Lactobacilli Differentially Modulate Expression of Cytokines and Maturation Surface Markers in Murine Dendritic Cells

Dendritic cells (DC) play a pivotal immunoregulatory role in the Th1, Th2, and Th3 cell balance and are present throughout the gastrointestinal tract. Thus, DC may be targets for modulation by gut microbes, including ingested probiotics. In the present study, we tested the hypothesis that species of Lactobacillus, important members of the gut flora, differentially activate DC. Bone marrow-derived murine DC were exposed to various lethally irradiated Lactobacillus spp. and resultant culture supernatants were analyzed for IL-6, IL-10, IL-12, and TNF-alpha. Substantial differences were found among strains in the capacity to induce IL-12 and TNF-alpha production in the DC. Similar but less pronounced differences…