Heterodimeric proteins and methods for producing and purifying them

1. A cell line expressing a heterodimeric protein, wherein the heterodimeric protein comprises:

a hinge region comprising a first immunoglobulin-like hinge polypeptide and a second immunoglobulin-like hinge polypeptide which interact together to form a dimeric hinge interface, wherein electrostatic interactions between one or more charged amino acids within the hinge interface favor interaction between the first and second hinge polypeptides over interaction between two first hinge polypeptides or two second hinge polypeptides, thereby promoting heterodimer formation over homodimer formation, wherein

(a) the hinge region is a human IgG1 hinge region, wherein each of the first hinge polypeptide and the second hinge polypeptide comprises amino acid modifications relative to a wild-type IgG1 hinge region at a position of Asp221 and Pro228, according to EU numbering scheme, wherein the wild-type amino acid in the first hinge polypeptide is replaced with an amino acid having an opposite charge to the corresponding amino acid in the second hinge polypeptide, and the heterodimeric protein further comprising an immunoglobulin-like CH3 region comprising a first CH3 polypeptide fused to the first hinge polypeptide and a second CH3 polypeptide fused to the second hinge polypeptide, wherein the first CH3 polypeptide and the second CH3 polypeptide comprise at least one amino acid modification relative to a wild-type IgG1 CH3 region sequence at a position of Tyr349, Leu368, Phe405, or Lys409, according to EU numbering scheme; or

(b) the hinge region is a human IgG2 hinge region, wherein each of the first hinge polypeptide and the second hinge polypeptide comprises at least two amino acid modifications relative to a wild-type IgG2 hinge region at a position of Cys223, Glu225 or Pro228, according to EU numbering scheme, wherein the wild-type amino acid in the first hinge polypeptide is replaced with an amino acid having an opposite charge to the corresponding amino acid in the second hinge polypeptide, and the heterodimeric protein further comprising an immunoglobulin-like CH3 region comprising a first CH3 polypeptide fused to the first hinge polypeptide and a second CH3 polypeptide fused to the second hinge polypeptide, wherein the first CH3 polypeptide and the second CH3 polypeptide comprise at least one amino acid modification relative to a wild-type IgG2 CH3 region sequence at a position of Leu368 or Lys409, according to EU numbering scheme.

2. The cell line of claim 1 , wherein the hinge region of the heterodimeric protein is a human IgG2 hinge region, the first hinge polypeptide comprises the amino acid modification of Cys223Arg, Glu225Arg and Pro228Arg, the second hinge polypeptide comprises the amino acid modification of Cys223Glu and Pro228Glu, and wherein (i) the first CH3 polypeptide comprises the amino acid modification of Lys409Arg and the second CH3 polypeptide comprises the amino acid modification of Leu368Glu or Leu368Asp, (ii) the first CH3 polypeptide comprises the amino acid modification of Leu368Glu or Leu368Asp, and the second CH3 polypeptide comprises the amino acid modification of Lys409Arg, or (iii) each of the CH3 polypeptide comprises the amino acid modification of Lys409Arg.

3. The cell line of claim 2 , wherein the first CH3 polypeptide comprises the amino acid modification of Lys409Arg and the second CH3 polypeptide comprises the amino acid modification of Leu368Glu.

4. The cell line of claim 2 , wherein the heterodimeric protein is a full length human IgG2 antibody.

5. The cell line of claim 2 , wherein the heterodimeric protein is a full length human IgG2 delta A antibody comprising two heavy chains, and wherein each heavy chain comprises an amino acid modification of Ala330Ser and Pro331Ser, according to EU numbering scheme.

6. The cell line of claim 1 , wherein the hinge region is a human IgG1 hinge region, and wherein the first hinge polypeptide comprises the amino acid modification of Asp221Arg and Pro228Arg, the second hinge polypeptide comprises amino acid modification of Asp221Glu and Pro228Glu, and wherein (i) the first CH3 polypeptide comprises the amino acid modification of Lys409Arg and the second CH3 polypeptide comprises the amino acid modification of Leu368Glu or Leu368Asp, or (ii) each of the CH3 polypeptide comprises the amino acid modification of Lys409Arg.

7. The cell line of claim 6 , wherein the first CH3 polypeptide comprises the amino acid modification of Lys409Arg and the second CH3 polypeptide comprises the amino acid modification of Leu368Glu.

8. The cell line of claim 6 , wherein the heterodimeric protein is a full length human IgG1 antibody.

9. A method of producing the heterodimeric protein of claim 1 , comprising the steps of:

a) culturing a host cell comprising a nucleic acid encoding the first hinge and CH3 polypeptides and a nucleic acid encoding the second hinge and CH3 polypeptides, wherein the cultured host cell expresses the first and second hinge and CH3 polypeptides; and

b) optionally, recovering the heterodimeric protein from the host cell culture.

10. A method of producing the heterodimeric protein of claim 1 , comprising the steps of:

a) expressing the first hinge and CH3 polypeptides in a first host cell;

b) expressing the second hinge and CH3 polypeptides in a second host cell;

c) optionally, isolating the first hinge and CH3 polypeptides and the second hinge and CH3 polypeptides; and

d) incubating the first and second hinge and CH3 polypeptides under a condition suitable for dimerization to produce the heterodimeric protein.

11. The method of claim 10 , wherein the condition of step d) is to incubate the two hinge and CH3 polypeptides of step c) with a reducing agent.

12. The method of claim 11 , wherein the reducing agent is glutathione.