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

AIMS: To analyse the effect of Enterococcus faecalis CECT7121 on intestinal epithelial cells (IECs) and its effects on the mucosal immune response. METHODS AND RESULTS: 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. CONCLUSIONS: Enterococcus faecalis CECT7121 stimulates local mucosal immunity and adheres to IECs without inducing inflammatory signals. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results indicate that, apart from its already reported systemic immune activity, Ent. faecalis CECT7121 has a modulatory effect at a local level.