AU2007254697A1 - Synergistic inhibition of HIV-1 fusion and attachment, compositions and antibodies thereto-I - Google Patents

Description

28-12-'07 15:50 FROM- T-346 P006/071 F-936 Australian Patents Act 1990 Regulation 3,2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title "Synergistic inhibition of HIV-1 fusion and attachment, compositions and antibodies thereto-l" The following statement is a full description of this invention, including the best method of performing it known to us:- Q:'rB F MKRP ENERALI 2489940.-41yv f1iiB.4s COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:50 FROM- T-346 P07/71 F-936 SYNERGISTIC INHIBITION OF HIV-1 FUSION AND ATTACHMENT, o COMPOSITIONS AND ANTIBODIES THERETO-I 0 This is a divisional of Australian patent application O 5 No. 2004205164, the entire contents of which are incorporated herein by reference.

Th-s applicaticn claims priority of U.S. Serial No.

00 C] 09/212,793, filed December 16, 1998, and of U.E. Provisional Application No. 60/112,532, filed December 16, 1998, the contents of which is hereby incorporated by reference.

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j Throughout this application, various publications are IC referenced by Arabic numerals. Full citations for these r publications may be found at the end of the specification o immediately preceding the claims. The disclosure of these C] 15 publications is hereby incorporated by reference into this application to describe more fully the art to which this invention pertains.

Background of the Invention Human immunodeficiency virus type 1 (HIV-1) induces viral-tocell membrane fusion to gain entry into target cells 66). The first high-affinity interaction between the virion and the cell surface is the binding of the viral surface glycoprotein gpl20 to the CD4 antigen (13, 30, 41, 42). This in turn induces conformational changes in gpl20, which enable it to interact with one of several chemokine receptors (4, 21, 36). The CC-chemokine receptor CCR5 is the major coreceptor for macrophage-tropic (R5) strains, and plays a crucial role in the sexual transmission of HIV-1 5, 21, T cell line-tropic (X4) viruses use CXCR4 to enter target cells, and usually, but not always, emerge late in disease progression or as a consequence of virus propagation in tissue culture 5, 21, 36). Some primary HIV-1 isolates are dual-tropic (R5X4) since they can use both co-receptors, though not always with the same efficiency (11, 57).

Mutagenesis studies coupled with the resolution of the core crystal structure demonstrated that the co-receptorbinding site on gpl20 comprises several conserved residues (32, 53, COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:50a FROM- T-346 P008/071 F-936 O It. has been demonstrated that tyrosines and negatively CA charged residues in the amino-terminal domain (Nt) of Sare essential for gpl20 binding to the co-receptor, and for S1HIV-1 fusion and entry 18, 20, 22, 28, 31, 52, 54).

00 5 Residues in the extracellular loops (ECL) 1-3 of CCR5 were dispensable for co-receptor function, yet the CCR5 interdomain configuration had to be maintained for optimal viral fusion and entry This led to the conclusion either that \D gpl20 forms interactions with a diffuse surface on the ECLs, zi 10 or that the Nt is maintained in a functional conformation by C( bonds with residues in the ECLs. Studies with chimeric cooreceptors and anti-CCR5 monoclonal antibodies have also shown o the importance of the extracellular loops for viral entry 54, 64).

Molecules that specifically bind to CCR5 and CXCR4 and block interactions with their ligands are a powerful tool to further probe the structure/function relationships of the coreceptors. Characterizing such compounds could also assist in designing effective therapeutic agents that target coreceptor-mediated steps of viral entry. Inhibitors of or CXCR4 co-receptor function identified to date are diverse in nature and include small molecules, peptides, chemokines and their derivatives, and monoclonal antibodies (mAbs). The mechanisms of action of the small molecules that block entry by interfering with CXCR4 co-receptor function are not well understood (17, 49, 55, 68). One such inhibitor, the anionic small molecule AMD3100, depends on residues in ECL2 and the fourth trans-membrane (TM) domain of CXCR4 to inhibit viral entry, but it is not clear whether it does so by disrupting binding to CXCR4 or post-binding steps leading to membrane fusion (16, 34, 55). To date, no small molecules have been reported that specifically block CCR5-mediated HIV- 1 entry. Inhibition of HIV-1 entry by chemokines is mediated by at least two distinct mechanisms: blockage of the interaction and internalization of the chemokine/receptor complex 26, 59, 63). The variant AOP- RANTES also inhibits recycling of CCR5 to the cell surface COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:50 FROM- T-346 P009/071 F-936 -3- 56). Variants such as RANTES 9-68 and Met-kANTES only Cs prevent the gpl20/CCR5 interaction and do not down-regulate o CCR5 SDF-1 variants presumably act through a similar 0 mechanism to block viral entry mediated by CXCR4 (12, 27, OO 5 39). Only one anti-CXCR4 mAb, 12G5, has been characterized CN for its anti-viral properties. The efficiency .of 12G5 inhibition of viral entry has been reported to be both celland isolate-dependent (43, 58). This mAb binds to the ECL2 0D of CXCR4, but the mechanism by which it inhibits entry is unknown Few of the anti-CCR5 mAbs characterized to date Cl efficiently prevent HIV-1 entry (28, 64). Interestingly, mAbs whose epitopes lie in the Nt domain of CCRS, which contains o the gpl20-binding site, inhibit viral fusion and entry less efficiently than mAb 2D7, whose epitope lies in ECL2. 2D7 also antagonizes CC-chemokine activity (64).

A panel of six murine mAbs, designated PAB, PA9, PA10, PAIl, PAl2 and PA14 have been isolated and characterized. All six mAbs specifically bound to CCR5V cells but with different efficiencies that were cell type-dependent. Epitope mapping studies identified the residues that are important for mAb binding and also revealed information about the folding and interactions of the CCR5 extracellular domains. All mAbs inhibited HIV-1 fusion and entry, but there was no correlation between the ability of a mAb to inhibit fusion and -entry and its ability to inhibit binding of gpl20/sCD4 to CCR5' cells.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:51 FROM- T-346 P010/071 F-936 0 o Summarv of the Invention: ci 0 This invention provides a composition for inhibiting HIV-1 a infection comprising at least two compounds in synergistically effective amounts for inhibiting HIV-i 00 c- infection, wherein at least one of the compounds prevents the productive interaction between HIV-1 and an HIV-1 fusion coreceptor.

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SThis invention also provides a composition which inhibits fusion of HIV-1 or an HIV-1 envelope glycoprotein' cell to a target cell, comprising at least two compounds in o synergistically effective amounts for inhibiting fusion of Ci HIV-1 or an HIV-l envelope glycoprotein' cell to a target cell, wherein at least one of the compounds prevents the productive interaction between HIV-1 and HIV-1 fusion coreceptor.

This invention also provides a method of treating a subject afflicted with HIV-1 which comprises administering to the subject an effective dose of said compositions.

This invention also provides a method of preventing a subject from contracting HIV-1 which comprises administering to the subject an effective dose of said compositions.

This invention also provides an anti-CCRS monoclonal antibody selected from the group consisting of PA8, PA9, PA10, PAll, PA12, and PA14.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:51 FROM- T-346 P011/071 F-936 SBrief Descriptionaof the Figures: ci 0) Fiaure 1: RJ0Bnding of anti-CCR5 monoclonal antibodies to 00 5 cellss: Flow cytometry was used to detect CCR5 protein expression on the surface of L1.2-CCR5* cells and freshly isolated, PHA/IL-2-stimulated PBMC. Cells were NO incubated with saturating concentrations of each mAb, l~ 10 which were detected with a PE-labeled anti-mouse IgG reporter antibody. Results from a representative o experiment are shown. Results for each mAb are 0- expressed both in mean fluorescence intensities and in gated cells. Since PA8-PA12 and PAl4 are all of the IgG1 subclass, their m.f.i. are directly comparable. 2D7 is ah IgG2a.

Figure 2: CT values for different combinations of mAbs and viral inhibitors: Experiments like those described in the legend of Fig.

7 were performed for different combinations of viral entry inhibitors. Anti-CCR5 mAbs were tested in combination with each other, CC-chemokines, and CD4- IgG2, which inhibits HIV-1 attachment to target cells.

The PAll and PA12 concentration range was 0-250 Mg/ml; the 2D7 and PA14 concentration range was 0-25 pg/ml; the RANTES concentration range was 0-250 ng/ml; the CD4-IgG2 concentration range was 0-25 pg/ml. The concentrations of single-agents or their mixtures required to produce 50% and 90% inhibition of fusion or entry were quantitatively compared in a term known as the Combination Index (CI).

Figure 3 IC0 values for inhibition of cell-cell fusion, viral entry and pn 20/sCD4 binding by anti-CCRS mAbs: For comparative purposes we have summarized the IC 50 COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:51 FROM- T-346 P012/071l F-936 -6- 0 o values obtained in the different assays that the antimAbs were tested in. ICo values were only calculated for mAbs that could inhibit >90% of fusion, Sentry or binding.

00 Figurp 4 Epitope mapping of anti-CCR5 mAbs: Q A two color staining protocol was used to assess binding of mAbs to mutant CCR5 proteins, tagged at the i) 10 C-terminus with the HA peptide. HeLa cells expressing point mutants were incubated with saturating Sconcentrations of each mAb followed by detection with Ci a PE-labeled anti-mouse IgG. Cell surface co-receptor expression was measured by double-staining of the cells with a FITC labeled anti-HA mAb. The four grids correspond to the four extracellular domains of The first row of every grid indicates the amino acid sequence of the corresponding CCR5 extracellular domain. Binding of anti-CCR5 mAbs to the alanine mutant of each residue is expressed as a percentage of binding to wild-type CCR5, as described in Materials and Methods.

Fi ure Tnhibition of calcium mobilization into CCR5 cells by anti-CCRS mAbs: L1.2-CCR5' cells were loaded with Indo-lAM and stimulated sequentially with an anti-CCRS mAb or PBS, followed with RANTES Fluorescence changes were measured with a spectrofluorometer and the tracings are from a representative experiment. Calcium flux inhibition by PAl4 and 2D7 was tested for a wide range of mAb concentrations Results are plotted as inhibition of calcium influx (relative fluorescence in the presence of mAb relative fluorescence in the absence of mAb)] x 100%, and are means of values from three independent experiments.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:51 FROM- T-346 P013/071 F-936 -7- 0 Figure 6 C( Inhibition of CCR5 co-receptor ._functon by anti-CCRS SmAbs: 0 Inhibition of cell-cell fusion by anti-CCR5 mAbs was 00 5 tested in the RET assay 0-250pg/ml of PA8-PA12, or 0-25pg/ml of PAl4 or 2D7, were added to a mix of HeLa- Envj-_rr and PM1 cells, labeled with F18 and R18 respectively. Fluorescence RET was measured after 4h of N0 incubation. Results are mean values from three S 10 independent experiments and are expressed as inhibition of fusion RET in the presence of mAb o RET in the absence of mAb)] x 100%. Inhibition of C HIV-1 entry by anti-CCR5 mAbs was tested in a single round of replication luciferase based entry assay UB7-CD4-CCR5' cells were infected with NLluc'env reporter virus carrying the JR-FL envelope in the presence of 0-250sg/ml of PA8-PA12, or 0-25g/ml PA14 or 2D7. Luciferase activity (relative light units, was measured in cell lysates 72h postinfection. Results are from a representative experiment and are expressed as inhibition of entry in the presence of mAb r.l.u. in the absence of mAb)] x 100%. Binding of biotinylated gpl20, sCD4 and bgpl20-CD4 complexes to L1.2-CCR5* cells Strong binding is observed when gpl20 derived from the virus HIV-J1_- is complexed with an equimolar amount of sCD4. No binding is observed in the absence of sCD4 or for gpl20 derived from the X4 virus HIV-1 Background binding to CCR5- L1.2 cells has been subtracted from all curves. Inhibition of gpl20/sCD4 binding to L1.2- CCRS cells was tested in the presence of varying concentrations of each antibody Cells were preincubated in 96-well plates with an anti-CCRS mAb followed by an incubation with a saturating concen:ration of biotinylated gpl20/sCD4. Finally, binding of PE-labeled streptavidin to cells was measured using a fluorescence plate reader. Results are from a representative experiment and are expressed as COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:52 FROM- T-346 P014/071 F-936 -8o inhibition of gpl20/sCD4 binding in the c presence of mAb m.f.i. in the absence of mAb)] x 100%.

00 0p 5 Firure 7_ Synergistic inhibition of cell-cell fusion by PA12 and 2D7: Dose-response curves were obtained for the mAbs used NO individually and in combination. 0-50g/ml of PA12, 0t/ 10 25g/ml 2D7, or a combination of the two in a 2:1 ratio, were added to a mix of HeLa-EnvE-rL, and PM1 O cells, labeled with RIB and F18 respectively.

Ci Fluorescence RET was measured after 4 hours of incubation. Results are expressed as inhibition of fusion and are the means of values from three independent experiments. Data were analyzed using the median effect principle, which can be written f i/[1 (1) where f is the fraction affected/inhibited, c is concentration, K is the concentration of agent required to produce the median effect, and m is an empirical coefficient describing the shape of the dose-response curve. Equation is a generalized form of the equations describing Michaelis-Menton enzyme kinetics, Langmuir adsorption isotherms, and Henderson- Hasselbalch ionization equilibria, for which m 1. In the present case, K is equal to the ICso value. K and m were determined by curve-fitting the dose-response curves and Equation was rearranged to allow calculation of c for a given f. The best-fit parameters for K and c are 8.8mg/ml and 0.54 for PA12, 0.36pg/ml and 0.68 for 2D7, and 0.11g/ml and 1.1 for their combination. These curves are plotted and indicate a reasonable goodness-of-fit between experiment and theory.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:52 FROM- T-346 P015/071 F-936 -9- O Detailed Description of .the iinention: This invention provides a composition for inhibiting HIV-1 Sinfection comprising at leasc two compounds in 0 synergistically effective amounts for inhibiting HIV-1 00 5 infection, wherein at least one of the compounds prevents with the productive interaction between HIV-1 and an HIV-1 fusion co-receptor.

VO As used herein, "composition" means a mixture. The compositions include but are not limited to those suitable C for oral, rectal, intravaginal, topical, nasal, opthalmic, Sor parenteral administration to a subject. As used herein, C "parenteral" includes but is not limited to subcutaneous, intravenous, intramuscular, or intrasternal injections or infusion techniques.

As used herein, "HIV-1" means the human immunodeficiency virus type-1. HIV-1 includes but is not limited to extracellular virus particles and the forms of HIV-1 found in HIV-1 infected cells.

As used herein, "HIV- infection" means the introduction of HIV-1 genetic information into a target cell, such as by fusion of the target cell membrane with HIV-1 or an HIV-1 envelope glycoprotein cell. The target cell may be a bodily cell of a subject. In the preferred embodiment, the target cell is a bodily cell from a human subject.

As used herein, "inhibiting HIV-1 infection" means the reduction of the amount of HIV-1 genetic information introduced into a target cell population as compared to the amount that would be introduced without said composition.

As used herein, "compound" means a molecular entity, including but not limited to peptides, polypeptides, and other organic or inorganic molecules and combinations thereof.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:52 FROM- T-46 P016/0371 F-936 0 As used herein, "synergistically effective" means that the o combined effect of the compounds when used in combination is Sgreater than their additive effects when used individually.

0 C 5 As used herein, "productive interaction" means that the interaction of HIV-1 and the HIV-1 co-receptor would lead to the fusion of said HIV-1 or HIV-1 envelope glycoprotein' cell CO and the membrane bearing the co-receptor.

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As used herein, "prevents the productive interaction" means 1 that the amount of interaction is reduced as compared to the o amount that would occur without the compound. The

C

N interactions may be prevented by masking or altering interactive regions on the co-receptor or HIV-1 or by altering the expression, aggregation, conformation, or association state of the co-receptor.

As used herein, "HIV-1 fusion co-receptor" means a cellular receptor that mediates fusion between the target cell expressing the receptor and HIV-1 or an HIV-1 envelope glycoprotein- cell. HIV-1 fusion co-receptors include but are not limited to CCRS, CXCR4 and other chemokine receptors.

This invention also provides a composition which inhibits fusion of HIV-1 or an HIV-1 envelope glycoprotein' cell to a target cell, comprising at least two compounds in synergistically effective amounts for inhibiting fusion of HIV-1 or an HIV-1 envelope glycoprotein' cell to a target cell, wherein at least one of the compounds prevents the productive interaction between HIV-1 and an HIV-1 fusion coreceptor.

As used herein, "fusion" means the joining or union of the lipid bilayer membranes found on mammalian cells or viruses such as HIV-1. This process is distinguished from the attachment of HIV-I to a target cell. Attachment is mediated by the binding of the HIV-1 exterior glycoprotein to the human CD4 receptor, which is not a fusion co-receptor.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:53 FROM- T-346 P017/71 F-936 -11- O As used herein, "inhibits" means that the amount is reduced C as compared with the amount that would occur without the c composition.

00 5 As used herein, "target cell" means a cell capable of being C infected by or fusing with HIV-1 or HIV-1 infected cells.

As used herein, "chemokine" means a cytokine that can stimulate leukocyte movement. They may be characterized as either cys-cys or cys-X-cys depending on whether the two C amino terminal cysteine residues are immediately adjacent or Sseparated by one amino acid. It includes but is not limited oto RANTES, MIP-la, MIP-10, SDF-1 or another chemokine which blocks HIV-1 infection.

In one embodiment of the above compositions, the co-receptor is a chemokine receptor. In the preferred embodiment of the above compositions, the chemokine receptor is CCRS or CXCR4.

Several other chemokine and related receptors are known to function as HIV co-receptors including but not limited to CCR2, CCR3, CCRS, STRL33, GPR-15, CX3CR1 and APJ (69).

As used herein, "chemokine receptor" means a member of a homologous family of seven-transmembrane spanning cell surface proteins that bind chemokines.

As used herein, "CCRS" is a chemokine receptor which binds members of the C-C group of chemokines and whose amino acid sequence comprises that provided in Genbank Accession Number 1705896 and related polymorphic variants.

As used herein, "CXCR4" is a chemokine receptor which binds members of the C-X-C group of chemokines and whose amino acid sequence comprises that provided in Genbank Accession Number 400654 and related polymorphic variants.

In one embodiment of the above compositions, at least one of the compounds is a nonpeptidyl molecule. In one embodiment, COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:53 FROM- T-346 P018/71 F-936 -12- 0 o the nonpeptidyl molecule is the bicyclam compound AMD3100.

ci 0 1 6).

0 As used herein, "nonpeptidyl molecule" means a molecule that C 5 does not consist in its entirety of a linear sequence of amino acids linked by peptide bonds. A nonpeptidyl molecule may, however, contain one or more peptide bonds.

In one embodiment of the above compositions, at least one of 10 the compounds is an antibody. In one embodiment, the antibody is a monoclonal antibody. In another embodiment, the antibody o is a anti-chemokine receptor antibody. In one embodiment, the Ci antibody is an anti-CXCR4 antibody. In a further embodiment, the anti CXCR4 antibody is 12G5. In a preferred embodiment, the antibody is an anti-CCR5 antibody- The antiantibody includes but is not limited to PA8, PA9, PA11, PAl2, PA14 and 2D7. In this composition the compounds are in an appropriate ratio. The ratio ranges from 1:1 to 1000:1.

The monoclonal antibodies PA8, PA9, PA10, PAll, PA12 and PA14 were deposited pursuant to and in satisfaction of, the requirements of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure with the American Type Culture Collection (ATCC), 10801 University Boulevard, Manassas, Virginia 20110- 2209 on December 2, 1998 under the following Accession Nos.: ATCC Accession No. HB-12605 (PA8), ATCC Accession No. HB- 12606 (PA9), ATCC Accession No.HB-12607 (PA10), ATCC Accession No. HB-12608 (P11), ATCC Accession No. HB-12609 (PAl2) ATCC Accession No. HB-12610 (PA14).

In another embodiment of the above compositions, two or more of the compounds are antibodies. In one embodiment of the invention, the antibodies include but are not limited to PA8, PA9, PA10, PA11, PAl2, PA14 and 2D7. In this composition the antibodies are in an appropriate ratio. The ratio ranges from 1:1 to 50:1.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:53 FROM- T-346 P019/071 F-936 -13- O As used herein, "antibody" means an immunoglobulin molecule (C comprising two heavy chains and two light chains and which S grecognizes an antigen. The immunoglobulin molecule may derive 0 from any of the commonly known classes, including but not 00 5 limited to IgA, secretory IgA, IgG and IgM. IgG subclasses are also well known to those in the art and include but are not limited to human IgG1, IgG2, IgG3 and IgG4. It includes, by way of example, both naturally occurring and non-naturally \O occurring antibodies. Specifically, "antibody" includes polyclonal and monoclonal antibodies, and monovalent and C divalent fragments thereof. Furthermore, "antibody" includes Schimeric antibodies, wholly synthetic antibodies, single o chain antibodies, and fragments thereof. Optionally, an antibody can be labeled with a detectable marker. Detectable markers include, for example, radioactive or fluorescent markers. The antibody may be a human or nonhuman antibody.

The nonhuman antibody may be humanized by recombinant methods to reduce its immunogenicity in man. Methods for humanizing antibodies are known to those skilled in the art.

As used herein, "monoclonal antibody," also designated as mAb, is used to describe antibody molecules whose primary sequences are essentially identical and which exhibit the same antigenic specificity. Monoclonal antibodies may be produced by hybridoma, recombinant, transgenic or other techniques known to one skilled in the art.

As used herein, "anti-chemokine receptor antibody" means an antibody which recognizes and binds to an epitope on a chemokine receptor. As used herein, "anti-CCR5 antibody" means a monoclonal antibody which recognizes and binds to an epitope on the CCR5 chemokine.receptor.

As used herein, "appropriate ratio" means mass or molar ratios wherein the compounds are. synergistically effective.

In one embodiment of the above compositions, at least one compound is a chemokine or chemokine derivative. The COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:53 FROM- T-346 P020/71 F-936 -14o chemokines include but are not lim: .ed to RANTES, MIP-1Q, C] MXP-1P, SDF-1 or a combination thereof. In this composition, Sthe compounds are in an appropriate ratio. The chemokine 0 derivatives include but are not limited to Met-RANTES, AOP- 00 5 RANTES, RANTES 9-68, or a combination thereof.

ci As used herein, "chemokine derivative" means a chemically modified chemokine. The chemical modifications include but NO are not limited to amino acid substitutions, additions or 10 deletions, non-peptidyl additions or oxidations. One skilled C in the art will be able to make such derivatives.

C In another embodiment of the above compositions, at least one compound is an antibody and at least one compound is a chemokine or chemokine derivative. In this composition, the compounds are in an appropriate ratio. The ratio ranges from 100:1 to 1000:1.

In another embodiment of the above compositions, at least one compound binds to the gp41 subunit of the HIV-1 envelope glycoprotein. In one embodiment, at least one compound is the peptide inhibitor of HIV-1 entry In another embodiment of the above compositions, at least one of the compounds inhibits the attachment of HIV-1 to a target cell. In one embodiment, at least one compound binds CD4. In one embodiment, at least one compound is an HIV-1 envelope glycoprotein. In one embodiment, at least one compound is an anti-CD4 antibody. In one embodiment, at least one compound binds to the HIV-1 envelope glyoprotein. In one embodiment, at least one compound is an antibody to the HIV-1 envelope glycoprotein. In one embodiment, at least one compound is a CD4-based protein. In one embodiment, at least one compound is CD4-IgG2.

In another embodiment of the above compositions, at least one compound is an antibody and at least one compound binds to an HIV-1 envelope glycoprotein. In one embodiment, the COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:54 FROM- T-46 P021/71 F-936 O compound is a CD4-based protein. In one embodiment, the C( compound is CD4-IgG2. In this composition, the compounds are 0 in an appropriate ratio. The ratio ranges from 1:1 to 10:1.

0U 00 5 As used herein, "attachment" means the process that is C mediated by the binding of the HIV-1 envelope glycoprotein to the human CD4 receptor, which is not a fusion co-receptor.

As used herein, "CD4" means the mature, native, membrane- S 10 bound CD4 protein comprising a cytoplasmic domain, a C( hydrophobic transmembrane domain, and an extracellular domain o which binds to the HIV-1 gpl20 envelope glycoprotein.

0 As used herein, "HIV-1 envelope glycoprotein" means the HIV-1 encoded protein which comprises the gpl20 surface protein, the gp41 transmembrane protein and oligomers and precursors thereof.

As used herein, "CD4-based protein" means any protein comprising at least one sequence of amino acid residues corresponding to that portion of CD4 which is required for CD4 to form a complex with the HIV-1 gpl20 envelope glycoprotein.

As used herein, "CD4-IgG2" means a heterotetrameric CD4-human IgG2 fusion protein encoded by the expression vectors deposited under ATCC Accession Numbers 75193 and 75194.

In one embodiment of the above compositions at least one of the compounds comprises a polypeptide which binds to a epitope. In one embodiment, the epitope is located in the Nterminus, one of the three extracellular loop regions or a combination thereof. In one embodiment, the epitope is located in the N-terminus. The epitope can comprise N13 and Y15 in the N-terminus. The epitope can comprise comprises Q4 in the N-terminus. In another embodiment, the epitope includes residues in the N-terminus and second extracellular loop. The epitope can comprise D2, Y3, Q4,S7, PS and N13 in COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:54 FROM- T-346 P022/071 F-936 -16the N-terminus and Y176 and T177 in the second extracellular loop- The epitope can comprise D2, Y3, Q4, P8 and N13 in the N-terminus and Y176 and T177 in the second extracellular loop. The epitope can comprise D2 in the N-terminus and R168 and Y176 in the second extracellular loop. In one embodiment, the epitope is located in the second extra cellular loop. The epitope can comprise Q170 and K171 in the second extracellular loop. The epitope can comprise Q170 and E172 in the second extra cellular loop.

As used herein, the following standard abbreviations are used throughout the specification to indicate specific amino acids: A=ala-alanine N-asn=asparagine C-cys=cysteine E=glu=glutamic acid H=his=histidine L=leu=leucine M=met=methionine P=pro=proline T=thr-threonine Y tyr=tyrosine R=arg=arginine D-asp=aspartic acid Q=gln=glutamine G=gly=glycine I=ile=isoleucine K=lys=lysine F=phe=phenylalanine S=ser=serine w-trpntryptophan V=val-valine As used herein, "polypeptide" linked by a peptide bond.

means two or more amino acids As used herein, "epitope" means a portion of a molecule or molecules that forms a surface for binding antibodies or other compounds. The epitope may comprise contiguous or noncontiguous amino acids, carbohydrate or other nonpeptidyl moities or oligomer-specific surfaces.

As used herein, "N-terminus" means the sequence of amino acids spanning the initiating methionine and the first transmembrane region.

As used herein, "second extra cellular loop" means the COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:54 FROM- T-46 P023/071 F-936 -17o sequence of amino acids that span the fourth and fifth 0 transmembrane regions and are presented on the surface.

e In one embodiment of the above compositions at least one of 00 5 the compounds comprises a light chain of an antibody. In Ci another embodiment of the above compositions at least one of the compounds comprises a heavy chain of an antibody. In another embodiment of the above compositions at least one of the compounds comprises the Fab portion of an antibody. In

VO

4 10 another embodiment of the above compositions at least one of Ci the-compounds comprises the variable domain of an antibody- In another embodiment, the antibody is produced as a single o polypeptide or "single chain" antibody which comprises the heavy and light chain variable domains genetically linked via an intervening sequence of amino acids. In another embodiment of the above compositions at least one of the compounds comprises one or more CDR portions of an antibody.

As used herein, "heavy chain" means the larger polypeptide of an antibody molecule composed of one variable domain (VH) and three or four constant domains (CH1, CH2, CH3, and CH4), or fragments thereof.

As used herein, "light chain" means the smaller polypeptide of an antibody molecule composed of one variable domain (VL) and one constant domain or fragments thereof.

As used herein, "Fab" means a monovalent antigen binding fragment of an immunoglobulin that consists of one light chain and part of a heavy chain. It can be obtained by brief papain digestion or by recombinant methods.

As used herein, "F(ab')2 fragment" means a bivalent antigen binding fragment of an immunoglobulin that consists of both light chains and part of both heavy chains. It cen be obtained by brief pepsin digestion or recombinant methods.

As used herein, "CDR" or "complementarity determining region" COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:54 FROM- T-346 P024/071 F-936 -18o means a highly variable sequence of amino acids n the 0 variable domain of an antibody.

This invention provides the above compositions and a OO 5 pharmaceutically acceptable carrier. Pharmaceutically (c acceptable carriers are well known to those skilled in the art. Such pharmaceutically acceptable carriers may include but are not limited to aqueous or non-aqueous solutions, suspensions, and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils Cq such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, o alcoholic/aqueous solutions, emulsions or suspensions, saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's or fixed oils. Intravenous vehicles include fluid and nutrient replenishers, electrolyte replenishers such as those based on Ringer's dextrose, and the like. Preservatives and other additives may also be present, such as, for example, antimicrobials, antioxidants, chelating agents, inert gases and the like.

This invention provides a method of treating a subject afflicted with HIV-1 which comprises administering to the subject an effective dose of the above compositions.

As used herein, "subject" means any animal or artificially modified animal capable of becoming HIV-infected.

Artificially modified animals include, but are not limited to, SCID mice with human immune systems. The animals include but are not limited to mice, rats, dogs, guinea pigs, ferrets, rabbits, and primates. In the preferred embodiment, the subject is a human.

As used herein, "treating" means either slowing, stopping or reversing the progression of an HIV-1 disorder. In the preferred embodiment, "treating" means reversing the progression to the point of eliminating the disorder. As used COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:55 FROM- T-346 P025/071 F-936 -19o herein, "treating" alsc means the reduction of the number of o viral infections, reduction of the number of infectious viral O particles, reduction of the number of virally infected cells, or the amelioration of symptoms associated with HIV-1.

00 c- As used herein, "afflicted with HIV-1" means that the subject has at least one cell which has been infected by HIV-I.

ON As used herein, "administering" may be effected or performed

VO

10 using any of the methods known to one skilled in the art. The methods may comprise intravenous, intramuscular or subcutaneous means.

0 Ci The dose of the composition of the invention will vary depending on the subject and upon the particular route of administration used. Dosages can range from 0.1 to 100,000 pg/kg. Based upon the composition, the dose can be delivered continuously, such as by continuous pump, or at periodic intervals. For example, on one or more separate occasions.

Desired time intervals of multiple doses of a particular composition can be determined without undue experimentation by one skilled in the art.

As used herein, "effective dose" means an amount in sufficient quantities to either treat the subject or prevent the subject from becoming HIV-1 infected. A person of ordinary skill in the art can perform simple titration experiments to determine what amount is required to treat the subject.

This invention provides a method of preventing a subject from contracting HIV-1 which comprises administering to the subject an effective dose of the above compositions.

As used herein, "contracting HIV-1" means becoming infected with HIV-1, whose genetic information replicates in and/or incorporates into the host cells.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:55 FROM- T-46 P026/71 F-936 o This invention provides an anti-CCRS monoclonal antibody. The c antibody includes but is not limited to the following: PA8 S(ATCC Accession No. HB-12605), PA9 (ATCC Accession No. HB- S12606), PA10 (ATCC Accession No. HB-12607), PAll (ATCC 00 5 Accession No. HB-12608), PA12 (ATCC Accession No. HB-12609), and PA14 (ATCC Accession No. HB-12610).

This invention provides humanized forms of the above Santibodies.

V CAs used herein, "humanized" describes antibodies wherein Ssome, most or all of the amino acids outside the CDR regions C- are replaced with corresponding amino acids derived from human immunoglobulin molecules. In one embodiment of the humanized forms of the antibodies, some, most or all of the amino acids outside the CDR regions have been replaced with amino acids from human immunoglobulin molecules but where some, most or all amino acids within one or more CDR regions are unchanged. Small additions, deletions, insertions, substitutions or modifications of amino acids are permissible as long as they would not abrogate the ability of the antibody to bind a given antigen. Suitable human immunoglobulin molecules would include IgGI, IgG2, IgG3, IgG4, IgA and IgM molecules. A "humanized" antibody would retain a similar antigenic specificity as the original antibody, in the present invention, the ability to bind

CCRS.

This invention provides isolated nucleic acid molecules encoding these anti-CCR5 monoclonal antibodies or their humanized versions. The nucleic acid molecule can be RNA, DNA or cDNA. In one embodiment, the nucleic acid molecule encodes the light chain. In one embodiment, the nucleic acid molecule encodes the heavy chain. In one embodiment, the nucleic acid encodes both the heavy and light chains. In one embodiment, one or more nucleic acid molecules encode the Fab portion.

In one embodiment, one or more nucleic acid molecules encode CDR portions. In one embodiment, the nucleic acid molecule COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:55 FROM- T-346 P027/071 F-936 -21- 0 encodes the variable domain.

0 This invention will be better understood from the 0 Experimental Details which follow. However, one skilled in 00 5 the art will readily appreciate that the specific methods and C results discussed are merely illustrative of the invention as described more fully in the claims which follow thereafter.

0 cO

OD

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:56 FROM- T-346 P028/071 F-936 -22o Experimental Details: ci 0) A. Materials and Methods 0 00 c0 5 1) Reacents MAb 2D7 was purchased from Pharmingen (San Diego, CA) and CCand CXC-chemokines were obtained from R&D Systems C (Minneapolis, MN) CD4-IgG2 soluble CD4 and recombinant HIV-la,.FL gpl20, were produced by Progenics Pharmaceuticals, Inc. (59).

ci S2) Isolation and nurification of anti-CCR5 mAbs Ci L1.2-CCR54 cells (63) were incubated for 16h in the presence of 5mM sodium butyrate, which activates transcription from the cytomegalovirus (CMV) promoter that controls expression, resulting in a 10-fold increase in cell surface co-receptor density. Female Balb/c mice were immunized intraperitoneally with 10' L1.2-CCR5* cells at 3-week intervals, and administered an intravenous boost of 10' L1.2-

CCRS

4 cells three days prior to splenectomy. Splenocytes were fused with the Sp2/0 cell line. In a primary screen, supernatants from ten thousand hybridoma cultures were tested; one hundred and twenty of these inhibited HIV-1 envelope-mediated fusion between PM1 cells which naturally express CCR5 and CD4, and HeLa-Envf-n cells in a resonance energy transfer (RET) assay, as previously described (19, 38). Hybridomas that produced the most potently inhibitory supernatants and that also stained cells were sub-cloned by limiting dilution. Ascites fluids were prepared by Harlan Bioproducts for Science, Inc.

(Indianapolis, IN) from Balb/c mice that were injected with hybridomas producing the anti-CCR5 mAbs PAS, PA9, PA10, PAll, PAl2 and PAI4. The mAbs were individually purified to homogeneity by precipitation with ammonium sulfate followed by protein-A chromatography. All mAbs were resuspended in phosphate buffered saline (PBS) at a final concentration of Smg/ml.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:56 FROM- T-346 P029/071 F-936 -23- O 3) Fluorescence activated cell sorting (FACS) analvsis 0 and ecpitQop mapping of anti-CCRS mAbs O Flow cytometry was used to detect cell-surface reactivity of mAbs PA8-PA12 and PAl4 with CCR5. Sodium butyrate treated O 5 L1.2-CCR5* cells were incubated with 0.25gg of 00 C-i antibody, for 20min at 4*C in 0.1% sodium azide (NaN,) in 1l of Dulbedco's PBS (DPBS). The CCRS mAb 2D7 was used as a positive control, a non-specific murine IgG1 was used as a negative control. The cells were spun down, washed and incubated with phycoerythrin (PE)-labeled goat anti-mouse IgG S(Caltag, Burlingame, CA) diluted 1:100, under the same conditions as the first antibody incubation. Finally, cells o were analyzed by flow cytometry. PBMC were isolated and C stimulated as previously described (60) and stained using similar methods.

A similar procedure was used for epitope mapping of the anti- CCRS mAbs. A panel of seventy CCR5 point mutants has been described (20, 24, 52). The coding sequences of these proteins are sub-cloned into the pcDNA3.1 vector (Stratagene) from which transcription can be driven by a 5' T7-polymerase promoter. The CCR5 mutants carry a 9-residue hemaglutinin (HA) tag at the C-terminus for detection of protein in cell lysates or by flow cytometry. HeLa cells (2x106) were incubated for 5h with 2 0g/ml lipofectin and an equal amount of wild-type or mutant CCR5-expressing plasmid in OPTI-MEM (Life Technologies, Gaithersburg, MD). The cells were then infected for 12h with 2x107 p.f.u. of vTF7 (23) to boost expression, detached with 2mM ethylenediamine tetracetic acid (EDTA) in PBS and washed once with binding buffer

BSA,

0.05% NaN, in DPBS). Cells (Ix106) were surface labeled with mAbs as described in the previous paragraph, washed once with the incubation buffer and resuspended in iml of Ix FACSlyse in water (Becton Dickinson) for 30min at room temperature, to permeabilize the cell membranes. The cells were then spun down, washed with the incubation buffer and incubated for Ih at 37CC with 4pg/ml of a fluorescein isothiocyanate

(FITC)-

labeled mouse anti-HA mAb (BabCo, Richmond, CA) for COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:56 FROM- T-346 P030/071 F-936 -24- O intracellular labeling. Finally, cells were washed once with CA binding buffer and once with DPBS, resuspended in 1% formaldehyde in PBS and analyzed by flow cytometry. The extent of binding of a mAb to mutant CCR5 was determined by OO 5 the equation (mutant CCR5 PE m.f.i. wt CCR5 PE C (mutant CCR5 FITC m.f.i. wt CCRS FITC x100%. This normalizes mAb binding for mutant co-receptor expression levels.

l 10 4) c p20/asCD4-binding assay C gpl20 was biotinylated using NHS-biotin (Pierce, Rockford, o IL) according to the manufacturer's instructions, and C uncoupled biotin was removed by diafiltration. Sodium butyrate-treated L1.2-CCR5* cells were incubated with varying dilutions of an equimolar mixture of sCD4 and biotinylated or 1.25g/ml of sCD4 and 2.5g/ml of biotinylated in the presence of varying concentrations of mAbs PAS-PA12, PAl4, 2D7 or a non-specific murine IgG1, for lh at room temperature in 0.1% NaN 3 in DPBS. Cells were washed with the incubation buffer and incubated with streptavidin-PE (Becton Dickinson) diluted 1:50, for lh at room temperature. Finally, cells were washed with binding buffer and analyzed using a fluorescence plate reader (Perspective Biosystems, Pramingham, MA) Inhibition of envelope-mediated cel1-cell fusion and HIV-1 entry by anti-CCRS mAbs HIV-1 envelope-mediated fusion between HeLa-Env_,L' and PM1 cells was detected using the RET assay. Equal numbers (2x10 4 of fluorescein octadecyl ester (F1B)-labeled envelopeexpressing cells and octadecyl rhodamine (R18)-labeled PM1 cells were plated in 96-well plates in 15% fetal calf serum in DPBS and incubated for 4h at 37°C in the presence of varying concentrations of the anti-CCR5 mAbs, PA8-PA12, PAl4, 2D7 or a non-specific murine IgG1. Fluorescence RET was measured with a Cytofluor plate-reader (PerSeptive Biosystems) and RET was determined as previously described (38).

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:56 FROM- T-346 P031/071 F-936 O NLluc*env viruses complemented in trans by envelope glycoproteins from JR-FL or Gun-i were produced as previously described U87MG-CD4CCR5* cells (14) were infected with 0 chimeric, reporter viruses containing 50-100ng/ml p24 in the 00 5 presence of varying concentrations of the individual mAbs.

After 2h at 37C, virus-containing media were replaced by fresh, mAb-containing media. Fresh media, without antibodies, were added again after 12 hours. After a total of 72h, 100l NO of lysis buffer (Promega) were added to the cells and luciferase activity was measured as described The inhibition of HIV-1 infection is defined as [l-(r.l.u o in the presence of antibody r.l.u in the absence of C antibody)] x 100%.

6) Calcium signaling assays The fluorochrome Indo-1AM (Molecular Probes, Eugene, OR) was added to sodium butyrate treated L1.2-CCR5* cells at a final concentration of 5pM. After incubation at 37°C for 30min, the cells were washed once and resuspended in Hank's buffered saline. Cells were stimulated sequentially with an anti-CCRS mAb or PBS, followed 60s later with RANTES. MAbs PA8-PAl2 and PA14 were used at a concentration of 100g/ml, 2D7 at 20pg/ml and RANTES at 250ng/ml. Calcium flux inhibition by PA14 and 2D7 was also tested for a wide range of mAb concentrations, ranging from 0-100pg/ml. Intracellular calcium levels were monitored using a Perkin-Elmer fluorescence spectrophotometer by measuring the ratio of fluorescence emissions at 402nm (bound dye) and 486nm (free dye) following excitation at 358nm.

B. Results and Discussion 1) Isolatino an.i-CCR5 monoclonal antibhodes PAS. PA9, PA11, PAl2 and PA14 It was found that peptides corresponding to the extracellular domains of CCR5 are inefficient at raising specific, hightiter antibody responses against the native, cell surface COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:57 FROM- T-;346 P032/071 F-936 -26o receptor (50. Balb/C mice were immunized, therefore, with L1.2-CCR5' cells and hybridoma culture supernatants were tested for their ability to inhibit JR-FL envelope-mediated 0 membrane fusion with CD4 4 CCR5 PM1 cells in the RET assay 00 5 (19, 38). Even though well over a hundred supernatants inhibited cell-cell fusion by only six designated PAS, PA9, PA10, PAll, PA12 and PA14 specifically and intensely stained L1.2-CCR5 but not the parental L1.2 cells, NO as demonstrated by flow cytometry (data not shown). Based on previous experience, it was assumed that the other mAbs ^C capable of inhibiting cell-cell fusion were probably directed Sagainst cell surface adhesion molecules such as LFA-1 (37).

O Hybridomas PA8-PA12 and PA14 were determined by isotyping ELISA (Cappell, Durham, NC) to secrete IgGI mAbs. Ascites fluids were prepared from Balb/C mice that were injected with the six hybridomas and the IgG1 fractions were purified. PAS, PA9, PAll, PAl2 and PA14 exhibited distinct isoelectric focussing profiles, whereas PA10 had a very similar profile to that of PA9 and therefore may be a second isolate of the same mAb (data not shown).

2) MAb binding to CCR5+ cells None of the purified anti-CCR5 mAbs stained the parental L1.2 cell line (data not shown). However, mAbs PA9-PA12 and PA14 stained and PA8 stained of L1.2-CCR5 4 cells as determined by flow cytometry, showing they recognized (Table The anti-CCR5 mAb 2D7, which was a positive control in our experiments, also stained >90% of L1.2-CCR5* cells. PA8-PA12 and PAl4 are all IgG1, and react equally well with a goat anti-mouse IgG, whereas 2D7 is an IgG2a and may react differently with the reporter antibody. Only mean fluorescence intensities measured with mAbs PA8-PA12 and PAl4 therefore are directly comparable. The rank order of mean fluorescence intensities was PA12~ PAll> (2D7=) PA14- PAD10 PA9> PA8. The difference between PA12 m.f.i. and PA8 m.f.i. was three-fold. Differences in staining intensity between PA8 and the other mAbs remained constant over a wide range of concentrations (data not shown) and COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:57 FROM- T-346 P033/071 F-936 -27- O probably do not correspond to differences in mAb affinities C9 for CCR5. This implies that PA8 interacts only with a subset Sof CCR5 molecules present on the surface of L1.2-CCR5' cells.

00 5 Compared with L1.2-CCR5+ cells, mitogen-stimulated

PBMC

exhibited different patterns of staining by the mAbs. 2D7 and PA14 stained PAll and PA12 stained 0> PA8, PAS and PA10 stained of PBMC (Table The mean \0 fluorescence intensities of the stained PBMC were about tenfold lower than those obtained with LI.2-CCR5' cells for each C( mAb; their rank order was (2D7>) PAl4> PA12" PA11" PA10~ PA9~ PA8. Again, this differed somewhat from the order of Sreactivities observed on CCR5 transfectants. The difference between PA9 m.f.i. and PA14 m.f.i. was seven-fold. Other groups have observed similar differences in the ability of mAbs to stain stable, CCR5' cell lines versus PBMC This may be due to cell-specific differences in conformation, post-translational modification or oligomerization. Alternatively, association with other cell surface molecules may differ between cells. Since an obvious choice for such a molecule would be the CD4 cell surface antigen, which is absent from L1.2-CCR5 cells and present on PBMCs, we also tested the ability PAS-PA12, PA14 and 2D7 to stain HeLa cells transiently expressing CCR5 alone or with CD4. No differences were observed in the ability of any of the mAbs to stain cell surface CCR5 in the presence of CD4 (data not shown). If there is an association between these two proteins, it does not involve epitopes recognized by the mAbs available to us. Alternatively, an association between CCR5 and CD4 might only occur on primary lymphocytes.

3) Epjitope mapping of the mAbs using CCR5 alanine mutants None of the antibodies were able to detect reduced and denatured CCR5 protein by Western blotting indicating that they recognize conformationally sensitive epitopes (data not shown MAb epitope mapping studies were performed using a panel of seventy alanine point mutants of residues in the Nt and ECLs of CCR5. HeLa cells were lipofected with mutant or COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:57 FROM- T-46 P034/71 F-936 -28- O wild type CCR5 coding sequences appended with C-terminal HA (C tags, and infected with vTF7 (23) to boost co-receptor expression. The cells were then incubated with the 0 mAbs and their binding was revealed by a PE-labeled goat 00 5 anti-mouse IgG. A second, intracellular stain was performed with a FITC-labeled anti-HA mAb (BabCo). This internal control allowed us to directly normalize staining by the anti-CCR5 mAbs for mutant co-receptor expression levels on NO the cell surface. Hence, mAb binding to each mutant is S 10 expressed as a percentage of binding to wild-type CCRS C (Figure 1).

0 Certain point mutations reduced the binding of all of the antibodies to CCR5 by In general, PA8-PA12 were the most affected, PA14 and 2D7 the least affected by this class of mutants, which included the cysteine pair C101A and C178A, the Nt mutants Y10A, D11A, K25A, the ECLI mutant D95A, the ECL2 mutants K171A/E172A, Q188A, K191A/N192A, and the ECL3 mutants F263A and F264A (Fig. One interpretation is that these residues are not part of the mAb epitopes per se, but that changing them to alanines causes conformational perturbations that have a common effect on binding of all mAbs. We assumed that if a mutation lowered binding of an individual mAb by and did not also lower binding of most of the other antibodies, the residue was probably a direct contributor to the epitope recognized by the mAb.

Using these stringent guidelines, it was concluded that the seven anti-CCR5 mAbs recognize overlapping but distinct epitopes (Pig. MAb PA8 binding to CCR5 depended on N13 and Y15 in the Nt. MAb PA9 and PA10 required D2, Y3, Q4, P8 and N13 in the Nt, and Y176 and T177 in ECL2. MAb PA9 also required 57 in the Nt. MAb PAll and PAl2 binding depended on Q4 in the Nt. PAl4 required D2 in the Nt, and R168 and Y176 in ECL2. Finally, mAb 2D7 required Q170 and K171/E172 in ECL2 in order to bind to 4) Chemokine .iqnaling in the presence of anti-CCR5 mAbs Chemokine receptor-binding agents can be antagonists or, more COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:58 FROM- T-346 P035/071 F-936 -29- O rarely, agonists of receptor-mediated intracellular Cq signaling. Alternatively, they could have no effect on 0 signaling. CCRS is able to bind three CC-chemokines, RANTES, 0 MIP-la and MIP-15, and transduce a signal that modulates 00 5 cytosolic calcium levels. We therefore tested the C' agonist/antagonist activity of various concentrations of mAbs PA8-PA12, PA14 and 2D7. Changes in intracellular calcium concentrations, (Ca2+)i, were measured in Indo-l-loaded L1.2- CCR5* cells. None of the mAbs stimulated a change in (Ca2*)i, indicating that they are not agonists for CCR5. PA8-PA12 were Ci also unable to inhibit Ca 2 fluxes induced by RANTES (Fig.2a o- and data not shown), even at concentrations as high as S100g/ml, showing they are not antagonists either. These concentrations provide saturating binding of the mAbs to L1.2-CCR5' cells, as shown by flow cytometry and the gpl20/CCR5 binding assay (Fig. 3d and data not shown). MAbs PA14 and 2D7, however, blocked calcium mobilization induced by RANTES, although with different potencies (Fig.2a, The ICso for PA14 calcium influx inhibition was 50pg/ml, which was approximately 8-fold higher than the IC 50 for 2D7 (Fig.

2b). RANTES-, MIP-la- and MIP-1P-induced calcium fluxes were each inhibited by similar concentrations of PA14 (data not shown). None of the mAbs affected SDF-l-induced calcium mobilization in Ll.2-CCR5 cells, which endogenously express CXCR4 (data not shown). Finally, neither mAbs nor CCchemokines affected cytosolic calcium levels in parental L1.2 cells (data not shown).

Inhibition of CCR5 co-receptor function by the mAbs MAbs PA8-PA12 and PA14 were initially selected on the basis of their ability to inhibit HIV-1 envelope-mediated cell-cell fusion. This activity was confirmed and quantified for the purified mAbs. As expected, all six mAbs, as well as mAb 2D7, blocked fusion between CD4CCR5' PM1 cells and HeLa-Env._-rL cells in the RET assay. The rank order of potency was 2D7~ PA14> PAl2> PAll> PA10- PA9 PA8 (Fig. 3a). IC0 values for PAl4 and 2D7 were 1.7pg/ml and 1.6pg/ml respectively, for PAll and PA12 these were 25.Sg/ml and 10.Opg/ml respectively COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:58 FROM- T-346 P036/071 F-936 o (Table 3) PA8, PA9 and PA10 inhibited fusion by only 10-15%

C

at 300pg/ml. None of the mAbs affected fusion between PM1 Scells and HeLa-EnvA' cells, which express the full length envelope protein from an X4 virus (data not shown).

00 The ability of the different anti-CCR5 mAbs to inhibit entry of a prototypic R5 virus, JR-FL, and a R5X4 virus, Gun-1, in a single-round of replication, luciferase-based entry assay NO was also tested. The rank order of potency in the entry assay I) 10 was similar to the one determined in the cell-cell fusion C' assay (Fig. 3b). A >50% inhibition of JR-FL or Gun-i entry o with PAB-PA11 was unable to be obtained. The ICo value for 0 PA12 was 2.5 pg/ml. However, inhibition of entry by >60% with this mAb was unable to be obtained. The IC, values for PA14 and 2D7 inhibition of JR-FL entry were determined to be 0.024 and 0.026 pg/ml respectively (Table and were lower then those obtained in the fusion assay. Entry of dualtropic Gun-1 was 2-3-fold more sensitive to inhibition by mAbs than JR-FL entry (data not shown).

Anti-co-receptor mAbs might inhibit envelope-mediated fusion either by directly affecting the gpl20/CCR5 interaction or by impeding post-binding steps involved in the formation of an active fusion complex. To determine the mechanism of inhibition cf viral fusion and entry by PA8-PA12 and PA14, the ability of the different mAbs to block the gpl20/CCR5 interaction was tested. For this an assay that detects binding to L1.2-CCR5' cells of biotinylated HIV-R1,,_ complexed with sCD4 was used. No binding of .biotinylated gpl20 was observed in the absence of sCD4 or CCR5, or when

HIV-

1 gpl23 was used (Fig. 3c).

With the exception of PA8, all mAbs abrogated gpl20/sCD4 binding to L1.2-CCR5* (Fig. 3d). Inhibition by PAB saturated at which concurs with flow cytometry data (Table 1) in suggesting that this mAb binds only to a subset of molecules on L1.2-CCR5' cells. MAbs PA9, PA10, PA11 and PA12 inhibited binding with ICso values of 0.24, 0.13, 0.33, 0.24 COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:58 FROM- T-346 P07/71 F-936 -31- Spg/ml respectively (Table 3 Surprisingly, mAbs PA14 and 2D7

C

were the two least efficient inhibitors of gpl20/sCD4 O binding, with IC 0 s values of 1.58 and 1.38 pg/ml respectively 0 (Table Therefore, there was no correlation between the 0 0 5 ability of a mAb to inhibit gpl20/CD4/CCR5-mediated membrane fusion and entry and its ability to block gpl20/sCD4 binding to the co-receptor.

1- NO 6) Synergistic inhibition of HIV-1 fusion by combinations I/ 10 of anti-CCR5 mAhs and other viral entry inhibitors 0 Co-receptor-specific agents may act at multiple stages of the CA entry process and exhibit non-additive effects when used in combination. From a clinical perspective, it is important to determine the interactions of co-receptor-specific drug candidates with endogenous chemokines, which may afford some level of protection against disease progression. CCR5 mAbs were therefore tested in combination with each other or with RANTES, or with CD4-IgG2, which binds to HIV-1 gpl20 to inhibit attachment to target cells. Dose-response curves were obtained for the agents used individually and in combination in viral fusion and entry assays. Data were analyzed using the median effect principle The concentrations of single-agents or their mixtures required to produce a given effect were quantitatively compared in a term known as the Combination Index A CI value greater than 1 indicates antagonism, CI 1 indicates an additive effect, and CI 1 indicates a synergistic effect wherein the presence of one agent enhances the effect of another.

Combinations of PA12 and 2D7 were the most potently synergistic, with CI values ranging between 0.02 and 0.29, depending on the ratio of the antibodies (Fig. 4 and Table The degree of synergy is known to vary with the stoichiometry of the agents. The viral entry and fusion assays were generally consistent in identifying mAb combinations that are highly synergistic, PAl2 and 2D7; moderately synergistic, PA12 and PA14; additive, PAll and COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:59 FROM- T-346 P038/071 F-936 -32o PA12; and weakly antagonistic, PA14 and 2D7. The lack of synergy between PA14 and 2D7 is not surprising given that Sthese mAbs cross-compete for binding to CCR5 cells as 0 determined by flow cytometry (data not shown). The 00 5 observation of an additive effect of PAll and PA12 may be an indication that these mAbs bind to slightly different epitopes in CCR5, while sharing a dependency on residue Q4 in the Nt.

The ability of mAbs PA12, PA14 and 2D7 to synergize with RANTES in blocking cell-cell fusion was also tested. PA12 and SRANTES combinations exhibited moderate synergy (Table 2).

Ci PA14 and 2D7 exhibited no synergy with RANTES, which is consistent with these mAbs being inhibitory of RANTES binding and signaling (Fig. 2a, Finally, we tested synergy between mAbs PA12, PA14, 2D7 and CD4-IgG2, which interacts with gpl20. We observed moderate synergy between PA12 and CD4-IgG2 but no synergy between PA14 or 2D7 and CD4-IgG2 (Table 2).

Exerimental Discussion Six murine anti-CCRS IgGI mAbs were isolated and characterized. Whereas PA8, PA9, PAll, PAl2 and PA14 are distinct molecular species, PA9 and PA0 are indistinguishable by the analyses and therefore are probably the same mAb. All of the mAbs that were isolated recognize complex conformational epitopes, as is,,often the case with mAbs raised against native, cell surface proteins. Epitope mapping was performed for all mAbs using a panel of alanine point mutants. Residues that affected binding of all mAbs similarly were assumed to cause conformational perturbations in the co-receptor and not to constitute part of the mAb epitopes. Only two such residues, Y10 and D11, have been shown to affect HIV-1 entry (20, 52). The PA8, PAll and PA12 epitopes are located exclusively in the Nt domain.

Consistent with this result, PA8 was able to bind a biotinylated Nt peptide, containing residues D2 through R31, in an ELISA (data not shown). However, PAll and PAl2, whose COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:59 FROM- T-346 P039/071 F-936 -33o binding strongly depended only on Q4, did not bind the Nt (C peptide in solution (data not shown) One possibility is that Sthe Nt peptide does not assume the proper conformation for C recognition by PAll and PA12, whereas PA8 binding may be less 00 5 conformation-dependent. Alternatively, PA1 and PA12 might interact with residues that we have not mutated, or form weak bonds with amino acids located in other domains of CCR5, or bind peptide backbone atoms whose presentation may be sO unchanged by mutagenesis. Antibodies PA9, PAl0 and PA14 10 recognized epitopes that included residues in both the Nt and C( ECL2 domains of CCR5, whereas the 2D7 epitope was located o exclusively in ECL2.

The PA14 epitope comprises both D2 in the Nt and R168 in ECL2 indicating that these two residues are proximal to one another within the context of a mAb footprint. They may even directly interact with one another through their opposite charges.

MAbs PA8-PA12 and PA14 stained CCR5 cells with different intensities and in a cell type-dependent manner. All mAbs except PA8 stained >90% L.2-CCR5* cells, the highest mean fluorescence intensity being observed with PAll and PAl2.

However, PA14 and 2D7 stained the highest percentage of PBMC and also yielded the highest mean fluorescence intensities on these cells. Hill et al. (28) have recently characterized a panel of anti-CCR5 mAbs that similarly stained transfected cells, but only two of eight stained PBMC, and none stained primary monocytes. A low affinity for CCR5 probably accounted for the non-reactivity of two of the mAbs with primary cells, but this was unlikely to be the explanation for the failure of the other four to react. In our mAb panel, we observe the most intense staining of PBMC by mAbs 2D7 and PA14 that have epitopes located entirely or partially in the first ten residues of ECL2. Hill et al. report, however, that mAbs specific for the Nt and ECL1 stain PBMCs, while mAbs to ECL2 and ECL3 do not stain PBMC, so a consistent pattern of reactivity has not been identified. One explanation for cell COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:59 FROM- T-346 P040/071 F-936 1-34- O type-specific staining by mAbs would be that activated PBMCs (and monocytes) secrete CC-chemokines that bind to cell surface CCRE, masking some mAb epitopes. Iowever, one would Sexpect this to be especially true for PA14 and 2D7, which are 0 0 5 antagonists of chemokine-induced calcium mobilization and presumably compete with CC-chemokines for binding to CCRS.

Yet these mAbs stain PBMC the most intensely. Alternatively, C differential CCR5 epitope exposure may reflect cell typespecific receptor oligomerization, association with other V 10 cell-surface molecules, or different post-translational modifications such as glycosylation. We have shown that o differences in mAb binding probably do not reflect cell type- Ci specific differences in CD4/CCR5 interactions.

MAbs PA8-PA12 did not inhibit CC-chemokine induced calcium mobilization in CCR5 cells, nor did they mediate signaling through CCR5. MAbs 2D7 and PA14 were inhibitors of CCchemokine induced calcium mobilization, but 2D7 was almost an order of magnitude more potent than PA14. This may be because the PA14 epitope overlaps less with the CC-chemokine binding domain on CCR5 than the 2D7 epitope. All of the mAbs also blocked HIV-1 entry and envelope-mediated membrane fusion, but inhibition of cell-cell fusion required in some cases almost two orders of magnitude more antibody than what was needed to block viral entry. Presumably, more gpl20/CD4/CCR5 interactions as well as interactions between adhesion molecules are established and act cooperatively during cell-cell fusion, compared to virus-cell fusion, making it more difficult to inhibit. This is commonly observed with antibodies to LFA-1 or to the HIV-1 envelope glycoprotein (45, 51). PA8, PA9 and PA10 were unable to block cell-cell fusion by >15% and viral entry by even at the highest antibody concentrations. However, >90% inhibition of fusion could be attained with PAll, PAl2 and PA14, and inhibition of entry could be attained with PA14. The most potent of the six mAbs in blocking fusion and entry was PA14, which was as effective as 2D7. Surprisingly, PA14 and 2D7 were among the least potent inhibitors of gpl20/sCD4 binding COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 15:59 FROM- T-346 P041/071 F-936 O to L1.2-CCR5' cells, whereas PA9-PA12 blocked with similar C( potencies, and PA8 was unable to block >40% of gpl20/sCD4 0 binding. These observations raise questions about the nature Sof the CCR5 molecules presented on different cells and about 00 5 the mechanisms of inhibition of viral fusion and entry. It C may be that CCRS on L1.2 cells, used in the mAb and binding assays, is not in an identical conformation to l^ on PBMC, used in the mAb-binding assay, or to CCR5 on PM1 and \D U87MG cells used in the fusion and entry assays.

C The low staining of PBMC and the partial inhibition of fusion Sand entry by some of our mAbs indicate that they are only o able to bind to a subset of CCR5 molecules expressed on primary lymphocytes, PM1 and U87MG-CD4'CCR5' cell lines.. Yet, other than PA8, all mAbs are able to stain >90% L1.2-CCR5 cells and to completely block binding of the gpl20/sCD4 complex to these cells. At least one difference between LI.2and the other cells that we have used is the density of co-receptor protein on the cell surface. Indeed, we estimate that the L1I2-CCR5* cells express 10- to 100-fold more cell surface co-receptor than PM1 and U87MG-CD4'CCR5 4 cells. But when HeLa cells are engineered to transiently express as much co-receptor as the L1.2-CCR5* cell line, we are still unable to detect gpl20/sCD4 binding to them (data not shown). Overexpression of CCR5 on L1.2, along with other cell-specific factors therefore, might favor a co-receptor conformation that prominently exposes the Nt, making it more accessible to both mAbs and gpl20. Such a conformation might be induced by receptor oligomerization, by diminished or altered associations with cell surface proteins or by receptor interactions with G proteins (25, 62). Do multiple conformations of CCR5 co-exist on the cell surface, and are they all permissive for viral entry? The patterns of mAb reactivity would suggest so, since HIV-1 entry and fusion can occur, albeit at reduced levels, in the presence of mAb concentrations that saturate epitopes required for binding to L1.2-CCR5+ cells. We favor the hypothesis that the co-receptor molecules present on L1.2-CCR5" cells possess one COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 16:00 FROM- T-46 P042/071 F-936 S-36- SHIV-1 entry-competent conformation whereas CCRS mole:ules on PBMC, PM1 and CCRS' U87MG exist in multiple, entry-competent Sstates that display different mAb reactivities. Whereas PA14 and 2D7 may recognize all conformations, other mAbs may not.

00 5 Why L1.2 cells are conducive to a particular fusion-competent conformation remains to be determined.

It has recently been demonstrated that the NO domain lies in the first twenty residues of the CCRS Nt domain. MAbs to the gpl20-binding domain on ,CCR5 potently Ci block this interaction but are not nearly as efficient at o inhibiting HIV-1 fusion and entry into target cells as PA14 Cq and 2D7, whose epitopes lie outside this region. PA14 recognizes the tip of the Nt and residues in ECL2, whereas the 2D7 epitope is located exclusively in ECL2. At the mechanism of action of these mAbs can only be speculated. It may be that their binding to the first few residues of ECL2 induces conformational changes in the co-receptor that prevent membrane fusion. Alternatively, obstruction of ECL2 epitopes might impede co-receptor oligomerization and the formation of a fusion-competent protein complex. Yet another possibility is that residues in ECL2 face the inside of the fusion pore and binding of the mAbs impedes gp41 from inserting the fusion peptide into the plasma membrane. In contrast, mAbs PA8-PA12 probably inhibit fusion and entry only by directly competing for binding with gpl20/CD4 complexes. We do not know if parameters other than epitope exposure and affinity for CCR5 determine the efficacy of viral entry inhibition by these mAbs. It is unclear why inhibiting steps subsequent to the interaction would be more efficient than directly blocking that interaction. One way to explain this would be to assume that the off rate of gpl20 binding to CCR5 is much lower than the on rate of mAb binding to CCR5, Thus, every time a mAb detaches itself from a co-receptor molecule, a virionassociated gpl20 molecule replaces it in a quasi-irreversible fashion since this interaction leads to membrane fusion.

COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 16:00 FROM- T-346 P043/071 F-936 -37- O Synergy between combinations of anti-CCR5 mAbs is probably (C a result of their interactions with distinct epitopes that o are involved in inter-dependent, consecutive steps of HIV-1 C entry. The degree of synergy observed between PA12 and 2D7 00 5 (CI<O.1 under many circumstances) is extraordinary since CI values <0.2 are rarely observed for combinations of anti-HIV- 1 antibodies (33, 35, 61), reverse transcriptase inhibitors or protease inhibitors Because of its potency, \O the PA12:2D7 combination was examined in multiple assay formats and concentration ratios, for which consistently high CA levels of synergy were observed. Moderate synergy was 0 observed for PA12 combined with PA14. We also observed Smoderate synergy between PA12 and CD4-IgG2. The CD4/gpl20 complex is metastable and if it is unable to interact with a co-receptor, decays into a non-fusogenic state .(45-48) Since PA12 directly blocks the gpl20-binding site on its presence may shift the equilibrium towards inactivation" of the gpl20/CD4 complex. This would explain why we observe synergy between CD4-IgG2 and mAb PA12 with respect to inhibition of fusion and entry. The lack of synergy between mAb PA14 and CD4-IgG2 suggests that they act on two nonconsecutive and independent steps of viral entry. A combination of further studies will be needed to determine the precise mechanisms of synergy of the different compounds with respect to inhibition of viral fusion and entry.

The above results are consistent with a model wherein HIV-1 entry occurs in three distinct steps involving receptor binding, co-receptor binding, and co-receptor mediated membrane fusion. Separate co-receptor binding and fusion events are suggested by the lack of correlation between the monoclonal antibodies' abilities to block gpl20 binding and HIV-1 fusion/entry. The chronology of events during fusion is further suggested by the patterns of synergies observed.

Agents, such as PA12, that potently inhibit the middle step of the process, namely gp 120 binding, act synergistically with inhibitors of prior and subsequent steps.

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01 C-OMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28

Claims (20)

1. 28-12-'87 16:03 FROM- T-346 P054/071 F-936 o THE CLAIMS DEFINING THE INVE:cTION ARE AS FOLLOWS: C< 1i A composition for inhibiting HIV-1 :nfection comprisinz C) at least two compounds in synergistically effective 0 amounts for inhibiting HIV-1 infection, wherein at 0 5 least one of the compounds prevents the productive interaction between HIV-1 and an HIV-1 fusion co- receptor. 2. A composition which inhibits fusion of HIV-1 or an HIV- V) 10 1 envelope glycoprotein cell to a target cell, C] comprising at least two compounds in synergistically Seffective amounts for inhibiting fusion of HIV-1 or an C HIV-1 envelope glycoprotein' cell to a target cell, wherein at least one of the compounds prevents the productive interaction between HIV-1 and an HIV-1 fusion co-receptor. 3. The composition of claims 1 or 2 wherein the co- receptor is a chemokine receptor. 4. The composition of claim 3, wherein the chemokine receptor is CCR5 or CXCR4. The composition of claim 1 or 2 wherein at least one of the compounds is an antibody. 6. The composition of claim 5, wherein the antibody is a monoclonal antibody. 7. The composition of claim 5, wherein the antibody is an anti-chemokine receptor antibody. 8. The composition of claim 7, wherein the antibody is an anti-CCRS antibody. 9. The composition of claims 1 or 2, wherein two or more compounds are antibodies. COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'97 16:03 FROM- T-346 P055/871 F-936 0 0 9- 0~ c The ccmposition of claims 8, whdrgit: .ne antibody i o PA3, PA9, PA10, PAll, PA12, FAL4, 2D7 or a combinatior- 0 thereof. ci 5 11. The composition of claim 10, wherein the antlbodies are in an appropriate ratio. C 12. The composition of claim 11, wherein the ratio ranges from 1:1 to 50:1. 13. The composition of claim 9, wherein the antibody is o PAS, PA9, PA1O, PAll, PA12, PA14, 2D7 or a combination Cl thereof. 14. The composition of claim 13, wherein the antibodies are in an appropriate ratio. The composition of claim 14, wherein the ratio ranges from 1:1 to 50:1. 16. The composition of claims 1 or 2 wherein at least one compound is a chemokine or a chemokine derivative. 17. The composition of claim 16, wherein the chemokine is RANTES, MIP-la, MIP-1I, SDF-1 or a combination thereof- 18. The composition of claim 16, wherein the chemokine derivative is Met-RANTES, AOP-RANTES or RANTES 9-68 or a combination thereof. 19. The composition of claim 16, wherein the compounds are in an appropriate ratio. The composition of claim 5, wherein at least one compound is a chemokine or chemokine derivative. 21. The composition of claim 20, wherein the chemokine is RANTES, MIP-la, MIP-1p, SDF-1 or a combination thereof. COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 16:04 FROM- T-346 P056071 F-936 22. The composition of claim 20, where cn. e c::ihemrr ne 0 C) derivative is Met-RANTES, AOP-RANTES or RANTL. 9-68 or 0 a combination thereof. 00 ci 23. The composition of claim 20, wherein the compounds are in an appropriate ratio. NO 24. The composition of claims 1 or 2, wherein at least one 10 of the compounds is a nonpeptidyl molecule. ci o 25. The composition of claim 24, wherein the nonpeptidyl C molecule is the bicyclam AMD3100. 26. The composition of claims 1 or 2 wherein at least one of the compounds inhibits the attachment of HIV-1 to a target cell. 27. The composition of claim 26, wherein at least one of the compounds binds CD4. 28. The composition of claim 27, wherein at least one of the compounds is an HIV-1 envelope glycoprotein.
2. 29. The composition of claim .27, wherein at least one of the compounds is an anti-CD4 antibody. The composition of claim 26, wherein at least one of the compounds binds to the HIV-1 envelope glycoprotein.
3. 31. The composition of claim 26, wherein at least one of the compounds is a CD4-based protein.
4. 32. The composition of claim 31, wherein at least one of the compounds is CD4-IgG2.
5. 33. The composition if claim 26, wherein at least one of the compounds is an antibody to an HIV-I envelope COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 16:04 FROM- T-346 P057/071 F-936 1- -51- 0 o glycoprctein. ci 0 S34. The composition of claim 26, wherein the compounds are 0 in an appropriate ratio. 00 ci The composition of claim 34, wherein the ratio ranges from 1:1 to 10:1. NO 36. The composition of claim 5 wherein at least one of the 'I- 10 compounds inhibits the attachment of HIV-1 to a target cell. 0 0- 37. The composition of claim 36, wherein at least one of the compounds binds CD4.
6. 38. The composition of claim 37, wherein at least one of the compounds is an HIV-1 envelope glycoprotein.
7. 39. The composition of claim of claim 37, wherein at least one of the compounds is an anti-CD4 antibody. The composition of claim 36, wherein at least one of the compounds binds to the HIV-1 envelope glycoprotein.
8. 41. The composition of claim 36, wherein at least one of the compounds is a CD4-based protein.
9. 42. The composition of claim 41, wherein at least one of the compounds is CD4-IgG2.
10. 43. The composition if claim 36, wherein at least one of the compounds is an antibody to an HIV-1 envelope glycoprotein.
11. 44. The composition of claim 36, wherein the compounds are in an appropriate ratio. The composition of claim 44, wherein the ratio ranges COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 16:04 FROM- T-346 P058/071 F-936 i -52- 0 0 fror: I. to "3:1. 0 0 46. The composition of claims 1 or 2, wherein a, least one Sof the compounds comprises a polypeptide which binds to 00 5 a CCR5 epitope. The composition of claim 46, wherein the epitope is located in the N-terminus. VO V 10 48. The composition of claim 46, wherein the compound is a p- polypeptide. Ci 49. The composition of claim 47, wherein the epitope comprises N13 and Y15 in the N-terminus. The composition of claim 46, wherein the epitope includes residues in the N-terminus and second extracellular loop.
12. 51. The composition of claim 50, wherein the epitope comprises D2, Y3, Q4, S7, P8 and N13 in the N-terminus and Y176 and T177 in the second extracellular loop. The composition of claim 50, wherein the epitope comprises D2, Y3, Q4, P8 and N13 in the N-terminus and Y176 and T177 in the second extracellular loop.
13. 53. The composition of claim 47, wherein the epitope comprises Q4 in the N-terminus.
14. 54. The composition of claim 50, wherein the epitope comprises D2 in the N-terminus and R16B and Y176 in the second extracellular loop.
15. 55. The composition of claim 46, wherein the epitope is located in the second extra cellular loop.
16. 56- The composition of claim 55, wherein the epitope COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28 28-12-'07 16:04 FROM- T-346 P059/071 F-936 -53- o comprises Q70 and K171 in the secend .eracc! Cl loop, U
17. 57. The composition of claim 55, wherein the epitope comprises Q170 and E172 in the second extra cellular Cl loop.
18. 58. The composition of claims I or 2 wherein at least one INO of the compounds comprises a light chain of an 10 antibody. V') S9. The composition of claims I or 2 wherein at least one oof the compounds comprises a heavy chain of an antibody. The composition of claims 1 or 2 wherein at least one of the compounds comprises the Fab portion of an antibody.
19. 61. The composition of claims 1 or 2 wherein at least one of the compounds comprises the variable domain of an antibody.
20. 62. The composition of claims I or 2 wherein at least one of the compounds comprises one or more CDR portions of •an antibody. COMS ID No: ARCS-173801 Received by IP Australia: Time 16:07 Date 2007-12-28