STABLE IGG4 ANTIBODIES

1 . A stabilized IgG4 antibody, comprising a heavy chain and a light chain, wherein said heavy chain comprises a human IgG4 constant region having (i) a substitution of the Arg residue at EU index position 409, the Phe residue at position 405, or the Lys residue at position 370, and (ii) a substitution of the Leu residue at position 235 by Glu, with the proviso that if the antibody has a Lys, Ala, Thr, Met or Leu at the position corresponding to 409, then the antibody does not comprise a Cys-Pro-Pro-Cys sequence (SEQ ID NO:50) in the hinge region.

2 . The stabilized IgG4 antibody of claim 1 , wherein said heavy chain comprises a human IgG4 constant region having a Lys, Ala, Thr, Met and Leu at the position corresponding to 409 and/or a residue selected from the group consisting of: Ala, Val, Gly, Ile or Leu at the position corresponding to 405, and wherein said antibody does not comprise a Cys-Pro-Pro-Cys sequence (SEQ ID NO: 50) in the hinge region.

3 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises a Lys, Ala, Thr, Met or Leu residue at the position corresponding to 409.

4 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises a Lys, Thr, Met or Leu residue at the position corresponding to 409.

5 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises a Lys, Met or Leu residue at the position corresponding to 409.

6 . The stabilized IgG4 antibody of claim 1 , wherein the CH3 region of the antibody has been replaced by the CH3 region of human IgG1, of human IgG2 or of human IgG3.

7 . The stabilized IgG4 antibody of claim 1 , wherein said antibody at the position corresponding to 405 has a residue which has a lower mass than Phe.

8 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises an Ala or Leu residue at the position corresponding to 405.

9 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises a Thr residue at the position corresponding to 370.

10 .- 11 . (canceled)

12 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises one or more of the following substitutions: an Ala at position 234, an Ala at position 236, an Ala at position 237, an Ala at position 297, an Ala or Val at position 318, an Ala at position 320, an Ala or Gln at position 322.

13 .- 15 . (canceled)

16 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises a CPSC sequence (amino acids 106-109 of SEQ ID NO:39) in the hinge region.

17 .- 19 . (canceled)

20 . The stabilized IgG4 antibody of claim 1 , wherein said antibody is selected from the group consisting of: a human antibody, a humanized antibody and a chimeric antibody.

21 . The stabilized IgG4 antibody of claim 1 , wherein said antibody comprises a human kappa light chain.

22 . The stabilized IgG4 antibody of claim 1 , wherein the antibody comprises a human lambda light chain.

23 . The stabilized IgG4 antibody of claim 1 , wherein said antibody is a bivalent antibody.

24 . The stabilized IgG4 antibody of claim 1 , wherein said antibody is a full-length antibody.

25 . The stabilized IgG4 antibody of claim 1 , wherein said antibody is linked to a cytotoxic agent; a radioisotope; or a prodrug or drug.

26 . The stabilized IgG4 antibody of claim 1 , wherein the antibody binds erythropoietin, beta-amyloid, thrombopoietin, interferon-alpha (2a and 2b), interferon-beta (1b), interferon-gamma, TNFR I (CD120a), TNFR II (CD120b), IL-1R type 1 (CD121a), IL-1R type 2 (CD121b), IL-2, IL2R (CD25), IL-2R-beta (CD123), IL-3, IL-4, IL-3R (CD123), IL-4R (CD124), IL-5R (CD125), IL-6R-alpha (CD126), IL-6R-beta (CD130), IL-8, IL-10, IL-11, IL-15, IL-15BP, IL-15R, IL-20, IL-21, TCR variable chain, RANK, RANK-L, CTLA4, CXCR4R, CCR5R, TGF-beta1, TGF-beta2, TGF-beta3, G-CSF, GM-CSF, MIF-R (CD74), M-CSF-R (CD115), GM-CSFR (CD116), soluble FcRI, sFcRII, sFcRIII, FcRn, Factor VII, Factor VIII, Factor IX, VEGF, VEGFxxxb, alpha-4 integrin, Cd11a, CD18, CD20, CD38, CD25, CD74, FcalphaRI, FcepsilonRI, acetyl choline receptor, fas, fasL, TRAIL, hepatitis virus, hepatitis C virus, envelope E2 of hepatitis C virus, tissue factor, a complex of tissue factor and Factor VII, EGFr, CD4, CD28, VLA-1, VLA-2, VLA-3, VLA-4, LFA-1, MAC-1, I-selectin, PSGL-1, ICAM-I, P-selectin, periostin, CD33 (Siglec 3), Siglec 8, TNF, CCL1, CCL2, CCL3, CCL4, CCL5, CCL11, CCL13, CCL17, CCL18, CCL20, CCL22, CCL26, CCL27, CX3CL1, LIGHT, EGF, TGFalpha, HGF, PDGF, NGF, complement, C1q, C4, C2, C3, C5, C6, C7, C8, C9, MBL, factor B, a Matrix Metallo Protease, any of MMP1 to MMP28, CD32b, CD200, CD200R, Killer Immunoglobulin-Like Receptors (KIRs), NKG2D, leukocyte-associated immunoglobulin-like receptors (LAIRs), ly49, PD-L2, CD26, BST-2, ML-IAP (melanoma inhibitor of apoptosis protein), cathepsin D, CD40, CD40R, CD86, a B cell receptor, CD79, PD-1 or a T cell receptor.

27 .- 69 . (canceled)

70 . The stabilized IgG4 antibody of claim 1 , wherein the antibody does not comprise both a Lys at position 409 and a Leu at position 309.

71 . The stabilized IgG4 antibody of claim 70 , wherein the heavy chain comprises a human IgG4 constant region having a Lys, Ala, Thr, Met or Leu at the position corresponding to 409 and/or an Ala, Val, Gly, Phe, or Leu at the position corresponding to 405.

72 . A pharmaceutical composition comprising a stabilized IgG4 antibody as defined in claim 1 .

73 . (canceled)

74 . A method for producing the stabilized IgG4 antibody of claim 1 , said method comprising expressing a nucleic acid construct encoding said antibody in a host cell and optionally purifying said antibody.

75 . (canceled)

76 . The stabilized antibody of claim 1 , wherein the amino acid at EU position 228 of the IgG4 constant region is Ser.