Radioimmunoimaging of human bladder tumor xenografts in nude mice by using monoclonal antibodies.

Monoclonal antibodies HBJ127 and HBJ8, raised against T24 human bladder cancer cells, predominantly react with the cells in proliferating stages and with a portion of epithelial tumor cells, respectively. To investigate the in vivo localization of these monoclonal antibodies, the antibodies were labeled with radioiodine and indium-111 (111In) and injected into nude mice transplanted with human bladder tumors. The BT-11 bladder tumor had the highest concentration of radioiodinated HBJ127 and HBJ8 monoclonal antibodies, with 11.6 and 14.3% of the injected dose per gram and with a tumor-to-blood ratio of 2.6 and 1.6, respectively, at 4 days after the administration. An irrelevant monoclonal antibody did not show any specific accumulation in the BT-11 tumor. The 111In-labeled HBJ127 antibody was also localized in the tumor with a higher tumor-to-blood ratio than the radioiodinated antibody. The xenografted BT-11 tumor was successfully visualized with the radiolabeled HBJ127 and HBJ8 antibodies by scintigraphy. These monoclonal antibodies and the human bladder tumor xenografts may provide a good model for radioimmunoimaging and possibly therapy.