Murine immunomodulation of IL-10 and IL-12 induced by new isolates from avian type 2 Lactobacillus acidophilus.

Several bacterial and immunogenic factors are involved in the host response to probiotic strains of Lactobacillus. Here, we report the isolation of new intestinal lactobacilli from chicken, with different immunomodulating properties on lymphoid cells from SJL and C57BL/6 mice. Analysis of biochemical markers in the Lactobacillus acidophilus CBA4P, CBA3P, and TPA3P isolates reveal that these bacterial isolates belong to the type 2 prototype, although they differ from each other. The effect of conditioned media (CM) from SJL- and C57BL/6-derived peritoneal macrophages incubated with the 3 sonicated bacterial isolates from chicken, as well as with Lactobacillus rhamnosus 9595, Escherichia coli lipopolysaccharide, or Staphylococcus aureus peptidoglycan were compared. Our results show that the CM of macrophages from C57BL/6 and SJL mice treated with the CBA4P isolate stimulated syngeneic splenic lymphocytes at a level similar to the one induced with CM from peptidoglycan-stimulated macrophages. In contrast, the CM from TPA3P- and CBA3P-treated macrophages promoted low or no stimulation of lymphoid cells. Incubation of splenic cells with CM from macrophages treated with L. rhamnosus or TPA3P led to a relative decrease in the percentages of splenic CD4+ T cells, whereas the relative percentages of B cells increased. The CBA4P and CBA3P isolates induced higher levels of gamma interferon when compared with the TPA3P isolate. The effects of the lactobacilli isolates differed according to the mouse strain used but correlated with the production of macrophagic tumor necrosis factor alpha and interleukins 6, 10, and 12 and with the modulation of the p38 mitogen-activated protein kinase (MAPK). Taken together, these results indicate that the immunomodulating properties of the new L. acidophilus isolates depend on their capacity to induce production of interleukins 10 and 12 by macrophages, which is under genetic control and depends on the p38 MAPK pathway.