FIBROBLAST GROWTH FACTOR RECEPTOR 3 (FGFR3) BINDING PROTEINS

RELATED APPLICATIONS

[0001] This application claims the benefit and priority of U.S. Provisional Application No. 61/077,278, filed July 1, 2008, the entire contents of which are incorporated herein by reference.

FIELD OF INVENTION [0002] The field of the invention is molecular biology, immunology and oncology. More particularly, the field is antibody-based binding proteins that bind human fibroblast growth factor receptor 3 (FGFR3).

BACKGROUND

[0003] Fibroblast Growth Factor Receptor 3 (FGFR3) is one member of a family of receptor tyrosine kinases (FGFRl, FGFR2, FGFR3, FGFR4) that binds fibroblast growth factors (FGFs) (Keegan et al. (1991) PROC. NATL. ACAD. SCI. USA 88: 1095-1099). FGF receptors are characterized as having three extracellular immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tyrosine kinase domain. FGF ligand binding induces FGF receptor dimerization and tyrosine autophosphorylation resulting in cell proliferation, differentiation, and migration (Gomez-Roman et al. (2005) CLIN. CANCER RES. 11:459-65; Chang et al. (2005) BLOOD 106:353-6; Eswarakumar et al. (2005) CYTOKINE GROWTH FACTOR REV. 16(2) : 139-49) .

[0004] Alternative splicing of the FGFR3 transcript results in two isoforms, IHb and IHc. The FGFR3 isoforms are differentially expressed with epithelial cells expressing predominantly the IHb isoform, whereas fibroblast cells express a mixture of IHb and IIIc transcripts (Scotet et al. (1995) BiocHiM. BIOPHYS. ACTA 1264:238-42). In addition, the IHb and IIIc splice variants differ in their specificity for FGF ligand. The IHb splice variant has high affinity for FGFl (acidic FGF) ligand and lower affinity for FGF8 (androgen-induced growth factor) and FGF9 (glial activating factor) (Chellaiah et al. (1999) J. BlOL. CHEM. 274:34785-94; Gomez-Roman et al. (2005) supra). The IIIc splice variant is characterized as a promiscuous receptor binding numerous FGF ligands including FGFl, FGF2, FGF4, FGF8, FGF9, FGF16, FGF17, FGF18, FGF19, FGF20, FGF21, and FGF23 (Chellaiah et al. (1994) J. BIOL. CHEM. 269:11620-7; Gomez-Roman et al. (2005) supra; Ornitz et al. (1996) J. BIOL. CHEM. 271(25): 15292-7; Lee et al. (2000) J. BIOL. CHEM. 275(43):33679-87). [0005] The FGFR3-FGF signaling pathway plays a role in the differentiation of adipocytes, chondrocytes and neurons, wound healing, angiogenesis, embryo development, and malignancies (Keegan et al. (1991) supra). Activating mutations of FGFR3 have been associated with cancer and skeletal disorders including dwarfism, achondroplasia, and hypochondroplasia (Gomez-Roman et al. (2005) supra; Delezoide et al. (1997) HUMAN MOL. GENETICS 6:1899-1906). Certain FGFR3 antibodies are known. See, e.g., U.S. 2005/0147612 (Yayon).

[0006] Antibodies are multimeric proteins that contain four polypeptide chains (Figure 1). Two of the polypeptide chains are called heavy chains (H chains), and two of the polypeptide chains are called light chains (L chains). The immunoglobulin heavy and light chains are connected by an interchain disulfide bond. The immunoglobulin heavy chains are connected by interchain disulfide bonds. A light chain consists of one variable region (V _L in Figure 1) and one constant region (C _L in Figure 1). The heavy chain consists of one variable region (V _H in Figure 1) and at least three constant regions (CH ₁ , CH ₂ and CH ₃ in Figure 1). The variable regions determine the specificity of the antibody. [0007] Each variable region comprises three hypervariable regions also known as complementarity determining regions (CDRs) flanked by four relatively conserved framework regions (FRs). The three CDRs, referred to as CDR ₁ , CDR ₂ , and CDR ₃ , contribute to the antibody binding specificity.

[0008] Although certain anti-FGFR3 antibodies are known in the art, there is still a need for additional FGFR3 modulators that can be used as therapeutic and diagnostic agents.

SUMMARY OF THE INVENTION

[0009] The invention is based, in part, upon the discovery of a family of binding proteins that specifically bind human FGFR3. The binding proteins contain FGFR3 binding sites based on the CDRs of a family of antibodies that specifically bind FGFR3. The binding proteins can be used as diagnostic and therapeutic agents. When used as a therapeutic agent, the binding proteins are engineered, e.g., humanized, to reduce or eliminate an immune response when administered to a human patient.

[0010] The binding proteins prevent or inhibit the activation of (i.e., neutralize) human FGFR3. In some embodiments, the binding proteins prevent FGFR3 from binding to a ligand, e.g., FGFl, thereby neutralizing FGFR3 activation. The binding proteins can be used to inhibit the proliferation of tumor cells or stimulate the proliferation of chondrocytes. Furthermore, when administered to a mammal, the binding proteins can inhibit or reduce tumor growth in the mammal.

[0011] These and other aspects and advantages of the invention will become apparent upon consideration of the following figures, detailed description, and claims. As used herein, "including" means without limitation, and examples cited are non-limiting.

DESCRIPTION OF THE DRAWINGS

[0012] The invention can be more completely understood with reference to the following drawings.

[0013] Figure 1 (prior art) is a schematic representation of a typical antibody. [0014] Figure 2 is a schematic diagram showing the amino acid sequence of the complete immunoglobulin heavy chain variable region of antibodies 15D8, 27H2, 2G4, 4E7 (7D12), and 20B4. The amino acid sequences for each antibody are aligned against one another, and CDR ₁ , CDR ₂ , and CDR ₃ are identified in boxes. The unboxed sequences represent framework (FR) sequences. [0015] Figure 3 is a schematic diagram showing the CDR ₁ , CDR ₂ , and CDR ₃ sequences for each of the immunoglobulin heavy chain variable region sequences in Figure 2. For antibody 15D8, three alternative CDR ₂ sequences are shown (15D8, 15D8-2, and 15D8-3).

[0016] Figure 4 is a schematic diagram showing the amino acid sequence of the complete immunoglobulin light chain variable region of antibodies 15D8, 27H2, 2G4, 4E7 (7D12), and 20B4. The amino acid sequences for each antibody are aligned against one another, and CDR ₁ , CDR ₂ , and CDR ₃ are identified in boxes. The unboxed sequences represent framework (FR) sequences.

[0017] Figure 5 is a schematic diagram showing the CDR ₁ , CDR ₂ , and CDR ₃ sequences for each of the immunoglobulin light chain variable region sequences in Figure 4. [0018] Figure 6 is a graph summarizing results from an experiment to measure neutralization activity of negative control IgGl (A) and anti-FGFR3 monoclonal antibodies 15D8 (X), 27H2 (+), 2G4 (■), 4E7 (T), 7D12 (0), and 20B4 (•) to inhibit FGFR3 binding to FGFl. [0019] Figure 7 is a graph summarizing results from an experiment to measure neutralization activity of negative control IgGl Fab (D) and anti-FGFR3 Fab fragments 15D8 (0), 27H2 (•), 2G4 (*), 4E7 (■), and 7D12 ( A) to inhibit FGFR3 binding to FGFl.

[0020] Figure 8 is a graph summarizing results from an experiment to measure anti- proliferation activity of negative control (murine IgGl) (■) and anti-FGFR3 monoclonal antibodies 15D8 (T), 27H2 (♦), 2G4 (•), and 20B4 ( A) in FDCP-FGFR3 IIIc-109 cells.

[0021] Figure 9 is a graph summarizing results from an experiment to measure tumor inhibitory activity of a murine IgG control at 20 mg/kg (♦) and anti-FGFR3 antibody 15D8 in a OPM-2 xenograft tumor model (antibody 15D8 at 5 mg/kg (■); antibody 15D8 at 10 mg/kg (A); and antibody 15D8 at 20 mg/kg (•)). [0022] Figure 10 is a graph summarizing results from an experiment to measure tumor inhibitory activity of a murine IgG control at 1 mg/kg (♦) and anti-FGFR3 antibodies dosed in an OPM-2 xenograft tumor model (murine antibody 15D8 at 1 mg/kg (A); murine antibody 4E7 at 1 mg/kg (X); murine antibody 27H2 at 1 mg/kg (o); and murine antibody 2G4 at 1 mg/kg (Δ)). DETAILED DESCRIPTION

[0023] The invention is based, in part, upon the discovery of a family of binding proteins that specifically bind and neutralize the activity of human FGFR3. The binding proteins can be used in a variety of diagnostic and therapeutic applications. The binding proteins are based upon the antigen binding sites of certain monoclonal antibodies that have been selected for their ability to bind and neutralize the activity of FGFR3. The binding proteins contain immunoglobulin variable region CDR sequences that define a binding site for FGFR3.

[0024] In view of the neutralizing activity of these antibodies, they are useful for modulating the growth and/or proliferation of certain cancer cells. When used as a therapeutic agent, the binding proteins can be engineered to minimize or eliminate an immune response when administered to a human patient. In some embodiments of the invention, the binding proteins are fused or conjugated to other moieties, such as detectable labels (e.g., radiolabels) or effector molecules (e.g., other proteins or small molecule therapeutics). Various features and aspects of the invention are discussed in more detail below.

I - Binding Proteins That Bind FGFR3 [0025] In certain embodiments of the invention, the binding protein comprises (i) an immunoglobulin heavy chain variable region comprising the structure CDR _HI -CDR _H2 -CDR _H3 and (ii) an immunoglobulin light chain variable region comprising three complementarity determining regions (CDRs), wherein the immunoglobulin heavy chain variable region and the immunoglobulin light chain variable region together define a single binding site for binding human FGFR3. CDR _HI comprises the amino acid sequence X ₁ Tyr Asn Met Tyr (SEQ ID NO: 81), wherein amino acid X ₁ is Asp or Ser. CDR _H2 comprises the amino acid sequence Tyr He Asp Pro Tyr Asn GIy GIy Thr X ₂ X ₃ Asn X ₄ X ₅ Phe X ₆ GIy (SEQ ID NO: 82), wherein amino acid X ₂ is Arg or Ser, amino acid X ₃ is Asp or Tyr, amino acid X ₄ is GIn or Pro, amino acid X ₅ is a Lys or Ser, and amino acid X ₆ is Lys or GIn. CDR _H3 comprises the amino acid sequence X ₇ X ₈ GIy X ₉ X ₁₀ X ₁₁ X ₁₂ Xi ₃ Phe X ₁₄ Tyr (SEQ ID NO: 89), wherein amino acid X ₇ is GIu or Ser, amino acid X ₈ is GIy or Leu, amino acid X ₉ is Asn or a peptide bond, amino acid X ₁₀ is Tyr or a peptide bond, amino acid X ₁₁ is GIu or a peptide bond, amino acid X ₁₂ is Ala or Pro, amino acid X ₁₃ is Trp or Asp, and amino acid X ₁₄ is Ala or Asp.

[0026] In some embodiments of the invention, the binding protein comprises (i) an immunoglobulin light chain variable region comprising the structure CDR _L1 -CDR _L2 -CDR _L3 and (ii) an immunoglobulin heavy chain variable region comprising three CDRs, wherein the immunoglobulin heavy chain variable region and the immunoglobulin light chain variable region together define a single binding site for binding human FGFR3. CDR _L1 comprises the amino acid sequence Ser Ala Ser Ser Ser VaI X ₁₅ Tyr Met X ₁₆ (SEQ ID NO: 83), wherein amino acid X ₁₅ is Ser or Asn, and X ₁₆ is Tyr or His. CDR _L2 comprises the amino acid sequence X ₁₇ Thr Ser X ₁₈ Leu Ala Ser (SEQ ID NO: 84), wherein the amino acid X ₁₇ is Leu or Asp, and the amino acid X ₁₈ is Asn, Lys, or Tyr. CDR _L3 comprises the amino acid sequence GIn GIn Trp X ₁₉ Ser X ₂ o Pro Leu Thr (SEQ ID NO: 85), wherein the amino acid X ₁₉ is Ser or Asn, and the amino acid X ₂ o is Asn or Tyr. [0027] In some embodiments, the binding protein comprises an immunoglobulin heavy chain variable region comprising the structure CDR _H1 -CDR _H2 -CDR _H3 , wherein (i) CDR _H1 comprises the amino acid sequence Ser Tyr Asn Met Tyr (SEQ ID NO: 17), (ii) CDR _H2 comprises the amino acid sequence Tyr He Asp Pro Tyr Asn GIy GIy Thr X ₁ X ₂ Asn X ₃ X ₄ Phe X ₅ GIy (SEQ ID NO: 86), wherein amino acid X ₁ is Arg or Ser, amino acid X ₂ is Asp or Tyr, amino acid X ₃ is GIn or Pro, amino acid X ₄ is Lys or Ser, and amino acid X ₅ is Lys or GIn, and (iii) CDR _H3 comprises the amino acid sequence GIu GIy GIy Asn Tyr GIu Ala Trp Phe Ala Tyr (SEQ ID NO: 19), and an immunoglobulin light chain variable region comprising the structure CDR _L1 -CDR _L2 -CDR _L3 , wherein (i) CDR _L1 comprises the amino acid sequence Ser Ala Ser Ser Ser VaI Ser Tyr Met Tyr (SEQ ID NO: 22), (ii) CDR _L2 comprises the amino acid sequence Leu Thr Ser X ₆ Leu Ala Ser (SEQ ID NO: 87), wherein the amino acid X ₆ is Asn or Tyr, and (iii) CDR _L3 comprises the amino acid sequence GIn GIn Trp Ser Ser X ₇ Pro Leu Thr (SEQ ID NO: 88), wherein the amino acid X ₇ is Asn or Tyr.

[0028] The binding protein can comprise both the immunoglobulin light chain and the immunoglobulin heavy chain sequences or the fragments thereof, described above. The binding protein can be an intact antibody or an antigen binding fragment thereof, or a biosynthetic antibody site.

[0029] In some embodiments, the CDR sequences of the immunoglobulin light chain and the immunoglobulin heavy chain are interposed with framework regions (FR). The framework regions optionally can be humanized or fully human.

[0030] In some embodiments of the invention, the binding protein comprises: (a) an immunoglobulin heavy chain variable region comprising the structure CDR _H1 -CDR _H2 -CDR _H3 and (b) immunoglobulin light chain variable region, wherein the heavy chain variable region and the light chain variable region together define a single binding site for binding human FGFR3. The CDR _H1 comprises a sequence selected from the group consisting of SEQ ID NO: 17 (15D8, 27H2, 4E7(7D12), 2G4) and SEQ ID NO: 29 (20B4). The CDR _H2 comprises a sequence selected from the group consisting of SEQ ID NO: 18 (15D8, 20B4), SEQ ID NO: 20 (15D8-2), SEQ ID NO: 21 (15D8-3), SEQ ID NO: 25 (27H2, 4E7(7D12)), and SEQ ID NO: 28 (2G4). The CDR _H3 comprises a sequence selected from the group consisting of SEQ ID NO: 19 (15D8, 27H2, 4E7(7D12), 2G4) and SEQ ID NO: 30 (20B4). Throughout the specification a particular SEQ ID NO. is followed in parentheses by the antibody that was the origin of that sequence. For example, "SEQ ID NO: 29 (20B4)" means SEQ ID NO: 29 comes from antibody 20B4.

[0031] In certain embodiments, the binding protein comprises an immunoglobulin heavy chain variable region comprising a CDR _H i comprising the sequence of SEQ ID NO: 17 (15D8), a CDR _H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 18 (15D8), SEQ ID NO: 20 (15D8-2), and SEQ ID NO: 21 (15D8-3), and a CDR _H3 comprising the sequence of SEQ ID NO: 19 (15D8). In a preferred embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising a CDR _H1 comprising the sequence of SEQ ID NO: 17 (15D8), a CDR _H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 18 (15D8), and a CDR _H3 comprising the sequence of SEQ ID NO: 19 (15D8).

[0032] In some embodiments, the binding protein comprises an immunoglobulin heavy chain variable region comprising a CDRm comprising the sequence of SEQ ID NO: 17 (27H2, 4E7(7D12)), a CDR _H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 25 (27H2, 4E7(7D12)), and a CDR _H3 comprising the sequence of SEQ ID NO: 19 (27H2, 4E7(7D12)).

[0033] In some embodiments, the binding protein comprises an immunoglobulin heavy chain variable region comprising a CDRm comprising the sequence of SEQ ID NO: 17 (2G4), a CDR _H2 comprising the sequence of SEQ ID NO: 28 (2G4), and a CDR _H3 comprising the sequence of SEQ ID NO: 19 (2G4).

[0034] In one embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising a CDRm comprising the sequence of SEQ ID NO: 29 (20B4), a CDR _H2 comprising the sequence of SEQ ID NO: 18 (20B4), and a CDR _H3 comprising the sequence of SEQ ID NO: 30 (20B4). [0035] Preferably, the CDRm, CDR _H2 , and CDR _H3 sequences are interposed between human or humanized immunoglobulin FRs. The binding protein can be an intact antibody, an antigen-binding antibody fragment, or a biosynthetic antibody site.

[0036] In some embodiments, the binding protein comprises (a) an immunoglobulin light chain variable region comprising the structure CDR _LI -CDR _L2 -CDR _L3 , and (b) an immunoglobulin heavy chain variable region, wherein the immunoglobulin light chain variable region and the immunoglobulin heavy chain variable region together define a single binding site for binding human FGFR3. The CDR _L1 comprises a sequence selected from the group consisting of SEQ ID NO: 22 (15D8, 27H2, 2G4, 4E7(7D12)) and SEQ ID NO: 31 (20B4); the CDR _L2 comprises a sequence selected from the group consisting of SEQ ID NO: 23 (15D8), SEQ ID NO: 26 (27H2, 2G4, 4E7(7D12)), and SEQ ID NO: 32 (20B4); and the CDR _L3 comprises a sequence selected from the group consisting of SEQ ID NO: 24 (15D8), SEQ ID NO: 27 (27H2, 2G4, 4E7(7D12)), and SEQ ID NO: 33 (20B4),.

[0037] In some embodiments, the binding protein comprises an immunoglobulin light chain variable region comprising: a CDR _LI comprising the sequence of SEQ ID NO: 22 (15D8); a CDR _L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 23 (15D8); and a CDR _L3 comprising the sequence of SEQ ID NO: 24 (15D8).

[0038] In one embodiment, the binding protein comprises an immunoglobulin light chain variable region comprising: a CDR _LI comprising the sequence of SEQ ID NO: 22 (27H2, 2G4, 4E7(7D12)); a CDR _L2 comprising the sequence of SEQ ID NO: 26 (27H2, 2G4, 4E7(7D12)); and a CDR _L3 comprising the sequence of SEQ ID NO: 27 (27H2, 2G4, 4E7(7D12)).

[0039] In one embodiment, the binding protein comprises an immunoglobulin light chain variable region comprising: a CDR _LI comprising the sequence of SEQ ID NO: 31 (20B4); a CDR _L2 comprising the sequence of SEQ ID NO: 32 (20B4); and a CDR _L3 comprising the sequence of SEQ ID NO: 33 (20B4). [0040] Preferably, the CDR _L1 , CDR _L2 , and CDR _L3 sequences are interposed between human or humanized immunoglobulin FRs. The binding protein can be an intact antibody, an antigen-binding antibody fragment, or a biosynthetic antibody site.

[0041] In some embodiments of the invention, the binding protein comprises: (a) an immunoglobulin heavy chain variable region comprising the structure CDR _HI -CDR _H2 -CDR _H3 and (b) an immunoglobulin light chain variable region comprising the structure CDR _LI -CDR _L2 - CDR _L3 , wherein the heavy chain variable region and the light chain variable region together define a single binding site for binding human FGFR3. The CDR _H i comprises SEQ ID NO: 17 (15D8, 27H2, 2G4, 4E7(7D12)); a CDR _H2 is selected from the group consisting of SEQ ID NO: 18 (15D8), SEQ ID NO: 20 (15D8-2), SEQ ID NO: 21 (15D8-3), SEQ ID NO: 25 (27H2, 4E7(7D12)), and SEQ ID NO: 28 (2G4); and the CDR _H3 comprises SEQ ID NO: 19 (15D8, 27H2, 2G4, 4E7(7D12)). The CDR _L1 comprises SEQ ID NO: 22 (15D8, 27H2, 2G4, 4E7(7D12)); a CDR _L2 is selected from the group consisting SEQ ID NO: 23 (15D8) and SEQ ID NO: 26 (27H2, 2G4, 4E7(7D12)); and a CDR _L3 is selected from the group consisting SEQ ID NO: 24 (15D8) and SEQ ID NO: 27 (27H2, 2G4, 4E7(7D12)).

[0042] In another embodiment, the binding protein comprises an immunoglobulin heavy chain variable region selected from the group consisting of SEQ ID NO: 2 (15D8), SEQ ID NO: 6 (27H2), SEQ ID NO: 10 (2G4), SEQ ID NO: 12 (4E7(7D12)), and SEQ ID NO: 14 (20B4), and an immunoglobulin light chain variable region selected from the group consisting of SEQ ID NO: 4 (15D8), SEQ ID NO: 8 (27H2, 2G4, 4E7(7D12)), and SEQ ID NO: 16 (20B4). [0043] In another embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising SEQ ID NO: 2 (15D8), and an immunoglobulin light chain variable region comprising SEQ ID NO: 4 (15D8).

[0044] In another embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising SEQ ID NO: 6 (27H2), and an immunoglobulin light chain variable region comprising SEQ ID NO: 8 (27H2).

[0045] In another embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising SEQ ID NO: 10 (2G4), and an immunoglobulin light chain variable region comprising SEQ ID NO: 8 (2G4).

[0046] In another embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising SEQ ID NO: 12 (4E7(7D12)), and an immunoglobulin light chain variable region comprising SEQ ID NO: 8 (4E7(7D12)).

[0047] In another embodiment, the binding protein comprises an immunoglobulin heavy chain variable region comprising SEQ ID NO: 14 (20B4), and an immunoglobulin light chain variable region comprising SEQ ID NO: 16 (20B4). [0048] In each of the foregoing embodiments, the binding protein can be an intact antibody, an antigen-binding antibody fragment, or a biosynthetic antibody site.

[0049] In other embodiments, the binding protein comprises (i) an immunoglobulin heavy chain selected from the group consisting of SEQ ID NO: 39 (15D8), SEQ ID NO: 43 (27H2), SEQ ID NO: 47 (2G4), SEQ ID NO: 51 (4E7(7D12)), and SEQ ID NO: 55 (20B4), and (ii) an immunoglobulin light chain selected from the group consisting of SEQ ID NO: 41 (15D8), SEQ ID NO: 45 (27H2), SEQ ID NO: 49 (2G4), SEQ ID NO: 53 (4E7(7D12)) and SEQ ID NO: 57 (20B4).

[0050] In another embodiment, the binding protein comprises an immunoglobulin heavy chain comprising SEQ ID NO: 39 (15D8), and an immunoglobulin light chain comprising SEQ ID NO: 41 (15D8).

[0051] In another embodiment, the binding protein comprises an immunoglobulin heavy chain comprising SEQ ID NO: 43 (27H2), and an immunoglobulin light chain comprising SEQ ID NO: 45 (27H2).

[0052] In another embodiment, the binding protein comprises an immunoglobulin heavy chain comprising SEQ ID NO: 47 (2G4), and an immunoglobulin light chain comprising SEQ ID NO: 49 (2G4).

[0053] In another embodiment, the binding protein comprises an immunoglobulin heavy chain comprising SEQ ID NO: 51 (4E7(7D12)), and an immunoglobulin light chain comprising SEQ ID NO: 53 (4E7(7D12)). [0054] In another embodiment, the binding protein comprises an immunoglobulin heavy chain comprising SEQ ID NO: 55 (20B4), and an immunoglobulin light chain comprising SEQ ID NO: 57 (20B4).

[0055] Each of the binding proteins described above can be an intact antibody, e.g., a monoclonal antibody. Alternatively, the binding protein can be an antigen binding fragment of an antibody, or can be a biosynthetic antibody binding site. Antibody fragments include Fab, Fab', (Fab') ₂ and Fv fragments. Techniques for making antibody fragments are known in the art. Biosynthetic antibody binding sites are known in the art, e.g., single Fv and sFv molecules. See, e.g., U.S. Patent No. 5,476,786. Other biosynthetic antibody binding sites include bispecific or bifunctional binding proteins, e.g., antibodies or antibody fragments that bind at least two different antigens. For example, bispecific binding proteins can bind human FGFR3 and another antigen of interest. Methods for making bispecific antibodies are known in art. Such methods include fusing hybridomas or by linking Fab' fragments. See, e.g., Songsivilai et αl. (1990) CLIN. EXP. IMMUNOL. 79: 315-325; Kostelny et αl. (1992) J. IMMUNOL. 148: 1547- 1553. [0056] In some embodiments of the invention, an isolated binding protein binds human FGFR3 with a K _D of 10 nM, 5 nM, 4 nM, 3 nM, 2 nM, or lower, wherein the K _D values are determined by surface plasmon resonance methods under the conditions described in Example

3. [0057] In some embodiments of the invention, an isolated binding protein binds human FGFR3 with a K _D of 200 pM, 150 pM, 100 pM, 90 pM, 80 pM, 70 pM, 60 pM, 50 pM, 40 pM, 30 pM, 20 pM, 10 pM, or lower, wherein the K _D values are determined by a kinetic exclusion assay (See, e.g., Darling and Brault (2004) ASSAY AND DRUG DEVELOPMENT TECHNOLOGIES 2: 647-657) under the conditions described in Example 7. [0058] In some embodiments, the binding proteins inhibit hFGFR3 from binding to FGFl. For example, the binding proteins can have an IC ₅₀ (concentration at 50% of maximum inhibition) of about 10, 11, 12, 13, 14, 15, 16, 17 or 18 nM, when assayed using the protocol described in Example 4.

II - Production of Binding Proteins [0059] Methods for producing binding proteins of the invention are known in the art. For example, DNA molecules encoding light chain variable regions and heavy chain variable regions can be chemically synthesized using the sequence information provided herein. Synthetic DNA molecules can be ligated to other appropriate nucleotide sequences, including, e.g., constant region coding sequences, and expression control sequences, to produce conventional gene expression constructs encoding the desired binding proteins. Production of defined gene constructs is within routine skill in the art. Alternatively, the sequences provided herein can be cloned out of hybridomas by conventional hybridization techniques or PCR techniques, using synthetic nucleic acid probes whose sequences are based on sequence information provided herein or prior art sequence information regarding genes encoding the heavy and light chains of murine antibodies in hybridoma cells.

[0060] The nucleic acids encoding the desired binding proteins can be introduced (ligated) into expression vectors, which can be introduced into a host cell through conventional transfection or transformation techniques. Exemplary host cells include E. coli cells, Chinese hamster ovary (CHO) cells, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g., Hep G2), and myeloma cells that do not otherwise produce immunoglobulin protein. Transfected host cells are grown under conditions that permit the host cells to express the genes of interest, e.g., genes that encode the immunoglobulin light or heavy chain variable regions.

[0061] Specific expression and purification conditions will vary depending upon the expression system employed. For example, if a gene is to be expressed in E. coli, it is first cloned into an expression vector by positioning the engineered gene downstream from a suitable bacterial promoter, e.g., Trp or Tac, and a signal sequence, e.g., a sequence encoding fragment B of protein A (FB). The expressed fusion protein accumulates in refractile or inclusion bodies in the bacterial cytoplasm, and may be harvested after disruption of the cells by French press or sonication. The refractile bodies then are solubilized, and the proteins refolded and cleaved by methods already established for other recombinant proteins.

[0062] If the engineered gene is to be expressed in eukaryotic host cells, e.g., myeloma cells or CHO cells, it is first inserted into an expression vector containing a suitable eukaryotic promoter, a secretion signal, immunoglobulin enhancers, and various introns. This expression vector optionally contains sequences encoding all or part of a constant region, enabling an entire, or a part of, a heavy or light chain to be expressed. The gene construct can be transfected into myeloma cells or CHO cells using established transfection protocols. Such transfected cells can express V _L or V _H fragments, V _L -V _H heterodimers, V _H -V _L or V _L -V _H single chain polypeptides, complete heavy or light immunoglobulin chains, or portions thereof, each of which may be attached to a protein domain having another function (e.g., cytotoxicity). III - Modifications to the Binding Proteins

[0063] The binding proteins can be modified to optimize performance, depending upon the intended use of the binding proteins. For example, when the binding protein is being used as a therapeutic agent, the binding protein can be modified to reduce its immunogenicity in a human patient. Alternatively or in addition, the binding protein can be fused or chemically conjugated to another protein or peptide, e.g., a growth factor, cytokine, or cytotoxin.

[0064] Various techniques for reducing or eliminating the antigenicity of antibodies and antibody fragments are known in the art. When the binding proteins are to be administered to a human, the binding proteins preferably are engineered ("humanized") to reduce or eliminate antigenicity in humans. Preferably, the humanized binding proteins have the same or substantially the same affinity for the antigen as the original non-humanized binding protein from which it was derived. [0065] In one humanization approach, chimeric proteins are created in which mouse immunoglobulin constant regions are replaced with human immunoglobulin constant regions. See, e.g., Morrison, et al. (1984) PROC. NAT. ACAD. SCI. 81: 6851-6855, Neuberger et al. (1984) NATURE 312: 604-608; U.S. Patent Nos. 6,893,625 (Robinson); 5,500,362 (Robinson); and 4,816,567 (Cabilly).

[0066] In another approach, known as CDR grafting, the CDRs of the light and heavy chain variable regions are grafted into frameworks from another species. For example, murine CDRs can be grafted into human FR sequences. In some embodiments of the invention, the CDRs of the light and heavy chain variable regions of an anti-FGFR3 antibody are grafted into human FRs or consensus human FRs. In order to create consensus human FRs, FRs from several human heavy chain or light chain amino acid sequences are aligned to identify a consensus amino acid sequence. CDR grafting is described in U.S. Patent Nos. 7,022,500 (Queen); 6,982,321 (Winter); 6,180,370 (Queen); 6,054,297 (Carter); 5,693,762 (Queen); 5,859,205 (Adair); 5,693,761 (Queen); 5,565,332 (Hoogenboom); 5,585,089 (Queen); 5,530,101 (Queen); Jones et al. (1986) NATURE 321: 522-525; Riechmann et al. (1988) NATURE 332: 323-327; Verhoeyen et al. (1988) SCIENCE 239: 1534-1536; and Winter (1998) FEBS LETT 430: 92-94.

[0067] In an approach called "superhumanization," human immunogenicity is reduced or eliminated by an alternative form of grafting. In superhumanization, human CDR sequences are chosen from a set of human germline genes based on the structural similarity of the human CDRs to those of the mouse antibody to be humanized. See, e.g., U.S. Patent No. 6,881,557 (Foote); and Tan et al. (2002) J. IMMUNOL 169:1119-1125.

[0068] Other methods to reduce immunogenicity include "reshaping," "hyperchimerization," and "veneering/resurfacing." See, e.g., Vaswami et al. (1998) ANNALS OF ALLERGY, ASTHMA, & IMMUNOL. 81: 105; Roguska et al. (1996) PROT. ENGINEER 9: 895- 904; and U.S. Patent No. 6,072,035 (Hardman). In the veneering/resurfacing approach, the surface accessible amino acid residues in the murine antibody are replaced by amino acid residues more frequently found at the same positions in a human antibody. This type of antibody resurfacing is described, e.g., in U.S. Patent No. 5,639,641 (Pedersen).

[0069] Another approach for converting a mouse antibody into a form suitable for medical use in humans is known as ACTIVMAB™ technology (Vaccinex, Inc., Rochester, NY), which involves a vaccinia virus-based vector to express antibodies in mammalian cells. High levels of combinatorial diversity of immunoglobulin heavy and light chains are said to be produced. See, e.g., U.S. Patent Nos. 6,706,477 (Zauderer); 6,800,442 (Zauderer); and 6,872,518 (Zauderer).

[0070] Another approach for converting a mouse antibody into a form suitable for use in humans is technology practiced commercially by KaloBios Pharmaceuticals, Inc. (Palo Alto, CA). This technology involves the use of a proprietary human "acceptor" library to produce an "epitope focused" library for antibody selection.

[0071] Another approach for modifying a mouse antibody into a form suitable for medical use in humans is HUMAN ENGINEERING™ (HE™) technology, which is practiced commercially by XOMA (US) LLC. See, e.g., International Application Publication No. WO 93/11794 and U.S. Patent Nos. 5,766,886; 5,770,196; 5,821,123; and 5,869,619.

[0072] Any suitable approach, including any of the above approaches, can be used to reduce or eliminate human immunogenicity of a binding protein of the invention.

[0073] Binding proteins of the invention can be conjugated to, or fused with, other molecules, depending upon their intended use. For example, if the binding protein is going to be used as a therapeutic, then the binding protein can be conjugated with another agent, for example, an effector molecule that modulates or otherwise promotes the therapy. A small molecule drug, a radiolabel or toxin, then, the agent can be chemically coupled to the binding protein using standard in vitro coupling chemistries. If the effector molecule is a protein or peptide, the binding protein can be chemically coupled to the effector using in vitro coupling chemistries or can be coupled to the effector as a fusion protein. Fusion proteins can be constructed and expressed using the techniques similar to those discussed in section II.

IV - Use of Binding Proteins

[0074] Binding proteins of the invention can be used as a research agent, diagnostic agent or therapeutic agent.

(1) Therapeutic Applications

[0075] Because the binding proteins of the invention prevent or inhibit the activation of FGFR3, they can be used in therapeutic applications. For example, certain binding proteins of the invention are useful in the prevention or treatment of hyperproliferative diseases or disorders, e.g., various forms of cancer and skeletal disorders. [0076] The binding proteins can be used to inhibit or reduce the proliferation of cancer cells. In such an approach, the cancer cells are exposed to a therapeutically effective amount of the binding protein so as to inhibit or reduce proliferation of the cancer cell. In some embodiments, the binding proteins inhibit cancer cell proliferation by at least 50%, 60%, 70%, 80%, 90%, or 95%.

[0077] In some embodiments, the binding protein is used to inhibit or reduce proliferation of a tumor cell wherein the binding protein inhibits binding of hFGFR3 to an FGF ligand, e.g., FGFl.

[0078] The binding protein can be used in a method to inhibit tumor growth in a mammal, e.g., a human patient. The method comprises administering to the mammal a therapeutically effective amount of the binding protein.

[0079] Cancers associated with FGFR3 activation include bladder cancer, cervical cancer, oral squamous cell cancer, non- small cell lung cancer, breast cancer, lymphoma, and multiple myeloma. [0080] Exemplary skeletal disorders that are associated with FGFR3 activation include achondroplasia, hypochondroplasia, dwarfism, thanatophoric dysplasia (TD) (clinical forms TD I and TD II), and craniosynostosis syndromes.

[0081] As used herein, "treat, "treating" and "treatment" mean the treatment of a disease in a mammal, e.g., in a human. This includes: (a) inhibiting the disease, i.e., arresting its development; (b) relieving the disease, i.e., causing regression of the disease state; and (c) curing the disease.

[0082] Generally, a therapeutically effective amount of active component will be in the range of 0.1 mg/kg to 100 mg/kg, e.g., 1 mg/kg to 100 mg/kg, 1 mg/kg to 10 mg/kg. The amount administered will depend on variables such as the type and extent of disease or indication to be treated, the overall health of the patient, the in vivo potency of the binding protein, the pharmaceutical formulation, and the route of administration. The initial dosage may be increased beyond the upper level in order to rapidly achieve the desired blood- level or tissue level. Alternatively, the initial dosage may be smaller than the optimum, and the daily dosage may be progressively increased during the course of treatment. Human dosage can be optimized, e.g., in a conventional Phase I dose escalation study designed to run from 0.5 mg/kg to 20 mg/kg. Dosing frequency can vary, depending on factors such as route of administration, dosage amount and the disease being treated. Exemplary dosing frequencies are once per day, once per week and once every two weeks. A preferred route of administration is parenteral, e.g., intravenous infusion. Formulation of monoclonal antibody-based drugs is within ordinary skill in the art. In some embodiments of the invention, the binding protein, e.g., monoclonal antibody, is lyophilized and reconstituted in buffered saline at the time of administration.

[0083] The binding proteins may be administered either alone or in combination with other pharmaceutically active ingredients, e.g., a chemotherapeutic drug. The other active ingredients, e.g., immunomodulators, can be administered together with the binding protein, before or after the binding protein.

[0084] For therapeutic use, the binding proteins preferably are combined with a pharmaceutically acceptable carrier. As used herein, "pharmaceutically acceptable carrier" means buffers, carriers, and excipients, that are suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. The carrier(s) should be "acceptable" in the sense of being compatible with the other ingredients of the formulations and not deleterious to the recipient. Pharmaceutically acceptable carriers include buffers, solvents, dispersion media, coatings, isotonic and absorption delaying agents, and the like, that are compatible with pharmaceutical administration. The use of such media and agents for pharmaceutically active substances is known in the art.

[0085] Pharmaceutical compositions containing binding proteins of the invention can be presented in a dosage unit form and can be prepared by any suitable method. A pharmaceutical composition should be formulated to be compatible with its intended route of administration. Examples of routes of administration are intravenous (IV), intradermal, inhalation, transdermal (topical), transmucosal, and rectal administration. A preferred route of administration for monoclonal antibodies is IV infusion. Useful formulations can be prepared by any of the methods well known in the pharmaceutical art, described, for example, in Remington's Pharmaceutical Sciences, 18th ed. (Mack Publishing Company, 1990).

[0086] Formulation components suitable for parenteral administration include 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 ethylene-diamine-tetra-acetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic.

[0087] In general, pharmaceutical compositions suitable for injection include aqueous solutions (where water soluble) or dispersions and powders for the extemporaneous preparation of sterile injectable solutions or dispersion. For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor ELTM (BASF, Parsippany, NJ) or phosphate buffered saline (PBS). It should be stable under the conditions of manufacture and storage and should 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 polyetheylene glycol), and suitable mixtures thereof. [0088] Pharmaceutical formulations preferably are sterile. Sterilization can be accomplished, for example, by filtration through sterile filtration membranes. Where the composition is lyophilized, sterilization using this method can be conducted prior to or following lyophilization and reconstitution. Once the pharmaceutical composition has been formulated, it can be stored, for example, in vials as a solution, suspension, gel, emulsion, solid, or as a dehydrated or lyophilized powder.

(2) Diagnostic Applications

[0089] When the binding proteins are used for diagnostic purposes, either in vitro or in vivo, the binding proteins typically are labeled either directly or indirectly with a detectable moiety. The detectable moiety can be any moiety that produces, either directly or indirectly, a detectable signal. The detectable moiety can be a radioisotope, e.g., ³ H, ¹⁴ C, ³² P, ³⁵ S, ¹²⁵ I or

¹³¹ I; a fluorescent or chemiluminescent compound, e.g., fluorescein isothiocyanate, rhodamine, or luciferin; an enzyme, e.g., alkaline phosphatase, beta-galactosidase, or horseradish peroxidase; a spin label; or a colored particle, e.g., a latex particle or gold particle. The binding protein can be conjugated to the detectable moiety by any suitable method. See, e.g., Hunter et αl. (1962) NATURE 144: 945; David et αl. {191 A) BIOCHEMISTRY 13: 1014; Pain et αl. (1981) J. IMMUNOL. METH. 40: 219; and Nygren (1982) J. HISTOCHEM. AND CYTOCHEM. 30: 407. [0090] The binding proteins can be employed in immunoassay techniques. Exemplary immunoassays include sandwich immunoassays, competitive immunoassays, and immunohistochemical procedures.

[0091] In a sandwich immunoassay, two antibodies that bind an analyte or antigen of interest are used, e.g., one immobilized onto a solid support, and one free in solution and labeled with a detectable moiety. When a sample containing the antigen is introduced into this system, the antigen binds to both the immobilized antibody and the labeled antibody, to form a "sandwich" immune complex on the surface of the support. The complexed protein is detected by washing away non-bound sample components and excess labeled antibody, and measuring the amount of labeled antibody complexed to protein on the support's surface. Alternatively, the antibody free in solution can be detected by a third antibody labeled with a detectable moiety which binds the free antibody. See, e.g., Butt, ed., (1984) PRACTICAL IMMUNOLOGY, Marcel Dekker, New York; Harlow et al. eds. (1988) ANTIBODIES, A LABORATORY APPROACH, Cold Spring Harbor Laboratory; and Diamandis et al., eds. (1996) IMMUNOASSAY, Academic Press, Boston.

[0092] Labeled binding proteins are useful as in vivo imaging agents, whereby the binding proteins can target the imaging agents to tissues of interest. An exemplary remotely detectable moiety for in vivo imaging is the radioactive atom Technetium ^"99 " ¹ ( ^99m Tc), a gamma emitter with a half- life of about six hours. Non-radioactive moieties useful in in vivo imaging include nitroxide spin labels, lanthanide and transition metal ions, all of which induce proton relaxation in situ. In addition to immunoimaging, the complexed radioactive moieties may be used in radioimmunotherapy protocols to destroy the targeted cell. Suitable isotopes for radioimmunotherapy include the radioactive atoms ⁹⁰ Yt, ¹³¹ I and ¹¹¹ In.

EXAMPLES [0093] The following Examples are merely illustrative and are not intended to limit the scope or content of the invention in any way.

Example 1 - Production of Anti-hFGFR3 Monoclonal Antibodies

[0094] This Example describes the production of a number of anti-hFGFR3 monoclonal antibodies. [0095] Immunizations, fusions, and primary screens were conducted at Maine Biotechnology Services Inc. following the Repetitive Immunization Multiple Sites (RIMMS) protocol. Five AJ mice and five Balb/c mice were immunized with recombinant human FGFR3 IHb (R&D Systems, Catalog No. 1264-FR-050) and FGFR3 IIIc (R&D Systems, Catalog No. 766-FR-050) where the Fc fragment was removed from each by Factor Xa protease cleavage. Two Balb/c mice with sera displaying highest anti-FGFR3 activity by Enzyme Linked Immunosorbent Assay (ELISA) were chosen for subsequent fusion. Spleens and lymph nodes from the appropriate mice were harvested. B -cells then were harvested and fused with a myeloma line. Fusion products were serially diluted onto forty 96-well plates to near clonality. Three thousand seven hundred and sixty- three supernatants from the resulting fusions were screened for their binding to recombinant human FGFR3 IHb and IIIc by ELISA. Three hundred fifty-six supernatants identified to contain antibodies to FGFR3 were further characterized by in vitro biochemical and cell-based assays as discussed in the following examples. A panel of hybridomas was selected and the hybridomas were subcloned and expanded. Hybridoma cell lines were transferred to BioXCell (formerly Bio-Express) for antibody expression and purification by affinity chromatography on Protein G resin under standard conditions.

Example 2 - Sequence Analysis of anti-hFGFR3 Monoclonal Antibodies [0096] This Example describes isotype and sequence analysis of the anti-FGFR3 monoclonal antibodies produced in Example 1. a. Determination of FGFR3 Murine Monoclonal Antibody Isotypes

[0097] The light-chain isotype and heavy chain isotype of each monoclonal antibody was determined using the IsoStrip Mouse Monoclonal Antibody Isotyping Kit according the manufacturer's instructions (Roche Applied Science). [0098] All antibodies were determined to be Kappa immunoglobulin light chain and IgGl immunoglobulin heavy chain.

Ix Determination of Nucleotide Sequences Encoding Immunoglobulin Heavy and Light Chain Variable Regions

[0099] The heavy and light chain variable regions of the mouse monoclonal antibodies were sequenced using 5' RACE. Total RNA was extracted from each monoclonal hybridoma cells line using the RNeasy Miniprep kit according to the manufacturer's instructions (Qiagen). Full-length first strand cDNA containing 5' ends was generated using the GeneRacer™ Kit according to the manufacturer's instructions (Invitrogen) using random primers for the purpose of 5' RACE (Rapid Amplification of cDNA Ends). [0100] The variable regions of the Kappa and Heavy (IgGl) immunoglobulin chains were amplified by PCR (Polymerase Chain Reaction) using the Expand High-Fidelity PCR System (Roche Applied Science) according the manufacturer's instructions. Heavy chain variable regions were amplified with the GeneRacer™ 5' Primer, 5'-cgactggagcacgaggacactga-3' (SEQ ID NO: 58) (Invitrogen), and a 3' IgGl Constant Region specific primer, either 5' tatgcaaggcttacaaccaca 3' (SEQ ID NO: 59) or 5' gccagtggatagacagatgggggtgtcg 3' (SEQ ID NO: 60). Kappa chain variable regions were amplified with the GeneRacer™ 5' Primer and a 3' Kappa Constant Region specific primer, either 5' ctcattcctgttgaagctcttgacaat 3' (SEQ ID NO: 61) or 5' cgactgaggcacctccagatgtt 3' (SEQ ID NO: 62).

[0101] Individual PCR products were isolated by agarose gel electrophoresis and purified using the Qiaquick Gel Purification kit according to the manufacturer's instructions (Qiagen). The PCR products were subsequently cloned into the pCR2.1 TOPO plasmid using the topoisomerase based cloning kit TOPO TA Cloning® Kit (with pCR®2.1-TOPO® vector) according to the manufacturer's instructions (Invitrogen) and transformed into DH5-alpha bacteria through standard molecular biology techniques. Plasmid DNA isolated from transformed bacterial clones was sequenced using M 13 Forward (5'

GTAAAACGACGGCCAGT 3') (SEQ ID NO: 63) and M13 Reverse primers (5' CAGGAAACAGCTATGACC 3') (SEQ ID NO: 64) by Agencourt Bioscience using standard dideoxy DNA sequencing methods to identify the sequence of the variable region sequences. The sequences were analyzed using Vector NTI software (Invitrogen) and the IMGT/V-Quest web server to identify and confirm variable region sequences.

[0102] The nucleic acid sequences encoding and the protein sequences defining each of the immunoglobulin heavy chain and light chain variable regions are summarized below (amino terminal signal peptide sequences are not shown). CDR sequences are shown in bold and are underlined in the amino acid sequences. [0103] Nucleic Acid Sequence Encoding the 15D8 Heavy Chain Variable Region (SEQ ID NO: 1)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc 121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagctac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagcctac

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca [0104] Protein Sequence Defining the 15D8 Heavy Chain Variable Region (SEQ ID NO: 2)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtsy 61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

[0105] Nucleic Acid Sequence Encoding the 15D8 Kappa Chain Variable Region (SEQ ID NO: 3)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga

121 tcctccccca aaccctggat ttatctcaca tcctacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtggatctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa 241 gatgctgcca cttattactg ccagcagtgg agtagttacc cgctcacgtt cggtgctgga

301 accaagctgg agctgaaa

[0106] Protein Sequence Defining the 15D8 Kappa Chain Variable Region (SEQ ID NO: 4)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt sylasgvpar 61 fsgsgsgtsy sltissmeae daatyycqqw ssypltfgag tklelk

[0107] Nucleic Acid Sequence Encoding the 27H2 Heavy Chain Variable Region (SEQ ID

NO: 5)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc 121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactaggtac

181 aaccagaagt tcaagggcaa ggccacaatg actgttgaca agtcctccag cacagcctac

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

[0108] Protein Sequence Defining the 27H2 Heavy Chain Variable Region (SEQ ID NO: 6)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtry 61 nqkfkgkatm tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

[0109] Nucleic Acid Sequence Encoding the 27H2 Kappa Chain Variable Region (SEQ ID NO: 7)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga

121 tcctccccca aaccctggat ttatctcaca tccaacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa 241 gatgctgcca cttattactg ccagcagtgg agtagtaacc cgctcacgtt cggtgctggg

301 accaagctgg agctgaaa [0110] Protein Sequence Defining the 27H2 Kappa Chain Variable Region (SEQ ID NO: 8)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt snlasqvpar 61 fsgsgsgtsy sltissmeae daatyycqqw ssnpltfqaq tklelk [0111] Nucleic Acid Sequence Encoding the 2G4 Heavy Chain Variable Region (SEQ ID NO: 9)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcaca agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagggac 181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag tacagcctac

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

[0112] Protein Sequence Defining the 2G4 Heavy Chain Variable Region (SEQ ID NO: 10) 1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtrd

61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

[0113] Nucleic Acid Sequence Encoding the 2G4 Kappa Chain Variable Region (SEQ ID

NO: 7)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc 61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga 121 tcctccccca aaccctggat ttatctcaca tccaacctgg cttctggagt ccctgctcgc 181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa 241 gatgctgcca cttattactg ccagcagtgg agtagtaacc cgctcacgtt cggtgctggg 301 accaagctgg agctgaaa

[0114] Protein Sequence Defining the 2G4 Kappa Chain Variable Region (SEQ ID NO: 8)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt snlasqvpar 61 fsgsgsgtsy sltissmeae daatyycqqw ssnpltfgag tklelk [0115] Nucleic Acid Sequence Encoding the 4E7 (7D12) Heavy Chain Variable Region (SEQ ID NO: 11)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactaggtac 181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagcctac

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

[0116] Protein Sequence Defining the 4E7 (7D12) Heavy Chain Variable Region (SEQ ID NO: 12)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtry 61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

[0117] Nucleic Acid Sequence Encoding the 4E7 (7D12) Kappa Chain Variable Region (SEQ ID NO: 7)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc 61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga 121 tcctccccca aaccctggat ttatctcaca tccaacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa

241 gatgctgcca cttattactg ccagcagtgg agtagtaacc cgctcacgtt cggtgctggg 301 accaagctgg agctgaaa

[0118] Protein Sequence Defining the 4E7 (7D12) Kappa Chain Variable Region (SEQ ID NO: 8)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt snlasgvpar

61 fsgsgsgtsy sltissmeae daatyycqqw ssnpltfgag tklelk

[0119] Nucleic Acid Sequence Encoding the 20B4 Heavy Chain Variable Region (SEQ ID NO: 13)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta ctcactcact gactacaaca tgtactgggt gaagcagagc 121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagctac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagccttc

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagatcgttg

301 ggacctgatt ttgactactg gggccaaggc accactctca cagtctcctc a [0120] Protein Sequence Defining the 20B4 Heavy Chain Variable Region (SEQ ID NO:

14)

1 eiqlqqsgpe lvkpgasvkv sckasgyslt dynmywvkqs hgkslewigy idpynggtsy

61 nqkfkgkatl tvdkssstaf mhlnsltsed savyycarsl gpdfdywgqg ttltvss [0121] Nucleic Acid Sequence Encoding the 20B4 Kappa Chain Variable Region (SEQ ID NO: 15)

1 caaattgttc tcacccagtc tccagcaatc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaaat tacatgcact ggtaccagca gaagtcaggc

121 acctccccca aaagatggat ttatgacaca tccaaactgg cttctggagt ccctgctcgc 181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa

241 gatactgcca cttattactg tcaacagtgg aatagtaacc cactcacgtt cggtgcgggg

301 accaagctgg agctgaaa

[0122] Protein Sequence Defining the 20B4 Kappa Chain Variable Region (SEQ ID NO: 16)

1 qivltqspai msaspgekvt mtcsasssvn ymhwyqqksg tspkrwiydt sklasgvpar

61 fsgsgsgtsy sltissmeae dtatyycqqw nsnpltfgag tklelk

[0123] Nucleic Acid Sequence Encoding the Murine IgGl Heavy Chain Constant Region Determined for 15D8, 20B4, 27H2, 2G4, and 4E7 (7D12) (SEQ ID NO: 34)

1 gccaaaacga cacccccatc tgtctatcca ctggcccctg gatctgctgc ccaaactaac

61 tccatggtga ccctgggatg cctggtcaag ggctatttcc ctgagccagt gacagtgacc

121 tggaactctg gatccctgtc cagcggtgtg cacaccttcc cagctgtcct gcagtctgac

181 ctctacactc tgagcagctc agtgactgtc ccctccagca cctggcccag cgagaccgtc 241 acctgcaacg ttgcccaccc ggccagcagc accaaggtgg acaagaaaat tgtgcccagg

301 gattgtggtt gtaagccttg catatgtaca gtcccagaag tatcatctgt cttcatcttc

361 cccccaaagc ccaaggatgt gctcaccatt actctgactc ctaaggtcac gtgtgttgtg

421 gtagacatca gcaaggatga tcccgaggtc cagttcagct ggtttgtaga tgatgtggag

481 gtgcacacag ctcagacgca accccgggag gagcagttca acagcacttt ccgctcagtc 541 agtgaacttc ccatcatgca ccaggactgg ctcaatggca aggagttcaa atgcagggtc

601 aacagtgcag ctttccctgc ccccatcgag aaaaccatct ccaaaaccaa aggcagaccg 661 aaggctccac aggtgtacac cattccacct cccaaggagc agatggccaa ggataaagtc 721 agtctgacct gcatgataac agacttcttc cctgaagaca ttactgtgga gtggcagtgg 781 aatgggcagc cagcggagaa ctacaagaac actcagccca tcatggacac agatggctct 841 tacttcgtct acagcaagct caatgtgcag aagagcaact gggaggcagg aaatactttc 901 acctgctctg tgttacatga gggcctgcac aaccaccata ctgagaagag cctctcccac 961 tctcctggta aa

[0124] Protein Sequence Defining the Murine IgGl Heavy Chain Constant Region Determined for 15D8, 20B4, 27H2, 2G4, and 4E7 (7D12) (SEQ ID NO: 35) 1 akttppsvyp lapgsaaqtn smvtlgclvk gyfpepvtvt wnsgslssgv htfpavlqsd

61 lytlsssvtv psstwpsetv tcnvahpass tkvdkkivpr dcgckpcict vpevssvfif

121 ppkpkdvlti tltpkvtcvv vdiskddpev qfswfvddve vhtaqtqpre eqfnstfrsv

181 selpimhqdw lngkefkcrv nsaafpapie ktisktkgrp kapqvytipp pkeqmakdkv

241 sltcmitdff peditvewqw ngqpaenykn tqpimdtdgs yfvysklnvq ksnweagntf 301 tcsvlheglh nhhtekslsh spgk

[0125] Nucleic Acid Sequence Encoding the Murine Kappa Light Chain Constant Region Determined for 15D8, 20B4, 27H2, 2G4, and 4E7 (7D12) (SEQ ID NO: 36)

1 cgggctgatg ctgcaccaac tgtatccatc ttcccaccat ccagtgagca gttaacatct 61 ggaggtgcct cagtcgtgtg cttcttgaac aacttctacc ccaaagacat caatgtcaag 121 tggaagattg atggcagtga acgacaaaat ggcgtcctga acagttggac tgatcaggac 181 agcaaagaca gcacctacag catgagcagc accctcacgt tgaccaagga cgagtatgaa 241 cgacataaca gctatacctg tgaggccact cacaagacat caacttcacc cattgtcaag 301 agcttcaaca ggaatgagtg t

[0126] Protein Sequence Defining the Murine Kappa Light Chain Constant Region Determined for 15D8, 20B4, 27H2, 2G4, and 4E7 (7D12) (SEQ ID NO: 37)

1 radaaptvsi fppsseqlts ggasvvcfln nfypkdmvk wkidgserqn gvlnswtdqd 61 skdstysmss tltltkdeye rhnsytceat hktstspivk sfnrnec

[0127] The amino acid sequences defining the immunoglobulin heavy chain variable regions for the antibodies produced in Example 1 are aligned in Figure 2. Amino terminal signal peptide sequences (for proper expression/secretion) are not shown. The sequences defining Complementary Determining Region (CDR) sequences (Kabat definition), CDR ₁ , CDR ₂ , and CDR ₃ , are identified by boxes. Figure 3 shows an alignment of the separate CDR ₁ , CDR ₂ , and CDR ₃ sequences for each of the antibodies.

[0128] The amino acid sequences defining the immunoglobulin light chain variable regions for the antibodies produced in Example 1 are aligned in Figure 4. Amino terminal signal peptide sequences (for proper expression/secretion) are not shown. The sequences defining CDR ₁ , CDR ₂ , and CDR ₃ are identified by boxes. Figure 5 shows an alignment of the separate CDR ₁ , CDR ₂ , and CDR ₃ sequences for each of the antibodies.

[0129] Monoclonal antibodies 4E7 and 7D12 have identical heavy chain sequences and identical light chain sequences. [0130] Table 1 is a concordance chart showing the SEQ ID NO. of each sequence discussed in this Example.

Table 1

[0131] To create the complete heavy or kappa chain antibody sequences, each variable sequence above is combined with its respective constant region. For example, a complete heavy chain comprises a heavy variable sequence followed by the murine IgGl heavy chain constant sequence and a complete kappa chain comprises a kappa variable sequence followed by the murine kappa light chain constant sequence.

[0132] The following sequences represent the actual or contemplated full length heavy and light chain sequences (i.e., containing both the variable and constant regions sequences) for each antibody described in this Example. The variable region sequences described herein can be ligated to each of a number of other constant region sequences known to those skilled in the art to produce active full length immunoglobulin heavy and light chains.

[0133] Nucleic Acid Sequence Encoding the Full Length 15D8 Heavy Chain Sequence

(15D8 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 38)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagctac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagcctac

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

361 gccaaaacga cacccccatc tgtctatcca ctggcccctg gatctgctgc ccaaactaac

421 tccatggtga ccctgggatg cctggtcaag ggctatttcc ctgagccagt gacagtgacc

481 tggaactctg gatccctgtc cagcggtgtg cacaccttcc cagctgtcct gcagtctgac

541 ctctacactc tgagcagctc agtgactgtc ccctccagca cctggcccag cgagaccgtc

601 acctgcaacg ttgcccaccc ggccagcagc accaaggtgg acaagaaaat tgtgcccagg

661 gattgtggtt gtaagccttg catatgtaca gtcccagaag tatcatctgt cttcatcttc

721 cccccaaagc ccaaggatgt gctcaccatt actctgactc ctaaggtcac gtgtgttgtg

781 gtagacatca gcaaggatga tcccgaggtc cagttcagct ggtttgtaga tgatgtggag

841 gtgcacacag ctcagacgca accccgggag gagcagttca acagcacttt ccgctcagtc 901 agtgaacttc ccatcatgca ccaggactgg ctcaatggca aggagttcaa atgcagggtc 961 aacagtgcag ctttccctgc ccccatcgag aaaaccatct ccaaaaccaa aggcagaccg

1021 aaggctccac aggtgtacac cattccacct cccaaggagc agatggccaa ggataaagtc 1081 agtctgacct gcatgataac agacttcttc cctgaagaca ttactgtgga gtggcagtgg 1141 aatgggcagc cagcggagaa ctacaagaac actcagccca tcatggacac agatggctct 1201 tacttcgtct acagcaagct caatgtgcag aagagcaact gggaggcagg aaatactttc 1261 acctgctctg tgttacatga gggcctgcac aaccaccata ctgagaagag cctctcccac 1321 tctcctggta aa [0134] Protein Sequence Defining the Full Length 15D8 Heavy Chain Sequence (15D8 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 39)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtsy

61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

121 akttppsvyp lapgsaaqtn smvtlgclvk gyfpepvtvt wnsgslssgv htfpavlqsd

181 lytlsssvtv psstwpsetv tcnvahpass tkvdkkivpr dcgckpcict vpevssvfif

241 ppkpkdvlti tltpkvtcvv vdiskddpev qfswfvddve vhtaqtqpre eqfnstfrsv

301 selpimhqdw lngkefkcrv nsaafpapie ktisktkgrp kapqvytipp pkeqmakdkv

361 sltcmitdff peditvewqw ngqpaenykn tqpimdtdgs yfvysklnvq ksnweagntf

421 tcsvlheglh nhhtekslsh spgk

[0135] Nucleic Acid Sequence Encoding the Full Length 15D8 Light Chain Sequence (15D8 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 40)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga

121 tcctccccca aaccctggat ttatctcaca tcctacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtggatctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa

241 gatgctgcca cttattactg ccagcagtgg agtagttacc cgctcacgtt cggtgctgga

301 accaagctgg agctgaaacg ggctgatgct gcaccaactg tatccatctt cccaccatcc

361 agtgagcagt taacatctgg aggtgcctca gtcgtgtgct tcttgaacaa cttctacccc

421 aaagacatca atgtcaagtg gaagattgat ggcagtgaac gacaaaatgg cgtcctgaac

481 agttggactg atcaggacag caaagacagc acctacagca tgagcagcac cctcacgttg

541 accaaggacg agtatgaacg acataacagc tatacctgtg aggccactca caagacatca

601 acttcaccca ttgtcaagag cttcaacagg aatgagtgt [0136] Protein Sequence Defining the Full Length 15D8 Light Chain Sequence (15D8 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 41)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt sylasgvpar

61 fsgsgsgtsy sltissmeae daatyycqqw ssypltfgag tklelkrada aptvsifpps

121 seqltsggas vvcflnnfyp kdinvkwkid gserqngvln swtdqdskds tysmsstltl

181 tkdeyerhns ytceathkts tspivksfnr nee

[0137] Nucleic Acid Sequence Encoding the Full Length 27H2 Heavy Chain Sequence

(27H2 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 42)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactaggtac

181 aaccagaagt tcaagggcaa ggccacaatg actgttgaca agtcctccag cacagcctac

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

361 gccaaaacga cacccccatc tgtctatcca ctggcccctg gatctgctgc ccaaactaac

421 tccatggtga ccctgggatg cctggtcaag ggctatttcc ctgagccagt gacagtgacc

481 tggaactctg gatccctgtc cagcggtgtg cacaccttcc cagctgtcct gcagtctgac

541 ctctacactc tgagcagctc agtgactgtc ccctccagca cctggcccag cgagaccgtc

601 acctgcaacg ttgcccaccc ggccagcagc accaaggtgg acaagaaaat tgtgcccagg

661 gattgtggtt gtaagccttg catatgtaca gtcccagaag tatcatctgt cttcatcttc 721 cccccaaagc ccaaggatgt gctcaccatt actctgactc ctaaggtcac gtgtgttgtg

781 gtagacatca gcaaggatga tcccgaggtc cagttcagct ggtttgtaga tgatgtggag

841 gtgcacacag ctcagacgca accccgggag gagcagttca acagcacttt ccgctcagtc

901 agtgaacttc ccatcatgca ccaggactgg ctcaatggca aggagttcaa atgcagggtc 961 aacagtgcag ctttccctgc ccccatcgag aaaaccatct ccaaaaccaa aggcagaccg

1021 aaggctccac aggtgtacac cattccacct cccaaggagc agatggccaa ggataaagtc

1081 agtctgacct gcatgataac agacttcttc cctgaagaca ttactgtgga gtggcagtgg

1141 aatgggcagc cagcggagaa ctacaagaac actcagccca tcatggacac agatggctct

1201 tacttcgtct acagcaagct caatgtgcag aagagcaact gggaggcagg aaatactttc 1261 acctgctctg tgttacatga gggcctgcac aaccaccata ctgagaagag cctctcccac

1321 tctcctggta aa

[0138] Protein Sequence Defining the Full Length 27H2 Heavy Chain Sequence (27H2 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 43) 1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtry

61 nqkfkgkatm tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

121 akttppsvyp lapgsaaqtn smvtlgclvk gyfpepvtvt wnsgslssgv htfpavlqsd

181 lytlsssvtv psstwpsetv tcnvahpass tkvdkkivpr dcgckpcict vpevssvfif

241 ppkpkdvlti tltpkvtcvv vdiskddpev qfswfvddve vhtaqtqpre eqfnstfrsv 301 selpimhqdw lngkefkcrv nsaafpapie ktisktkgrp kapqvytipp pkeqmakdkv

361 sltcmitdff peditvewqw ngqpaenykn tqpimdtdgs yfvysklnvq ksnweagntf 421 tcsvlheglh nhhtekslsh spgk

[0139] Nucleic Acid Sequence Encoding the Full Length 27H2 Light Chain Sequence (27H2 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 44)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga

121 tcctccccca aaccctggat ttatctcaca tccaacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa 241 gatgctgcca cttattactg ccagcagtgg agtagtaacc cgctcacgtt cggtgctggg

301 accaagctgg agctgaaacg ggctgatgct gcaccaactg tatccatctt cccaccatcc

361 agtgagcagt taacatctgg aggtgcctca gtcgtgtgct tcttgaacaa cttctacccc

421 aaagacatca atgtcaagtg gaagattgat ggcagtgaac gacaaaatgg cgtcctgaac

481 agttggactg atcaggacag caaagacagc acctacagca tgagcagcac cctcacgttg 541 accaaggacg agtatgaacg acataacagc tatacctgtg aggccactca caagacatca

601 acttcaccca ttgtcaagag cttcaacagg aatgagtgt

[0140] Protein Sequence Defining the Full Length 27H2 Light Chain Sequence (27H2 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 45) 1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt snlasgvpar

61 fsgsgsgtsy sltissmeae daatyycqqw ssnpltfgag tklelkrada aptvsifpps

121 seqltsggas vvcflnnfyp kdinvkwkid gserqngvln swtdqdskds tysmsstltl

181 tkdeyerhns ytceathkts tspivksfnr nee

[0141] Nucleic Acid Sequence Encoding the Full Length 2G4 Heavy Chain Sequence (2G4 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 46)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcaca agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagggac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag tacagcctac 241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

361 gccaaaacga cacccccatc tgtctatcca ctggcccctg gatctgctgc ccaaactaac

421 tccatggtga ccctgggatg cctggtcaag ggctatttcc ctgagccagt gacagtgacc

481 tggaactctg gatccctgtc cagcggtgtg cacaccttcc cagctgtcct gcagtctgac 541 ctctacactc tgagcagctc agtgactgtc ccctccagca cctggcccag cgagaccgtc

601 acctgcaacg ttgcccaccc ggccagcagc accaaggtgg acaagaaaat tgtgcccagg

661 gattgtggtt gtaagccttg catatgtaca gtcccagaag tatcatctgt cttcatcttc

721 cccccaaagc ccaaggatgt gctcaccatt actctgactc ctaaggtcac gtgtgttgtg 781 gtagacatca gcaaggatga tcccgaggtc cagttcagct ggtttgtaga tgatgtggag

841 gtgcacacag ctcagacgca accccgggag gagcagttca acagcacttt ccgctcagtc

901 agtgaacttc ccatcatgca ccaggactgg ctcaatggca aggagttcaa atgcagggtc

961 aacagtgcag ctttccctgc ccccatcgag aaaaccatct ccaaaaccaa aggcagaccg

1021 aaggctccac aggtgtacac cattccacct cccaaggagc agatggccaa ggataaagtc 1081 agtctgacct gcatgataac agacttcttc cctgaagaca ttactgtgga gtggcagtgg

1141 aatgggcagc cagcggagaa ctacaagaac actcagccca tcatggacac agatggctct

1201 tacttcgtct acagcaagct caatgtgcag aagagcaact gggaggcagg aaatactttc

1261 acctgctctg tgttacatga gggcctgcac aaccaccata ctgagaagag cctctcccac

1321 tctcctggta aa

[0142] Protein Sequence Defining the Full Length 2G4 Heavy Chain Sequence (2G4 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 47)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtrd

61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa 121 akttppsvyp lapgsaaqtn smvtlgclvk gyfpepvtvt wnsgslssgv htfpavlqsd

181 lytlsssvtv psstwpsetv tcnvahpass tkvdkkivpr dcgckpcict vpevssvfif

241 ppkpkdvlti tltpkvtcvv vdiskddpev qfswfvddve vhtaqtqpre eqfnstfrsv

301 selpimhqdw lngkefkcrv nsaafpapie ktisktkgrp kapqvytipp pkeqmakdkv

361 sltcmitdff peditvewqw ngqpaenykn tqpimdtdgs yfvysklnvq ksnweagntf 421 tcsvlheglh nhhtekslsh spgk

[0143] Nucleic Acid Sequence Encoding the Full Length 2G4 Light Chain Sequence (2G4 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 48)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc 61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga

121 tcctccccca aaccctggat ttatctcaca tccaacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa

241 gatgctgcca cttattactg ccagcagtgg agtagtaacc cgctcacgtt cggtgctggg

301 accaagctgg agctgaaacg ggctgatgct gcaccaactg tatccatctt cccaccatcc 361 agtgagcagt taacatctgg aggtgcctca gtcgtgtgct tcttgaacaa cttctacccc

421 aaagacatca atgtcaagtg gaagattgat ggcagtgaac gacaaaatgg cgtcctgaac

481 agttggactg atcaggacag caaagacagc acctacagca tgagcagcac cctcacgttg

541 accaaggacg agtatgaacg acataacagc tatacctgtg aggccactca caagacatca

601 acttcaccca ttgtcaagag cttcaacagg aatgagtgt

[0144] Protein Sequence Defining the Full Length 2G4 Light Chain Sequence (2G4 Kappa

Chain Variable Region and Constant Region) (SEQ ID NO: 49)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt snlasgvpar

61 fsgsgsgtsy sltissmeae daatyycqqw ssnpltfgag tklelkrada aptvsifpps 121 seqltsggas vvcflnnfyp kdinvkwkid gserqngvln swtdqdskds tysmsstltl

181 tkdeyerhns ytceathkts tspivksfnr nee

[0145] Nucleic Acid Sequence Encoding the Full Length 4E7 (7D12) Heavy Chain

Sequence (4E7 (7D12) Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 50)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactaggtac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagcctac 241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

361 gccaaaacga cacccccatc tgtctatcca ctggcccctg gatctgctgc ccaaactaac

421 tccatggtga ccctgggatg cctggtcaag ggctatttcc ctgagccagt gacagtgacc

481 tggaactctg gatccctgtc cagcggtgtg cacaccttcc cagctgtcct gcagtctgac

541 ctctacactc tgagcagctc agtgactgtc ccctccagca cctggcccag cgagaccgtc

601 acctgcaacg ttgcccaccc ggccagcagc accaaggtgg acaagaaaat tgtgcccagg

661 gattgtggtt gtaagccttg catatgtaca gtcccagaag tatcatctgt cttcatcttc

721 cccccaaagc ccaaggatgt gctcaccatt actctgactc ctaaggtcac gtgtgttgtg

781 gtagacatca gcaaggatga tcccgaggtc cagttcagct ggtttgtaga tgatgtggag

841 gtgcacacag ctcagacgca accccgggag gagcagttca acagcacttt ccgctcagtc

901 agtgaacttc ccatcatgca ccaggactgg ctcaatggca aggagttcaa atgcagggtc

961 aacagtgcag ctttccctgc ccccatcgag aaaaccatct ccaaaaccaa aggcagaccg

1021 aaggctccac aggtgtacac cattccacct cccaaggagc agatggccaa ggataaagtc

1081 agtctgacct gcatgataac agacttcttc cctgaagaca ttactgtgga gtggcagtgg

1141 aatgggcagc cagcggagaa ctacaagaac actcagccca tcatggacac agatggctct

1201 tacttcgtct acagcaagct caatgtgcag aagagcaact gggaggcagg aaatactttc

1261 acctgctctg tgttacatga gggcctgcac aaccaccata ctgagaagag cctctcccac

1321 tctcctggta aa

[0146] Protein Sequence Defining the Full Length 4E7 (7D12) Heavy Chain Sequence (4E7 (7D12) Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 51)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtry

61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa

121 akttppsvyp lapgsaaqtn smvtlgclvk gyfpepvtvt wnsgslssgv htfpavlqsd

181 lytlsssvtv psstwpsetv tcnvahpass tkvdkkivpr dcgckpcict vpevssvfif

241 ppkpkdvlti tltpkvtcvv vdiskddpev qfswfvddve vhtaqtqpre eqfnstfrsv

301 selpimhqdw lngkefkcrv nsaafpapie ktisktkgrp kapqvytipp pkeqmakdkv

361 sltcmitdff peditvewqw ngqpaenykn tqpimdtdgs yfvysklnvq ksnweagntf

421 tcsvlheglh nhhtekslsh spgk

[0147] Nucleic Acid Sequence Encoding the Full Length 4E7 (7D12)Light Chain Sequence (4E7 (7D12) Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 52)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga

121 tcctccccca aaccctggat ttatctcaca tccaacctgg cttctggagt ccctgctcgc

181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa

241 gatgctgcca cttattactg ccagcagtgg agtagtaacc cgctcacgtt cggtgctggg

301 accaagctgg agctgaaacg ggctgatgct gcaccaactg tatccatctt cccaccatcc

361 agtgagcagt taacatctgg aggtgcctca gtcgtgtgct tcttgaacaa cttctacccc

421 aaagacatca atgtcaagtg gaagattgat ggcagtgaac gacaaaatgg cgtcctgaac

481 agttggactg atcaggacag caaagacagc acctacagca tgagcagcac cctcacgttg

541 accaaggacg agtatgaacg acataacagc tatacctgtg aggccactca caagacatca

601 acttcaccca ttgtcaagag cttcaacagg aatgagtgt

[0148] Protein Sequence Defining the Full Length 4E7 (7D12) Light Chain Sequence (4E7 (7D12) Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 53)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt snlasgvpar

61 fsgsgsgtsy sltissmeae daatyycqqw ssnpltfgag tklelkrada aptvsifpps

121 seqltsggas vvcflnnfyp kdinvkwkid gserqngvln swtdqdskds tysmsstltl

181 tkdeyerhns ytceathkts tspivksfnr nee [0149] Nucleic Acid Sequence Encoding the Full Length 20B4 Heavy Chain Sequence

(20B4 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 54) i gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta ctcactcact gactacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagctac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagccttc

241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagatcgttg

301 ggacctgatt ttgactactg gggccaaggc accactctca cagtctcctc agccaaaacg

361 acacccccat ctgtctatcc actggcccct ggatctgctg cccaaactaa ctccatggtg

421 accctgggat gcctggtcaa gggctatttc cctgagccag tgacagtgac ctggaactct

481 ggatccctgt ccagcggtgt gcacaccttc ccagctgtcc tgcagtctga cctctacact

541 ctgagcagct cagtgactgt cccctccagc acctggccca gcgagaccgt cacctgcaac

601 gttgcccacc cggccagcag caccaaggtg gacaagaaaa ttgtgcccag ggattgtggt

661 tgtaagcctt gcatatgtac agtcccagaa gtatcatctg tcttcatctt ccccccaaag

721 cccaaggatg tgctcaccat tactctgact cctaaggtca cgtgtgttgt ggtagacatc

781 agcaaggatg atcccgaggt ccagttcagc tggtttgtag atgatgtgga ggtgcacaca

841 gctcagacgc aaccccggga ggagcagttc aacagcactt tccgctcagt cagtgaactt

901 cccatcatgc accaggactg gctcaatggc aaggagttca aatgcagggt caacagtgca

961 gctttccctg cccccatcga gaaaaccatc tccaaaacca aaggcagacc gaaggctcca

1021 caggtgtaca ccattccacc tcccaaggag cagatggcca aggataaagt cagtctgacc

1081 tgcatgataa cagacttctt ccctgaagac attactgtgg agtggcagtg gaatgggcag

1141 ccagcggaga actacaagaa cactcagccc atcatggaca cagatggctc ttacttcgtc

1201 tacagcaagc tcaatgtgca gaagagcaac tgggaggcag gaaatacttt cacctgctct

1261 gtgttacatg agggcctgca caaccaccat actgagaaga gcctctccca ctctcctggt

1321 aaa

[0150] Protein Sequence Defining the Full Length 20B4 Heavy Chain Sequence (20B4 Heavy Chain Variable Region and IgGl Constant Region) (SEQ ID NO: 55)

1 eiqlqqsgpe lvkpgasvkv sckasgyslt dynmywvkqs hgkslewigy idpynggtsy

61 nqkfkgkatl tvdkssstaf mhlnsltsed savyycarsl gpdfdywgqg ttltvssakt

121 tppsvyplap gsaaqtnsmv tlgclvkgyf pepvtvtwns gslssgvhtf pavlqsdlyt

181 lsssvtvpss twpsetvtcn vahpasstkv dkkivprdcg ckpcictvpe vssvfifppk

241 pkdvltitlt pkvtcvvvdi skddpevqfs wfvddvevht aqtqpreeqf nstfrsvsel

301 pimhqdwlng kefkcrvnsa afpapiekti sktkgrpkap qvytipppke qmakdkvslt

361 cmitdffped ltvewqwngq paenykntqp imdtdgsyfv ysklnvqksn weagntftcs

421 vlheglhnhh tekslshspg k

[0151] Nucleic Acid Sequence Encoding the Full Length 20B4 Light Chain Sequence (20B4 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 56)

1 caaattgttc tcacccagtc tccagcaatc atgtctgcat ctccagggga gaaggtcacc

61 atgacctgca gtgccagctc aagtgtaaat tacatgcact ggtaccagca gaagtcaggc

121 acctccccca aaagatggat ttatgacaca tccaaactgg cttctggagt ccctgctcgc

181 ttcagtggca gtgggtctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa

241 gatactgcca cttattactg tcaacagtgg aatagtaacc cactcacgtt cggtgcgggg

301 accaagctgg agctgaaacg ggctgatgct gcaccaactg tatccatctt cccaccatcc

361 agtgagcagt taacatctgg aggtgcctca gtcgtgtgct tcttgaacaa cttctacccc

421 aaagacatca atgtcaagtg gaagattgat ggcagtgaac gacaaaatgg cgtcctgaac

481 agttggactg atcaggacag caaagacagc acctacagca tgagcagcac cctcacgttg

541 accaaggacg agtatgaacg acataacagc tatacctgtg aggccactca caagacatca

601 acttcaccca ttgtcaagag cttcaacagg aatgagtgt [0152] Protein Sequence Defining the Full Length 20B4 Light Chain Sequence (20B4 Kappa Chain Variable Region and Constant Region) (SEQ ID NO: 57)

1 qivltqspai msaspgekvt mtcsasssvn ymhwyqqksg tspkrwiydt sklasgvpar 61 fsgsgsgtsy sltissmeae dtatyycqqw nsnpltfgag tklelkrada aptvsifpps 121 seqltsggas vvcflnnfyp kdinvkwkid gserqngvln swtdqdskds tysmsstltl 181 tkdeyerhns ytceathkts tspivksfnr nee

[0153] For convenience, Table 2 provides a concordance chart showing the correspondence between the full length sequences of the antibodies discussed in this Example with those presented in the Sequence Listing.

Table 2

Example 3 - Binding Affinities of Anti-FGFR3 Monoclonal Antibodies

[0154] The binding affinities and kinetics of interaction of the monoclonal antibodies (15D8, 27H2, 2G4, and 4E7(7D12)) produced in Example 1 against recombinant human FGFR3 (HIb and IIIc isoforms) Fc fusion protein (rhFGFR3 IHb Fc or rhFGFR3 IIIc Fc) were measured by surface plasmon resonance using a Biacore™ TlOO (Biacore) instrument.

[0155] Rabbit anti-mouse immunoglobulins (Biacore, Catalog No. BR- 1005- 14) were immobilized on carboxymethylated dextran CM4 sensor chips (Biacore, Catalog No. BR- 1005- 34) by amine coupling (Biacore, Catalog No. BR- 1000-50) using a standard coupling protocol according to manufacturer's instructions. The analyses were performed at 25 ⁰ C and 37 ⁰ C using PBS (Invitrogen, Catalog No. 14040-133) containing 0.05% surfactant P20 (Biacore, Catalog No. BR- 1000-54) as running buffer.

[0156] The antibodies were captured in an individual flow cell at a flow rate of 10 μl/min. Injection time was varied for each antibody to yield approximately 40-50 RU of antibody captured for each cycle. Buffer or rhFGFR3 IHb Fc (R&D Systems, Catalog No. 1264-FR- 050) or rhFGFR3 IIIc Fc (R&D Systems, Catalog No. 766-FR-050) diluted in running buffer was injected sequentially over a reference surface (no antibody captured) and the active surface (antibody to be tested) for 300 sec at 60 μl/min. The dissociation phase was monitored for 30 minutes. The surface was then regenerated with two 60-seconds injection of 10 mM Glycine- HCl, pH 1.7 (made from Glycine pH 1.5 (Biacore, Catalog No. BR- 1003-54) and pH 2.0 (Biacore, Catalog No. BR- 1003-55)) at a flow rate of 60 μl/min. rhFGFR3 Fc concentrations tested were 0.62 nM to 40 nM.

[0157] Kinetic parameters were determined using the kinetic function of the BIAevalutation software (Biacore) with double reference subtraction. Kinetic parameters for each antibody, k _a (association rate constant), k _< j (dissociation rate constant) and K _D (equilibrium dissociation constant) were determined. Kinetic values of the monoclonal antibodies at 25 ⁰ C are summarized in Table 3.

Table 3

Standard deviation not calculated when n < 3

[0158] Kinetic values of the monoclonal antibodies at 37 ⁰ C are summarized in Table 4. Table 4

Example 4 - Neutralization Activity of Anti-hFGFR3 Antibodies

[0159] The antibodies produced in Example 1 were characterized for their ability to inhibit recombinant hFGFR3 IHb binding to FGFl (also known as FGF acidic).

[0160] The antibodies were tested by ECL (Electrochemiluminescence) assay for inhibition of hFGFR3 IHB binding to FGF-I. MA2400 96- well high binding plates (Meso Scale Discovery, Catalog No. L15XB-6) were coated with 25 μl of 0.8 μg/mL FGF-I (R&D Systems, Catalog No. 232-FA-025) in PBS (Invitrogen, Catalog No. 14040-133) for 1 hour at room temperature with agitation. The plates then were washed 3 times with PBS and blocked with 200 μl of PBS containing 5% BSA (Sera Care Life Sciences, Catalog No. AP-4510-80) and 5 μg/mL heparin (Sigma, Catalog No. H4784) for 1 hour at room temperature. The antibodies (concentration range: 0.029-30 μg/mL) were incubated for 1 hour at room temperature with 1.7 μg/mL rhFGFR3 HIb Fc (R&D Systems, Catalog No. 1264-FR-050) and 5 μg/mL heparin. After washing the plates 3 times with PBS, 25 μl of the antibody- receptor mixture was added to the plates for another hour at room temperature with agitation. The plates were washed three times with PBS and incubated with 25 μl of 1 μg/mL ST-anti-human IgG antibody (Meso Scale Discovery, Catalog No. R32AJ-1) for 1 hour at room temperature with agitation. The plates then were washed 3 times with PBS, and 150 μl of IX read buffer (Meso Scale Discovery, Catalog No. R92TC-1) was added to each well before the plates were analyzed on a Sector Imager 2400 (Meso Scale Discovery) instrument.

[0161] The interaction of FGFl with FGFR3 was inhibited by 4E7, 7D12, 15D8, 27H2, 2G4, and 20B4 IgGl as shown in Figure 6. The interaction of FGFl with FGFR3 was also inhibited by Fab fragments as shown in Figure 7 (20B4 not shown). [0162] The IC ₅₀ and maximum percent inhibition values for the murine anti-human FGFR3 antibodies (IgGl) and Fab fragments (Fab) were calculated and are summarized in Table 5.

Table 5

* Standard deviation not calculated when n < 3

[0163] The results demonstrate that all the antibodies (i.e., 15D8, 27H2, 2G4, 4E7, 7D12) except for 20B4 efficiently neutralize hFGFR3 binding to FGFl. The 2G4 Fab fragment neutralized hFGFR3 binding to FGFl better than the 2G4 IgGl antibody.

Example 5 - Anti-Proliferative Activity of Anti-hFGFR3 Antibodies [0164] In this Example, the antibodies produced in Example 1 were characterized for their ability to inhibit FGFl dependent proliferation of cells.

[0165] FDCP-I cells (mouse bone marrow cells obtained from German Collection of Microorganisms and Cell Cultures) were transfected with plasmids encoding human FGFR3 IHb, FGFR3 IHc, or a mutant variant G380R (an activating mutation associated with the skeletal disorder, achondroplasia (Webster and Donoghue (1996) EMBO J. 15:520-527) by electroporation and selected with G418 (600 μg/mL). Single clones were isolated and tested for their FGFl -dependent proliferation in the absence of IL3 containing WEHI-conditioned medium. FDCP-FGFR3 IHb #122, FDCP-FGFR3 IIIc #109, FGFR3 IIIc G380R #1 exhibited FGF-I induced proliferation in the absence of IL3. [0166] To screen for antagonistic FGFR3 antibodies, hybridoma supernatants containing FGFR3 antibodies were added to FDCP-FGFR3 IHb #122 or FDCP-FGFR3 IIIc #109 cells cultured in basic growth medium (70% ISCOVE' s Modified Dulbecco's Medium (Invitrogen, Catalog No. 12440-053), 20% horse serum (Invitrogen, Catalog No. 26050-088) and 10% WEHI-culture medium (90% ISCOVE' s MDM + 10% FBS (Invitrogen, Catalog No. 10438- 026) + 2 mM L-glutamine (Invitrogen, Catalog No. 25030-081) + 0.0025 mM mercaptoethanol (Invitrogen, Catalog No. 21985-023))) at a 1:1 ratio (volume) in a 96-well plate (70,000 cells/ well) in the absence or presence of FGFl (8ng/mL) and heparin (5 μg/mL). MTT (3-(4,5- Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays were conducted two to three days post FGFl stimulation. Top antagonistic antibodies were selected for further characterization.

[0167] To test the effect of FGFR3 antibodies on the proliferation of various FGFR3-driven FDCP cells, varying amounts of antibodies were added to the cells along with FGFl (8ng/mL) and heparin (50 μg/mL). The cells were cultured in basic growth medium (70% ISCOVE' s, 20% horse serum and 10% WEHI-culture medium (90% Iscove's MDM + 10% FBS + 2 mM L-glutamine + 0.0025 mM mercaptoethanol)) in a 96-well plate (70,000 cells/ well). The final concentration of FGFl and heparin used in the assay is 8 ng/mL and 5 μg/mL, respectively. MTT assay was conducted one to three days post FGFl stimulation.

[0168] An example of the dose dependent inhibition of FDCP-FGFR3c cell proliferation by murine anti-human FGFR3 antibodies is shown in Figure 8. Inhibition data of FDCP-FGFR3 cell line proliferation with monoclonal antibodies (15D8, 27H2, 4E7, 2G4, and 20B4) are summarized in Table 6.

Table 6

[0169] The results in Table 6 demonstrate that all the antibodies (i.e., 15D8, 27H2, 4E7, 2G4) except for 20B4 strongly inhibited FGFl induced proliferation in FDCP-FGFR3 IHb and FDCP-FGFR3 IIIc cell lines. Inhibition by 20B4 was maximally 40% and an IC ₅₀ value was not calculated. The antibodies also have an inhibitory effect on FGFR3 IIIc G380R, a mutant variant that is correlated with the skeletal disorder, achondroplasia.

Example 6 - Tumor Inhibition in OPM-2 Xenograft Model

[0170] The ability of murine monoclonal antibodies of the invention to inhibit tumor growth was tested in an OPM-2 xenograft model. OPM-2 cells were grown in culture at 37°C in an atmosphere containing 5% CO ₂ , using RMPI medium (Invitrogen) containing 10% fetal bovine serum (Invitrogen). Cells were inoculated subcutaneously into the flank of 8-week old female CB.17 SCID mice (Taconic Labs) with 5 x 10 ⁶ cells per mouse in 50% matrigel (BD Biosciences, Cat No. 356237).

[0171] Tumor measurements were taken twice weekly using vernier calipers. Tumor volume was calculated using the formula: width x width x length/2. When tumors reached approximately 150 mm ³ , the mice were randomized into 4 groups of 10 mice each.

[0172] Each group (10 mice each) received one of the following treatments: murine IgG control at 20 mg/kg, or 15D8 at 5, 10 or 20 mg/kg. Treatment was given intra-peritoneal twice weekly for 2 weeks. Each 15D8 treatment group demonstrated similar tumor growth inhibition of 70% (p<0.001) as shown in Figure 9. All 15D8 treatments were well-tolerated with no significant body weight loss.

[0173] A study was performed to compare four of the murine antibodies. Each group (10 mice each) received one of the following treatments: murine IgG, 15D8, 4E7, 27H2, or 2G4, each dosed at 1 mg/kg. As can be seen in Figure 10, the four murine antibodies demonstrated similar efficacy at approximately 40% tumor growth inhibition in this model. [0174] Thus, these results demonstrate that treatment with the murine 15D8, 4E7, 27H2, and 2G4 antibodies slows tumor development.

Example 7 - Humanization of Anti-FGFR3 Antibodies a. Construction of Humanized and Chimeric Anti-FGFR3 Antibodies

[0175] This Example describes the humanization of the murine antibody designated 15D8, and the characterization of the resulting humanized antibody. The humanized anti-FGFR3 antibody was designed using the SUPERHUMANIZATION™ method (Arana Therapeutics Ltd. and Hwang, W.Y. et al. (2005) METHODS 36:35-42). Certain framework residues were converted to murine 15D8 residues to improve the antibody's affinity toward FGFR3, and the antibody's activity in inhibiting the biological activity of FGFR3, or both. The designed amino acid sequences were converted to codon-optimized DNA sequences, including (in the following order): 5' HindIII restriction site, Kozak consensus sequence, amino terminal signal sequence, humanized variable region, human IgGl or Kappa constant region, stop codon, and a 3' EcoRI restriction site.

[0176] Chimeric (murine variable region and human constant region) 15D8 heavy (human IgGl) and light (human Kappa) chains were also constructed. The murine variable regions were fused to the human constant region using overlap extension PCR, including (in the following order): 5' HindIII restriction site, Kozak consensus sequence, amino terminal signal sequence, mouse variable region, human IgGl or Kappa constant region, stop codon, and 3' EcoRI restriction site.

[0177] The humanized and chimeric IgGl heavy chains were subcloned into pEE6.4 (Lonza Biologies) via HindIII and EcoRI sites. The humanized and chimeric Kappa light chains were subcloned into pEE14.4 (Lonza Biologies) via HindIII and EcoRI sites.

[0178] Humanized antibody chains or chimeric antibody chains were transiently transfected into 293T cells to produce antibody for purification and subsequent in vitro analysis. Binding of the chimeric and humanized antibodies to human FGFR3 was measured as described below. The results are summarized in Table 9. Additionally, the chimeric and humanized antibodies were tested for inhibition of FGF-stimulated proliferation of FDCP-FGFR3b cells (as described in Example 5). The results are summarized in Table 10.

[0179] Each of the possible combinations of immunoglobulin heavy chain and immunoglobulin light chain variable regions are set forth in Table 7A. Table 7A

[0180] Each of the possible combinations of immunoglobulin heavy chains and immunoglobulin light chains are set forth in Table 7B.

Table 7B

[0181] The antibody constructs containing the full length chimeric or humanized immunoglobulin heavy and light chains are designated below:

Chimeric 15D8 = Full Length Chimeric 15D8 Heavy Chain (Mouse Variable Region and Human IgGl Constant Region) (SEQ ID NO: 66) plus Full Length Chimeric 15D8 Light Chain (Mouse Variable Region and Human Kappa Constant Region) (SEQ ID NO: 68)

Humanized 15D8 = Full Length Humanized 15D8 Heavy Chain (Humanized Variable Region and Human IgGl Constant Region) (SEQ ID NO: 74) plus Full Length Humanized 15D8 Light Chain (Humanized Variable Region and Human Kappa Constant Region) (SEQ ID NO: 76) [0182] The nucleic acid sequences encoding and the polypeptide sequences defining the chimeric and humanized antibodies are summarized below (amino terminal signal sequences are not shown). CDR sequences (Kabat definition) are shown in bold/underlined in the amino acid sequences.

[0183] Nucleic Acid Sequence Encoding the Full Length Chimeric 15D8 Heavy Chain (Mouse Variable Region and Human IgGl Constant Region) (SEQ ID NO: 65)

1 gagatccagc tgcagcagtc tggacctgag ctggtgaagc ctggggcttc agtgaaggta

61 tcctgcaagg cttctggtta tgcattcact agctacaaca tgtactgggt gaagcagagc

121 catggaaaga gccttgagtg gattggatat attgatcctt acaatggtgg tactagctac

181 aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagcctac 241 atgcatctca acagcctgac atctgaggac tctgcagtct attactgtgc aagagagggg

301 ggtaactacg aggcctggtt tgcttactgg ggccaaggga ctctggtcac tgtctctgca

361 gcctccacca agggcccatc ggtcttcccc ctggcaccct cctccaagag cacctctggg

421 ggcacagcgg ccctgggctg cctggtcaag gactacttcc ccgaaccggt gacggtgtcg

481 tggaactcag gcgccctgac cagcggcgtg cacaccttcc cggctgtcct acagtcctca 541 ggactctact ccctcagcag cgtggtgacc gtgccctcca gcagcttggg cacccagacc

601 tacatctgca acgtgaatca caagcccagc aacaccaagg tggacaagag agttgagccc

661 aaatcttgtg acaaaactca cacatgccca ccgtgcccag cacctgaact cctgggggga

721 ccgtcagtct tcctcttccc cccaaaaccc aaggacaccc tcatgatctc ccggacccct 781 gaggtcacat gcgtggtggt ggacgtgagc cacgaagacc ctgaggtcaa gttcaactgg

841 tacgtggacg gcgtggaggt gcataatgcc aagacaaagc cgcgggagga gcagtacaac

901 agcacgtacc gtgtggtcag cgtcctcacc gtcctgcacc aggactggct gaatggcaag

961 gagtacaagt gcaaggtctc caacaaagcc ctcccagccc ccatcgagaa gaccatctcc

1021 aaagccaaag ggcagccccg agaaccacag gtgtacaccc tgcccccatc ccgggaggag 1081 atgaccaaga accaggtcag cctgacctgc ctggtcaaag gcttctatcc cagcgacatc

1141 gccgtggagt gggagagcaa tgggcagccg gagaacaact acaagaccac gcctcccgtg

1201 ctggactccg acggctcctt cttcctctac agcaagctca ccgtggacaa gagcaggtgg

1261 cagcagggga acgtcttctc atgctccgtg atgcatgagg ctctgcacaa ccactacacg

1321 cagaagagcc tctccctgtc tccgggtaaa

[0184] Protein Sequence Defining the Full Length Chimeric 15D8 Heavy Chain (Mouse Variable Region and Human IgGl Constant Region) (SEQ ID NO: 66)

1 eiqlqqsgpe lvkpgasvkv sckasgyaft synmywvkqs hgkslewigy idpynggtsy

61 nqkfkgkatl tvdkssstay mhlnsltsed savyycareg gnyeawfayw gqgtlvtvsa 121 astkgpsvfp lapsskstsg gtaalgclvk dyfpepvtvs wnsgaltsgv htfpavlqss

181 glyslssvvt vpssslgtqt yicnvnhkps ntkvdkrvep kscdkthtcp pcpapellgg

241 psvflfppkp kdtlmisrtp evtcvvvdvs hedpevkfnw yvdgvevhna ktkpreeqyn

301 styrvvsvlt vlhqdwlngk eykckvsnka lpapiektis kakgqprepq vytlppsree

361 mtknqvsltc lvkgfypsdi avewesngqp ennykttppv ldsdgsffly skltvdksrw 421 qqgnvfscsv mhealhnhyt qkslslspgk

[0185] Nucleic Acid Sequence Encoding the Full Length Chimeric 15D8 Light Chain (Mouse Variable Region and Human Kappa Constant Region) (SEQ ID NO: 67)

1 caaattgttc tcacccagtc tccagcactc atgtctgcat ctccagggga gaaggtcacc 61 atgacctgca gtgccagctc aagtgtaagt tacatgtact ggtaccagca gaagccaaga 121 tcctccccca aaccctggat ttatctcaca tcctacctgg cttctggagt ccctgctcgc 181 ttcagtggca gtggatctgg gacctcttac tctctcacaa tcagcagcat ggaggctgaa 241 gatgctgcca cttattactg ccagcagtgg agtagttacc cgctcacgtt cggtgctgga 301 accaagctgg agctgaaacg aactgtggct gcaccatctg tcttcatctt cccgccatct 361 gatgagcagt tgaaatctgg aactgcctct gttgtgtgcc tgctgaataa cttctatccc 421 agagaggcca aagtacagtg gaaggtggat aacgccctcc aatcgggtaa ctcccaggag 481 agtgtcacag agcaggacag caaggacagc acctacagcc tcagcagcac cctgacgctg 541 agcaaagcag actacgagaa acacaaagtc tacgcctgcg aagtcaccca tcagggcctg 601 agctcgcccg tcacaaagag cttcaacagg ggagagtgt

[0186] Protein Sequence Defining the Full Length Chimeric 15D8 Light Chain (Mouse Variable Region and Human Kappa Constant Region) (SEQ ID NO: 68)

1 qivltqspal msaspgekvt mtcsasssvs ymywyqqkpr sspkpwiylt sylasgvpar 61 fsgsgsgtsy sltissmeae daatyycqqw ssypltfgag tklelkrtva apsvfifpps 121 deqlksgtas vvcllnnfyp reakvqwkvd nalqsgnsqe svteqdskds tyslsstltl 181 skadyekhkv yacevthqgl sspvtksfnr gee [0187] Nucleic Acid Sequence Encoding Humanized 15D8 (Hul5D8) Heavy Chain Variable Region (SEQ ID NO: 69)

1 gaggtccaac tggtgcaatc tggggctgag gtcaagaaac ccggggaatc tctcaaaatt

61 tcatgcaaag gttctggtta cagtttcacc tcatataaca tgtactgggt taggcagatg 121 cctggtaaag gcttggagtg gatggggtac attgatccct ataacggcgg cactagttac

181 aatcagaagt tcaagggcaa ggccacattg actgttgaca agtccatctc aactgcttac

241 ctgcaatggt cctctctcaa agccagcgac actgctatgt actactgcgc aagggaggga

301 ggcaattacg aggcttggtt cgcttattgg ggacaaggca ctcttgtcac cgtctcctca

[0188] Protein Sequence Defining Humanized 15D8 (Hul5D8) Heavy Chain Variable Region (SEQ ID NO: 70)

1 evqlvqsgae vkkpgeslki sckgsgysft synmywvrqm pgkglewmgy_ idpynggtsy

61 nqkfkgkatl tvdksistay lqwsslkasd tamyycareg gnyeawfayw gqgtlvtvss

[0189] Nucleic Acid Sequence Encoding Humanized 15D8 (Hul5D8) Light Chain Variable Region (SEQ ID NO: 71)

1 gatatccaac tcacccagtc cccttcatcc ctgtctgcat cagtcgggga cagagtgaca

61 attacttgtt ccgccagctc tagtgtctca tacatgtatt ggtttcagca aaagccagga

121 aaagctccca aacccctgat ctatctgacc agctatctgg caagcggcgt gccttctcgg 181 ttcagtggat cagggtccgg tacagacttt accctgacta ttagcagtct gcaaccagag

241 gacttcgcca cttattactg ccaacagtgg agttcatatc ccctgacttt tggcggaggg

301 accaaggtcg agatcaag

[0190] Protein Sequence Defining Humanized 15D8 (Hul5D8) Light Chain Variable Region (SEQ ID NO: 72) 1 diqltqspss lsasvgdrvt itcsasssvs ymywfqqkpg kapkpliyl^ sylasgvpsr 61 fsgsgsgtdf tltisslqpe dfatyycqqw ssypltfggg tkveik

[0191] Nucleic Acid Sequence Defining the Full Length Humanized 15D8 (Hul5D8) Heavy Chain (Humanized Variable Region and Human IgGl Constant Region) (SEQ ID NO: 73) 1 gaggtccaac tggtgcaatc tggggctgag gtcaagaaac ccggggaatc tctcaaaatt

61 tcatgcaaag gttctggtta cagtttcacc tcatataaca tgtactgggt taggcagatg

121 cctggtaaag gcttggagtg gatggggtac attgatccct ataacggcgg cactagttac

181 aatcagaagt tcaagggcaa ggccacattg actgttgaca agtccatctc aactgcttac

241 ctgcaatggt cctctctcaa agccagcgac actgctatgt actactgcgc aagggaggga 301 ggcaattacg aggcttggtt cgcttattgg ggacaaggca ctcttgtcac cgtctcctca

361 gcctcaacaa aaggaccaag tgtgttccca ctcgccccta gcagcaagag tacatccggg

421 ggcactgcag cactcggctg cctcgtcaag gattattttc cagagccagt aaccgtgagc

481 tggaacagtg gagcactcac ttctggtgtc catacttttc ctgctgtcct gcaaagctct

541 ggcctgtact cactcagctc cgtcgtgacc gtgccatctt catctctggg cactcagacc 601 tacatctgta atgtaaacca caagcctagc aatactaagg tcgataagcg ggtggaaccc

661 aagagctgcg acaagactca cacttgtccc ccatgccctg cccctgaact tctgggcggt

721 cccagcgtct ttttgttccc accaaagcct aaagatactc tgatgataag tagaacaccc

781 gaggtgacat gtgttgttgt agacgtttcc cacgaggacc cagaggttaa gttcaactgg

841 tacgttgatg gagtcgaagt acataatgct aagaccaagc ctagagagga gcagtataat 901 agtacatacc gtgtagtcag tgttctcaca gtgctgcacc aagactggct caacggcaaa

961 gaatacaaat gcaaagtgtc caacaaagca ctcccagccc ctatcgagaa gactattagt

1021 aaggcaaagg ggcagcctcg tgaaccacag gtgtacactc tgccacccag tagagaggaa

1081 atgacaaaga accaagtctc attgacctgc ctggtgaaag gcttctaccc cagcgacatc 1141 gccgttgagt gggagagtaa cggtcagcct gagaacaatt acaagacaac ccccccagtg 1201 ctggatagtg acgggtcttt ctttctgtac agtaagctga ctgtggacaa gtcccgctgg 1261 cagcagggta acgtcttcag ctgttccgtg atgcacgagg cattgcacaa ccactacacc 1321 cagaagtcac tgagcctgag cccagggaag

[0192] Protein Sequence Defining the Full Length Humanized 15D8 (Hul5D8) Heavy Chain (Humanized Variable Region and Human IgGl Constant Region) (SEQ ID NO: 74)

1 evqlvqsgae vkkpgeslki sckgsgysft synmywvrqm pgkglewmgy_ idpynggtsy 61 nqkfkgkatl tvdksistay lqwsslkasd tamyycareg gnyeawfayw gqgtlvtvss

121 astkgpsvfp lapsskstsg gtaalgclvk dyfpepvtvs wnsgaltsgv htfpavlqss

181 glyslssvvt vpssslgtqt yicnvnhkps ntkvdkrvep kscdkthtcp pcpapellgg

241 psvflfppkp kdtlmisrtp evtcvvvdvs hedpevkfnw yvdgvevhna ktkpreeqyn

301 styrvvsvlt vlhqdwlngk eykckvsnka lpapiektis kakgqprepq vytlppsree 361 mtknqvsltc lvkgfypsdi avewesngqp ennykttppv ldsdgsffly skltvdksrw

421 qqgnvfscsv mhealhnhyt qkslslspgk

[0193] Nucleic Acid Sequence Encoding the Full Length Humanized 15D8 (Hul5D8) Light Chain (Humanized Variable Region and Human Kappa Constant Region) (SEQ ID NO: 75)

1 gatatccaac tcacccagtc cccttcatcc ctgtctgcat cagtcgggga cagagtgaca

61 attacttgtt ccgccagctc tagtgtctca tacatgtatt ggtttcagca aaagccagga

121 aaagctccca aacccctgat ctatctgacc agctatctgg caagcggcgt gccttctcgg

181 ttcagtggat cagggtccgg tacagacttt accctgacta ttagcagtct gcaaccagag 241 gacttcgcca cttattactg ccaacagtgg agttcatatc ccctgacttt tggcggaggg 301 accaaggtcg agatcaagcg cacagtcgcc gctccctccg tgttcatctt tccaccaagt 361 gatgagcaac tgaagtctgg tactgcttca gtcgtgtgtc tgctgaacaa tttctaccct 421 cgagaagcca aagtccaatg gaaggtagac aacgcactgc agtccggcaa tagccaagaa 481 tcagttaccg aacaggattc aaaggacagt acatattccc tgagcagcac tctgaccctg 541 tcaaaggccg attacgagaa acacaaggtc tatgcttgcg aagtgacaca tcagggactg 601 tccagcccag tgacaaaatc ttttaaccgt ggggagtgt

[0194] Protein Sequence Defining the Full Length Humanized 15D8 (Hul5D8) Light

Chain (Humanized Variable Region and Human Kappa Constant Region) (SEQ ID NO: 76)

1 diqltqspss lsasvgdrvt itcsasssvs ymywfqqkpg kapkpliyl^ sylasgvpsr 61 fsgsgsgtdf tltisslqpe dfatyycqqw ssypltfggg tkveikrtva apsvfifpps 121 deqlksgtas vvcllnnfyp reakvqwkvd nalqsgnsqe svteqdskds tyslsstltl 181 skadyekhkv yacevthqgl sspvtksfnr gee

[0195] Nucleic Acid Sequence Encoding Human IgGl Heavy Chain Constant Region (SEQ ID NO: 77)

1 gcctccacca agggcccatc ggtcttcccc ctggcaccct cctccaagag cacctctggg

61 ggcacagcgg ccctgggctg cctggtcaag gactacttcc ccgaaccggt gacggtgtcg

121 tggaactcag gcgccctgac cagcggcgtg cacaccttcc cggctgtcct acagtcctca 181 ggactctact ccctcagcag cgtggtgacc gtgccctcca gcagcttggg cacccagacc

241 tacatctgca acgtgaatca caagcccagc aacaccaagg tggacaagag agttgagccc

301 aaatcttgtg acaaaactca cacatgccca ccgtgcccag cacctgaact cctgggggga

361 ccgtcagtct tcctcttccc cccaaaaccc aaggacaccc tcatgatctc ccggacccct

421 gaggtcacat gcgtggtggt ggacgtgagc cacgaagacc ctgaggtcaa gttcaactgg 481 tacgtggacg gcgtggaggt gcataatgcc aagacaaagc cgcgggagga gcagtacaac 541 agcacgtacc gtgtggtcag cgtcctcacc gtcctgcacc aggactggct gaatggcaag 601 gagtacaagt gcaaggtctc caacaaagcc ctcccagccc ccatcgagaa gaccatctcc 661 aaagccaaag ggcagccccg agaaccacag gtgtacaccc tgcccccatc ccgggaggag 721 atgaccaaga accaggtcag cctgacctgc ctggtcaaag gcttctatcc cagcgacatc 781 gccgtggagt gggagagcaa tgggcagccg gagaacaact acaagaccac gcctcccgtg 841 ctggactccg acggctcctt cttcctctac agcaagctca ccgtggacaa gagcaggtgg 901 cagcagggga acgtcttctc atgctccgtg atgcatgagg ctctgcacaa ccactacacg 961 cagaagagcc tctccctgtc tccgggtaaa

[0196] Protein Sequence Defining Human IgGl Heavy Chain Constant Region (SEQ ID NO: 78)

1 astkgpsvfp lapsskstsg gtaalgclvk dyfpepvtvs wnsgaltsgv htfpavlqss

61 glyslssvvt vpssslgtqt yicnvnhkps ntkvdkrvep kscdkthtcp pcpapellgg

121 psvflfppkp kdtlmisrtp evtcvvvdvs hedpevkfnw yvdgvevhna ktkpreeqyn

181 styrvvsvlt vlhqdwlngk eykckvsnka lpapiektis kakgqprepq vytlppsree

241 mtknqvsltc lvkgfypsdi avewesngqp ennykttppv ldsdgsffIy skltvdksrw

301 qqgnvfscsv mhealhnhyt qkslslspgk

[0197] Nucleic Acid Sequence Encoding Human Kappa Chain Constant Region (SEQ ID NO: 79)

1 cgaactgtgg ctgcaccatc tgtcttcatc ttcccgccat ctgatgagca gttgaaatct

61 ggaactgcct ctgttgtgtg cctgctgaat aacttctatc ccagagaggc caaagtacag

121 tggaaggtgg ataacgccct ccaatcgggt aactcccagg agagtgtcac agagcaggac

181 agcaaggaca gcacctacag cctcagcagc accctgacgc tgagcaaagc agactacgag

241 aaacacaaag tctacgcctg cgaagtcacc catcagggcc tgagctcgcc cgtcacaaag

301 agcttcaaca ggggagagtg t

[0198] Protein Sequence Defining Human Kappa Chain Constant Region (SEQ ID NO: 80)

1 rtvaapsvfi fppsdeqlks gtasvvcllnn fypreakvq wkvdnalqsg nsqesvteqd 61 skdstyslss tltlskadye khkvyacevt hqglsspvtk sfnrgec

[0199] For convenience, Table 8 provides a concordance chart showing the SEQ ID NO. of each sequence discussed in this Example.

Table 8

Ix Binding Affinities of Humanized and Chimeric Anti-FGFR3 Monoclonal Antibodies

[0200] The binding affinities of monoclonal 15D8, chimeric 15D8, and humanized 15D8 antibodies for recombinant human FGFR3 IIIc Fc fusion protein was measured using a kinetic exclusion assay, KinExA® technology (Sapidyne Instruments, Inc.). First, beads were prepared for the purpose of detecting anti-FGFR3 antibody that is unbound to FGFR3 IIIc Fc. This was done by adding 1 ml recombinant human FGFR3IIIc Fc (R&D Systems, Inc.) 10 ug/ml in PBS to 200 mg polymethyl methacrylate (PMMA) hard beads. The suspension was mixed and rotated for two hours at room temperature. Next, the mixture was centrifuged and supernatant was discarded. The bead pellet was rinsed once with 1 ml BSA 10 mg/ml in PBS by incubation for 1 hour at room temperature with rotation. The beads were resuspended in 27 ml PBS with 0.02% NaN ₃ . Next, a fixed concentration of anti-FGFR3 antibody (0.5 nM) was incubated in solution with a series of FGFR3 IIIc Fc concentrations (started with 50 nM (in PBS BSA (1 mg/ml)) and serially diluted 1:2 in PBS BSA(I mg/ml) to obtain 50 to 0.0122 nM FGFR3 III Fc) at room temperature for at least 4 hours to allow equilibrium to be reached. By measuring the amount of anti-FGFR3 antibody that is not bound to FGFR3 IIIc Fc, the KD was determined. Unbound anti-FGFR3 antibody was detected by allowing the anti-FGFR3 antibody/FGFR3 IIIc Fc solution to flow through the FGFR3 IIIc Fc PMMA beads. The anti- FGFR3 antibody captured by these beads was then detected with Cy5-conjugated anti-human secondary antibody 0.3 ug/ml (Jackson ImmunoResearch) or Cy5-conjugated anti-mouse secondary antibody (Jackson ImmunoResearch) 0.5ug/ml in PBS BSA 1 mg/ml. The detected signal for captured anti-FGFR3 antibody is directly proportional to the remaining free binding sites, thus allowing KD determination. The experiments were repeated, varying the concentrations of anti-FGFR3 antibody or FGFR3 III Fc used in solution, and the KD was calculated with the KinExA® software using n-curve analysis. The resulting data are shown in Table 9. These data demonstrated that 15D8, chimeric 15D8, and humanized 15D8 strongly bind FGFR3 with nearly equal affinity.

Table 9

α Antiproliferative Activity of Humanized and Chimeric Anti-FGFR3 Monoclonal Antibodies

[0201] The chimeric and humanized 15D8 antibodies were tested for inhibition of FGFl- induced proliferation of FDCP-FGFR3 IHb #122, as described in Example 5. Inhibition data are summarized in Table 10.

Table 10

[0202] The results in Table 10 demonstrate that chimeric 15D8 and humanized 15D8 strongly inhibited FGFl -induced proliferation in FDCP-FGFR3 IHb cells with nearly equal potency.

INCORPORATION BY REFERNCE

[0203] The entire disclosure of each of the patent documents and scientific articles referred to herein is incorporated by reference for all purposes. EQUIVALENTS

[0204] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

[0205] What is claimed is :