Potentiation of the tumor-specific immune response by Corynebacterium parvum.

Strong, specific, cell-mediated antitumor immunity resulted from the sc injection into mice of Corynebacterium parvum (CP) mixed with irradiated cells from mastocytoma P815 (MA), whereas injection of irradiated MA alone was without effect. Maximum immunity was achieved with small doses of CP, and the injection sites of CP and irradiated MA did not need to be coincident but required common lymphoid drainage for immunity to result. The process was largely T-cell dependent but not dependent on the development of a specific immune response to CP; it was also demonstrable and effective in a therapy situation. No such immunity was evident after systemic administration of CP and irradiated MA. Simultaneous systemic injection of CP and irradiated MA did, however, nonspecifically reduce the enhancing effect of systemic injection of irradiated MA alone.