Patent ID: 8193322

Claim:
A heterodimeric polypeptide comprising (a) a human or humanized IgG1, IgG2, or IgG4 heavy chain from an antibody that binds specifically to an antigen and that comprises an Fe region, wherein the heavy chain comprises a heavy chain variable (V H ) region, followed by a first heavy chain constant (C H 1) region, followed by a hinge region, followed by a second heavy chain constant (C H 2) region, followed by a third heavy chain constant (C H 3) region, and (b) a fusion protein, wherein the fusion protein comprises a light chain from the antibody followed by a human IgG1, IgG2, or IgG4 Fe molecule, wherein the light chain comprises a light chain variable (V L ) region followed by a light chain constant (C L ) region and wherein the human IgG1, IgG2, or IgG4 Fe molecule comprises a hinge region followed by a C H 2 region followed by a C H 3 region, wherein (i) the first five amino acids of the hinge region of the fusion protein are deleted, or (ii) the hinge region of the fusion protein is not shortened or lengthened, wherein the heavy chain and the fusion protein are two polypeptide chains that are oriented identically with respect to their N- and C-termini and associate to form the heterodimeric polypeptide, wherein the heterodimeric polypeptide is monovalent, and wherein the heterodimeric polypeptide is capable of specifically binding to the antigen.