Beneficial effect of probiotic consumption on the Immune System

MALDONADO GALDEANO, CAROLINA; CAZORLA, SILVIA INES; LEMME DUMIT, JOSÉ MARÍA; VELEZ, EVA M. M.; PERDIGÓN, GABRIELA.

ANNALS OF NUTRITION AND METABOLISM

KARGER

Lugar: Basel; Año: 2019 vol. 74 p. 115 - 124

0250-6807

Background: The gastrointestinal tract is one of the most active microbiologically ecosystems that play a crucial role for the functioning of the Mucosal Immune System (MIS). In this ecosystem, probiotic microorganisms that enter orally stimulate the Immune System and induce a network of signals mediated by the whole bacteria or their cell wall structure. Summary: Probiotic interact with intestinal epithelial cells (IECs) or immune cells associated to the lamina propria, and induce the production of different cytokines or chemokine. Namely, MCP1 (macrophage chemoattractant) produced by the IECs that sends signals to others immune cells, enhancing the MIS activation. We demonstrate that probiotics bacteria interact with the IECs and stimulate the mucosal immunity by increasing: the number of IgA+ cells in the intestine, bronchus and, mammary gland and the activation of T cells with the corresponding cytokine production. Specifically, probiotics activate T regulatory cells that release IL-10 release. Interestingly, probiotics reinforce the intestinal barrier by increase of goblet and Paneth cell. Not less important, we demonstrated that long term probiotic consumption does not affect the intestinal homeostasis.We also determined the importance of the probiotic viability in the interaction with the epithelial cell and macrophages, which are mediated by Toll like receptors (TLRs), favoring, mainly, the innate immune response. Macrophages and DCs play an important role in the innate immune response without inducing an inflammatory response, just a slight increase in the cellularity of the lamina propria. We recently, demonstrated the effectiveness of probiotics in the protective response against Salmonella Typhimurium infection, by an increase in the microbicidal activity of the peritoneal and spleen macrophages. Probiotics efficacy has also been confirmed in malnutrition models. In that sense, we observed in undernourished and obesity mice, an improvement in the Immune System functionality as well as in the histology of both the intestine and the thymus after probiotics oral administration We determined in a respiratory allergy model, that a probiotic fermented milk (PFM) diminished the IgE levels by a shift to a Th1 immune response, which favor the production of IgG instead of IgE. Key Messages: We conclude that probiotics bacteria, its cell wall and also a PFM have relevant effects on the functionality of the MIS and the immune surveillance, through the activation of multiple mechanisms.