The correlation of susceptibility of different Propionibacterium strains to macrophage killing and antitumor activity.

The stimulation of the reticuloendothelial system and antitumor activity against sarcoma-L-1 of three different strains of Propionibacterium was investigated. The bacteria injected intraperitoneally with a single dose of 1 mg per mouse appeared to possess different effectiveness in both assays used. The same strains were examined for their susceptibility to phagocytosis and intracellular killing by murine peritoneal macrophages. The results obtained showed correlations between Propionibacterium resistance to degradation by phagocytic cells and their antitumor and stimulatory activities. It is concluded that the potency of antitumor and stimulatory activities of different strains of Propionibacterium are closely related to their cell wall structure.