Lasting rejection of mammary adenocarcinoma cell tumors in DBA-2 mice with intratumor injection of killed Corynebacterium parvum.

Preparations of killed Corynebacterium parvum were injected into 14-day-old growing mammary adenocarcinoma cell tumors in DBA/2 mice. The tumors and the microscopic métastasesundergo rapid and lasting rejection and the animals are protected against challenges of large quantities of tumor cells of the same line. This protection can be overcome if the challenge dose is massive. Groups of tumor-bearing animals treated with s.c. injections of killed C. parvum on the ipsilateral side or with i.p. in jections demonstrate suppression of tumor growth and longer survival time, compared with animals receiving killed C. parvum s.c. on the contralateral side or intratumor injections of Hanks' solution.