Immune mechanisms induced by a probiotic fermented milk administration in an experimental model of allergy

MALDONADO C.; PERDIGÓN, G.; VELEZ, E.M.; MESON O.; BIBAS BONET, M.E.

Buenos Aires

Congreso; 1° Congreso Franco-Argentino de Inmunología. LVIII Reunión de la Sociedad de Inmunología Argentina; 2010

Sociedad Argentina de Inmunología - SAI

It was reported the beneficial effect of probiotic in diseases, but the mechanisms involved are not well known. We study if a probiotic fermented milk (PFM) has positive effect on an experimental model of allergy and to determine the immune mechanisms involved. Mice were divided into 5 groups: normal control (NC), Basal (B 5d PFM); Control sensitization (CS), Previous (P 5d PFM+OVA+H2O), Continuous (C 5d PFM+ovo+PFM). CS, P and C groups were sensitized with ovalbumin (OVA) at 1% followed by daily exposures to aerosolized OVA for 10d. Samples were taken at 7 and 15 days post-sensitization (dps). We determined anti-OVA-specific-IgE (aOVAIgE) and IL10 in serum, total IgA, IL10 and IFNgamma in intestinal fluid (IF) by ELISA. IL2 , IL4 and IL10+ cells were mesured in small intestine (SI) by IFI. In large intestine (LI) we determine total populations of anaerobes, lactobacilli, bifidobacteria and enterobacteria in selective media. At 7 dps, levels of aOVAIgE decreased and IL10 increased significantly in P and C groups (339±72 and 126±38) vs. CS (47±12 pg/ml). IL10+ cells were significantly increased in lamina propria (LP) of SI in P and C groups for 7 dps (20±5 and 17±1) and 15 dps (16±3 and 25±6) vs. CS (7±2), but without release of this cytokine in IF as well as for IFNgamma. The Nº of IL2+ cells in all the experimental groups did not change compared with NC. IL4+ cells decreased to 15 dps in groups P and C (10±3 and 15±3) vs CS (21±1). For 7 and 15 dps total IgA levels remain high compared to NC and B. With regard to the intestinal microbiota we determined a reduction of enterobacteria in P and C groups, and increases of bifidobacteria associated with down regulation in B and C. PFM admistration had a beneficial effect in this model evidenced by low leves of aOVAIgE, decrease in the Nº of IL4+ cells in LP and increases of IL10 in serum. High levels of IL10 did not interfer with the total IgA production in gut. Bifidobacteria could be involved in the immune regulation observed.