Bispecific antibodies and methods for production thereof
The invention relates to an ex vivo method for the generation of a bispecific antibody, comprising the steps of: a) providing a first antibody having a first binding specificity, wherein said first antibody comprises an IgG4-like CH3 region, b) providing a second antibody having a second binding specificity which differs from said first binding specificity, wherein said second antibody comprises an IgG4-like CH3 region, c) incubating said first and second antibodies together under reducing conditions which allow the cysteines in the core hinge region to undergo disulfide-bond isomerization, and d) obtaining a bispecific antibody. The invention furthermore relates to bispecific antibodies obtainable by the method of the invention.
1. An isolated bispecific antibody comprising a first half-molecule comprising a first IgG1 heavy chain constant region and a second half-molecule comprising a second IgG1 heavy chain constant region, wherein the first and second IgG1 heavy chain constant region comprises SEQ ID NO: 19, but with
(a) one or more of the following amino acid substitutions in the CH3 region:
(i) Arg (R) in position 238 has been replaced by Gln (Q);
(ii) Asp (D) in position 239 has been replaced by Glu (E);
(iii) Lys (K) in position 292 has been replaced by Arg (R), Tyr (Y) or Phe (F);
(iv) Gln (Q) in position 302 has been replaced by Glu (E); and
(v) Pro (P) in position 328 has been replaced by Leu (L); and
(b) a core hinge region comprising the amino acid sequence CPPC (SEQ ID NO: 28), CSPC (SEQ ID NO: 30), CRPC (SEQ ID NO: 31) or CPRC (SEQ ID NO: 32).
2. The bispecific antibody of claim 1 , wherein Lys (K) in position 292 has been replaced by Arg (R) in the CH3 region of the first and second IgG1 heavy chain constant region.
3. The bispecific antibody of claim 1 , wherein the Lys (K) in position 292 has been replaced by Tyr (Y) or Phe (F) in the CH3 region of the first and second IgG1 heavy chain constant region.
4. The bispecific antibody of claim 1 , wherein the CH3 region of the first and/or the second IgG1 heavy chain constant region is an IgG4 CH3 region.
5. A pharmaceutical composition comprising the bispecific antibody of claim 1 and a pharmaceutically acceptable carrier.
6. A pharmaceutical composition comprising the bispecific antibody of claim 4 and a pharmaceutically acceptable carrier.