Selective cytotoxicity of adriamycin immunoconjugate of monoclonal antibody MSN-1 to endometrial adenocarcinoma in vitro and in vivo

Missile therapy, which destroys cancer cells specifically, has been regarde d as an effective treatment modality for carcinoma. The monoclonal antibody MSN-1 (IgM), which reacts strongly with endometrial adenocarcinomas, was c ombined with adriamycin (ADM) by a disulfide bond using N-succinimidyl-3-(2 -pyridyldithio) propionate (SPDP) and 2-iminothiolane. Its selective cytoto xicity against SNG-II was examined in a colony formation in vitro, and on a thymic mice in vivo. The results of our study suggest that the 'inhibitory concentration' or IC50, of the MSN-1-ADM immunoconjugate against SNG-II to be 57 times that of ADM alone in vitro. The reductions in resected weights of target tumor cells, at the local site of the MSN-1-ADM immunoconjugate t reatment, were 25% with caudal vein administration, and 38% with local admi nistration, as compared with the untreated group, in vivo. There was no wei ght loss in treated mice. Our results suggest that this MSN-1-ADM immunocon jugate has potential clinical application in the treatment of endometrial a denocarcinomas.