Production of a monoclonal antibody-bleomycin conjugate utilizing dextran T-40 and the antigen-targeting cytotoxicity of the conjugate.

Bleomycin (BLM), a potent anticancer glycopeptide antibiotic, was linked covalently to murine monoclonal anti-HLA IgG1 antibody (H-1) with the use of dextran T-40. As determined spectrophotometrically, the conjugate was composed of 57.5 moles BLM per mole antibody. Of the substituted BLM, 18.4% (10.6 moles BLM per mole antibody) exhibited antimicrobial activity. The BLM-(H-1) conjugate showed stronger cytotoxicity than BLM alone against HLA-bearing cells in cultivation after a 30-min exposure to the drugs. In the same experiment, the conjugate was less toxic than BLM against cells lacking HLA.