The Structure of an Antitumor CH2-domain-deleted Humanized Antibody Original Research Article

CH2-domain-deleted CC49 (HuCC49ΔCH2), a recombinant humanized antibody that recognizes the TAG-72 antigen expressed on a variety of human carcinomas, is secreted from cultured cells as a mixture of two homodimeric isoforms. Isoform A contains two covalent interchain disulfide bonds at heavy chain positions 239 and 242, while isoform B fails to develop any interchain disulfide bonds but has 239–242 intrachain disulfide bonds instead. Form A is currently in preclinical development as a therapeutic agent for treating colorectal carcinoma, though form B shows equal efficacy.