EFFECT OF NON-PATHOGENIC AND PROBIOTIC BACTERIA ON THE GUT IMMUNE SYSTEM

DOGI, C.; MARIA CAROLINA MALDONADO GALDEANO; PERDIGÓN, G.

CORDOBA

Congreso; Congreso Latinoamericano de Inmunología; 2005

Aims: To compare, using BALB/c mice, the effect of indigenous (IN) and exogenous (EX) bacteria: Lactobacillus fermentum (Lf) and Lactobacillus acidophilus (La) and a probiotic bacterium: Lactobacillus casei CRL 431 (Lc) on the gut immune system (GIS). Methodology: Mice were fed during 2, 5 or 7 days with 104 CFU ml-1 of IN strains and 108 CFU ml-1 of EX or Lc. The daily dose was selected by determination of absence of bacterial translocation to liver. The numbers of IgA, IL10, IFNg, TNFa and CD206 positive cells were determined in the lamina propria of the small intestine by immunofluorescence. Results were expressed as the number of positive fluorescent cells per ten fields. Results: All strains assayed induced a significant increase of IgA+ cells in the small intestine after 7 days administration (EX La 169±15; IN La 164±21; EX Lf 156±13; Lc 230±23; control 110±10). Only EX Lf did not increase the number of IFNg+ cells (control 17±5). All EX strains increased TNFa+ cells after 5 days administration (Lc 74±5; EX Lf 35±5; Ex La 36±3; control 24±6). For IL10, each strain showed a different behavior. The number of CD206+ cells increased in mice fed with Lc and with EX Lf for all administration periods. Conclusion: All the strains stimulated the GIS increasing the IgA+ cells and proinflammatory or regulatory cytokines. An important activation of macrophages has been shown for some strains through the increase of CD206 (mannose receptor) involved principally in the innate immune response. These effects were dose and strain dependent.