Probiotic activity of Enterococcus faecalis CECT7121: effects on mucosal immunity and intestinal epithelial cells.

Abstract

To analyse the effect of Enterococcus faecalis CECT7121 on intestinal epithelial cells (IECs) and its effects on the mucosal immune response. Enterococcus faecalis CECT7121 showed a high adhesion capacity to completely and heterogeneously differentiated human intestinal epithelial cell line (Caco-2 cells). In addition, the contact of this bacterium with Caco-2 cells did not induce inflammatory chemokines (IL-8 and CCL-20). The presence of IgA(+) and IL-6(+) cells in the small intestine, as well as the production of inflammatory cytokines (TNFα, IL-6 and IL-12) in the gut, was determined after intragastric inoculation of Ent.faecalis CECT7121 in BALB/c mice. The administration of Ent.faecalis CECT7121 increased the number of IgA(+) cells in the intestinal lamina propria without modifying the percentage of IL-6(+) cells. No differences were observed in the cytokines measured in the intestinal extracts between probiotic-treated and control mice. Enterococcus faecalis CECT7121 stimulates local mucosal immunity and adheres to IECs without inducing inflammatory signals. Our results indicate that, apart from its already reported systemic immune activity, Ent.faecalis CECT7121 has a modulatory effect at a local level.