Heterodimeric human IgG1 polypeptides with isoelectric point modifications

A method of separating heterodimeric antibodies from homodimeric antibodies, the method comprising:

• (a) providing a mixture comprising heterodimeric antibodies and homodimeric antibodies,
• wherein the heterodimeric antibodies comprise a first human IgG1 heavy chain constant region and a second human IgG1 heavy chain constant region, wherein the first human IgG1 heavy chain constant region comprises the amino acid modifications L351K and T366K, wherein numbering is according to the EU index, wherein the first human IgG1 constant region and the second human IgG1 constant region have at least 95% sequence identity to SEQ ID NO:
• 2,
• wherein the homodimeric antibodies comprise a first homodimeric antibody comprising two of the first human IgG1 heavy chain constant regions and a second homodimeric antibody comprising two of the second human IgG1 heavy chain constant regions,
• wherein the difference in the isoelectric point between each of the heterodimeric antibodies and the first homodimeric antibody and each of the heterodimeric antibodies and the second homodimeric antibody is at least 0.2 logs, and
• (b) separating the heterodimeric antibodies from the first and second homodimeric antibodies by ion exchange chromatography based on the difference in the isoelectric points between the heterodimeric antibodies and the homodimeric antibodies.