Comparison of host responses induced by Salmonella typhimurium infection in genetically resistant and susceptible mice

A/J and BALB/c mice differ genetically in their resistance to the facultative intracellular bacterium Salmonella typhimurium. We compared the responses of these strains of mice to a virulent S. typhimurium infection. BALB/c mice mobilised more peritoneal exudate cells in response to the infection than did A/J mice 30 h after infection, but the increase in bacterial counts in the livers and spleens of BALB/c mice was 10-fold higher than in A/J mice. The response to Concanavalin A (Con A) of spleen cells from BALB/c mice was depressed, and both L3T4+ and Lyt-2+ T cell subpopulations were decreased following the infection, whereas the response to Con A of A/J mice was increased and the T cell subpopulations were not altered significantly. These results suggest that A/J mice respond more actively to S. typhimurium infection than do BALB/c mice, and this may be related to the natural resistance of mice.