Administration of kefir-fermented milk protects mice against Giardia intestinalis infection

CORREA FRANCO, M; GOLOWCZYC, M; DE ANTONI, GL; PÉREZ, PF; HUMEN, MA; SERRADELL, MA

JOURNAL OF MEDICAL MICROBIOLOGY

SOC GENERAL MICROBIOLOGY

Lugar: London; Año: 2013 vol. 62 p. 1815 - 1822

0022-2615

Giardiasis, caused by the protozoan Giardia intestinalis, is one of the most common intestinal diseases worldwide and constitutes an important problem for public health systems of different countries. Kefir is a probiotic beverage obtained through fermentation of milk with ?kefir grains?, which consisting mainly of bacteria and yeasts that coexist in a complex symbiotic association. In this work, we studied the ability of kefir to protect mice from a G. intestinalis infection, and characterized the host immune response to this probiotic in the context of the intestinal infection. Six to eight weeks old C75BL/6 mice were separated into 4 groups: C (control mice), K (mice receiving 1/100 dilution of kefir in drinking water for 14 days), G (mice infected orally with 4x107 trophozoites of G. intestinalis at day 7), and GK (kefir-treated G. intestinalis-infected mice), and were sacrificed at 2 and 7 days post-infection (pi). Kefir administration was able to significantly reduce the intensity of Giardia infection at 7 days pi. An increase in CD4+ T cells percentage at 2 days pi was observed in Peyer´s patches (PP) of mice belonging to G group compared with C and K groups, meanwhile in GK group, the percentage of CD4+ T cells in PP was similar to controls. At 2 days pi, a reduction in the percentage of B220+ MHC-II medium in PP was observed in infected mice compared with the other groups. At 7 days pi, Giardia-infected mice showed a reduction in RcF+ cells compared with C group, suggesting a downregulation of inflammatory response. However, in K and GK groups, the percentages of RcF+ cells did not differ from controls. An increment in IgA+ cells was observed in the lamina propria of K group compared with to control at 2 days pi. Interestingly, the diminished number of IgA+ cells registered in G group at 7 days pi, was restored by kefir feeding although the increase of IgA+ cells was no longer observed in K group at that time. No significant differences in CXCL10 expression were registered between groups, in concordance with the absence of inflammation in small intestinal tissue. Interestingly, a slight reduction on CCL20 expression was observed in G group suggesting that G. intestinalis might downregulate its expression as a way to evade inflammatory immune response. On the other hand, a trend to an increase in TNF- expression was observed in K group, meanwhile GK group showed a significant increment in its expression. Moreover, kefir receiving-mice (K and GK groups) showed an increment in the expression of IFN-, the most relevant Th1-cytokine, at 2 days pi. Our results demonstrated that feeding with kefir reduces G. intestinalis infection and promotes the activation of different mechanisms of humoral and cellular immunity down-regulated by parasitic infection, which contributes to protection.