Interactions Between Macrophages of Guinea Pigs and Salmonellae II. Phagocytosis of Salmonella typhimurium by Macrophages of Normal Guinea Pigs.

Peritoneal macrophages from normal guinea pigs were allowed to phagocytize Salmonella typhimurium in vitro. The extent of phagocytosis was determined by quantitative viable counts of the bacteria released after lysis of the phagocytes with sodium deoxycholate. It was shown that the avirulent strain RIA of salmonellae was more susceptible to ingestion by macrophages than the virulent strain SR-11. The presence of immune serum in the phagocytic mixture greatly enhanced the extent with which strain SR-11 was phagocytized. Also, the virulent bacteria recovered from infected mice exhibited a greater resistance to phagocytosis than those maintained in artificial media.