Natural killer cell activity against uninfected and Salmonella typhimurium-infected murine fibroblast L929 cells

Splenic and peritoneal cells from uninfected mice exhibited selective cytotoxic activity against Salmonella-infected L929 fibroblast cells. Although the level of killing was low, the results were significantly different from the killing of uninfected L929 cells (p < 0.01) by either effector cell population. Salmonella typhimurium-activated splenic and peritoneal exudate (PE) cells exhibited enhanced killing of Salmonella-infected L929 targets and YAC-1 cells compared to endogenous natural killer activity by splenic and peritoneal cells from uninfected mice. When Salmonella-infected (60 h postinfection) or uninfected mice received an i.p. injection of anti-asialo GM1 12 h prior to harvesting the splenic or peritoneal cells (72 h postinfection), target cell killing was < 2%. In all cases, activated PE cells exhibited the greatest killing activity against uninfected and Salmonella-infected L929 fibroblast cells and YAC-1 targets (p < 0.01).