[Application of monoclonal antibodies to diagnosis and treatment of small cell lung cancers].

Recently we developed monoclonal antibodies against small cell lung cancer (SCLC) and applied them for diagnosis using histology and imaging, and treatment using SCLC transplanted into nude mice. One monoclonal antibody designated TFS-2 is cytotoxic to SCLC cells with complement. This antibody seems to be useful for purging tumor cells from the bone marrow in vitro when autologous bone marrow transplantation is applied. The other monoclonal antibody, TFS-4, has a high specificity to SCLC. This antibody was useful for diagnosis of SCLC using histology, and for the detection of metastatic tumor cells in the bone marrow. It was possible using imaging by radioisotope-labelled TFS-4 to reveal the localization of SCLC transplanted into nude mice. As for treatment with TFS-4, we injected 500 mu Ci of 131I-labeled TFS-4 into nude mice bearing SCLC, and recognized a reduction in tumor size of about 60%.