Activation of the innate immunity by a probiotic bacterium and fermented milk containing this microorganism

MALDONADO GALDEANO C; DE MORENO DE LEBLANC A; DOGI C.A; S CHAVES; CARMUEGA E; WEILL R; PERDIGON G

Workshop; 1st International Immunonutrition Workshop; 2007

Improvement of the immune status of the host is one of the beneficial properties attributed to probiotics. Previous results have shown that the effect induced by a probiotic strain Lactobacillus casei CRL 431 is through innate immunity. The present work investigated the behaviour of another probiotic bacterium Lactobacillus casei DN 114001 in relation to the interaction between the epithelial and immune cells, using mice as the experimental model. Using electron microscopy and fluorescent bacteria it was demonstrated that this bacterium interacts with the intestinal epithelial cells and the small fragments of the bacterium can internalize and make contact with the immune cells (macrophages and dendritic cells) present in Peyer patches and in the lamina propria of the small and large intestine. These antigenic particles remain in the gut for 72 h, similar to other particulate antigens. A subsequent study investigated the effect of the inclusion of this probiotic bacterium in fermented milk on the mucosal innate immune system of the gut in BALBc mice. The fermented milk was administered to the mice for five consecutive days, which was previously determined to the optimal dose to stimulate the immune response. At the end of the administration period the animals were killed and the small and large intestine was removed for the determination of: (a) the number of IgA- and cytokine (IL-10, interferon (IFN-g), TNF producing cells in histological slices of both intestines; (b) the expression in the lamina propria of the small intestine of the