EFFECT OF GELONIN IMMUNOCONJUGATE WITH MONOCLONAL-ANTIBODY MSN-1 TO ENDOMETRIAL ADENOCARCINOMA ON ANTIGEN-PRODUCING TUMOR-CELLS IN-VIVO

Missile therapy, which destroys cancer cells specifically, has been ad vocated as an effective modality for the treatment of carcinoma. We ha ve developed an immunoconjugate consisting of the monoclonal antibody MSN-1 (IgM), which reacts strongly with endometrial adenocarcinomas, c ombined with a plant hemitoxin named gelonin via a disulfide bond usin g N-succinimidyl-3-(2-pyridyldithio)propionate and 2-iminothiolane, an d examined its selective cytotoxicity in athymic mice. The reductions in resected weights of target tumor cells, at the local site of MSN-1- gelonin immunoconjugate treatment, were 96% with local administration and 75% with caudal vein administration, as compared with the untreate d group. There was no weight loss in treated mice. Our results suggest that this MSN-1-gelonin immunoconjugate has potential clinical applic ations in the treatment of endometrial adenocarcinomas.