Mouse strain differences in macrophage activation and anti-tumor activity induced by Propionibacterium acnes...

Effect of Propionibacterium acnes on macrophage activation and antitumor activity was examined in ddN and SL mice. (1) Carbon clearance was enhanced to the same extent by P. acnes treatment in both strains. (2) Number of peritoneal macrophages increased to the same extent by P. acnes treatment in both strains. (3) Adhesiveness of peritoneal macrophages, as demonstrated by inhibition or migration or an increase in spreading cells, was enhanced more efficiently in ddN than in SL mice P. acnes treatment. (4) Mice of both strains died in a similar patterns, when they were not pretreated in any way. The treatment with P. acnes conferred antitumor activity of a higher degree in ddN than in SL mice. (5) Peritoneal macrophages of ddN mice treated with P. acnes exhibited an antitumor activity in in vivo neutralization test. These results suggest that strain difference in augmentation of antitumor activity by P. acnes is ascribed to distinct sensitivity of macrophage functions to a stimulative effect of P. acnes in the mouse strains.