Adoptive transfer of natural killer cell activity in B6D2F1 mice challenged with Salmonella typhimurium

The purpose of this study was to extend our previous findings as to the role of murine NK cells in host protection to a challenge infection with virulent Salmonella typhimurium SR-11. B6D2F1 mice were depleted of NK cells with anti-asialo GM1 or a monoclonal antibody, anti-NK 1.1, followed by a salmonellae challenge. Significantly decreased numbers of splenic bacteria (P less than 0.005) in the NK cell-depleted mice were note at 12, 24, and 48 hr postchallenging, compared to the sham-injected control animals. When Percoll gradient-enriched large granular lymphocytes (NK cells) were adoptively transferred to NK cell-depleted mice followed by challenging, the splenic bacterial numbers were comparable to those present in NK cell-intact, control mice. These data indicate that large granular lymphocytes (NK cells) are responsible for the down-regulation of the protective host response in mice challenged with the facultative intracellular parasite. S. typhimurium.