Differential Immune Response of Lactobacillus plantarum 286 Against Salmonella Typhimurium Infection in Conventional and Germ-Free Mice

We aimed at evaluating in vivo the probiotic potential of Lactobacillus plantarum 286 against Salmonella enterica serov. Typhimurium. Colonization capacity and antagonistic activity were determined in feces of gnotobiotic mice. Survival to infection, translocation, histopathology, IgA and cytokine levels (IL-10, IL-6, IFN-gamma, TNF-alpha, TGF-beta) were determined both in conventional and germ-free mice followed L. plantarum 286 administration and Salmonella infection. L. plantarum 286 colonized the intestine of gnotobiotic mice, where it produced antagonistic substances against S. Typhimurium. In conventional animals, the administration of this strain increased intestinal IgA levels and reduced the inflammatory response and the tissue damage caused by S. Typhimurium. Reduction of tissue damage in the intestine and liver of germ-free animals was also observed, however the immune response elicited was different in either model. L. plantarum 286 showed in vivo probiotic properties in both murine models. Probiotic capacity results may depend on the animal model chosen.