Specific targeting of mitomycin C to tumors by anti-gastric cancer monoclonal antibody.

In the present study, an anti-gastric cancer monoclonal antibody, MGb2, was chosen to prepare antibody-mitomycin C (MMC) conjugate with dextran T-40 as intermediary. Twenty molecules of MMC were introduced into each molecule of antibody while the antigen-binding capacity of the antibody was kept well. The conjugate showed selective cytotoxicity upon human gastric cancer cell line SGC-7901. Radioimmunoimaging and biodistribution studies indicated that after conjugation with MMC via dextran T-40 as intermediary, the tumor localization capacity of the antibody was well retained. When tested in nude mice, inoculated with human gastric carcinoma SGC-7901 in bilateral subrenal capsules, intraperitoneal injection of the conjugate daily for 6 days at a dose of 1 mg/kg gave a tumor inhibitory rate of 68.67%, which was far better than that of free MMC or irrelevant conjugate. No synergetic effect was found in regard to the mixture of MGb2 with MMC.