Growth retardation and prevention of Ehrlich solid tumor by Clostridium perfringens type A spores and culture supernatant.

When given by direct s.c. injection into the Ehrlich solid carcinoma 1 week after s.c. tumor transfer, viable crude spores of Clostridium perfringens type A (attenuated mutant strain LNG11 ATCC 29348) inhibited tumor growth and significantly prolonged the life span of male outbred Swiss mice. Under these conditions a concentrated sterile supernatant of a C. perfringens culture proved to be slightly more effective than were viable crude spores. In contrast viable crude spores were ineffective in the treatment of female Swiss mice, but the sterile supernatant retained significant activity. When given at the time and site of s.c. grafting of Ehrlich tumor cells, a concentrated sterile supernatant of a C. perfringens culture prevented tumor growth in 80% of male outbred Swiss mice. Under these conditions viable crude spores prevented tumor growth in 70% of mice and significantly prolonged the life span in the other 30%. When given by i.p. injection and before i.p. grafting of tumor cells, viable crude spores of C. perfringens prevented Ehrlich ascites tumor in 5 of 12 Swiss mice and prolonged life span in the other 7. In contrast concentrated sterile supernatant and viable purified spores were ineffective in the prevention or delay of the growth of Ehrlich ascites tumor. These data indicate that C. perfringens can be a potent antitumor agent without producing the harmful anaerobic infection of solid tumors (clostridial oncolysis.