatant.
FIG. 30 is an illustration depicting the purification of a TLR4/MD-2 chimeric protein
according to the invention from infected Sf9 cell lysates,
FIG. 31 is a graph depicting the inhibition of lipopolysaccharide-(LPS) induced IL-8
production using a soluble chimeric TLR4/MD-2 protein according to the present invention.
FIG. 32A illustrates a nucleic acid sequence encoding the accessory protein MD-1 (SEQ
ID NO:41).
FIG. 32B depicts an amino acid sequence of a mature MD-I accessory protein in a preferred
embodiment of the invention (SEQ ID NO:42).
FIG. 33A illustrates a nucleic acid sequence encoding the accessory protein MD-2 (SEQ
ID NO:43).
FIG. 33B depicts an amino acid sequence of a mature MD-2 accessory protein (SEQ ID
NO:44).
Detailed Description of the Invention
[0024] The present invention relates to monoclonal antibodies that neutralize the activation
of the TLR4/MD-2 receptor complex. In particular, the invention provides monoclonal
antibodies that bind a human TLR4/MD-2 receptor complex wherein the monoclonal antibody
inhibits at least 50% of lipopolysaccharide (LPS) - induced IL-8 production in a solution
comprising human TLR4/MD-2 tarnsfected HEK293 cells wherein said antibody is added
to said solution at a concentration of 10ng/ml, as compared to the level of LPS-induced
IL-8 production in the absence of said monoclonal antibody. In addition, some monoclonal,
antibodies of the invention also recognize TLR4 when not complexed with MD-2. Exemplary
antibodies of the invention include, for example, the 18H10 antibody (Figures 6A-6F),
the 16G7 antibody (Figures 13A-13F), the 15Cl antibody (Figures 18A-18F) and the 7E3
antibody (Figures 25A-25F).
[0025] We also disclose soluble chimeric toll receptor proteins (also referred to herein
as toll-like receptor proteins), methods for expressing toll receptor proteins, and
methods for purifying such proteins in a soluble form. The chimeric proteins are useful,
e.g., in generating antibodies.
[0026] TLRs recognize microbial particles and activate immune cells against the source of
these microbial particles. (
See Takeda et al., Annu. Rev. Immunol., 21: 335-76 (2003), ). TLR4 and MD-2 have been shown to form a complex on the cell surface, and
the presence of MD-2 appears essential for the responsiveness of TLR4 to various ligands,
including LIPS. LPS is a gram-negative bacterial outer membrane glycolipid that is
capable of strongly activating the innate immune system. LPS has been implicated as
one of the major factors activating the immune system during the severe generalized
inflammation resulting from gram-negative infection. (
Lakhani et al., Curr. Opin. Pediatr. 15: 278-282 (2003),
[0027] LPS delivers signals to immune cells via its multi-chain receptor in which the TLR4/MD-2
complex is the principle signaling component. LPS has been shown to exert its effects
on the immune system via signaling through TLR4. LPS rapidly binds to the lipopolysaccharide-binding
protein (LBP) in the bloodstream, and in this form, LPS interacts with the GPI-anchored
cell surface protein CD14. LPS is then transferred to TLR4, which transduces an intracellular
activation signal. Another protein, MD-2, has been found to be necessary for signal
transduction via TLR4 to occur. MD-2 interacts directly with TLR4 and plays an important
role in its post-translational modification and intracellular trafficking. In addition,
MD-2 has been shown to directly bind LPS, which demonstrates the importance of this
accessory protein in the LPS receptor complex. (
See Miyake K., Int. Immunopharmacol. 3:119-128 (2003)).
[0028] Accordingly, neutralization of LPS signaling mediated by the TLR4/MD-2 complex is
a potential therapeutic strategy in the treatment of disorders such as, for example,
acute systemic inflammation and sepsis induced by gram-negative bacterial infection.
Definitions:
[0029] Unless otherwise defined, scientific and technical terms used in connection with
the present invention shall have the meanings that are commonly understood by those
of ordinary skill in the art. Further, unless otherwise required by context, singular
terms shall include pluralities and plural terms shall include the singular. Generally,
nomenclatures utilized in connection with, and techniques of, cell and tissue culture,
molecular biology, and protein and oligo- or polynucleotide chemistry and hybridization
described herein are those well known and commonly used in the art. Standard techniques
are used for recombinant DNA, oligonucleotide synthesis, and tissue culture and transformation
(
e.g., electroporation, lipofection). Enzymatic reactions and purification techniques
are performed according to manufacturer's specifications or as commonly accomplished
in the art or as described herein. The foregoing techniques and procedures are generally
performed according to conventional methods well known in the art and as described
in various general and more specific references that are cited and discussed throughout
the present specification.
See e.g., Sambrook et al. Molecular Cloning: A Laboratory Manual (2d ed., Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, N.Y. (1989)). The nomenclatures utilized in connection with, and the laboratory procedures and
techniques of, analytical chemistry, synthetic organic chemistry, and medicinal and
pharmaceutical chemistry described herein are those well known and commonly used in
the art. Standard techniques are used for chemical syntheses, chemical analyses, pharmaceutical
preparation, formulation, and delivery, and treatment of patients.
[0030] As utilized in accordance with the present disclosure, the following terms, unless
otherwise indicated, shall be understood to have the following meanings:
[0031] As used herein, the term "antibody" refers to immunoglobulin molecules and immunologically
active portions of immunoglobulin (Ig) molecules,
i.e., molecules that contain an antigen binding site that specifically binds (immunoreacts
with) an antigen. By "specifically bind" or "immunoreacts with" or "immunospecifically
bind" is meant that the antibody reacts with one or more antigenic determinants of
the desired antigen and does not react with other polypeptides or binds at much lower
affinity (K
d > 10
-6). Antibodies include, but are not limited to, polyclonal, monoclonal, chimeric, dAb
(domain antibody), single chain, F
ab, F
ab' and F
(ab')2 fragments, scFvs, and an F
ab expression library.
[0032] The basic antibody structural unit is known to comprise a tetramer. Each tetramer
is composed of two identical pairs of polypeptide chains, each pair having one "light"
(about 25 kDa) and one "heavy" chain (about 50-70 kDa). The amino-terminal portion
of each chain includes a variable region of about 100 to 110 or more amino acids primarily
responsible for antigen recognition. The carboxy-terminal portion of each chain defines
a constant region primarily responsible for effector function. In general, antibody
molecules obtained from humans relate to any of the classes IgG, IgM, IgA, IgE and
IgD, which differ from one another by the nature of the heavy chain present in the
molecule. Certain classes have subclasses as well, such as IgG
1, IgG
2, and others. Furthermore, in humans, the light chain may be a kappa chain or a lambda
chain.
[0033] The term "monoclonal antibody" (MAb) or "monoclonal antibody composition", as used
herein, refers to a population of antibody molecules that contain only one molecular
species of antibody molecule consisting of a unique light chain gene product and a
unique heavy chain gene product. In particular, the complementarity determining regions
(CDRs) of the monoclonal antibody are identical in all the molecules of the population.
MAbs contain an antigen binding site capable of immunoreacting with a particular epitope
of the antigen characterized by a unique binding affinity for it.
[0034] The term "antigen-binding site," or "binding portion" refers to the part of the immunoglobulin
molecule that participates in antigen binding. The antigen binding site is formed
by amino acid residues of the N-terminal variable ("V") regions of the heavy ("H")
and light ("L") chains. Three highly divergent stretches within the V regions of the
heavy and light chains, referred to as "hypervariable regions," are interposed between
more conserved flanking stretches known as "framework regions," or "FRs". Thus, the
term "FR" refers to amino acid sequences which are naturally found between, and adjacent
to, hypervariable regions in immunoglobulins. In an antibody molecule, the three hypervariable
regions of a light chain and the three hypervariable regions of a heavy chain are
disposed relative to each other in three dimensional space to form an antigen-binding
surface. The antigen-binding surface is complementary to the three-dimensional surface
of a bound antigen, and the three hypervariable regions of each of the heavy and light
chains are referred to as "complementarity-determining regions," or "CDRs." The assignment
of amino acids to each domain is in accordance with the definitions of
Kabat Sequences of Proteins of Immunological Interest (National Institutes of Health,
Bethesda, Md. (1987 and 1991)), or
Chothia & Lesk J. Mol. Biol. 196:901-917 (1987),
Chothia et al. Nature 342:878-883 (1989).
[0035] As used herein, the term "epitope" includes any protein determinant capable of specific
binding to an immunoglobulin, an scFv, or a T-cell receptor. The term "epitope" includes
any protein determinant capable of specific binding to an immunoglobulin or T-cell
receptor. Epitopic determinants usually consist of chemically active surface groupings
of molecules such as amino acids or sugar side chains and usually have specific three
dimensional structural characteristics, as well as specific charge characteristics.
For example, antibodies may be raised against N-terminal or C-terminal peptides of
a polypeptide. An antibody is said to specifically bind an antigen when the dissociation
constant is ≤ 1 µM; preferably ≤ 100 nM and most preferably ≤ 10 nM.
[0036] As used herein, the terms "immunological binding," and "immunological binding properties"
refer to the non-covalent interactions of the type which occur between an immunoglobulin
molecule and an antigen for which the immunoglobulin is specific. The strength, or
affinity of immunological binding interactions can be expressed in terms of the dissociation
constant (K
d) of the interaction, wherein a smaller K
d represents a greater affinity. Immunological binding properties of selected polypeptides
can be quantified using methods well known in the art. One such method entails measuring
the rates of antigen-binding site/antigen complex formation and dissociation, wherein
those rates depend on the concentrations of the complex partners, the affinity of
the interaction, and geometric parameters that equally influence the rate in both
directions. Thus, both the "on rate constant" (K
on) and the "off rate constant" (K
off) can be determined by calculation of the concentrations and the actual rates of association
and dissociation.
(See Nature 361:186-87 (1993)). The ratio of K
off/K
on enables the cancellation of all parameters not related to affinity, and is equal
to the dissociation constant K
d. (
See, generally, Davies et al. (1990) Annual Rev Biochem 59:439-473). An antibody of the present invention is said to specifically bind to the Toll-like
Receptor 4 (TLR4)/MD-2 complex or to TLR4 when not complexed to MD-2, when the equilibrium
binding constant (K
d) is ≤1 µM, preferably ≤ 100 nM, more preferably ≤ 10 nM, and most preferably ≤ 100
pM to about 1 pM, as measured by assays such as radioligand binding assays or similar
assays known to those skilled in the art.
[0037] The term "isolated polynucleotide" as used herein shall mean a polynucleotide of
genomic, cDNA, or synthetic origin or some combination thereof, which by virtue of
its origin the "isolated polynucleotide" (1) is not associated with all or a portion
of a polynucleotide in which the "isolated polynucleotide" is found in nature, (2)
is operably linked to a polynucleotide which it is not linked to in nature, or (3)
does not occur in nature as part of a larger sequence.
[0038] The term "isolated protein" referred to herein means a protein of cDNA, recombinant
RNA, or synthetic origin or some combination thereof, which by virtue of its origin,
or source of derivation, the "isolated protein" (1) is not associated with proteins
found in nature, (2) is free of other proteins from the same source,
e.g., free of marine proteins, (3) is expressed by a cell from a different species, or
(4) does not occur in nature.
[0039] The term "polypeptide" is used herein as a generic term to refer to native protein,
fragments, or analogs of a polypeptide sequence. Hence, native protein fragments,
and analogs are species of the polypeptide genus. Preferred polypeptides in accordance
with the invention comprise the human heavy chain immunoglobulin molecules represented
in Figures 6B, 13B, 18B and 25B and the human light chain immunoglobulin molecules
represented in Figures 6E, 13E, 18 and 25, as well as antibody molecules formed by
combinations comprising the heavy chain immunoglobulin molecules with light chain
immunoglobulin molecules, such as kappa light chain immunoglobulin molecules, and
vice versa, as well as fragments and analogs thereof.
[0040] The term "naturally-occurring" as used herein as applied to an object refers to the
fact that an object can be found in nature. For example, a polypeptide or polynucleotide
sequence that is present in an organism (including viruses) that can be isolated from
a source in nature and which has not been intentionally modified by man in the laboratory
or otherwise is naturally-occurring.
[0041] The term "operably linked" as used herein refers to positions of components so described
are in a relationship permitting them to function in their intended manner. A control
sequence "operably linked" to a coding sequence is ligated in such a way that expression
of the coding sequence is achieved under conditions compatible with the control sequences.
[0042] The term "control sequence" as used herein refers to polynucleotide sequences which
are necessary to effect the expression and processing of coding sequences to which
they are ligated. The nature of such control sequences differs depending upon the
host organism in prokaryotes, such control sequences generally include promoter, ribosomal
binding site, and transcription termination sequence in eukaryotes, generally, such
control sequences include promoters and transcription termination sequence. The term
"control sequences" is intended to include, at a minimum, all components whose presence
is essential for expression and processing, and can also include additional components
whose presence is advantageous, for example, leader sequences and fusion partner sequences.
The term "polynucleotide" as referred to herein means a polymeric boron of nucleotides
of at least 10 bases in length, either ribonucleotides or deoxynucleotides or a modified
form of either type of nucleotide. The term includes single and double stranded forms
of DNA.
[0043] The term oligonucleotide referred to herein includes naturally occurring, and modified
nucleotides linked together by naturally occurring, and non-naturally occurring oligonucleotide
linkages. Oligonucleotides are a polynucleotide subset generally comprising a length
of 200 bases or fewer. Preferably oligonucleotides are 10 to 60 bases in length and
most preferably 12, 13, 14, 15, 16, 17, 18, 19, or 20 to 40 bases in length. Oligonucleotides
are usually single stranded,
e.g., for probes, although oligonucleotides may be double stranded,
e.g., for use in the construction of a gene mutant. Oligonucleotides of the invention
are either sense or antisense oligonucleotides.
[0044] The term "naturally occurring nucleotides" referred to herein includes deoxyribonucleotides
and ribonucleotides. The term "modified nucleotides" referred to herein includes nucleotides
with modified or substituted sugar groups and the like. The term "oligonucleotide
linkages" referred to herein includes Oligonucleotides linkages such as phosphorothioate,
phosphorodithioate, phosphoroselerloate, phosphorodiselenoate, phosphoroanilothioate,
phoshoraniladate, phosphoronmidate, and the like.
See e.g., LaPlanche et al. Nucl. Acids Res. 14:9081 (1986);
Stec et al. J. Am. Chem. Soc. 106:6077 (1984),
Stein et al. Nucl. Acids Res. 16:3209 (1988),
Zon et al. Anti Cancer Drug Design 6:539 (1991);
Zon et al. Oligonucleotides and Analogues: A Practical Approach, pp. 87-108 (F. Eckstein,
Ed., Oxford University Press, Oxford England (1991));
Stec et al. U.S. Patent No. 5,151,510;
Uhlmann and Peyman Chemical Reviews 90:543 (1990). An oligonucleotide can include a label for detection, if desired.
[0045] The term "selectively hybridize" referred to herein means to detectably and specifically
bind. Polynucleotides, oligonucleotides and fragments thereof in accordance with the
invention selectively hybridize to nucleic acid strands under hybridization and wash
conditions that minimize appreciable amounts of detectable binding to nonspecific
nucleic acids. High stringency conditions can be used to achieve selective hybridization
conditions as known in the art and discussed herein. Generally, the nucleic acid sequence
homology between the polynucleotides, oligonucleotides, and fragments of the invention
and a nucleic acid sequence of interest will be at least 80%, and more typically with
preferably increasing homologies of at least 85%, 90%, 95%, 99%, and 100%. Two amino
acid sequences are homologous if there is a partial or complete identity between their
sequences. For example, 85% homology means that 85% of the amino acids are identical
when the two sequences are aligned for maximum matching. Gaps (in either of the two
sequences being matched) are allowed in maximizing matching gap lengths of 5 or less
are preferred with 2 or less being more preferred. Alternatively and preferably, two
protein sequences (or polypeptide sequences derived from them of at least 30 amino
acids in length) are homologous, as this term is used herein, if they have an alignment
score of at more than 5 (in standard deviation units) using the program ALIGN with
the mutation data matrix and a gap penalty of 6 or greater. See
Dayhoff, M.O., in Atlas of Protein Sequence and Structure, pp. 101-110 (Volume 5,
National Biomedical Research Foundation (1972)) and
Supplement 2 to this volume, pp. 1-10. The two sequences or parts thereof are more preferably homologous if their amino
acids are greater than or equal to 50% identical when optimally aligned using the
ALIGN program. The term "corresponds to" is used herein to mean that a polynucleotide
sequence is homologous (
i.e., is identical, not strictly evolutionarily related) to all or a portion of a reference
polynucleotide sequence, or that a polypeptide sequence is identical to a reference
polypeptide sequence. In contradistinction, the term "complementary to" is used herein
to mean that the complementary sequence is homologous to all or a portion of a reference
polynucleotide sequence. For illustration, the nucleotide sequence "TATAC" corresponds
to a reference sequence "TATAC" and is complementary to a reference sequence "GTATA".
[0046] The following terms are used to describe the sequence relationships between two or
more polynucleotide or amino acid sequences: "reference sequence", "comparison window",
"sequence identity", "percentage of sequence identity", and "substantial identity".
A "reference sequence" is a defined sequence used as a basis for a sequence comparison
a reference sequence may be a subset of a larger sequence, for example, as a segment
of a full-length cDNA or gene sequence given in a sequence listing or may comprise
a complete cDNA or gene sequence. Generally, a reference sequence is at least 18 nucleotides
or 6 amino acids in length, frequently at least 24 nucleotides or 8 amino acids in
length, and often at least 48 nucleotides or 16 amino acids in length. Since two polynucleotides
or amino acid sequences may each (1) comprise a sequence (
i.e., a portion of the complete polynucleotide or amino acid sequence) that is similar
between the two molecules, and (2) may further comprise a sequence that is divergent
between the two polynucleotides or amino acid sequences, sequence comparisons between
two (or more) molecules are typically performed by comparing sequences of the two
molecules over a "comparison window" to identify and compare local regions of sequence
similarity. A "comparison window", as used herein, refers to a conceptual segment
of at least 18 contiguous nucleotide positions or 6 amino acids wherein a polynucleotide
sequence or amino acid sequence may be compared to a reference sequence of at least
18 contiguous nucleotides or 6 amino acid sequences and wherein the portion of the
polynucleotide sequence in the comparison window may comprise additions, deletions,
substitutions, and the like (
i.e., gaps) of 20 percent or less as compared to the reference sequence (which does not
comprise additions or deletions) for optimal alignment of the two sequences. Optimal
alignment of sequences for aligning a comparison window may be conducted by the local
homology algorithm of
Smith and Waterman Adv. Appl. Math. 2:482 (1981), by the homology alignment algorithm of
Needleman and Wunsch J. Mol. Biol. 48:443 (1970), by the search for similarity method of
Pearson and Lipman Proc. Natl. Acad. Sci. (U.S.A.) 85:2444 (1988), by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA
in the Wisconsin Genetics Software Package Release 7.0, (Genetics Computer Group,
575 Science Dr., Madison, Wis.), Geneworks, or MacVector software packages), or by
inspection, and the best alignment (
i.e., resulting in the highest percentage of homology over the comparison window) generated
by the various methods is selected.
[0047] The term "sequence identity" means that two polynucleotide or amino acid sequences
are identical (
i.e., on a nucleotide-by-nucleotide or residue-by-residue basis) over the comparison
window. The term "percentage of sequence identity" is calculated by comparing two
optimally aligned sequences over the window of comparison, determining the number
of positions at which the identical nucleic acid base (
e.g., A, T, C, G, U or I) or residue occurs in both sequences to yield the number of
matched positions, dividing the number of matched positions by the total number of
positions in the comparison window (
i.e., the window size), and multiplying the result by 100 to yield the percentage of
sequence identity. The terms "substantial identity" as used herein denotes a characteristic
of a polynucleotide or amino acid sequence, wherein the polynucleotide or amino acid
comprises a sequence that has at least 85 percent sequence identity, preferably at
least 90 to 95 percent sequence identity, more usually at least 99 percent sequence
identity as compared to a reference sequence over a comparison window of at least
18 nucleotide (6 amino acid) positions, frequently over a window of at least 24-48
nucleotide (8-16 amino acid) positions, wherein the percentage of sequence identity
is calculated by comparing the reference sequence to the sequence which may include
deletions or additions which total 20 percent or less of the reference sequence over
the comparison window. The reference sequence may be a subset of a larger sequence.
[0048] As used herein, the twenty conventional amino acids and their abbreviations follow
conventional usage. See
Immunology - A Synthesis (2nd Edition, E.S. Golub and D.R. Gren, Eds., Sinauer Associates,
Sunderland7 Mass. (1991)). Stereoisomers (
e.g., D- amino acids) of the twenty conventional amino acids, unnatural amino acids such
as α-, α-disubstituted amino acids, N-alkyl amino acids, lactic acid, and other unconventional
amino acids may also be suitable components for polypeptides of the present invention.
Examples of unconventional amino acids include: 4 hydroxyproline, γ-carboxyglutamate,
ε-N,N,N-trimethyllysine, ε -N-acetyllysine, O-phosphoserine, N- acetylserine, N-formylmethionine,
3-methylhistidine, 5-hydroxylysine, σ-N-methylarginine, and other similar amino acids
and imino acids (
e.g., 4-hydroxyproline). In the polypeptide notation used herein, the left-hand direction
is the amino terminal direction and the right-hand direction is the carboxy-terminal
direction, in accordance with standard usage and convention.
[0049] Similarly, unless specified otherwise, the left-hand end of single- stranded polynucleotide
sequences is the 5' end the left-hand direction of double-stranded polynucleotide
sequences is referred to as the 5' direction. The direction of 5' to 3' addition of
nascent RNA transcripts is referred to as the transcription direction sequence regions
on the DNA strand having the same sequence as the RNA and which are 5' to the 5' end
of the RNA transcript are referred to as "upstream sequences", sequence regions on
the DNA strand having the same sequence as the RNA and which are 3' to the 3' end
of the RNA transcript are referred to as "downstream sequences".
[0050] As applied to polypeptides, the term "substantial identity" means that two peptide
sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default
gap weights, share at least 80 percent sequence identity, preferably at least 90 percent
sequence identity, more preferably at least 95 percent sequence identity, and most
preferably at least 99 percent sequence identity.
[0051] Preferably, residue positions which are not identical differ by conservative amino
acid substitutions.
[0052] Conservative amino acid substitutions refer to the interchangeability of residues
having similar side chains. For example, a group of amino acids having aliphatic side
chains is glycine, alanine, valine, leucine, and isoleucine; a group of amino acids
having aliphatic-hydroxyl side chains is serine and threonine; a group of amino acids
having amide- containing side chains is asparagine and glutamine; a group of amino
acids having aromatic side chains is phenylalanine, tyrosine, and tryptophan; a group
of amino acids having basic side chains is lysine, arginine, and histidine; and a
group of amino acids having sulfur- containing side chains is cysteine and methionine.
Preferred conservative amino acids substitution groups are: valine-leucine-isoleucine,
phenylalanine-tyrosine, lysine-arginine, alanine valine, glutamic- aspartic, and asparagine-glutamine.
[0053] As discussed herein, minor variations in the amino acid sequences of antibodies or
immunoglobulin molecules are contemplated as being encompassed by the present invention,
providing that the variations in the amino acid sequence maintain at least 75%, more
preferably at least 80%, 90%, 95%, and most preferably 99%. In particular, conservative
amino acid replacements are contemplated. Conservative replacements are those that
take place within a family of amino acids that are related in their side chains. Genetically
encoded amino acids are generally divided into families: (1) acidic amino acids are
aspartate, glutamate; (2) basic amino acids are lysine, arginine, histidine; (3) non-polar
amino acids are alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine,
tryptophan, and (4) uncharged polar amino acids are glycine, asparagine, glutamine,
cysteine, serine, threonine, tyrosine. The hydrophilic amino acids include arginine,
asparagine, aspartate, glutamine, glutamate, histidine, lysine, serine, and threonine.
The hydrophobic amino acids include alanine, cysteine, isoleucine, leucine, methionine,
phenylalanine, proline, tryptophan, tyrosine and valine. Other families of amino acids
include (i) serine and threonine, which are the aliphatic-hydroxy family; (ii) asparagine
and glutamine, which are the amide containing family; (iii) alanine, valine, leucine
and isoleucine, which are the aliphatic family; and (iv) phenylalanine, tryptophan,
and tyrosine, which are the aromatic family. For example, it is reasonable to expect
that an isolated replacement of a leucine with an isoleucine or valine, an aspartate
with a glutamate, a threonine with a serine, or a similar replacement of an amino
acid with a structurally related amino acid will not have a major effect on the binding
or properties of the resulting molecule, especially if the replacement does not involve
an amino acid within a framework site. Whether an amino acid change results in a functional
peptide can readily be determined by assaying the specific activity of the polypeptide
derivative. Assays are described in detail herein. Fragments or analogs of antibodies
or immunoglobulin molecules can be readily prepared by those of ordinary skill in
the art. Preferred amino- and carboxy-termini of fragments or analogs occur near boundaries
of functional domains. Structural and functional domains can be identified by comparison
of the nucleotide and/or amino acid sequence data to public or proprietary sequence
databases. Preferably, computerized comparison methods are used to identify sequence
motifs or predicted protein conformation domains that occur in other proteins of known
structure and/or function. Methods to identify protein sequences that fold into a
known three-dimensional structure are known.
Bowie et al. Science 253:164 (1991). Thus, the foregoing examples demonstrate that those of skill in the art can recognize
sequence motifs and structural conformations that may be used to define structural
and functional domains in accordance with the invention.
[0054] Preferred amino acid substitutions are those which: (1) reduce susceptibility to
proteolysis, (2) reduce susceptibility to oxidation, (3) alter binding affinity for
forming protein complexes, (4) alter binding affinities, and (4) confer or modify
other physicochemical or functional properties of such analogs. Analogs can include
various muteins of a sequence other than the naturally-occurring peptide sequence.
For example, single or multiple amino acid substitutions (preferably conservative
amino acid substitutions) may be made in the naturally- occurring sequence (preferably
in the portion of the polypeptide outside the domain(s) forming intermolecular contacts.
A conservative amino acid substitution should not substantially change the structural
characteristics of the parent sequence (
e.g., a replacement amino acid should not tend to break a helix that occurs in the parent
sequence, or disrupt other types of secondary structure that characterizes the parent
sequence). Examples of art-recognized polypeptide secondary and tertiary structures
are described in
Proteins, Structures and Molecular Principles (Creighton, Ed., W. H. Freeman and Company,
New York (1984));
Introduction to Protein Structure (C. Branden and J. Tooze, eds., Garland Publishing,
New York, N.Y. (1991)); and
Thornton et at. Nature 354:105 (1991).
[0055] The term "polypeptide fragment" as used herein refers to a polypeptide that has an
amino terminal and/or carboxy-terminal deletion, but where the remaining amino acid
sequence is identical to the corresponding positions in the naturally-occurring sequence
deduced, for example, from a full length cDNA sequence. Fragments typically are at
least 5, 6, 8 or 10 amino acids long, preferably at least 14 amino acids long' more
preferably at least 20 amino acids long, usually at least 50 amino acids long, and
even more preferably at least 70 amino acids long. The term "analog" as used herein
refers to polypeptides which are comprised of a segment of at least 25 amino acids
that has substantial identity to a portion of a deduced amino acid sequence and which
has specific binding to TLR4/MD2 complex or TLR4 alone, under suitable binding conditions.
Typically, polypeptide analogs comprise a conservative amino acid substitution (or
addition or deletion) with respect to the naturally-occurring sequence. Analogs typically
are at least 20 amino acids long, preferably at least 50 amino acids long or longer,
and can often be as long as a full-length naturally-occurring polypeptide.
[0056] Peptide analogs are commonly used in the pharmaceutical industry as non-peptide drugs
with properties analogous to those of the template peptide. These types of non-peptide
compound are termed "peptide mimetics" or "peptidomimetics".
Fauchere, J. Adv. Drug Res. 15:29 (1986),
Veber and Freidinger TINS p.392 (1985); and
Evans et al. J. Med. Chem. 30:1229 (1987). Such compounds are often developed with the aid of computerized molecular modeling.
Peptide mimetics that are structurally similar to therapeutically useful peptides
may be used to produce an equivalent therapeutic or prophylactic effect. Generally,
peptidomimetics are structurally similar to a paradigm polypeptide (
i.e., a polypeptide that has a biochemical property or pharmacological activity), such
as human antibody, but have one or more peptide linkages optionally replaced by a
linkage selected from the group consisting of: -- CH
2NH--, --CH
2S-, --CH
2-CH
2--, --CH=CH--(cis and trans), --COCH
2--, CH(OH)CH
2--, and -CH
2SO--, by methods well known in the art. Systematic substitution of one or more amino
acids of a consensus sequence with a D-amino acid of the same type (
e.g., D-lysine in place of L-lysine) may be used to generate more stable peptides. In
addition, constrained peptides comprising a consensus sequence or a substantially
identical consensus sequence variation may be generated by methods known in the art
(
Rizo and Gierasch Ann. Rev. Biochem. 61:387 (1992)); for example, by adding internal cysteine residues capable of forming intramolecular
disulfide bridges which cyclize the peptide.
[0057] The term "agent" is used herein to denote a chemical compound, a mixture of chemical
compounds, a biological macromolecule, or an extract made from biological materials.
[0058] As used herein, the terms "label" or "labeled" refers to incorporation of a detectable
marker,
e.g., by incorporation of a radiolabeled amino acid or attachment to a polypeptide of
biotinyl moieties that can be detected by marked avidin (
e.g., streptavidin containing a fluorescent marker or enzymatic activity that can be
detected by optical or calorimetric methods). In certain situations, the label or
marker can also be therapeutic. Various methods of labeling polypeptides and glycoproteins
are known in the art and may be used. Examples of labels for polypeptides include,
but are not limited to, the following: radioisotopes or radionuclides (
e.g.,
3H,
14C,
15N,
35S,
90Y,
99Tc,
111In,
125I,
131I), fluorescent labels (
e.g., FITC, rhodamine, lanthanide phosphors), enzymatic labels (
e.g., horseradish peroxidase, p-galactosidase, luciferase, alkaline phosphatase), chemiluminescent,
biotinyl groups, predetermined polypeptide epitopes recognized by a secondary reporter
(
e.g., leucine zipper pair sequences, binding sites for secondary antibodies, metal binding
domains, epitope tags). In some embodiments, labels are attached by spacer arms of
various lengths to reduce potential steric hindrance. The term "pharmaceutical agent
or drug" as used herein refers to a chemical compound or composition capable of inducing
a desired therapeutic effect when properly administered to a patient.
[0060] The term "antineoplastic agent" is used herein to refer to agents that have the functional
property of inhibiting a development or progression of a neoplasm in a human, particularly
a malignant (cancerous) lesion, such as a carcinoma, sarcoma, lymphoma, or leukemia.
Inhibition of metastasis is frequently a property of antineoplastic agents.
[0061] As used herein, "substantially pure" means an object species is the predominant species
present (
i.e., on a molar basis it is more abundant than any other individual species in the composition),
and preferably a substantially purified fraction is a composition wherein the object
species comprises at least about 50 percent (on a molar basis) of all macromolecular
species present.
[0062] Generally, a substantially pure composition will comprise more than about 80 percent
of all macromolecular species present in the composition, more preferably more than
about 85%, 90%, 95%, and 99%. Most preferably, the object species is purified to essential
homogeneity (contaminant species cannot be detected in the composition by conventional
detection methods) wherein the composition consists essentially of a single macromolecular
species.
[0063] The term patient includes human and veterinary subjects.
Antibodies
[0064] Monoclonal antibodies of the invention have the ability to inhibit LPS-induced IL-8
production. Inhibition is determined, for example, in the human whole blood and huTLR4/MD2
transfected HEK 293 cellular assays described herein. Exemplary monoclonal antibodies
include, for example, the antibodies referred to herein as "18H10", "16G7", "15C1"
and "7E3". The 18H10 antibody recognizes the TLR4/MD-2 complex, but does not recognize
an MD-2 protein when not complexed with TLR4. The 16G7, 15C1 and 7E3 monoclonal antibodies
recognize the TLR4/MD-2 complex. 15C1 and 16G7 also recognize TLR4 when not complexed
with MD-2.
[0065] Also included in the invention are antibodies that bind to the same epitope as the
antibodies described herein. Those skilled in the art will recognize that it is possible
to determine, without undue experimentation, if a monoclonal antibody has the same
specificity as a monoclonal antibody of the invention (
e.g., monoclonal antibody 18H10, 16G7, 15C1 and/or 7E3) by ascertaining whether the former
prevents the latter from binding to the TLR4/MD-2 complex or to TLR4 when not complexed
to MD-2. If the monoclonal antibody being tested competes with the monoclonal antibody
of the invention, as shown by a decrease in binding by the monoclonal antibody of
the invention, then it is likely that the two monoclonal antibodies bind to the same,
or a closely related, epitope. Another way to determine whether a monoclonal antibody
has the specificity of a monoclonal antibody of the invention is to pre-incubate the
monoclonal antibody of the invention with the TLR4/MD-2 complex or a soluble TLR4
protein (with which it is normally reactive), and then add the monoclonal antibody
being tested to determine if the monoclonal antibody being tested is inhibited in
its ability to bind the TLR4/MD-2 complex or to bind TLR4 and TLR4 complexed with
MD-2. If the monoclonal antibody being tested is inhibited then, in all likelihood,
it has the same, or functionally equivalent, epitopic specificity as the monoclonal
antibody of the invention. Screening of monoclonal antibodies of the invention, can
be also carried out by measuring LPS-induced IL-8 production and determining whether
the test monoclonal antibody is able to neutralize LPS-induced IL-8 production.
[0066] Various procedures known within the art may be used for the production of polyclonal
or monoclonal antibodies directed against the TLR4/MD-2 complex, or to TLR4 when not
complexed to MD-2, or against derivatives, fragments, analogs homologs or orthologs
thereof. (
See, for example, Antibodies: A Laboratory Manual, Harlow E, and Lane D, 1988, Cold Spring Harbor Laboratory
Press, Cold Spring Harbor, NY ).
[0067] Antibodies are purified by well-known techniques, such as affinity chromatography
using protein A or protein G, which provide primarily the IgG fraction of immune serum.
Subsequently, or alternatively, the specific antigen which is the target of the immunoglobulin
sought, or an epitope thereof, may be immobilized on a column to purify the immune
specific antibody by immunoaffinity chromatography. Purification of immunoglobulins
is discussed, for example, by
D. Wilkinson (The Scientist, published by The Scientist, Inc., Philadelphia PA, Vol.
14, No. 8 (April 17, 2000), pp. 25-28).
[0068] The antibodies of the invention (
e.g., 18H10, 16G7, 15C1 and 7E3) are monoclonal antibodies. Monoclonal antibodies that
neutralize LPS-signaling that is mediated by the TLR4/MD-2 complex are generated,
e.g., by immunizing BALB/c mice with combinations of cell transfectants expressing high
levels of TLR4 and MD-2 on their surface and a recombinant soluble chimeric protein
comprising both TLR4 and MD-2 tethered by a flexible linker sequence. Hybridomas resulting
from myeloma/B cell fusions are then screened for reactivity to this TLR4/MD-2 complex.
[0069] Monoclonal antibodies are prepared, for example, using hybridoma methods, such as
those described by
Kohler and Milstein, Nature, 256:495 (1975). In a hybridoma method, a mouse, hamster, or other appropriate host animal, is typically
immunized with an immunizing agent to elicit lymphocytes that produce or are capable
of producing antibodies that will specifically bind to the immunizing agent. Alternatively,
the lymphocytes can be immunized
in vitro.
[0070] The immunizing agent will typically include the protein antigen, a fragment thereof
or a fusion protein thereof. Generally, either peripheral blood lymphocytes are used
if cells of human origin are desired, or spleen cells or lymph node cells are used
if non-human mammalian sources are desired. The lymphocytes are then fused with an
immortalized cell line using a suitable fusing agent, such as polyethylene glycol,
to form a hybridoma cell (
Goding, Monoclonal Antibodies: Principles and Practice, Academic Press, (1986) pp.
59-103). Immortalized cell lines are usually transformed mammalian cells, particularly myeloma
cells of rodent, bovine and human origin. Usually, rat or mouse myeloma cell lines
are employed. The hybridoma cells can be cultured in a suitable culture medium that
preferably contains one or more substances that inhibit the growth or survival of
the unfused, immortalized cells. For example, if the parental cells lack the enzyme
hypoxanthine guanine phosphoribosyl transferase (HGPRT or HPRT), the culture medium
for the hybridomas typically will include hypoxanthine, aminopterin, and thymidine
("HAT medium"), which substances prevent the growth of HGPRT-deficient cells.
[0071] Preferred immortalized cell lines are those that fuse efficiently, support stable
high level expression of antibody by the selected antibody-producing cells, and are
sensitive to a medium such as HAT medium. More preferred immortalized cell lines are
murine myeloma lines, which can be obtained, for instance, from the Salk Institute
Cell Distribution Center, San Diego, California and the American Type Culture Collection,
Manassas, Virginia. Human myeloma and mouse-human heteromyeloma cell lines also have
been described for the production of monoclonal antibodies. (
See Kozbor, J. Immunol., 133:3001 (1984);
Brodeur et al., Monoclonal Antibody Production Techniques and Applications, Marcel
Dekker, Inc., New York, (1987) pp. 51-63)).
[0072] The culture medium in which the hybridoma cells are cultured can then be assayed
for the presence of monoclonal antibodies directed against the antigen. Preferably,
the binding specificity of monoclonal antibodies produced by the hybridoma cells is
determined by immunoprecipitation or by an
in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunoabsorbent assay
(ELISA). Such techniques and assays are known in the art. The binding affinity of
the monoclonal antibody can, for example, be determined by the Scatchard analysis
of
Munson and Pollard, Anal. Biochem., 107:220 (1980). Moreover, in therapeutic applications of monoclonal antibodies, it is important
to identify antibodies having a high degree of specificity and a high binding affinity
for the target antigen.
[0074] The monoclonal antibodies secreted by the subclones can be isolated or purified from
the culture medium or ascites fluid by conventional immunoglobulin purification procedures
such as, for example, protein A-Sepharose, hydroxylapatite chromatography, gel electrophoresis,
dialysis, or affinity chromatography.
[0075] Monoclonal antibodies can also be made by recombinant DNA methods, such as those
described in
U.S. Patent No. 4,816,567. DNA encoding the monoclonal antibodies of the invention can be readily isolated
and sequenced using conventional procedures (
e.g., by using oligonucleotide probes that are capable of binding specifically to genes
encoding the heavy and light chains of murine antibodies). The hybridoma cells of
the invention serve as a preferred source of such DNA. Once isolated, the DNA can
be placed into expression vectors, which are then transfected into host cells such
as simian COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells that do not
otherwise produce immunoglobulin protein, to obtain the synthesis of monoclonal antibodies
in the recombinant host cells. The DNA also can be modified, for example, by substituting
the coding sequence for human heavy and light chain constant domains in place of the
homologous murine sequences (
see U.S. Patent No. 4,816,567;
Morrison, Nature 368, 812-13 (1994)) or by covalently joining to the immunoglobulin coding sequence all or part of the
coding sequence for a non-immunoglobulin polypeptide. Such a non-immunoglobulin polypeptide
can be substituted for the constant domains of an antibody of the invention, or can
be substituted for the variable domains of one antigen-combining site of an antibody
of the invention to create a chimeric bivalent antibody.
[0076] Fully human antibodies are antibody molecules in which the entire sequence of both
the light chain and the heavy chain, including the CDRs, arise from human genes. Such
antibodies are termed "human antibodies", or "fully human antibodies" herein. Monoclonal
antibodies can be prepared by using trioma technique; the human B-cell hybridoma technique
(see Kozbor, et al., 1983 Immunol Today 4: 72); and the EBV hybridoma technique to produce monoclonal antibodies
(see Cole, et al., 1985 In: MONOCLONAL ANTIBODIES AND CANCER THERAPY, Alan R. Liss, Inc.,
pp., 77-96). Monoclonal antibodies may be utilized and may be produced by using human hybridomas
(
see Cote, et al., 1983. Proc Natl Acad Sci USA 80: 2026-2030) or by transforming human B-cells with Epstein Barr Virus
in vitro (see
Cole, et al., 1985 In: MONOCLONAL ANTIBODIES AND CANCER THERAPY, Alan R. Liss, Inc.,
pp.77-96).
[0077] In addition, human antibodies can also be produced using additional techniques, including
phage display libraries. (
See Hoogenboom and Winter, J. Mol. Biol., 227:381 1 (1991);
Marks et al., J. Mol. Biol., 222:581 (1991)). Similarly, human antibodies can be made by introducing human immunoglobulin loci
into transgenic animals,
e.g., mice in which the endogenous immunoglobulin genes have been partially or completely
inactivated. Upon challenge, human antibody production is observed, which closely
resembles that seen in humans in all respects, including gene rearrangement, assembly,
and antibody repertoire. This approach is described, for example, in
U.S. Patent Nos. 5,545,807;
5,545,806;
5,569,825;
5,625,126;
5,633,425;
5,661,016, and in
Marks et al., Bio/Technology 10, 779-783 (1992);
Lonberg et al., Nature 368 856-859 (1994);
Morrison, Nature 368, 812-13 (1994);
Fishwild et al, Nature Biotechnology 14, 845-51 (1996);
Neuberger, Nature Biotechnology 14, 826 (1996); and
Lonberg and Huszar, Intern. Rev. Immunol. 13 65-93 (1995).
[0078] Human antibodies may additionally be produced using transgenic nonhuman animals which
are modified so as to produce fully human antibodies rather than the animal's endogenous
antibodies in response to challenge by an antigen. (
See PCT publication WO94/02602). The endogenous genes encoding the heavy and light immunoglobulin chains in the
nonhuman host have been incapacitated, and active loci encoding human heavy and light
chain immunoglobulins are inserted into the host's genome. The human genes are incorporated,
for example, using yeast artificial chromosomes containing the requisite human DNA
segments. An animal which provides all the desired modifications is then obtained
as progeny by crossbreeding intermediate transgenic animals containing fewer than
the full complement of the modifications. An example of such a nonhuman animal is
a mouse termed the Xenomouse™ as disclosed in
PCT publications WO 96/33735 and
WO 96/34096. This animal produces B cells which secrete fully human immunoglobulins. The antibodies
can be obtained directly from the animal after immunization with an immunogen of interest,
as, for example, a preparation of a polyclonal antibody, or alternatively from immortalized
B cells derived from the animal, such as hybridomas producing monoclonal antibodies.
Additionally, the genes encoding the immunoglobulins with human variable regions can
be recovered and expressed to obtain the antibodies directly, or can be further modified
to obtain analogs of antibodies such as, for example, single chain Fv (scFv) molecules.
[0079] An example of a method of producing a nonhuman host, exemplified as a mouse, lacking
expression of an endogenous immunoglobulin heavy chain is disclosed in
U.S. Patent No. 5,939,598. It can be obtained by a method, which includes deleting the J segment genes from
at least one endogenous heavy chain locus in an embryonic stem cell to prevent rearrangement
of the locus and to prevent formation of a transcript of a rearranged immunoglobulin
heavy chain locus, the deletion being effected by a targeting vector containing a
gene encoding a selectable marker; and producing from the embryonic stem cell a transgenic
mouse whose somatic and germ cells contain the gene encoding the selectable marker.
[0080] One method for producing an antibody of interest, such as a human antibody, is disclosed
in
U.S. Patent No. 5,916,771. This method includes introducing an expression vector that contains a nucleotide
sequence encoding a heavy chain into one mammalian host cell in culture, introducing
an expression vector containing a nucleotide sequence encoding a light chain into
another mammalian host cell, and fusing the two cells to form a hybrid cell. The hybrid
cell expresses an antibody containing the heavy chain and the light chain.
[0081] In a further improvement on this procedure, a method for identifying a clinically
relevant epitope on an immunogen, and a correlative method for selecting an antibody
that binds immunospecifically to the relevant epitope with high affinity, are disclosed
in
PCT publication WO 99/53049.
[0082] The antibody can be expressed by a vector containing a DNA segment encoding the single
chain antibody described above.
[0083] These can include vectors, liposomes, naked DNA, adjuvant-assisted DNA. gene gun,
catheters, etc. Vectors include chemical conjugates such as described in
WO 93/64701, which has targeting moiety (
e.g. a ligand to a cellular surface receptor), and a nucleic acid binding moiety (
e.g. polylysine), viral vector (
e.g. a DNA or RNA viral vector), fusion proteins such as described in
PCT/US 95/02140 (
WO 95/22618) which is a fusion protein containing a target moiety (
e.g. an antibody specific for a target cell) and a nucleic acid binding moiety (
e.g. a protamine), plasmids, phage, etc. The vectors can be chromosomal, non-chromosomal
or synthetic.
[0084] Preferred vectors include viral vectors, fusion proteins and chemical conjugates.
Retroviral vectors include moloney murine leukemia viruses. DNA viral vectors are
preferred. These vectors include pox vectors such as orthopox or avipox vectors, herpesvirus
vectors such as a herpes simplex I virus (HSV) vector (
see Geller, A. I. et al., J. Neurochem, 64:487 (1995);
Lim, F., et al., in DNA Cloning: Mammalian Systems, D. Glover, Ed. (Oxford Univ. Press,
Oxford England) (1995);
Geller, A. I. et al., Proc Natl. Acad. Sci.: U.S.A. 90:7603 (1993);
Geller, A. I., et al., Proc Natl. Acad. Sci USA 87:1149 (1990), Adenovirus Vectors (
see LeGal LaSalle et al., Science, 259:988 (1993);
Davidson, et al., Nat. Genet 3:219 (1993);
Yang, et al., J. Virol. 69:2004 (1995) and Adeno-associated Virus Vectors (
see Kaplitt, M. G.. et al., Nat. Genet. 8:148 (1994).
[0085] Pox viral vectors introduce the gene into the cells cytoplasm. Avipox virus vectors
result in only a short term expression of the nucleic acid. Adenovirus vectors, adeno-associated
virus vectors and herpes simplex virus (HSV) vectors are preferred for introducing
the nucleic acid into neural cells. The adenovirus vector results in a shorter term
expression (about 2 months) than adeno-associated virus (about 4 months), which in
turn is shorter than HSV vectors. The particular vector chosen will depend upon the
target cell and the condition being treated. The introduction can be by standard techniques,
e.g. infection, transfection, transduction or transformation. Examples of modes of gene
transfer include
e.g., naked DNA, CaPO
4 precipitation, DEAE dextran, electroporation, protoplast fusion, lipofection, cell
microinjection, and viral vectors.
[0086] The vector can be employed to target essentially any desired target cell. For example,
stereotaxic injection can be used to direct the vectors (
e.g. adenovirus, HSV) to a desired location. Additionally, the particles can be delivered
by intracerebroventricular (icv) infusion using a minipump infusion system, such as
a SynchroMed Infusion System. A method based on bulk flow, termed convection, has
also proven effective at delivering large molecules to extended areas of the brain
and may be useful in delivering the vector to the target cell.
(See Bobo et al., Proc. Natl. Acad. Sci. USA 91:2076-2080 (1994);
Morrison et al., Am. J. Physiol. 266:292-305 (1994)). Other methods that can be used include catheters, intravenous, parenteral, intraperitoneal
and subcutaneous injection, and oral or other known routes of administration.
[0087] These vectors can be used to express large quantities of antibodies that can be used
in a variety of ways. For example, to detect the presence of the TLR4/MD-2 complex
and/or TLR4 in a sample. The antibody can also be used to try to bind to and disrupt
TLR4/MD-2 complex-related signaling.
[0088] Techniques can be adapted for the production of single-chain antibodies specific
to an antigenic protein of the invention (
see e.g., U.S. Patent No. 4,946,778). In addition, methods can be adapted for the construction of F
ab expression libraries (
see e.g., Huse, et al., 1989 Science 246: 1275-1281) to allow rapid and effective identification of monoclonal F
ab fragments with the desired specificity for a protein or derivatives, fragments, analogs
or homologs thereof. Antibody fragments that contain the idiotypes to a protein antigen
may be produced by techniques known in the art including, but not limited to: (i)
an F
(ab')2 fragment produced by pepsin digestion of an antibody molecule; (ii) an F
ab fragment generated by reducing the disulfide bridges of an F
(ab')2 fragment; (iii) an F
ab fragment generated by the treatment of the antibody molecule with papain and a reducing
agent and (iv) F
v fragments. The invention also includes F
v, F
ab, F
ab' and F
(ab')2 anti-TLR4/MD2 complex fragments or anti-TLR4 fragments, single chain anti-TLR4/MD2
or anti-TLR4 antibodies, bispecific anti-TLR4/MD2 or anti-TLR4 antibodies and heteroconjugate
anti-TLR4/MD2 or anti-TLR4 antibodies.
[0089] Bispecific antibodies are antibodies that have binding specificities for at least
two different antigens. In the present case, one of the binding specificities is for
the TLR4/MD2 complex and/or TLR4 when not complexed with MD-2. The second binding
target is any other antigen, and advantageously is a cell-surface protein or receptor
or receptor subunit.
[0090] Methods for making bispecific antibodies are known in the art. Traditionally, the
recombinant production of bispecific antibodies is based on the co-expression of two
immunoglobulin heavy-chain/light-chain pairs, where the two heavy chains have different
specificities (
Milstein and Cuello, Nature, 305:537-539 (1983)). Because of the random assortment of immunoglobulin heavy and light chains, these
hybridomas (quadromas) produce a potential mixture of ten different antibody molecules,
of which only one has the correct bispecific structure. The purification of the correct
molecule is usually accomplished by affinity chromatography steps. Similar procedures
are disclosed in
WO 93/08829, published 13 May 1993, and in
Traunecker et al., EMBO J., 10:3655-3659 (1991).
[0091] Antibody variable domains with the desired binding specificities (antibody-antigen
combining sites) can be fused to immunoglobulin constant domain sequences. The fusion
preferably is with an immunoglobulin heavy-chain constant domain, comprising at least
part of the hinge, CH2, and CH3 regions. It is preferred to have the first heavy-chain
constant region (CH1) containing the site necessary for light-chain binding present
in at least one of the fusions. DNAs encoding the immunoglobulin heavy-chain fusions
and, if desired, the immunoglobulin light chain, are inserted into separate expression
vectors, and are co-transfected into a suitable host organism. For further details
of generating bispecific antibodies see, for example,
Suresh et al., Methods in Enzymology, 121:210 (1986).
[0092] According to another approach described in
WO 96/27011, the interface between a pair of antibody molecules can be engineered to maximize
the percentage of heterodimers which are recovered from recombinant cell culture.
The preferred interface comprises at least a part of the CH3 region of an antibody
constant domain. In this method, one or more small amino acid side chains from the
interface of the first antibody molecule are replaced with larger side chains (
e.g. tyrosine or tryptophan). Compensatory "cavities" of identical or similar size to
the large side chain(s) are created on the interface of the second antibody molecule
by replacing large amino acid side chains with smaller ones (
e.g. alanine or threonine). This provides a mechanism for increasing the yield of the
heterodimer over other unwanted end-products such as homodimers.
[0093] Bispecific antibodies can be prepared as full length antibodies or antibody fragments
(
e.g. F(ab')
2 bispecific antibodies). Techniques for generating bispecific antibodies from antibody
fragments have been described in the literature. For example, bispecific antibodies
can be prepared using chemical linkage.
Brennan et al., Science 229:81 (1985) describe a procedure wherein intact antibodies are proteolytically cleaved to generate
F(ab')
2 fragments. These fragments are reduced in the presence of the dithiol complexing
agent sodium arsenite to stabilize vicinal dithiols and prevent intermolecular disulfide
formation. The Fab' fragments generated are then converted to thionitrobenzoate (TNB)
derivatives. One of the Fab'-TNB derivatives is then reconverted to the Fab'-thiol
by reduction with mercaptoethylamine and is mixed with an equimolar amount of the
other Fab'-TNB derivative to form the bispecific antibody. The bispecific antibodies
produced can be used as agents for the selective immobilization of enzymes.
[0094] Additionally, Fab' fragments can be directly recovered from E. coli and chemically
coupled to form bispecific antibodies.
Shalaby et al., J. Exp. Med. 175:217-225 (1992) describe the production of a fully humanized bispecific antibody F(ab')
2 molecule. Each Fab' fragment was separately secreted from E. coli and subjected to
directed chemical coupling in vitro to form the bispecific antibody. The bispecific
antibody thus formed was able to bind to cells overexpressing the ErbB2 receptor and
normal human T cells, as well as trigger the lytic activity of human cytotoxic lymphocytes
against human breast tumor targets.
[0095] Various techniques for making and isolating bispecific antibody fragments directly
from recombinant cell culture have also been described. For example, bispecific antibodies
have been produced using leucine zippers.
Kostelny et al., J. Immunol. 148(5):1547-1553 (1992). The leucine zipper peptides from the Fos and Jun proteins were linked to the Fab'
portions of two different antibodies by gene fusion. The antibody homodimers were
reduced at the hinge region to form monomers and then re-oxidized to form the antibody
heterodimers. This method can also be utilized for the production of antibody homodimers.
The "diabody" technology described by
Hollinger et al., Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993) has provided an alternative mechanism for making bispecific antibody fragments.
The fragments comprise a heavy-chain variable domain (V
H) connected to a light-chain variable domain (V
L) by a linker which is too short to allow pairing between the two domains on the same
chain. Accordingly, the V
H and V
L domains of one fragment are forced to pair with the complementary V
L and V
H domains of another fragment, thereby forming two antigen-binding sites. Another strategy
for making bispecific antibody fragments by the use of single-chain Fv (sFv) dimers
has also been reported. See,
Gruber et al., J. Immunol. 152:5368 (1994).
[0097] Exemplary bispecific antibodies can bind to two different epitopes, at least one
of which originates in the protein antigen of the invention. Alternatively, an anti-antigenic
arm of an immunoglobulin molecule can be combined with an arm which binds to a triggering
molecule on a leukocyte such as a T-cell receptor molecule (
e.g. CD2, CD3, CD28, or B7), or Fc receptors for IgG (FcγR), such as FcγRI (CD64), FcγRII
(CD32) and FcγRIII (CD16) so as to focus cellular defense mechanisms to the cell expressing
the particular antigen. Bispecific antibodies can also be used to direct cytotoxic
agents to cells which express a particular antigen. These antibodies possess an antigen-binding
arm and an arm which binds a cytotoxic agent or a radionuclide chelator, such as EOTUBE,
DPTA, DOTA, or TETA. Another bispecific antibody of interest binds the protein antigen
described herein and further binds tissue factor (TF).
[0098] Heteroconjugate antibodies are also within the scope of the present invention. Heteroconjugate
antibodies are composed of two covalently joined antibodies. Such antibodies have,
for example, been proposed to target immune system cells to unwanted cells
(see U.S. Patent No. 4,676,980), and for treatment ofHIV infection
(see WO 91/00360;
WO 92/200373;
EP 03089). It is contemplated that the antibodies can be prepared
in vitro using known methods in synthetic protein chemistry, including those involving crosslinking
agents. For example, immunotoxins can be constructed using a disulfide exchange reaction
or by forming a thioether bond. Examples of suitable reagents for this purpose include
iminothiolate and methyl-4-mercaptobutyrimidate and those disclosed, for example,
in
U.S. Patent No. 4,676,980.
[0099] It can be desirable to modify the antibody of the invention with respect to effector
function, so as to enhance,
e.g., the effectiveness of the antibody in treating diseases and disorders associated
with aberrant LPS signaling. For example, cysteine residue(s) can be introduced into
the Fc region, thereby allowing interchain disulfide bond formation in this region.
The homodimeric antibody thus generated can have improved internalization capability
and/or increased complement-mediated cell killing and antibody-dependent cellular
cytotoxicity (ADCC).
(See Caron et al., J. Exp Med., 176: 1191-1195 (1992) and
Shopes, J. Immunol., 148: 2918-2922 (1992)). Alternatively, an antibody can be engineered that has dual Fc regions and can
thereby have enhanced complement lysis and ADCC capabilities. (
See Stevenson et al., Anti-Cancer Drug Design, 3: 219-230 (1989)).
[0100] The invention also pertains to immunoconjugates comprising an antibody conjugated
to a cytotoxic agent such as a toxin (
e.g., an enzymatically active toxin of bacterial, fungal, plant, or animal origin, or
fragments thereof), or a radioactive isotope (
i.e., a radioconjugate).
[0101] Enzymatically active toxins and fragments thereof that can be used include diphtheria
A chain, nonbinding active fragments of diphtheria toxin, exotoxin A chain (from Pseudomonas
aeruginosa), ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites
fordii proteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII, and
PAP-S), momordica charantia inhibitor, curcin, crotin, sapaonaria officinalis inhibitor,
gelonin, mitogellin, restrictocin, phenomycin, enomycin, and the tricothecenes. A
variety of radionuclides are available for the production of radioconjugated antibodies.
Examples include
212Bi,
131I,
131In,
90Y, and
186Re
[0102] Conjugates of the antibody and cytotoxic agent are made using a variety of bifunctional
protein-coupling agents such as N-succinimidyl-3-(2-pyridyldithiol) propionate (SPDP),
iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate
HCL), active esters (such as disuccinimidyl suberate), aldehydes (such as glutareldehyde),
bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives
(such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates
[0103] (such as tolyene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene).
For example, a ricin immunotoxin can be prepared as described in Vitetta et al., Science
238: 1098 (1987). Carbon-14-labeled 1-isothiocyanatobenzyl-3-methyldiethylene triaminepentaacetic
acid (MX-DTPA) is an exemplary chelating agent for conjugation of radionucleotide
to the antibody. (
See WO94/11026).
[0105] Coupling may be accomplished by any chemical reaction that will bind the two molecules
so long as the antibody and the other moiety retain their respective activities. This
linkage can include many chemical mechanisms, for instance covalent binding, affinity
binding, intercalation, coordinate binding and complexation. The preferred binding
is, however, covalent binding. Covalent binding can be achieved either by direct condensation
of existing side chains or by the incorporation of external bridging molecules. Many
bivalent or polyvalent linking agents are useful in coupling protein molecules, such
as the antibodies of the present invention, to other molecules. For example, representative
coupling agents can include organic compounds such as thioesters, carbodiimides, succinimide
esters, diisocyanates, glutaraldehyde, diazobenzenes and hexamethylene diamines. This
listing is not intended to be exhaustive of the various classes of coupling agents
known in the art but, rather, is exemplary of the more common coupling agents. (
See Killen and Lindstrom, Jour. Immun. 133:1335-2549 (1984);
Jansen et al., Immunological Reviews 62:185-216 (1982); and
Vitetta et al., Science 238:1098 (1987).
[0106] Preferred linkers are described in the literature. (
See, for example, Ramakrishnan, S. et al., Cancer Res. 44:201-208 (1984) describing use of MBS (M-maleimidobenzoyl-N-hydroxysuccinimide
ester)
. See also, U.S. Patent No. 5,030,719, describing use of halogenated acetyl hydrazide derivative coupled to an antibody
by way of an oligopeptide linker. Particularly preferred linkers include: (i) EDC
(1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride; (ii) SMPT (4-succinimidyloxycarbonyl-alpha-methyl-alpha-(2-pridyl-dithio)-toluene
(Pierce Chem. Co., Cat. (21558G); (iii) SPDP (succinimidyl-6 [3-(2-pyridyldithio)
propionamido]hexanoate (Pierce Chem. Co., Cat #21651G); (iv) Sulfo-LC-SPDP (sulfosuccinimidyl
6 [3-(2-pyridyldithio)-propianamide] hexanoate (Pierce Chem. Co. Cat. #2165-G); and
(v) sulfo-NHS (N-hydroxysulfo-succinimide: Pierce Chem. Co., Cat. #24510) conjugated
to EDC.
[0107] The linkers described above contain components that have different attributes, thus
leading to conjugates with differing physio-chemical properties. For example, sulfo-NHS
esters of alkyl carboxylates are more stable than sulfo-NHS esters of aromatic carboxylates.
NHS-ester containing linkers are less soluble than sulfo-NHS esters. Further, the
linker SMPT contains a sterically hindered disulfide bond, and can form conjugates
with increased stability. Disulfide linkages, are in general, less stable than other
linkages because the disulfide linkage is cleaved
in vitro, resulting in less conjugate available. Sulfo-NHS, in particular, can enhance the
stability of carbodimide couplings. Carbodimide couplings (such as EDC) when used
in conjunction with sulfo-NHS, forms esters that are more resistant to hydrolysis
than the carbodimide coupling reaction alone.
[0108] The antibodies disclosed herein can also be formulated as immunoliposomes. Liposomes
containing the antibody are prepared by methods known in the art, such as described
in
Epstein et al., Proc. Natl. Acad. Sci. USA, 82: 3688 (1985);
Hwang et al., Proc. Natl Acad. Sci. USA, 77: 4030 (1980); and
U.S. Pat. Nos. 4,485,045 and
4,544,545. Liposomes with enhanced circulation time are disclosed in
U.S. Patent No. 5,013,556.
[0109] Particularly useful liposomes can be generated by the reverse-phase evaporation method
with a lipid composition comprising phosphatidylcholine, cholesterol, and PEG-derivatized
phosphatidylethanolamine (PEG-PE). Liposomes are extruded through filters of defined
pore size to yield liposomes with the desired diameter. Fab' fragments of the antibody
of the present invention can be conjugated to the liposomes as described in
Martin et al., J. Biol. Chem., 257: 286-288 (1982) via a disulfide-interchange reaction.
Use of antibodies against the TLR4/MD2 complex and antibodies against TLR4
[0110] It will be appreciated that administration of therapeutic entities in accordance
with the invention will be administered with suitable carriers, excipients, and other
agents that are incorporated into formulations to provide improved transfer, delivery,
tolerance, and the like. A multitude of appropriate formulations can be found in the
formulary known to all pharmaceutical chemists:
Remington's Pharmaceutical Sciences (15th ed, Mack Publishing Company, Easton, PA
(1975)), particularly Chapter 87 by Blaug, Seymour, therein. These formulations include, for example, powders, pastes, ointments, jellies,
waxes, oils, lipids, lipid (cationic or anionic) containing vesicles (such as Lipofectin™),
DNA conjugates, anhydrous absorption pastes, oil-in-water and water-in-oil emulsions,
emulsions carbowax (polyethylene glycols of various molecular weights), semi-solid
gels, and semi-solid mixtures containing carbowax. Any of the foregoing mixtures may
be appropriate in treatments and therapies in accordance with the present invention,
provided that the active ingredient in the formulation is not inactivated by the formulation
and the formulation is physiologically compatible and tolerable with the route of
administration. See also
Baldrick P. "Pharmaceutical excipient development: the need for preclinical guidance."
Regul. Toxicol Pharmacol. 32(2):210-8 (2000),
Wang W. "Lyophilization and development of solid protein pharmaceuticals." Int. J.
Pharm. 203(1-2):1-60 (2000),
Charman WN "Lipids, lipophilic drugs, and oral drug delivery-some emerging concepts."
J Pharm Sci.89(8):967-78 (2000),
Powell et al. "Compendium of excipients for parenteral formulations" PDA J Pharm Sci
Technol. 52:238-311 (1998) and the citations therein for additional information related to formulations, excipients
and carriers well known to pharmaceutical chemists.
[0111] Therapeutic formulations of the invention, which include a monoclonal antibody of
the invention, are used to treat or alleviate a symptom associated with an immune-related
disorder. The present invention also provides methods of treating or alleviating a
symptom associated with an immune-related disorder. A therapeutic regimen is carried
out by identifying a subject,
e.g., a human patient suffering from (or at risk of developing) an immune-related disorder,
using standard methods.
[0112] Antibodies of the invention, which are capable of inhibiting LPS-induced IL-8 production,
are useful therapeutic tools in the treatment of disorders, such as, for example,
acute inflammation and sepsis induced by microbial products (
e.g., LPS) and exacerbations arising from this acute inflammation, such as, for example,
chronic obstructive pulmonary disease and asthma (
see O'Neill, Curr. Opin. Pharmacol. 3: 396-403 (2003), ). Such antibodies are also useful in treating neurodegenerative autoimmune diseases.
(
Lehnardt et al., Proc. Natl. Acad. Sci. USA 100: 8514-8519(2003),).
[0113] In addition, the antibodies of the invention are for use in the treatment of osteoarthritis,
and rheumatoid arthritis which are caused by mechanical stress, which, in turn, induces
endogenous soluble "stress" factors that trigger TLR4. Endogenous soluble stress factor
include e.g., Hsp60 (see
Ohashi et al., J. Immunol. 164: 558-561 (2000)) and fibronectin (see
Okamura et al, J. Biol. Chem. 276: 10229-10233 (2001) and heparan sulphate, hyaluronan, gp96, [beta]-Defensin-2 or surfactant protein
A (see e.g.,
Johnson et al, Crit. Rev. Immunol., 23(1-2):15-44 (2003). The antibodies of the invention are also for use in the treatment of ventilator-induced
lung injury ("VILI"), also referred to as ventilation-associated lung injury ("VALI").
[0114] The invention also provides antibodies as described above for use in treating chronic
inflammation (e.g., chronic inflammation associated with allergic conditions and asthma),
acute inflammation, and autoimmune diseases (e.g., inflammatory bowel disorder). Treatment
of atherosclerosis is also comtemplated (see
O'Neill, Curr. Opin. Pharmacol. 3: 396-403 (2003).
[0115] Symptoms associated with these immune-related disorders include, for example, inflammation,
fever, general malaise, fever, pain, often localized to the inflamed area, rapid pulse
rate, joint pain or aches (arthralgia), rapid breathing or other abnormal breathing
patterns, chills, confusion, disorientation, agitation, dizziness, cough, dyspnea,
pulmonary infections, cardiac failure, respiratory failure, edema, weight gain, mucopurulent
relapses, cachexia, wheezing, headache, and abdominal symptoms such as, for example,
abdominal pain, diarrhea or constipation.
[0116] Efficaciousness of treatment is determined in association with any known method for
diagnosing or treating the particular immune-related disorder. Alleviation of one
or more symptoms of the immune-related disorder indicates that the antibody confers
a clinical benefit.
[0117] Methods for the screening of antibodies that possess the desired specificity include,
but are not limited to, enzyme linked immunosorbent assay (ELISA) and other immunologically
mediated techniques known within the art.
[0118] Antibodies directed against the TLR4/MD-2 complex or to TLR4 when not complexed to
MD-2 (or a fragment thereof) may be used in methods known within the art relating
to the localization and/or quantitation of the TLR4/MD-2 complex or TLR4 (
e.g., for use in measuring levels of the TLR4/MD-2 complex or TLR4 within appropriate
physiological samples, for use in diagnostic methods, for use in imaging the protein,
and the like). In a given embodiment, antibodies specific to the TLR4/MD-2 complex,
or TLR4, or derivative, fragment, analog or homolog thereof, that contain the antibody
derived antigen binding domain, are utilized as pharmacologically active compounds
(referred to hereinafter as "Therapeutics").
[0119] An antibody specific for the TLR4/MD-2 complex or TLR4 can be used to isolate the
TLR4/MD-2 complex or a TLR4 polypeptide by standard techniques, such as immunoaffinity,
chromatography or immunoprecipitation. Antibodies directed against the TLR4/MD-2 complex
or a TLR4 protein (or a fragment thereof) can be used diagnostically to monitor protein
levels in tissue as part of a clinical testing procedure,
e.g., to, for example, determine the efficacy of a given treatment regimen. Detection
can be facilitated by coupling (
i.e., physically linking) the antibody to a detectable substance. Examples of detectable
substances include various enzymes, prosthetic groups, fluorescent materials, luminescent
materials, bioluminescent materials, and radioactive materials. Examples of suitable
enzymes include horseradish peroxidase, alkaline phosphatase, β-galactosidase, or
acetylcholinesterase; examples of suitable prosthetic group complexes include streptavidin/biotin
and avidin/biotin; examples of suitable fluorescent materials include umbelliferone,
fluorescein, fluorescein isothiocyanate, rhodamine, dichlorotriazinylamine fluorescein,
dansyl chloride or phycoerythrin; an example of a luminescent material includes luminol;
examples of bioluminescent materials include luciferase, luciferin, and aequorin,
and examples of suitable radioactive material include
125I,
131I,
35S or
3H.
[0120] Antibodies of the invention, including polyclonal, monoclonal, humanized and fully
human antibodies, may be used as therapeutic agents. Such agents will generally be
employed to treat or prevent a disease or pathology associated with aberrant TLR4
signaling in a subject. An antibody preparation, preferably one having high specificity
and high affinity for its target antigen, is administered to the subject and will
generally have an effect due to its binding with the target. Administration of the
antibody may abrogate or inhibit or interfere with the signaling function of the target
(
e.g., the TLR4/MD-2 complex). Administration of the antibody may abrogate or inhibit
or interfere with the binding of the target (e.g., TLR4) with an endogenous ligand
(
e.g., TLR4 or the MD-2 accessory protein) to which it naturally binds. For example, the
antibody binds to the target and neutralizes LPS-induced IL-8 production.
[0121] A therapeutically effective amount of an antibody of the invention relates generally
to the amount needed to achieve a therapeutic objective. As noted above, this may
be a binding interaction between the antibody and its target antigen that, in certain
cases, interferes with the functioning of the target. The amount required to be administered
will furthermore depend on the binding affinity of the antibody for its specific antigen,
and will also depend on the rate at which an administered antibody is depleted from
the free volume other subject to which it is administered. Common ranges for therapeutically
effective dosing of an antibody or antibody fragment of the invention may be, by way
of nonlimiting example, from about 0.1 mg/kg body weight to about 50 mg/kg body weight.
Common dosing frequencies may range, for example, from twice daily to once a week.
[0122] Antibodies specifically binding the TLR4/MD-2 complex or a TLR4 protein or a fragment
thereof of the invention can be administered for the treatment of disorders associated
with aberrant LPS signaling in the form of pharmaceutical compositions. Principles
and considerations involved in preparing such compositions, as well as guidance in
the choice of components are provided, for example, in
Remington : The Science And Practice Of Pharmacy 19th ed. (Alfonso R. Gennaro, et
al., editors) Mack Pub. Co., Easton, Pa. : 1995;
Drug Absorption Enhancement: Concepts, Possibilities, Limitations, And Trends, Harwood
Academic Publishers, Langhorne, Pa., 1994; and
Peptide And Protein Drug Delivery (Advances In Parenteral Sciences, Vol. 4), 1991,
M. Dekker, New York.
[0123] Where antibody fragments are used, the smallest inhibitory fragment that specifically
binds to the binding domain of the target protein is preferred. For example, based
upon the variable-region sequences of an antibody, peptide molecules can be designed
that retain the ability to bind the target protein sequence. Such peptides can be
synthesized chemically and/or produced by recombinant DNA technology. (
See, e.g., Marasco et al., Proc. Natl. Acad. Sci. USA, 90: 7889-7893 (1993)). The formulation can also contain more than one active compound as necessary for
the particular indication being treated, preferably those with complementary activities
that do not adversely affect each other. Alternatively, or in addition, the composition
can comprise an agent that enhances its function, such as, for example, a cytotoxic
agent, cytokine, chemotherapeutic agent, or growth-inhibitory agent. Such molecules
are suitably present in combination in amounts that are effective for the purpose
intended.
[0124] The active ingredients can also be entrapped in microcapsules prepared, for example,
by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose
or gelatin-microcapsules and poly-(methylmethacrylate) microcapsules, respectively,
in colloidal drug delivery systems (for example, liposomes, albumin microspheres,
microemulsions, nano-particles, and nanocapsules) or in macroemulsions.
[0125] The formulations to be used for
in vivo administration must be sterile. This is readily accomplished by filtration through
sterile filtration membranes.
[0126] Sustained-release preparations can be prepared. Suitable examples of sustained-release
preparations include semipermeable matrices of solid hydrophobic polymers containing
the antibody, which matrices are in the form of shaped articles,
e.g., films, or microcapsules. Examples of sustained-release matrices include polyesters,
hydrogels (for example, poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)),
polylactides (
U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and γ ethyl-L-glutamate, non-degradable ethylene-vinyl
acetate, degradable lactic acid-glycolic acid copolymers such as the LUPRON DEPOT
™ (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide
acetate), and poly D-(-)-3-hydroxybutyric acid. While polymers such as ethylene-vinyl
acetate and lactic acid-glycolic acid enable release of molecules for over 100 days,
certain hydrogels release proteins for shorter time periods.
[0127] An antibody according to the invention can be used as an agent for detecting the
presence of the TLR4/MD-2 complex or a TLR4 protein (or a protein fragment thereof)
in a sample. For such uses, the antibody may contain a detectable label. Antibodies
are polyclonal, or more preferably, monoclonal. An intact antibody, or a fragment
thereof (
e.g., F
ab, scFv, or F
(ab)2) is used. The term "labeled", with regard to the probe or antibody, is intended to
encompass direct labeling of the probe or antibody by coupling (
i.e., physically linking) a detectable substance to the probe or antibody, as well as
indirect labeling of the probe or antibody by reactivity with another reagent that
is directly labeled. Examples of indirect labeling include detection of a primary
antibody using a fluorescently-labeled secondary antibody and end-labeling of a DNA
probe with biotin such that it can be detected with fluorescently-labeled streptavidin.
The term "biological sample" is intended to include tissues, cells and biological
fluids isolated from a subject, as well as tissues, cells and fluids present within
a subject. Included within the usage of the term "biological sample", therefore, is
blood and a fraction or component of blood including blood serum, blood plasma, or
lymph. That is, the detection method of the invention can be used to detect an analyte
mRNA, protein, or genomic DNA in a biological sample
in vitro as well as
in vivo. for example,
in vitro techniques for detection of an analyte mRNA include Northern hybridizations and
in situ hybridizations.
In vitro techniques for detection of an analyte protein include enzyme linked immunosorbent
assays (ELISAs), Western blots, immunoprecipitations, and immunofluorescence.
In vitro techniques for detection of an analyte genomic DNA include Southern hybridizations.
Procedures for conducting immunoassays are described, for example in "
ELISA: Theory and Practice: Methods in Molecular Biology", Vol. 42, J. R. Crowther
(Ed.) Human Press, Totowa, NJ, 1995; "
Immunoassay", E. Diamandis and T. Christopoulus, Academic Press, Inc., San Diego,
CA, 1996; and "
Practice and Theory of Enzyme Immunoassays", P. -Tijssen, Elsevier Science Publishers,
Amsterdam, 1985. Furthermore, in vivo techniques for detection of an analyte protein include introducing
into a subject a labeled anti-analyte protein antibody. For example, the antibody
can be labeled with a radioactive marker whose presence and location in a subject
can be detected by standard imaging techniques.
Chimeric polypeptides
[0128] The chimeric peptides disclosed herein include a first and second domain operably
linked together. The first domain includes at least a portion of a toll-like receptor
polypeptide, while the second domain includes at least a portion of an MD accessory
protein. The first and second domains can occur in any order in the peptide, and the
peptide can include one or more of each domain. The chimeric protein comprises at
least one biologically active portion of a toll-like receptor polypeptide or MD accessory
protein. The chimeric peptide is soluble. By soluble is meant the ability to dissolve
in a fluid.
[0129] A " toll-like receptor polypeptide" refers to a polypeptide having an amino acid
sequence corresponding to at least a portion of a toll-like receptor polypeptide.
A toll-like receptor polypeptide includes, for example, TLRs 1-10 and RP105. The toll-like
receptor polypeptide, and/or nucleic acids encoding the toll-like receptor polypeptide,
can be constructed using toll-like receptor polypeptide encoding sequences that are
known in the art and are described in,
e.g. GenBank Accession Nos. (CAH72620; CAH72619; NP_003254; NP_003255; NP_003259; NP_006059;
NP_057646; NP_003256; AAH33651; CAD99157; AAM23001; BAB43955; AAF05316; AAK26744;
AAF78037; AAF78036; AAF78035; BAB19259; AAF64061; AAF60188; AAF89753; AAF07823; BAA78631;
AAC34135; AAC34134; AAC34133; AAC34137) . Within the chimeric protein the toll-like
receptor polypeptide can correspond to all or a portion of a toll-like receptor polypeptide.
Preferably the toll-like receptor polypeptide includes the extracellular portion of
the polypeptide.
[0130] An "MD accessory protein" refers to a polypeptide having an amino acid sequence corresponding
to at least a portion of a MD accessory protein. The MID protein is,
e.g., MD-1 or MD-2. The MD accessory protein, and/or nucleic acids encoding the MD accessory
protein, can be constructed using MD accessory protein encoding sequences that are
known in the art and are described in,
e.g. GenBank Accession Nos. GenBank Accession Nos. 095711 (MD-1); AAC98152 (MD-1); Q9Y6Y9
(MD-2); NP_056179 (MD-2); AAH20690 (MD-2); and BAA78717 (MD-2). Exemplary MD accessory
protein and nucleic acid sequences are is shown in Figures 32A, 32B, 33A and 33B.
Within the chimeric protein the MD accessory protein can correspond to all or a portion
of a MD accessory protein.
[0131] The chimeric protein may be linked to one or more additional moieties. For example,
the chimeric protein may additionally be linked to a GST fusion protein in which the
glycoprotein Ibα fusion protein sequences are fused to the C-terminus of the GST (
i.e., glutathione S-transferase) sequences. Such fusion proteins can facilitate the purification
of chimeric protein.
[0132] In another embodiment, the chimeric protein is includes a heterologous signal sequence
(
i.e., a polypeptide sequence that is not present in a polypeptide encoded by a toll-like
receptor polypeptide or MD accessory protein nucleic acid) at its N-terminus. For
example, the native toll-like receptor polypeptide signal sequence can be removed
and replaced with a signal sequence from another protein. In certain host cells (
e.g., mammalian host cells), expression and/or secretion of chimeric protein can be increased
through use of a heterologous signal sequence.
[0133] An chimeric protein can be produced by standard recombinant DNA techniques. For example,
DNA fragments coding for the different polypeptide sequences are ligated together
in-frame in accordance with conventional techniques,
e.g., by employing blunt-ended or stagger-ended termini for ligation, restriction enzyme
digestion to provide for appropriate termini, filling-in of cohesive ends as appropriate,
alkaline phosphatase treatment to avoid undesirable joining, and enzymatic ligation.
In another embodiment, the fusion gene can be synthesized by conventional techniques
including automated DNA synthesizers. Alternatively, PCR amplification of gene Fragments
can be carried out using anchor primers that give rise to complementary overhangs
between two consecutive gene fragments that can subsequently be annealed and reamplified
to generate a chimeric gene sequence (see, for example,
Ausubel et al. (eds.) CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, John Wiley & Sons, 1992). Moreover, many expression vectors are commercially available that encode a fusion
moiety (
e.g., an Fc region of an immunoglobulin heavy chain). A glycoprotein Ibα encoding nucleic
acid can be cloned into such an expression vector such that the fusion moiety is linked
in-frame to the immunoglobulin protein.
[0134] Within the chimeric protein, the term "operatively linked" is intended to indicate
that the first and second polypeptides are chemically linked (most typically via a
covalent bond such as a peptide bond) in a manner that allows for at least one function
associated with the toll-like receptor polypeptide and MD accessory protein. When
used to refer to nucleic acids encoding the chimeric protein the term operatively
linked means that a nucleic acid encoding the toll-like receptor polypeptide or MD
accessory protein are fused in-frame to each other. The MD accessory protein can be
fused to the N-terminus or C-terminus of the toll-like receptor polypeptide. Optionally,
the toll-like receptor polypeptide and MD accessory protein are linked via a spacer
arm. Spacer arms provide intramolecular flexibility or adjust intramolecular distances
between conjugated moieties and thereby may help preserve biological activity. A spacer
arm may be in the form of a polypeptide moiety that includes spacer amino acids,
e.g. proline, serine or glycine. Preferably the toll-like receptor polypeptide and MD
accessory protein are linked via a flexible glycine/serine linker. Alternatively,
a spacer arm may be part of the cross-linking reagent, such as in "long-chain SPDP"
(Pierce Chem. Co., Rockford, IL., cat No. 21651 H).
[0135] The toll-like receptor polypeptide and the MD accessory protein may be linked by
chemical coupling in any suitable manner known in the art. Many known chemical cross-linking
methods are non-specific,
i.e.; they do not direct the point of coupling to any particular site on the toll-like
polypeptide or MD accessory protein. As a result, use of non-specific cross-linking
agents may attack functional sites or sterically block active sites, rendering the
conjugated proteins biologically inactive.
[0136] One way to increasing coupling specificity is to directly chemical coupling to a
functional group found only once or a few times in one or both of the polypeptides
to be cross-linked. For example, in many proteins, cysteine, which is the only protein
amino acid containing a thiol group, occurs only a few times. Also, for example, if
a polypeptide contains no lysine residues, a cross-linking reagent specific for primary
amines will be selective for the amino terminus of that polypeptide. Successful utilization
of this approach to increase coupling specificity requires that the polypeptide have
the suitably rare and reactive residues in areas of the molecule that may be altered
without loss of the molecule's biological activity.
[0137] Cysteine residues may be replaced when they occur in parts of a polypeptide sequence
where their participation in a cross-linking reaction would otherwise likely interfere
with biological activity. When a cysteine residue is replaced, it is typically desirable
to minimize resulting changes in polypeptide folding. Changes in polypeptide folding
are minimized when the replacement is chemically and sterically similar to cysteine.
For these reasons, serine is preferred as a replacement for cysteine. As demonstrated
in the examples below, a cysteine residue may be introduced into a polypeptide's amino
acid sequence for cross-linking purposes. When a cysteine residue is introduced, introduction
at or near the amino or carboxy terminus is preferred. Conventional methods are available
for such amino acid sequence modifications, whether the polypeptide of interest is
produced by chemical synthesis or expression of recombinant DNA.
[0138] Coupling of the two constituents can be accomplished via a coupling or conjugating
agent. There are several intermolecular cross-linking reagents which can be utilized,
See
for example, Means and Feeney, CHEMICAL MODIFICATION OF PROTEINS, Holden-Day, 1974, pp. 39-43. Among these reagents are, for example, J-succinimidyl 3-(2-pyridyldithio) propionate
(SPDP) or N, N'- (1,3-phenylene) bismaleimide (both of which are highly specific for
sulfhydryl groups and form irreversible linkages); N, N'-ethylene-bis- (iodoacetamide)
or other such reagent having 6 to 11 carbon methylene bridges (which relatively specific
for sulfhydryl groups); and 1,5-difluoro-2, 4-dinitrobenzene (which forms irreversible
linkages with amino and tyrosine groups). Other cross-linking reagents useful for
this purpose include: p,p'-difluoro-m,m'-dinitrodiphenylsulfone (which forms irreversible
cross-linkages with amino and phenolic groups); dimethyl adipimidate (which is specific
for amino groups); phenol-1,4-disulfonylchloride (which reacts principally with amino
groups); hexamethylenediisocyanate or diisothiocyanate, or azophenyl-p-diisocyanate
(which reacts principally with amino groups); glutaraldehyde (which reacts with several
different side chains) and disdiazobenzidine (which reacts primarily with tyrosine
and histidine).
[0139] Cross-linking reagents may be homobifunctional,
i.e., having two functional groups that undergo the same reaction. A preferred homobifunctional
cross-linking reagent is bismaleimidohexane ("BMH"). BMH contains two maleimide functional
groups, which react specifically with sulfhydryl-containing compounds under mild conditions
(pH 6.5-7.7). The two maleimide groups are connected by a hydrocarbon chain. Therefore,
BMH is useful for irreversible cross-linking of polypeptides that contain cysteine
residues.
[0140] Cross-linking reagents may also be heterobifunctional. Heterobifunctional cross-linking
agents have two different functional groups, for example an amine-reactive group and
a thiol-reactive group, that will cross-link two proteins having free amines and thiols,
respectively. Examples of heterobifunctional cross-linking agents are succinimidyl
4-(N-maleimidomethyl) cyclohexane-1-carboxylate ("SMCC"), m-maleimidobenzoyl-N-hydroxysuccinimide
ester ("MBS"), and succinimide 4-(p-maleimidophenyl) butyrate ("SMPB"), an extended
chain analog of MBS. The succinimidyl group of these cross-linkers reacts with a primary
amine, and the thiol-reactive maleimide forms a covalent bond with the thiol of a
cysteine residue.
[0141] Cross-linking reagents often have low solubility in water. A hydrophilic moiety,
such as a sulfonate group, may be added to the cross-linking reagent to improve its
water solubility. Sulfo-MBS and sulfo-SMCC are examples of cross-linking reagents
modified for water solubility.
[0142] Many cross-linking reagents yield a conjugate that is essentially non-cleavable under
cellular conditions. However, some cross-linking reagents contain a covalent bond,
such as a disulfide, that is cleavable under cellular conditions. For example, Traut's
reagent, dithiobis (succinimidylpropionate) ("DSP"), and N-succinimidyl 3-(2-pyridyldithio)
propionate ("SPDP") are well-known cleavable cross-linkers. The use of a cleavable
cross-linking reagent permits the cargo moiety to separate from the transport polypeptide
after delivery into the target cell. Direct disulfide linkage may also be useful.
[0144] Also disclosed are derivatives, fragments, homologs, analogs and variants of the
chimeric peptides and nucleic acids encoding these peptides. For nucleic acids, derivatives,
fragments, and analogs provided herein are defined as sequences of at least 6 (contiguous)
nucleic acids, and which have a length sufficient to allow for specific hybridization.
For amino acids, derivatives, fragments, and analogs provided herein are defined as
sequences of at least 4 (contiguous) amino acids, a length sufficient to allow for
specific recognition of an epitope.
[0145] The length of the fragments are less than the length of the corresponding full-length
nucleic acid or polypeptide from which the chimeric peptide, or nucleic acid encoding
same, is derived. Derivatives and analogs may be full length or other than full length,
if the derivative or analog contains a modified nucleic acid or amino acid. Derivatives
or analogs of the chimeric peptides include,
e.g., molecules including regions that are substantially homologous to the peptides,
in various embodiments, by at least about 30%, 50%, 70%, 80%, or 95%, 98%, or even
99%, identity over an amino acid sequence of identical size or when compared to an
aligned sequence in which the alignment is done by a computer homology program known
in the art. For example sequence identity can be measured using sequence analysis
software (Sequence Analysis Software Package of the Genetics Computer Group, University
of Wisconsin Biotechnology Center, 1710 University Avenue, Madison, Wis. 53705), with
the default parameters therein.
[0146] Where a particular polypeptide is said to have a specific percent identity to a reference
polypeptide of a defined length, the percent identity is relative to the reference
peptide. Thus, a peptide that is 50% identical to a reference polypeptide that is
100 amino acids long can be a 50 amino acid polypeptide that is completely identical
to a 50 amino acid long portion of the reference polypeptide. It might also be a 100
amino acid long polypeptide, which is 50% identical to the reference polypeptide over
its entire length. Of course, other polypeptides will meet the same criteria.
Pharmaceutical compositions.
[0147] The antibodies of the invention (also referred to herein as "active compounds"),
and derivatives, fragments, analogs and homologs thereof, can be incorporated into
pharmaceutical compositions suitable for administration. Such compositions typically
comprise the antibody and a pharmaceutically acceptable carrier. As used herein, the
term "pharmaceutically acceptable carrier" is intended to include any and all solvents,
dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption
delaying agents, and the like, compatible with pharmaceutical administration. Suitable
carriers are described in the most recent edition of Remington's Pharmaceutical Sciences,
a standard reference text in the field, which is incorporated herein by reference.
Preferred examples of such carriers or diluents include, but are not limited to, water,
saline, ringer's solutions, dextrose solution, and 5% human serum albumin. Liposomes
and non-aqueous vehicles such as fixed oils may also be used. The use of such media
and agents for pharmaceutically active substances is well known in the art. Except
insofar as any conventional media or agent is incompatible with the active compound,
use thereof in the compositions is contemplated. Supplementary active compounds can
also be incorporated into the compositions.
[0148] A pharmaceutical composition of the invention is formulated to be compatible with
its intended route of administration. Examples of routes of administration include
parenteral,
e.g., intravenous, intradermal, subcutaneous, oral (
e.g., inhalation), transdermal (
i.e., topical), transmucosal, and rectal administration. Solutions or suspensions used
for parenteral, intradermal, or subcutaneous application can include the following
components: a sterile diluent such as water for injection, saline solution, fixed
oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents;
antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such
as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic
acid (EDTA); buffers such as acetates, citrates or phosphates, and agents for the
adjustment of tonicity such as sodium chloride or dextrose. The pH can be adjusted
with acids or bases, such as hydrochloric acid or sodium hydroxide. The parenteral
preparation can be enclosed in ampoules, disposable syringes or multiple dose vials
made of glass or plastic.
[0149] Pharmaceutical compositions suitable for injectable use include sterile aqueous solutions
(where water soluble) or dispersions and sterile powders for the extemporaneous preparation
of sterile injectable solutions or dispersion. For intravenous administration, suitable
carriers include physiological saline, bacteriostatic water, Cremophor EL
™ (BASF, Parsippany, N.J.) or phosphate buffered saline (PBS). In all cases, the composition
must be sterile and should be fluid to the extent that easy syringeability exists.
It must be stable under the conditions of manufacture and storage and must be preserved
against the contaminating action of microorganisms such as bacteria and fungi. The
carrier can be a solvent or dispersion medium containing, for example, water, ethanol,
polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and
the like), and suitable mixtures thereof. The proper fluidity can be maintained, for
example, by the use of a coating such as lecithin, by the maintenance of the required
particle size in the case of dispersion and by the use of surfactants. Prevention
of the action of microorganisms can be achieved by various antibacterial and antifungal
agents, for example, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, and
the like. In many cases, it will be preferable to include isotonic agents, for example,
sugars, polyalcohols such as manitol, sorbitol, sodium chloride in the composition.
Prolonged absorption of the injectable compositions can be brought about by including
in the composition an agent which delays absorption, for example, aluminum monostearate
and gelatin.
[0150] Sterile injectable solutions can be prepared by incorporating the active compound
in the required amount in an appropriate solvent with one or a combination of ingredients
enumerated above, as required, followed by filtered sterilization. Generally, dispersions
are prepared by incorporating the active compound into a sterile vehicle that contains
a basic dispersion medium and the required other ingredients from those enumerated
above. In the case of sterile powders for the preparation of sterile injectable solutions,
methods of preparation are vacuum drying and freeze-drying that yields a powder of
the active ingredient plus any additional desired ingredient from a previously sterile-filtered
solution thereof.
[0151] Oral compositions generally include an inert diluent or an edible carrier. They can
be enclosed in gelatin capsules or compressed into tablets. For the purpose of oral
therapeutic administration, the active compound can be incorporated with excipients
and used in the form of tablets, troches, or capsules. Oral compositions can also
be prepared using a fluid carrier for use as a mouthwash, wherein the compound in
the fluid carrier is applied orally and swished and expectorated or swallowed. Pharmaceutically
compatible binding agents, and/or adjuvant materials can be included as part of the
composition. The tablets, pills, capsules, troches and the like can contain any of
the following ingredients, or compounds of a similar nature: a binder such as microcrystalline
cellulose, gum tragacanth or gelatin; an excipient such as starch or lactose, a disintegrating
agent such as alginic acid, Primogel, or corn starch; a lubricant such as magnesium
stearate or Sterotes; a glidant such as colloidal silicon dioxide; a sweetening agent
such as sucrose or saccharin; or a flavoring agent such as peppermint, methyl salicylate,
or orange flavouring.
[0152] For administration by inhalation, the compounds are delivered in the form of an aerosol
spray from pressured container or dispenser which contains a suitable propellant,
e.g., a gas such as carbon dioxide, or a nebulizer.
[0153] Systemic administration can also be by transmucosal or transdermal means. For transmucosal
or transdermal administration, penetrants appropriate to the barrier to be permeated
are used in the formulation. Such penetrants are generally known in the art, and include,
for example, for transmucosal administration, detergents, bile salts, and fusidic
acid derivatives. Transmucosal administration can be accomplished through the use
of nasal sprays or suppositories. For transdermal administration, the active compounds
are formulated into ointments, salves, gels, or creams as generally known in the art.
[0154] The compounds can also be prepared in the form of suppositories (
e.g., with conventional suppository bases such as cocoa butter and other glycerides)
or retention enemas for rectal delivery.
[0155] In one embodiment, the active compounds are prepared with carriers that will protect
the compound against rapid elimination from the body, such as a controlled release
formulation, including implants and microencapsulated delivery systems. Biodegradable,
biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides,
polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Methods for preparation
of such formulations will be apparent to those skilled in the art. The materials can
also be obtained commercially from Alza Corporation and Nova Pharmaceuticals, Inc.
Liposomal suspensions (including liposomes targeted to infected cells with monoclonal
antibodies to viral antigens) can also be used as pharmaceutically acceptable carriers.
These can be prepared according to methods known to those skilled in the art, for
example, as described in
U.S. Patent No. 4,522,811.
[0156] It is especially advantageous to formulate oral or parenteral compositions in dosage
unit form for ease of administration and uniformity of dosage. Dosage unit form as
used herein refers to physically discrete units suited as unitary dosages for the
subject to be treated; each unit containing a predetermined quantity of active compound
calculated to produce the desired therapeutic effect in association with the required
pharmaceutical carrier. The specification for the dosage unit forms of the invention
are dictated by and directly dependent on the unique characteristics of the active
compound and the particular therapeutic effect to be achieved, and the limitations
inherent in the art of compounding such an active compound for the treatment of individuals.
[0157] The pharmaceutical compositions can be included in a container, pack, or dispenser
together with instructions for administration.
Screening Methods
[0158] We also disclose methods (also referred to herein as "screening assays") for identifying
modulators,
i.e., candidate or test compounds or agents (
e.g., peptides, peptidomimetics, small molecules or other drugs) that modulate or otherwise
interfere with the binding of TLR4 to the MD-2 accessory protein, or candidate or
test compounds or agents that modulate or otherwise interfere with the signaling function
of TLR4 and/or the TLR4/MD-2 complex. Also disclosed are methods of identifying compounds
useful to treat disorders associated with aberrant LPS-signaling. We also disclose
compounds identified in the screening assays described herein.
[0159] In one aspect, we disclose assays for screening candidate or test compounds which
modulate the signaling function of the TLR4/MD-2 complex and/or the interaction between
TLR4 and MD-2. The test compounds can be obtained using any of the numerous approaches
in combinatorial library methods known in the art, including: biological libraries;
spatially addressable parallel solid phase or solution phase libraries; synthetic
library methods requiring deconvolution; the "one-bead one-compound" library method;
and synthetic library methods using affinity chromatography selection. The biological
library approach is limited to peptide libraries, while the other four approaches
are applicable to peptide, non-peptide oligomer or small molecule libraries of compounds.
(See, e.g.,
Lam, 1997. Anticancer Drug Design 12: 145).
[0160] A "small molecule" as used herein, is meant to refer to a composition that has a
molecular weight of less than about 5 kD and most preferably less than about 4 kD.
Small molecules can be, e.g., nucleic acids, peptides, polypeptides, peptidomimetics,
carbohydrates, lipids or other organic or inorganic molecules. Libraries of chemical
and/or biological mixtures, such as fungal, bacterial, or algal extracts, are known
in the art and can be screened with any of the assays disclosed herein.
[0161] Examples of methods for the synthesis of molecular libraries can be found in the
art, for example in:
DeWitt, et al, 1993. Proc. Natl. Acad. Sci. U.S.A. 90: 6909;
Erb, et al., 1994. Proc. Natl. Acad. Sci. U.S.A. 91: 11422;
Zuckermann, et al., 1994. J. Med. Chem. 37: 2678;
Cho, et al., 1993. Science 261: 1303;
Carrell, et al., 1994. Angew. Chem. Int. Ed. Engl. 33: 2059;
Carell, et al., 1994. Angew. Chem. Int. Ed. Engl. 33: 2061; and
Gallop, et al., 1994. J. Med. Chem. 37: 1233.
[0162] Libraries of compounds may be presented in solution (see e.g. ,
Houghten, 1992. Biotechniques 13: 412-421), or on beads (see
Lam, 1991. Nature 354: 82-84), on chips (see
Fodor, 1993. Nature 364: 555-556), bacteria (see
U.S. Patent No. 5,223,409), spores (see
U.S. Patent 5,233,409), plasmids (see
Cull, et al., 1992. Proc. Natl. Acad. Sci. USA 89: 1865-1869) or on phage (see
Scott and Smith, 1990. Science 249: 386-390; Devlin, 1990.
Science 249: 404-406;
Cwirla, et al, 1990. Proc. Natl. Acad. Sci. U.S.A. 87: 6378-6382;
Felici, 1991. J. Mol. Biol. 222: 301-310; and
U.S. Patent No. 5,233,409.).
[0163] A candidate compound may be introduced to an antibody- antigen complex and determining
whether the candidate compound disrupts the antibody- antigen complex, wherein a disruption
of this complex indicates that the candidate compound modulates the signaling function
of the TLR4/MD-2 complex and/or the interaction between TLR4 and MD-2. For example,
the antibody is monoclonal antibody 18H10, and the antigen is the TLR4/MD-2 complex.
Alternatively, the monoclonal antibody is 16G7, 5Cl, 15Cl, 7E3 or 7E3 and the antigen
is the TLR4/MD-2 complex or TLR4.
[0164] Alternatively, a TLR4/MD-2 complex is provided and exposed to at least one neutralizing
monoclonal antibody. Formation of an antibody-antigen complex is detected, and one
or more candidate compounds are introduced to the complex. If the antibody-antigen
complex is disrupted following introduction of the one or more candidate compounds,
the candidate compounds is useful to treat disorders associated with aberrant LPS-signaling.
[0165] In a further alternative, a soluble chimeric protein as described herein is provided
and exposed to at least one neutralizing monoclonal antibody. Formation of an antibody-
antigen complex is detected, and one or more candidate compounds are introduced to
the complex. If the antibody-antigen complex is disrupted following introduction of
the one or more candidate compounds, the candidate compounds is useful to treat disorders
associated with aberrant LPS-signaling.
[0166] Determining the ability of the test compound to interfere with or disrupt the antibody-antigen
complex can be accomplished, for example, by coupling the test compound with a radioisotope
or enzymatic label such that binding of the test compound to the antigen or biologically-active
portion thereof can be determined by detecting the labeled compound in a complex.
For example, test compounds can be labeled with
125I,
35S,
14C, or
3H, either directly or indirectly, and the radioisotope detected by direct counting
of radioemission or by scintillation counting. Alternatively, test compounds can be
enzymatically-labeled with, for example, horseradish peroxidase, alkaline phosphatase,
or luciferase, and the enzymatic label detected by determination of conversion of
an appropriate substrate to product.
[0167] The assay may comprise contacting an antibody-antigen complex with a test compound,
and determining the ability of the test compound to interact with the antigen or otherwise
disrupt the existing antibody-antigen complex. In this assay, determining the ability
of the test compound to interact with the antigen and/or disrupt the antibody-antigen
complex comprises determining the ability of the test compound to preferentially bind
to the antigen or a biologically-active portion thereof, as compared to the antibody.
[0168] Alternatively, the assay comprises contacting an antibody-antigen complex with a
test compound and determining the ability of the test compound to modulate the antibody-antigen
complex. Determining the ability of the test compound to modulate the antibody-antigen
complex can be accomplished, for example, by determining the ability of the antigen
to bind to or interact with the antibody, in the presence of the test compound.
[0169] Those skilled in the art will recognize that, in any of the screening methods disclosed
herein, the antibody may be a neutralizing antibody, such as monoclonal antibody 18H10,
16G7, 15Cl and/or 7E3, each of which modulates or otherwise interferes with LPS- induced
proinflammatory cytokine production.
[0170] The screening methods disclosed herein may be performed as a cell-based assay or
as a cell-free assay. The cell-free assays of the invention are amenable to use of
either the soluble form or the membrane-bound form of the TLR4 and/or TLR4 when completed
with MD-2, and fragments thereof. In the case of cell-free assays comprising the membrane-bound
forms of TLR4 and/or the TLR4/MD-2 complex, it may be desirable to utilize a solubilizing
agent such that the membrane-bound form of the proteins are maintained in solution.
Examples of such solubilizing agents include non-ionic detergents such as n-octylglucoside,
n-dodecylglucoside, n-dodecylmaltoside, octanoyl-N-methylglucamide, decanoyl-N-methylglucamide,
Triton
® X-100, Triton
® X-114, Thesit
®, Isotridecypoly(ethylene glycol ether)
n, N-dodecyl--,N,N-dimethyl-3-ammonio-1 -propane sulfonate, 3-(3-cholamidopropyl) dimethylamminiol-1
-propane sulfonate (CHAPS), or 3-(3-cholamidopropyl) dimethylamminiol-2-hydroxy-1-propane
sulfonate (CHAPSO).
[0171] In some assays, it may be desirable to immobilize either the antibody or the antigen
to facilitate separation of complexed from uncomplexed forms of one or both following
introduction of the candidate compound, as well as to accommodate automation of the
assay. Observation of the antibody-antigen complex in the presence and absence of
a candidate compound, can be accomplished in any vessel suitable for containing the
reactants. Examples of such vessels include microtiter plates, test tubes, and micro-centrifuge
tubes. In one embodiment, a fusion protein can be provided that adds a domain that
allows one or both of the proteins to be bound to a matrix. For example, GST-antibody
fusion proteins or GST-antigen fusion proteins can be adsorbed onto glutathione sepharose
beads (Sigma Chemical, St. Louis, MO) or glutathione derivatized microtiter plates,
that are then combined with the test compound, and the mixture is incubated under
conditions conducive to complex formation (
e.g., at physiological conditions for salt and pH). Following incubation, the beads or
microtiter plate wells are washed to remove any unbound components, the matrix immobilized
in the case of beads, complex determined either directly or indirectly. Alternatively,
the complexes can be dissociated from the matrix, and the level of antibody-antigen
complex formation can be determined using standard techniques.
[0172] Other techniques for immobilizing proteins on matrices can also be used in the screening
assays of the invention. For example, either the antibody (
e.g. 18H10, 16G7, 15C1, and/or 7E3) or the antigen (
e.g. the TLR4/MD-2 complex and/or a TLR4 protein) can be immobilized utilizing conjugation
of biotin and streptavidin. Biotinylated antibody or antigen molecules can be prepared
from biotin-NHS (N-hydroxy-succinimide) using techniques well-known within the art
(
e.g., biotinylation kit, Pierce Chemicals, Rockford, Ill.), and immobilized in the wells
of streptavidin-coated 96 well plates (Pierce Chemical). Alternatively, other antibodies
reactive with the antibody or antigen of interest, but which do not interfere with
the formation of the antibody-antigen complex of interest, can be derivatized to the
wells of the plate, and unbound antibody or antigen trapped in the wells by antibody
conjugation. Methods for detecting such complexes, in addition to those described
above for the GST-immobilized complexes, include immunodetection of complexes using
such other antibodies reactive with the antibody or antigen.
Diagnostic Assays
[0173] Antibodies of the present invention can be detected by appropriate assays,
e.g., conventional types of immunoassays. For example, a sandwich assay can be performed
in which the TLR4/MD-2 complex or a TLR4 protein or fragment thereof is affixed to
a solid phase. Incubation is maintained for a sufficient period of time to allow the
antibody in the sample to bind to the immobilized polypeptide on the solid phase.
After this first incubation, the solid phase is separated from the sample. The solid
phase is washed to remove unbound materials and interfering substances such as non-specific
proteins which may also be present in the sample. The solid phase containing the antibody
of interest (
e.g. monoclonal antibody 18H10, 16G7, 15C1 and/or 7E3) bound to the immobilized polypeptide
is subsequently incubated with a second, labeled antibody or antibody bound to a coupling
agent such as biotin or avidin. This second antibody may be another anti-TLR4/MD-2
complex antibody, another anti-TLR4 antibody or another antibody. Labels for antibodies
are well-known in the art and include radionuclides, enzymes (
e.g. maleate dehydrogenase, horseradish peroxidase, glucose oxidase, catalase), fluors
(fluorescein isothiocyanate, rhodamine, phycocyanin, fluorescarmine), biotin, and
the like. The labeled antibodies are incubated with the solid and the label bound
to the solid phase is measured. These and other immunoassays can be easily performed
by those of ordinary skill in the art.
[0174] One method for detecting the presence or absence of the TLR4/MD-2 complex or a.TLR4
protein in a biological sample involves obtaining a biological sample from a test
subject and contacting the biological sample with a labeled monoclonal antibody according
to the invention such that the presence of TLR4//MD-2 complex or TLR4 is detected
in the biological sample.
[0175] As used herein, the term "labeled", with regard to the probe or antibody, is intended
to encompass direct labeling of the probe or antibody by coupling (
i.e., physically linking) a detectable substance to the probe or antibody, as well as indirect
labeling of the probe or antibody by reactivity with another reagent that is directly
labeled. Examples of indirect labeling include detection of a primary antibody using
a fluorescently-labeled secondary antibody and end-labeling of a DNA probe with biotin
such that it can be detected with fluorescently-labeled streptavidin. The term "biological
sample" is intended to include tissues, cells and biological fluids isolated from
a subject, as well as tissues, cells and fluids present within a subject. That is,
the detection method of the invention can be used to detect TLR4/MD-2 complex or TLR4
in a biological sample
in vitro as well as
in vivo. For example,
in vitro techniques for detection of TLR4/MD-2 complex or TLR4 include enzyme linked immunosorbent
assays (ELISAs), Western blots, immunoprecipitations, and immunofluorescence. Furthermore,
in vivo techniques for detection of TLR4/MD-2 complex or TLR4 include introducing into a
subject a labeled anti-TLR4/MD-2 complex or anti-TLR4 antibody. For example, the antibody
can be labeled with a radioactive marker whose presence and location in a subject
can be detected by standard imaging techniques.
[0176] In one embodiment, the biological sample contains protein molecules from the test
subject. One preferred biological sample is a peripheral blood leukocyte sample isolated
by conventional means from a subject.
[0177] The invention also encompasses kits for detecting the presence of TLR4/MD-2 complex
or TLR4 in a biological sample. For example, the kit can comprise: a labeled compound
or agent capable of detecting TLR4/MD-2 complex or TLR4, when not complexed with MD-2,
(
e.g., an anti- TLR4/MD-2 complex monoclonal antibody or an anti-TLR4 monoclonal antibody)
in a biological sample; means for determining the amount of TLR4/MD-2 complex or TLR4
in the sample; and means for comparing the amount of TLR4/MD-2 complex or TLR4 in
the sample with a standard. The compound or agent can be packaged in a suitable container.
The kit can further comprise instructions for using the kit to detect TLR4/MD-2 complex
or TLR4 in a sample.
[0178] The invention will be further described in the following examples, which do not limit
the scope of the invention described in the claims.
Examples
Example 1: Materials and methods for the generation of 18H10 monoclonal antibody
A. Generation of stable TLR4/MD-2 transfectants
[0179] Stable TLR4/MD-2 transfectants were generated in CHO-K1 and HEK 293 cells. For CHO-K1
cells, human TLR4 cDNA encoding an N-terminal c-myc epitope tag was cloned into pCDNA3.1(-)hygro
(Invitrogen), and human MD-2 cDNA encoding C-terminal c-Myc and Protein C epitope
tags was cloned into pCDNA3 (Invitrogen). Both constructs were co-transfected into
CHO cells using Fugene 6
™ reagent (Roche), according to the manufacturer's guidelines. Antibiotic resistant
cells were selected in culture medium containing 500 µg/ml G418 and 250µg/ml hygromycin
B (both from Invitrogen).
[0180] To select for cells expressing the TLR4/MD-2 complex, 1x 10
7 cells/ml were incubated in 1x PBS supplemented with 1% BSA and 10 µg/ml anti-protein
C monoclonal antibody (Roche). Cells were washed once and then incubated in the same
buffer with PE-conjugated goat anti-mouse IgG (H+L) antibody (1:200 dilution; Anwara).
Cells were subsequently incubated with anti-PE microbeads (Miltenyi Biotec) and passed
through a Midi MACS LS column. Cells retained on the column were eluted and placed
back in culture with antibiotic selection. Rounds of sorting were continued until
a uniformly positive population of cells expressing the TLR4/MD-2 complex was obtained.
B. Generation of recombinant MD-2 and chimeric TLR4/MD-2 protein
[0181] To generate recombinant soluble MD-2, cDNA encoding the protein with C terminal FLAG
and 6 X HIS tags for detection and purification purposes was cloned into pFASTBAC1
and subsequently inserted into bacmid DNA by homologous recombination. Following generation
of a viral stock, Sf9 cells were superinfected. 48 hours later, the recombinant protein
was purified from infected cell supernatants using a NiNTA affinity matrix (Qiagen).
[0182] To generate the recombinant TLR4/MD-2 chimeric protein, cDNA encoding the extracellular
portion of human TLR4 linked to MD-2 via a glycine serine (GGGGS
3) linker was assembled using PCR. FLAG and 6xHIS tags were included at the C-terminus
of MD-2 for detection and purification purposes. The cDNA cassette was cloned into
the baculovirus expression vector pFASTBAC1 (Invitrogen) and subsequently inserted
into bacmid DNA by homologous recombination. Following generation of a viral stock,
Sf9 cells were superinfected. 48 hours later, the recombinant fusion protein was purified
from cell lysates using an anti-FLAG
™ M2 MAb affinity matrix (Sigma).
C. Immunization of Mice
[0183] 8 week old female BALB/c mice (IFFA CREDO) were immunized with a subcutaneous injection
(s.c.) of 10
6 CHO cells/ml in RIBI adjuvant (Sigma) at days 0, 7 and 28 as previously described
in
Buell et al., Blood 92: 3521-3528 (1998),
D. Specific Serum titrations
[0184] The mice were bled at days 0 and 14. TLR4/MD-2 specific antibody titers were assessed
in the sera by FACS analysis on TLR4/MD-2 transfected 293 cells. Cells were incubated
with mice sera at 1:250, 1:2500 and 1:25000 dilutions, washed, incubated with APC-conjugated
goat anti-mouse IgG (H+L) antibody (Molecular Probes) and analyzed on a FACScalibur
(Becton Dickenson) in the FL-4 channel.
E. B cell/myeloma fusions
[0185] Mice having specific TLR4/MD-2 serum antibodies were "hyperboosted" subcutaneously
(s.c.) with the chimeric TLR4/MD-2 fusion protein either 3 or 4 days prior to fusion.
Draining lymph nodes were obtained as a source of B cells for fusion with the mouse
myeloma cell line P3-X63-Ag8.653. B cell extraction and cellular fusions were performed
as previously described in
Buell et al., Blood 92: 3521-3528 (1998), . Cells were plated at an approximate concentration of 10
4 myeloma cells/well and grown for 10-14 days in culture medium supplemented with HAT
(Sigma).
F. Hybridoma Screening
[0186] Supernatants from wells containing viable hybridoma cells were screened on mock transfected
cells vs. TLR4/MD-2 transfected myeloma cells for TLR4/MD-2 specificity by FACS analysis.
Cells were then incubated with supernatant and goat-anti mouse IgG (H+L) antibody
(Molecular Probes). Cells were analyzed on a FACScalibur in the FL-4 channel.
G. Monoclonal antibody specificity by FACS
[0187] HEK 293 cells were plated in 6 well plates at a density of 2.5 x 10
5 cells/well in 2ml culture medium containing 10 % FBS. 16 hours post-plating, cells
were transfected with 0.75 µg of the appropriate vector(s) using Fugene
™ reagent (Roche) according to the manufacturer's guidelines. 48 hours post-transfection,
cells were stained with the appropriate monoclonal antibody (as indicated in Figure
4) and an APC-coupled goat anti-mouse IgG (H+L) antibody (Molecular Probes) and analyzed
using the FACScalibur in the FL-4 channel.
H Monoclonal antibody specificity by direct ELISA
[0188] Recombinant soluble MD-2 with C terminal FLAG and histidine epitope tags was coated
at a concentration of 5 µg/ml in 50 µl PBS on ELISA plates (Nunc Maxisorp). Wells
were blocked with 200 µl PBS 2 % BSA and subsequently incubated with the appropriate
MAb at the indicated concentration in PBS 1 % BSA. Following 3 wash steps with PBS
0.05 % Tween 20, 50 µl HRP conjugated goat anti-mouse IgG (H+L) at a 1:5000 dilution
was added to the wells. Following a further wash step, binding was revealed using
TMB substrate. Plates were read at a wavelength of 650 nm.
I Monoclonal antibody specificity by sandwich ELISA
[0189] For sample preparation, HEK 293 cells were transfected with the appropriate plasmid
constructs using the Fugene 6
™ transfection reagent as described in paragraph G above. 48 hours post-transfection,
cells were collected and cleared by centrifugation. Cells were subsequently incubated
with biotinylated 18H10 (10 µg/ml) and lysed in 20 mM Tris pH 7.4, 150 mM NaCl, 1
% NP40 containing COWLETE
™ protease inhibitors (Roche).
[0190] To perform the sandwich ELISA, Nunc maxisorp plate wells were coated with 50 µl of
the anti-FLAG
™ M2 MAb (Sigma) at a concentration of 5 µg/ml in PBS. Wells were blocked with 200
µl PBS 2 % BSA and subsequently incubated with 50 µl of the appropriate samples at
the indicated dilution. Wells were washed three times with 200 µl PBS 0.05 % Tween
20 and incubated with 50 µl of the appropriate antibody (10 µg/ml for biotinylated
18H10 and 12D4, 1 µg/ml for the polyclonal anti-MD-2 MAb). Following a wash step as
above, wells were incubated with 50 µl of the appropriate detection antibody (HRP
conjugated streptavidin at a dilution of 1:1500 for the biotinylated MAbs and HRP
conjugated anti-rabbit IgG (H+L) at a dilution of 1:5000 for the polyclonal rabbit
Ab). Following a further wash step, binding was revealed using TMB substrate. Plates
were read at a wavelength of 650 nm.
J. Cellular Assay 1
[0191] Monoclonal antibody was first purified from hybridoma cell supernatant using protein
G affinity chromatography.
[0192] TLR4/MD-2 transfected HEK 293 cells were plated in culture medium containing 10 %
FBS at 5 x 10
5 cells/ml in 96 well plates and left to adhere overnight. The culture medium was subsequently
removed and replaced with 100 µl culture medium containing 2 % FBS and the appropriate
monoclonal antibody at twice the desired final concentration for 30 minutes at 37
°C. LPS (K12LD25, Sigma) was then added to the cells at a concentration of 30 ng/ml
in 100 µl culture medium containing 2 % FBS. Cells were incubated at 37 °C for 16
hours and supernatants harvested. IL-8 content was measured by sandwich ELISA using
the monoclonal antibody pair 801E and M802B (Endogen).
K. Cellular Assay 2
[0193] Human whole blood was diluted 1:4 in RPMI (Sigma) and plated at 100 µl/well in 96
well plates with the appropriate monoclonal antibody at twice the desired final concentration
for 30 minutes at 37°C. LPS (K12LD25, Sigma), dosed at twice the desired final concentration,
was subsequently added in 100 µl RPMI containing 5 mg/ml HSA and incubated for 6 hours
at 37°C. Plates were then centrifuged at 2000 rpm for 5 minutes and the supernatant
from each well was retained. IL-8 concentrations were determined by sandwich ELISA
using the monoclonal antibody pair 801E and M802B (Endogen), as described above.
L. 18H10 VH and VL sequences
[0194] 10
7 hybridoma cells were harvested and washed once with PBS before being resuspended
in 1 ml Trizol
™ reagent (Invitrogen). Total RNA was subsequently extracted according to the manufacturer's
guidelines. cDNA encoding the VH and VL from three independent subclones of the 18H10
hybridoma was generated by RT-PCR with the mouse ScFv module (Amersham Biosciences)
according to the manufacturer's guidelines. Amplified products were cloned into the
pGEM-T easy vector (Promega Corp.) and sequenced using the T7 and SP6 primers.
[0195] The VH and VL cDNAs were subsequently cloned in mammalian expression vectors containing
the human IgG1 and human kappa constant regions respectively in order to express 7E3
as a chimeric MAb ("chimeric 7E3"). To produce recombinant chimeric MAb, HEK 293 cells
were plated in 6 well plates at a density of 2.5 x 10
5 cells/well in 2 ml culture medium containing 10 % FBS. 16 hours post-plating, cells
were transfected with 0.75 µg of the appropriate vector(s) using Fugene
™ reagent (Roche) according to the manufacturer's guidelines. 48 hours post-transfection,
supernatant was harvested and antibody was purified using protein G affinity chromatography.
Example 2: Generation of 18H10 MAbs directed against the human TLR4/MD-2 complex
[0196] Mice immunized with CHO cells expressing surface TLR4/MD-2 were monitored for specific
serum titers. Those showing a response to TLR4/MD-2 were "hyperboosted" with recombinant
TLR4/MD-2 chimeric protein. This strategy was chosen in order to ensure that the immune
system was initially exposed to a conformational TLR4/MD-2 complex whilst minimize
the response to non-specific CHO cellular antigens and simultaneously maximizing the
TLR4/MD-2-specific response upon hyperboosting. Screening by FACS of supernatants
from hybridomas resulting from B cell/myeloma fusions was performed on mock transfected
vs. TLR4/MD-2 transfected CHO cells. Monoclonal antibody from one particular clone,
referred to herein as 18H10, demonstrated specific binding to TLR4/MD-2 transfected
CHO cells (Figure 1). This antibody was found to have the IgG2b κ isotype, as determined
by FACS using the mouse Ig isotyping CBA kit (Beckton Dickenson).
Example 3: 18H10 MAb Neutralization of LPS activity on TLR4/MD-2 transfected HEK 293
cells
[0197] LPS is known to have the ability to induce IL-8 production in HEK 293 cells transfected
with the TLR4/MD-2 complex. The ability of 18H10 to inhibit this IL-8 induction was
analyzed by pre-incubating cells with the antibody for 30 minutes prior to LPS administration.
Figure 2 shows that 18H10 inhibited the effects of LPS on HEK 293 cells, even at concentrations
below 1 µg/ml.
Example 4: 18H10 MAb Neutralization of LPS activity on human whole blood
[0198] The ability of 18H10 to inhibit LPS-induced IL-8 production in human whole blood
was tested. 18H10 neutralizing activity was tested in blood from 3 different donors
using a range of monoclonal antibody concentrations from 0.5 to 10 µg /ml. Figure
3 demonstrates that 18H10 significantly reduced the level of IL-8 induced by LPS in
all 3 donors, as compared to an isotype matched control. 18H10 was found to be more
potent than a previously described α-TLR4 blocking monoclonal antibody (purchased
from e-biosciences). These results indicate that the neutralizing epitope recognized
by 18H10 on transfected HEK 293 cells is also exposed on the surface on cells in whole
blood, and that 18H10 is potent enough to inhibit the activity of LPS in whole blood,
even at concentrations below 1 µg/ml.
Example 5: 18H10 specificity
[0199] In order to determine the specificity of the 18H10 monoclonal antibody, the fact
that 18H10 does not recognize the rabbit ortholog of the TLR4/MD-2 complex (previously
cloned) was exploited. cDNAs for either human or rabbit TLR4 with N-terminal FLAG
™ epitope tag and either human or rabbit MD-2 with C-terminal c-Myc and protein C epitope
tags were transfected in HEK 293 cells in the following combinations: (1) human TLR4
and human MD-2; (2) rabbit TLR4 and rabbit MD-2; (3) human TLR4 and rabbit MD-2; (4)
rabbit TLR4 and human MD-2. Figure 4 shows FACS analysis of these cells following
antibody staining, which revealed that 18H10 recognized cells expressing the human
TLR4/MD-2 complex and a combination of human TLR4 and rabbit MD-2, but not the rabbit
TLR4/MD-2 complex nor a combination of rabbit TLR4 and human MD-2. These results indicate
that the epitope recognized by 18H10 is situated on human MD-2 (Figure 4).
[0200] Although 18H10 shows specificity for MD-2, it was determined that 18H10 only recognizes
MD-2 in the context of its interaction with TLR4. Using direct ELISA, no binding of
18H10 to recombinant soluble MD-2 generated with the baculovirus expression system
was detected (Figure 5a). In addition, figure 5b reveals that 18H10 only bound to
a complex of TLR4 and MD-2 as shown from co-transfected cell lysates, and did not
recognize either MD-2 alone in transfected cell lysates/supematants or TLR4 alone
in transfected cell lysates. These data indicate that 18H10 is specific for the TLR4/MD-2
complex and does not recognize either component of the complex separately.
Example 6: 18H10 VH and VL sequences
[0201] VH and VL sequences from the 18H10 hybridoma clone were amplified from total RNA
by RT-PCR. Sequence analysis is shown in Figures 6A-6F.
[0202] The 18H10 antibody includes a heavy chain variable region (SEQ ID NO:2, Figure 6B)
encoded by the nucleic acid sequence of SEQ ID NO:1 shown in Figure 6A, and a light
chain variable region (SEQ ID NO:7, Figure 6E) encoded by the nucleic acid sequence
of SEQ ID NO:6 shown in Figure 6D. The amino acids encompassing the complementarity
determining regions (CDR) as defined by Chothia et al. 1989, E.A. Kabat et al., 1991
are highlighted in underlined and italicized text in Figures 6B and 6E and shown in
Figures 6C and 6F. (
See Chothia, C, et al., Nature 342:877-883 (1989);
Kabat, EA, et al., Sequences of Protein of immunological interest, Fifth Edition,
US Department of Health and Human Services, US Government Printing Office (1991)). The heavy chain CDRs of the 18H10 antibody have the following sequences: DSYIH
(SEQ ID NO:3); WTDPENVNSIYDPRFQG (SEQ ID NO:4), and GYNGVYYAMDY (SEQ ID NO:5). The
light chain CDRs of the 18H10 antibody have the following sequences: SASSSVIYMH (SEQ
ID NO:8); RTYNLAS (SEQ ID NO:9); and HQWSSFPYT (SEQ ID NO:10).
Example 7: Chimeric 18H10 binds to hTLR4 hMD2 transfected CHO cells
[0203] In order to demonstrate the specificity of the cloned 18H10 VH and VL for the hTLR4/MD-2
complex, FACS analysis was performed on hTLR4/MD-2 transfected CHO cells using the
chimeric 18H10 MAb (Figure 6). Specific binding of MAb at the indicated concentration
was detected using an APC-labeled goat-anti-human IgG (H+L) secondary antibody. An
irrelevant isotype-matched IgG1 MAb was used as a control.
Example 8: Chimeric 18H10 inhibits LPS-induced IL-8 production in hTLR4 hMD2 transfected
HEK 293 cells
[0204] In order to demonstrate the neutralizing capacity of the cloned 18H10 VH and VL for
LPS, the ability of 18H10 to inhibit LPS dependent IL-8 induction of hTLR4/MD-2 transfected
HEK 293 cells was tested (as described above). Figure 7 shows that chimeric 18H10
inhibited the effects of-LPS on HEK 293 cells in a manner very similar to that of
the original 18H10 mouse MAb.
Example 9: Materials and methods for the generation of 16G7 monoclonal antibody
A. Generation of stable TLR4/MD-2 transfectants
[0205] Stable TLR4/MD-2 transfectants were generated in CHO-K1 and HEK 293 cells. For CHO-K1
cells, human TLR4 cDNA encoding an N-terminal c-myc epitope tag was cloned into pCDNA3.1(-)hygro
(Invitrogen), and human MD-2 cDNA encoding C-terminal c-Myc and Protein C epitope
tags was cloned into pCDNA3 (Invitrogen). Both constructs were co-transfected into
CHO cells using Fugene 6
™ reagent (Roche), according to the manufacturer's guidelines. Antibiotic resistant
cells were selected in culture medium containing 500 µg/ml G418 and 250µg/ml hygromycin
B (both from Invitrogen).
[0206] For HEK 293 cells, human TLR4 cDNA encoding an N-terminal FLAG
™ epitope tag was cloned into pCDNA33.1 (-)hygro (Invitrogen), and human MD-2 cDNA
encoding C-terminal FLAG
™ and 6 x Histidine epitope tags was cloned into pCDNA3 (Invitrogen). Both constructs
were transfected into HEK 293 cells, and antibiotic resistant cells were selected
in culture medium containing 500 µg/ml G418 and 250µg/ml hygromycin B (both from Invitrogen),
as described above.
[0207] To select for cells expressing the TLR4/MD-2 complex, 1x 10
7 cells/ml were incubated in 1x PBS supplemented with 1% BSA and either 10 µg/ml anti-protein
C monoclonal antibody (for CHO cells; Roche) or anti-FLAG monoclonal antibody (for
293 cells; Sigma). Cells were washed once and then incubated in the same buffer with
PE-conjugated goat anti-mouse IgG (H+L) antibody (1:200 dilution; Anwara). Cells were
subsequently incubated with anti-PE microbeads (Miltenyi Biotec) and passed through
a Midi MACS LS column. Cells retained on the column were eluted and placed back in
culture with antibiotic selection. Rounds of sorting were continued until a uniformly
positive population of cells expressing the TLR4/MD-2 complex was obtained.
B. Immunization of Mice
[0208] 8 week old female BALB/c mice (IFFA CREDO) were immunized as described above in Example
1, subsection C.
C. Specific Serum titrations
[0209] Mice sera titrations were performed as described above in Example 1, subsection D.
D. B cell/myeloma fusions
[0210] Mice having specific TLR4/MD-2 serum antibodies were "hyperboosted" subcutaneously
(s.c.) with TLR4/MD-2 transfected HEK 293 either 3 or 4 days prior to fusion. Draining
lymph nodes were obtained as a source of B cells for fusion with the mouse myeloma
cell line P3-X63-Ag8.653. B cell extraction and cellular fusions were performed as
previously described in
Buell et al., Blood 92: 3521-3528 (1998), . Cells were plated at an approximate concentration of 10
4 myeloma cells/well and grown for 10-14 days in culture medium supplemented with HAT
(Sigma).
E. Hybridoma Screening
[0211] Hybridomas were screened as described above in Example 1, subsection F.
F. Monoclonal antibody specificity
[0212] The specificity of the 16G7 monoclonal antibody was determined as described above
in Example 1, subsection G.
G. Cellular Assay 1
[0213] Cellular Assay I was performed as described above in Example 1, subsection J.
H. Cellular Assay 2
[0214] Cellular Assay II was performed as described above in Example 1, subsection K.
I. 16G7 VH and VL sequences
[0215] 10
7 hybridoma cells were harvested and washed once with PBS before being resuspended
in 1 ml Trizol
™ reagent (Invitrogen). Total RNA was subsequently extracted according to the manufacturer's
guidelines. cDNA encoding the VH and VL from the 16G7 clone was generated by RT-PCR
with the mouse ScFv module (Amersham Biosciences) according to the manufacturer's
guidelines. Amplified products were cloned into the pGEM-T easy vector (Promega Corp.)
and sequenced using the T7 and SP6 primers.
Example 10: Generation of 16G7 MAbs directed against the human TLR4/MD-2 complex
[0216] Mice immunized with CHO cells expressing surface TLR4/MD-2 were monitored for specific
serum titers. Those showing a response to TLR4/MD-2 were "hyperboosted" with HEK 293
TLR4//MD-2 transfectants. This strategy was chosen in order to minimize the response
to non-specific CHO cellular antigens, while simultaneously maximizing the TLR4/MD-2-specific
response. Screening by FACS of supernatants from hybridomas resulting from B cell/myeloma
fusions was performed on mock transfected vs. TLR4/MD-2 transfected CHO cells. Monoclonal
antibody from a specific clone, referred to herein as 16G7, demonstrated specific
binding to TLR4/MD-2 transfected CHO cells (Figure 9). 16G7 was found to have the
IgG1 κ isotype, as determined by FACS using the mouse Ig isotyping CBA kit (Beckton
Dickenson).
Example 11: 16G7 Neutralization of LPS activity on TLR4/MD-2 transfected HEK 293 cells
[0217] LPS is known to have ability to induce IL-8 production in HEK 293 cells transfected
with the TLR4/MD-2 complex. The ability of 16G7 to inhibit this IL-8 induction was
analyzed by pre-incubating cells with each antibody for 30 minutes prior to LPS administration.
Figure 10 shows that 16G7 inhibited the effects of LPS on HEK 293 cells, even at sub-microgram/ml
concentrations.
Example 12: 16G7 Neutralization of LPS activity on human whole blood
[0218] The ability of 16G7 to inhibit LPS-induced IL-8 production in human whole blood was
tested. 16G7 neutralizing activity was tested in blood from 3 different donors using
a range of monoclonal antibody concentrations from 0.5 to 5 µg /ml. Figure 11 demonstrates
that 16G7 significantly reduced the level of IL-8 induced by LPS in all 3 donors,
as compared to an isotype matched control. 16G7 was found to be more potent than a
previously described α-TLR4 blocking monoclonal antibody (from e-biosciences). (
See Shimazu et al. J. Exp. Med. 189: 1777-1782 (1999)). In some cases, 16G7 was found to be as potent as an α-CD14 blocking monoclonal
antibody that was also included in the study. (See
Kirkland et al. J.Biol. Chem. 268: 24818-24823(1993)). These results indicate that the neutralizing epitope recognized by 16G7 on transfected
HEK 293 cells is also exposed on the surface on cells in whole blood, and that 16G7
is potent enough to inhibit the activity of LPS in whole blood, even at concentrations
below 1 µg/ml.
Example 13: 16G7 specificity
[0219] In order to determine the specificity of the 16G7 monoclonal antibody, the fact that
16G7 does not recognize the rabbit ortholog of the TLR4/MD-2 complex (previously cloned)
was exploited. cDNAs for either rabbit or human TLR4 with N-terminal FLAG
™ epitope tag and MD-2 with C-terminal c-Myc and protein C epitope tags were transfected
in HEK 293 cells in the following combinations: (1) rabbit TLR4 and rabbit MD-2; (2)
human TLR4 and human MD-2; (3) rabbit TLR4 and human MD-2; (4) human TLR4 and rabbit
MD-2. Figure 12 shows FACS analysis of these cells following antibody staining, which
revealed that 16G7 recognized cells expressing the human TLR4/MD-2 complex and a combination
of human TLR4 and rabbit MD-2, but not the rabbit TLR4/MD-2 complex nor a combination
of rabbit TLR4 and human MD-2. These results indicate that the epitope recognized
by 16G7 is situated on human TLR4 (Figure 12).
Example 14: 16G7 VH and VL sequences
[0220] VH and VL sequences from the 16G7 hybridoma clone were amplified from total RNA by
RT-PCR. Sequence analysis is shown in Figures 13A-13F. Alignment of the 16G7, VH and
VL nucleotide sequences with known mouse VH and VL sequences (using the International
Immunogenetics Information System; which can be found at http://imgt.cines.fr) reveals
that the 16G7 VH sequence most closely resembles the IgHV1 subfamily, while the 16G7
VL belongs to the IgKV1 subfamily.
[0221] The 16G7 antibody includes a heavy chain variable region (SEQ ID NO:12, Figure 13B)
encoded by the nucleic acid sequence of SEQ ID NO:11 shown in Figure 13A, and a light
chain variable region (SEQ ID NO:17, Figure 13E) encoded by the nucleic acid sequence
of SEQ ID NO:16 shown in Figure 13D. The amino acids encompassing the CDR as defined
by Chothia et al. 1989, E.A. Kabat et al., 1991 are highlighted in underlined and
italicized text in Figures 13B and 13E and shown in Figures 13C and 13F. The heavy
chain CDRs of the 16G7 antibody have the following sequences: DYWIE (SEQ ID NO:13);
EILPGSGSTNYNEDFKD (SEQ ID NO:14); and EERAYYFGY (SEQ ID NO:15). The light chain CDRs
of the 16G7 antibody have the following sequences: RSSQSLENSNGNTYLN (SEQ ID NO:18);
RVSNRFS (SEQ ID NO:19); and LQVTHVPPT (SEQ ID NO:20).
Example 15: Materials and methods for the generation of 15C1 monoclonal antibody
A. Generation of stable TLR4/MD-2 transfectants
[0222] Stable TLR4/MD-2 transfectants were generated in CHO-K1 and HEK 293 cells as described
above in Example 9, subsection A.
B. Generation of recombinant MD-2 and chimeric TLR4/MD-2 protein
[0223] To generate recombinant soluble MD-2, cDNA encoding the protein with C terminal FLAG
and 6 X HIS tags for detection and purification purposes was cloned into pFASTBAC1
and subsequently inserted into bacmid DNA by homologous recombination. Following generation
of a viral stock, Sf9 cells were superinfected. 48 hours later, the recombinant protein
was purified from infected cell supernatants using a NiNTA affinity matrix (Qiagen).
[0224] To generate the recombinant TLR4/MD-2 chimeric protein, cDNA encoding the extracellular
portion of human TLR4 linked to MD-2
via a glycine serine (GGGGS
3) linker was assembled using PCR. FLAG and 6xHIS tags were included at the C-terminus
of MD-2 for detection and purification purposes. The cDNA cassette was cloned into
the baculovirus expression vector pFASTBAC1 (Invitrogen) and subsequently inserted
into bacmid DNA by homologous recombination. Following generation of a viral stock,
Sf9 cells were superinfected. 48 hours later, the recombinant fusion protein was purified
from cell lysates using an anti-FLAG
™ M2 MAb affinity matrix (Sigma).
C. Immunization of Mice
[0225] 8 week old female BALB/c mice (IFFA CREDO) were immunized as described above in Example
1, subsection C.
D. Specific Serum titrations
[0226] Mice serum titrations were performed as described above in Example 1, subsection
D.
E. B cell/myeloma fusions
[0227] B cell extraction and cellular fusion were performed and analyzed as described above
in Example 9, subsection D.
F. Hybridoma Screening
[0228] Hybridoma screening was performed as described above in Example 1, subsection F.
G. Monoclonal antibody specificity
[0229] The specificity of the 15C1 monoclonal antibody was determined as described above
in Example 1, subsection G.
H. Cellular Assay 1
[0230] Cellular Assay I was performed as described above in Example 1, subsection J.
I. Cellular Assay 2
[0231] Cellular Assay II was performed as described above in Example 1, subsection K.
J. 15C1 VH and VL sequences
[0232] 10
7 hybridoma cells were harvested and washed once with PBS before being resuspended
in 1 ml Trizol
™ reagent (Invitrogen). Total RNA was subsequently extracted according to the manufacturer's
guidelines. cDNA encoding the VH and VL from the 15C1 clone was generated by RT-PCR
with the mouse ScFv module (Amersham Biosciences) according to the manufacturer's
guidelines. Amplified products were cloned into the pGEM-T easy vector (Promega Corp.)
and sequenced using the T7 and SP6 primers.
[0233] The VH and VL cDNAs were subsequently cloned in mammalian expression vectors containing
the human IgG1 and human kappa constant regions respectively in order to express 15C1
as a chimeric MAb ("chimeric 15C1"). To produce recombinant chimeric MAb, HEK 293
cells were plated in 6 well plates at a density of 2.5 x 10
5 cells/well in 2 ml culture medium containing 10 % FBS. 16 hours post-plating, cells
were transfected with 0.75 µg of the appropriate vector(s) using Fugene
™ reagent (Roche) according to the manufacturer's guidelines. 48 hours post-transfection,
supernatant was harvested and antibody was purified using protein G affinity chromatography.
Example 16: Generation of MAbs directed against the human TLR4/MD-2 complex
[0234] Mice immunized with CHO cells expressing surface TLR4/MD-2 were monitored for specific
serum titers. Those showing a response to TLR4/MD-2 were "hyperboosted" with HEK 293
TLR4/MD-2 transfectants. This strategy was chosen in order to minimize the response
to non-specific CHO cellular antigens, while simultaneously maximizing the TLR4/MD-2-specific
response. Screening by FACS of supernatants from hybridomas resulting from B cell/myeloma
fusions was performed on mock-transfected vs. TLR4/MD-2-transfected CHO cells. Monoclonal
antibody from a specific clone, referred to herein as 15C1, demonstrated specific
binding to TLR4/MD-2 transfected CHO cells (Figure 14). 15C1 was found to have the
IgG1 κ isotype, as determined by FACS using the mouse Ig isotyping CBA kit (Beckton
Dickenson).
Example 17: Neutralization of LPS activity on TLR4/MD-2 transfected HEK 293 cells
[0235] LPS is known to have ability to induce IL-8 production in HEK 293 cells transfected
with the TLR4/MD-2 complex. The ability of 15C1 to inhibit this IL-8 induction was
analyzed by pre-incubating cells with each antibody for 30 minutes prior to LPS administration.
Figure 15 shows that 15C1 inhibited the effects of LPS on HEK 293 cells, even at sub-microgram/ml
concentrations.
Example 18: Neutralization of LPS activity on human whole blood
[0236] The ability of 15C1 to inhibit LPS-induced IL-8 production in human whole blood was
tested. 15C1 neutralizing activity was tested in blood from 3 different donors using
a range of monoclonal antibody concentrations from 0.5 to 5 µg /ml. Figure 16 demonstrates
that 15C1 significantly reduced the level of IL-8 induced by LPS in all 3 donors,
as compared to an isotype matched control. 15C1 was found to be more potent than a
previously described α-TLR4 blocking monoclonal antibody (from e-biosciences). (
See Shimazu et al. J. Exp. Med. 189: 1777-1782 (1999)). In some cases, 15C1 was found to be as potent as an α-CD14 blocking monoclonal
antibody that was also included in the study. (
See Kirkland et al. J.Biol. Chem. 268: 24818-24823(1993)). These results indicate that the neutralizing epitope recognized by 15C1 on transfected
HEK 293 cells is also exposed on the surface on cells in whole blood, and that 15C1
is potent enough to inhibit the activity of LPS in whole blood, even at concentrations
below 1 µg/ml.
Example 19:15C1 specificity
[0237] In order to determine the specificity of the 15C1 monoclonal antibody, the fact that
15C1 does not recognize the rabbit ortholog of the TLR4/MD-2 complex (previously cloned)
was exploited. cDNAs for either rabbit or human TLR4 with N-terminal FLAG
™ epitope tag and MD-2 with C-terminal c-Myc and protein C epitope tags were transfected
in HEK 293 cells in the following combinations: (1) mock vector (2) human TLR4 alone
(3) human TLR4 and human MD-2 (4) rabbit TLR4 and rabbit MD-2; ; (5) human TLR4 and
rabbit MD-2; (6) rabbit TLR4 and human MD-2. Figure 17 shows FACS analysis of these
cells following antibody staining, which revealed that 15C1 recognized cells expressing
human TLR4 alone, the human TLR4/MD-2 complex and a combination of human TLR4 and
rabbit MD-2, but not the rabbit TLR4/MD-2 complex nor a combination of rabbit TLR4
and human MD-2. These results indicate that the epitope recognized by 15C1 is situated
on human TLR4 (Figure 17).
Example 20: 15C1 VH and VL sequences
[0238] VH and VL sequences from the 15C1 hybridoma clone were amplified from total RNA by
RT-PCR. Sequence analysis is shown in Figures 18A-18F.
[0239] The 15C1 antibody includes a heavy chain variable region (SEQ ID NO:22, Figure 18B)
encoded by the nucleic acid sequence of SEQ ID NO:21 shown in Figure 18A, and a light
chain variable region (SEQ ID NO:27, Figure 18E) encoded by the nucleic acid sequence
of SEQ ID NO:26 shown in Figure 18D. The amino acids encompassing the CDR as defined
by Chothia et al. 1989, E.A. Kabat et al., 1991 are highlighted in underlined and
italicized text in Figures 18B and 18E and shown in Figures 18C and 18F. The heavy
chain CDRs of the 15C1 antibody have the following sequences: GGYSWH (SEQ ID NO:23);
YIHYSGYTDFNPSLKT (SEQ ID NO:24); and KDPSDGFPY (SEQ ID NO:25). The light chain CDRs
of the 15C1 antibody have the following sequences: RASQSISDHLH (SEQ ID NO:28); YASHAIS
(SEQ ID NO:29); and QNGHSFPLT (SEQ ID NO:30).
Example 21: Chimeric 15C1 binds to hTLR4 hMD2 transfected CHO cells
[0240] In order to demonstrate the specificity of the cloned 15C1 VH and VL for the hTLR4/MD-2
complex, FACS analysis on hTLR4/MD-2 transfected CHO cells using the chimeric 15C1
MAb was performed (Figure 19). Specific binding of MAb at the indicated concentration
was detected using an APC-labeled goat-anti-human IgG (H+L) secondary antibody. An
irrelevant isotype-matched IgG1 MAb was used as a control.
Example 22: Chimeric 15C1 inhibits LPS-induced IL-8 production in hTLR4 hMD2
transfected HEK 293 cells
[0241] In order to demonstrate the neutralizing capacity of the cloned 15C1 VH and VL for
LPS, the ability of 15C1 to inhibit LPS dependent IL-8 induction of hTLR4/MD-2 transfected
HEK 293 cells was tested (as described above). Figure 20 shows that chimeric 15C1
inhibited the effects of LPS on HEK 293 cells in a manner very similar to that of
the 15C1 MAb.
Example 23: Materials and methods for the generation of 7E3 monoclonal antibody
A. Generation of stable TLR4/MD-2 transfectants
[0242] Stable TLR4/MD-2 transfectants were generated in CHO-K1 and HEK 293 cells as described
above in Example 9, subsection A.
B. Generation of recombinant MD-2 and chimeric TLR4/MD-2 protein
[0243] Recombinant soluble MD-2 was generated as described above in Example 15, subsection
B.
[0244] To generate the recombinant TLR4/MD-2 chimeric protein, cDNA encoding the extracellular
portion of human TLR4 linked to MD-2
via a glycine serine (GGGGS
3) linker was assembled using PCR. FLAG and 6xHIS tags were included at the C-terminus
of MD-2 for detection and purification purposes. The cDNA cassette was cloned into
the baculovirus expression vector pFASTBAC1 (Invitrogen) and subsequently inserted
into bacmid DNA by homologous recombination. Following generation of a viral stock,
Sf9 cells were superinfected. 48 hours later, the recombinant fusion protein was purified
from cell lysates using an anti-FLAG
™ M2 MAb affinity matrix (Sigma).
C. Immunization of Mice
[0245] 8 week old female BALB/c mice (IFFA CREDO) were immunized as described above in Example
1, subsection C.
D. Specific Serum titrations
[0246] Mice serum titrations were performed as described above in Example 1, subsection
D.
E. B cell/myeloma fusions
[0247] B cell extraction and cellular fusion were performed and analyzed as described above
in Example 9, subsection D.
F. Hybridoma Screening
[0248] Hybridoma screening was performed as described above in Example 1, subsection F.
G. Monoclonal antibody specificity
[0249] The specificity of the 7E3 monoclonal antibody was determined as described above
in Example 1, subsection G.
H. Cellular Assay 1
[0250] Monoclonal antibody was first purified from hybridoma cell supernatant using protein
G affinity chromatography.
[0251] Cellular Assay I was performed as described above in Example 1, subsection J.
I. Cellular Assay 2
[0252] Cellular Assay II was performed as described above in Example 1, subsection K.
J. 7E3 VH and VL sequences
[0253] 10
7 hybridoma cells were harvested and washed once with PBS before being resuspended
in 1 ml Trizol
™ reagent (Invitrogen). Total RNA was subsequently extracted according to the manufacturer's
guidelines. cDNA encoding the VH and VL from the 7E3 clone was generated by RT-PCR
with the mouse ScFv module (Amersham Biosciences) according to the manufacturer's
guidelines. Amplified products were cloned into the pGEM-T easy vector (Promega Corp.)
and sequenced using the T7 and SP6 primers.
[0254] The VH and VL cDNAs were subsequently cloned in mammalian expression vectors containing
the human IgG1 and human kappa constant regions respectively in order to express 7E3
as a chimeric MAb ("chimeric 7E3"). To produce recombinant chimeric MAb, HEK 293 cells
were plated in 6 well plates at a density of 2.5 x 10
5 cells/well in 2 ml culture medium containing 10 % FBS. 16 hours post-plating, cells
were transfected with 0.75 µg of the appropriate vector(s) using Fugene
™ reagent (Roche) according to the manufacturer's guidelines. 48 hours post-transfection,
supernatant was harvested and antibody was purified using protein G affinity chromatography.
Example 24: Generation of MAbs directed against the human TLR4/MD-2 complex
[0255] Mice immunized with CHO cells expressing surface TLR4/MD-2 were monitored for specific
serum titers. Those showing a response to TLR4/MD-2 were "hyperboosted" with HEK 293
TLR4/MD-2 transfectants. This strategy was chosen in order to minimize the response
to non-specific CHO cellular antigens, while simultaneously maximizing the TLR4/MD-2-specific
response. Screening by FACS of supernatants from hybridomas resulting from B cell/myeloma
fusions was performed on mock transfected vs. TLR4/MD-2 transfected CHO cells. Monoclonal
antibody from a specific clone, referred to herein as 7E3, demonstrated specific binding
to TLR4/MD-2 transfected CHO cells (Figure 21). 7E3 was found to have the IgG1 κ isotype,
as determined by FACS using the mouse Ig isotyping CBA kit (Beckton Dickenson).
Example 25: Neutralization of LPS activity on TLR4/MD-2 transfected HEK 293 cells
[0256] LPS is known to have ability to induce IL-8 production in HEK 293 cells transfected
with the TLR4/MD-2 complex. The ability of 7E3 to inhibit this IL-8 induction was
analyzed by pre-incubating cells with each antibody for 30 minutes prior to LPS administration.
Figure 22 shows that 7E3 inhibited the effects of LPS on HEK 293 cells, even at sub-microgram/ml
concentrations.
Example 26: Neutralization of LPS activity on human whole blood
[0257] The ability of 7E3 to inhibit LPS-induced IL-8 production in human whole blood was
tested. 7E3 neutralizing activity was tested in blood from 3 different donors using
a range of monoclonal antibody concentrations from 0.5 to 5 µg /ml. Figure 23 demonstrates
that 7E3 significantly reduced the level of IL-8 induced by LPS in all 3 donors, as
compared to an isotype matched control. 7E3 was found to be more potent than a previously
described α-TLR4 blocking monoclonal antibody (purchased from e-biosciences). (
See Shimazu et al. J. Exp. Med. 189: 1777-1782 (1999)). In some cases, 7E3 was found to be as potent as an α-CD14 blocking monoclonal
antibody that was also included in the study. (
See Kirkland et al. J.Biol. Chem. 268: 24818-24823(1993)). These results indicate that the neutralizing epitope recognized by 7E3 on transfected
HEK 293 cells is also exposed on the surface on cells in whole blood, and that 7E3
is potent enough to inhibit the activity of LPS in whole blood, even at concentrations
below 1 µg/ml.
Example 27: 7E3 specificity
[0258] In order to determine the specificity of the 7E3 monoclonal antibody, the fact that
7E3 does not recognize the rabbit ortholog of the TLR4/MD-2 complex (previously cloned)
was exploited. cDNAs for either rabbit or human TLR4 with N-terminal FLAG
™ epitope tag and MD-2 with C-terminal c-Myc and protein C epitope tags were transfected
in HEK 293 cells in the following combinations: (1) mock vector (2) human TLR4 alone
(3) human TLR4 and human MD-2 (4) rabbit TLR4 and rabbit MD-2; ; (5) human TLR4 and
rabbit MD-2; (6) rabbit TLR4 and human MD-2. Figure 24 shows FACS analysis of these
cells following antibody staining, which revealed that 7E3 recognized cells expressing
the human TLR4/MD-2 complex and a combination of human TLR4 and rabbit MD-2, but not
the rabbit TLR4/MD-2 complex nor a combination of rabbit TLR4 and human MD-2. These
results indicate that the epitope recognized by 7E3 is situated human TLR4 but the
presence of MD-2 is essential for MAb binding (Figure 24).
Example 28: 7E3 VH and VL sequences
[0259] VH and VL sequences from the 7E3 hybridoma clone were amplified from total RNA by
RT-PCR. Sequence analysis is shown in Figures 25A-25F.
[0260] The 7E3 antibody includes a heavy chain variable region (SEQ ID NO:32, Figure 25B)
encoded by the nucleic acid sequence of SEQ ID NO:31 shown in Figure 25A, and a light
chain variable region (SEQ ID NO:37, Figure 25E) encoded by the nucleic acid sequence
of SEQ ID NO:36 shown in Figure 25D. The amino acids encompassing the CDR as defined
by Chothia et al. 1989, E.A. Kabat et al., 1991 are highlighted in underlined and
italicized text in Figures 25B and 25E and shown in Figures 25C and 25F. The heavy
chain CDRs of the 7E3 antibody have the following sequences: TYNIGVG (SEQ ID NO:33);
HIWWNDNIYYNTVLKS (SEQ ID NO:34); and MAEGRYDAMDY (SEQ ID NO:35). The light chain CDRs
of the 7E3 antibody have the following sequences: RASQDITNYLN (SEQ ID NO:38); YTSKLHS
(SEQ ID NO:39); and QQGNTFPWT (SEQ ID NO:40).
Example 29: Chimeric 7E3 binds to hTLR4 hMD2 transfected CHO cells
[0261] In order to demonstrate the specificity of the cloned 7E3 VH and VL for the hTLR4/MD-2
complex, FACS analysis on hTLR4/MD-2 transfected CHO cells using the chimeric 7E3
MAb was performed (Figure 26). Specific binding of MAb at the indicated concentration
was detected using an APC-labeled goat-anti-human IgG (H+L) secondary antibody. An
irrelevant isotype-matched IgG1 MAb was used as a control.
Example 30: Chimeric 7E3 inhibits LPS-induced IL-8 production in hTLR4 hMD2 transfected
HEK 293 cells
[0262] In order to demonstrate the neutralizing capacity of the cloned 7E3 VH and VL for
LPS, the ability of 7E3 to inhibit LPS dependent IL-8 induction of hTLR4/MD-2 transfected
HEK 293 cells was tested as described above. Figure 27 shows that chimeric 7E3 inhibited
the effects of LPS on HEK 293 cells.
Example 31: Construction of TLR4/MD-2 fusion protein cDNA and cloning into pFASTBAC1.
[0263] The extracellular portion of TLR4 linked to MD-2 via a glycine serine (GGGGS
3) linker was assembled using PCR. FLAG and 6xHIS tags were included at the C-terminus
of MD-2 for detection and purification purposes. (Figure 28).
[0264] FIGS. 28A-C illustrate the construction of this TLR4/MD-2 fusion protein cDNA according
to the present invention. cDNA encoding the extracellular portion of human TLR4 (sTLR4)
was amplified by PCR, and unique NheI/XhoI restriction sites were introduced into
5' non-annealing primer extensions. The (GGGGS)
3 coding sequence and unique XhoI site was introduced into the 5' non-annealing extension
of the sense primer, and a unique HindIII site was introduced into the 5' non-annealing
extension of the antisense primer. (Panel A). Panel B depicts the sequential cloning
of the amplified sTLR4 and (GGGGS)
3 / MD-2 cDNAs into pFASTBAC1 between the unique XbaI and HindIII restriction site.
Panel C depicts a proposed protein product following expression of the sTLR4/MD-2
cDNA in Sf9 cells.
Example 32: Expression of the TLR4/MD-2 chimeric protein in SF9 cell lysates and supernatants
[0265] The cDNA cassette of Example 1 was cloned into the baculovirus expression vector
pFASTBAC1 (Invitrogen) and subsequently inserted into bacmid DNA by homologous recombination.
Following generation of a viral stock, Sf9 cells were superinfected and expression
of the TLR4/MD-2 fusion protein was analyzed in the cell lysate at 48 and 72 hours
post infection by Western blotting. (Figure 29).
[0266] Figure 29 demonstrates the expression of a TLR4/MD-2 chimeric protein of the invention
in Sf9 cell lysates and supernatants. Protein expression in the Sf9 cell lysates and
supernatants was detected by Western blotting using the anti-FLAG M2 antibody: Lane
1 depicts cleared lysate at 48 hours post infection; lane 2 depicts cleared lysate
at 72 hours post infection; lane 3 depicts cleared supernatant at 48 hours post infection;
lane 4 depicts cleared supernatant at 72 hours post infection; and lane 5 contains
a reference protein (FLAG tagged). The molecular weight marker sizes in Figure 29
are shown in KDa. The predicted molecular weight of TLR4/MD-2 chimeric protein is
approximately 90 KDa, and the appearance of probable degradation product occurs at
approximately 28KDa.
Example 33: Purification of the TLR4/MD-2 chimeric protein from infected SF9 cell
lysates
[0267] To purify the fusion protein, Sf9 cells were harvested 48 hours post superinfection
and lysed in 20 mM Tris pH7.4, 150 mM NaCl, 1% NP40 with COMPLETE
™ protease inhibitors (Roche) at a concentration of 5 volumes/gram cells. Following
a fifteen hour (15') incubation at 4 °C, lysates were cleared by centrifugation (4000
rpm) and filtration (0.22µm) and passed through an anti-FLAG M2 MAb affinity matrix
(Sigma). Unbound protein was removed from the matrix by successive washing with 20
mM Tris (pH 7.4), 150 mM NaCl, 1% NP40 and 20mM Tris (pH 7.4), 150 mM NaCl. Bound
protein was eluted from the column with 100 mM glycine (pH 2.75) and collected in
0.5 ml fractions. Fractions were rapidly brought to neutral pH through the addition
of 50 µl of 1M Tris (pH 9). Protein content was analyzed by western blotting (with
peroxidase conjugated anti-FLAG M2) and Coomassie brilliant blue staining. (Figure
30).
[0268] Figure 30 demonstrates the presence of purified TLR4/MD-2 chimeric protein in infected
Sf9 cell lysates. Protein in the cell lysates was detected by Coomassie brilliant
blue staining (FIG. 30, left panel) or Western blotting (FIG. 30, right panel) using
the anti-FLAG M2 antibody. Lanes 1-5 depict 0.5ml eluted fractions from the anti-FLAG
M2 affinity column.
Example 34: Inhibition of LPS induced IL-8 production using chimeric soluble TLR4/MD-2
[0269] Lipopolysaccharide (LPS) (15 ng/ml) was preincubated with a purified chimeric TLR4/MD-2
according to the present invention at varying concentrations and subsequently incubated
with TLR4/MD-2 transfected HEK 293 cells. Figure 31 is a graph depicting IL-8 production
in the cell culture medium 24 hours post treatment.
[0270] As seen in Figure 31, purified chimeric TLR4/MD-2 was shown to have an inhibitory
effect on the LPS-induced IL-8 production in TLR4/MD-2 transfected HEK cells, thereby
indicating that the purified TLR4/MD-2 protein of the invention was at least partially
conformationally correct.
Other Embodiments
[0271] While the invention has been described in conjunction with the detailed description
thereof, the foregoing description is intended to illustrate and not limit the scope
of the invention, which is defmed by the scope of the appended claims.