Radioimmunotherapy of xenografted human bladder cancer using monoclonal antibody against blood group A-related antigen.

An IgG3 murine monoclonal antibody 1G3.10 was generated against a human urinary bladder carcinoma cell line TSGH-8301. The tumor-associated antigen recognized by the monoclonal antibody is a blood group A-related substance. From fluorescence-activated cell sorter analysis, a direct cytolytic effect of tumor cells by the antibody at concentrations of more than 10 micrograms/ml was seen. The antibody could target iodine-131 to established subcutaneous human bladder carcinoma xenografts in BALB/c nude mice. Monoclonal antibody alone also showed some inhibitory effect on xenografted tumor growth. In this study, radiolabeled monoclonal antibody 1G3.10 presented more effective cytotoxicity than antibody alone from in vitro and in vivo experiments.