The Effect of Whole-Body X Irradiation on the Bactericidal Activity of Phagocytic Cells I. Survival of Pseudomonas Aeruginosa Within Phagocytes from Peritoneal Exudates of Mice

1. The number of intracellular Pseudomonas aeruginosa able to survive within phagocytes was determined in peritoneal exudates from immunized and nonimmunized mice five days after exposure to 100, 300, 500, or 700 r X radiation. 2. The number of viable Pseudomonas was determined by culturing dilutions of ground phagocytes. 3. Determinations were limited to intracellular Pseudomonas by maintaining the phagocytes in mediums containing a bactericidal concentration of polymyxin B. 4. The numbers of intracellular bacteria surviving in phagocytes from nonimmunized mice were greatest in cells from mice receiving the highest doses of X radiation. 5. Phagocytes from previously immunized mice destroyed intracellular Pseudomonas more rapidly than did phagocytes from nonimmunized mice. This was true even though the donor mice had been irradiated.