Spontaneous regression of syngeneic transplanted tumors in rats pretreated with the antileukemia drug busulfan.
Lethal growth of a syngeneic transplanted tumor (KMT-17) was inhibited in WKA rats pretreated with the antileukemia drug busulfan. The effect of busulfan was short-lasting, and administration of the drug after tumor challenge had little effect on the lethal growth of the tumor. After spontaneous regression of the tumor in rats pretreated with busulfan, specific transplantation resistance to identical tumor was acquired. Busulfan did not exhibit its effect in rats irradiated before tumor challenge. As shown by the Winn test, spleen cells from rats immunized with inactivated tumor cells after busulfan treatment inhibited growth of admixed tumor cells more strongly than did spleen cells from rats immunized without busulfan treatment. Enhancement of immune response to tumor cells rather than tumoricidal activity by busulfan was suggested.
D000818:Animals; D000951:Antigens, Neoplasm; D002066:Busulfan / Q000008:administration & dosage* / Q000494:pharmacology; D007109:Immunity / Q000187:drug effects / Q000528:radiation effects; D009368:Neoplasm Transplantation; D051381:Rats; D011919:Rats, Inbred Strains; D012513:Sarcoma, Experimental / Q000188:drug therapy* / Q000276:immunology; D013154:Spleen / Q000276:immunology; D013997:Time Factors; D014185:Transplantation, Isogeneic; D014965:X-Rays
D000951:Antigens, Neoplasm; D002066:Busulfan