Modulation of the immune response by the non-bacterial fraction derived from kefir.

VINDEROLA, C.G.; DUARTE, J.; PERDIGÓN, G.; FARNWORTH, E.; MATAR, C.

Roma (Italia)

Simposio; 3rd Probiotics, Prebiotics and New Foods.; 2005

Probiotic microorganisms can exert their beneficial properties as viable cells or by modulating immune response via their metabolites. Kefir, a complex fermented milk, modulates the immune response at local (intestinal mucosa) and distant sites, upon recent studies conducted in our lab. The aim of this project was to study the effects of the non-bacterial fraction of kefir on the gut immune response. BALB/c mice received orally kefir supernatant for 2, 5 or 7 days. The number of IgA+, IgG+, IL-4+, IL-10+, IL-6+, IFNgamma+ and TNFalpha+ cells was determined on histological slices of small (SI) and large intestine (LI) and cytokines were also measured in blood serum and intestinal fluids by ELISA. In the SI, the number of IgA+ cells increased for all feeding periods assessed, but not for IgG+ cells, compared to control mice. The cytokines IL-4+, IL-10+ and IL-6+ cells showed an enhancement when compared to IFN+ and TNF+ cells. The same immune response profile was observed in the LI, but to a lesser magnitude. This might be due to the highest absorption of soluble metabolites in the LI. In blood serum, cytokines (mainly IL-10) increased for all feeding periods. In the intestinal fluid we observed that only IL-6 was secreted into the lumen. IL-6 was also produced by intestinal epithelial cells as observed in our previous studies. We concluded that the soluble metabolites of kefir stimulate the gut immune response increasing the IgA+ cells and cytokine release, with an important induction of the regulatory cytokine IL-10.