MALDONADO GALDEANO Maria Carolina
capítulos de libros
LACTIC ACID BACTERIA AND THE MUCOSAL IMMUNE SYSTEM
MARIA CAROLINA MALDONADO GALDEANO; ALEJANDRA DE MORENO DE LEBLANC; GABRIELA PERDIGÓN
Pediatric Gastroenterology, Hepatology and Nutrition
Lugar: BOLOGNA; Año: 2004; p. 333 - 342
The multiple interactions between the prokaryotic cells that colonize the gut, between resident eukaryotic and prokaryotic cells and between host cells and pathogenic or non-pathogenic bacteria are still poorly understood. The interaction between pathogenic bacteria and intestinal ecosystem has been widely studied, but little is known about the interaction between non-pathogenic bacteria such as probiotic bacteria and the host. This last question is further complicated if we consider the twofold role of the normal microflora: 1) the suppression of immune function to prevent food allergies and inflammatory diseases, and 2) the induction of specific response mainly mediated by the production of secretory IgA to protect against infections. The modulation of the mucosal immune system at the intestinal level by probiotic bacteria is exerted by ability to interact with the associated immune cells. Viability is a very important condition for such immunostimulation, but some non viable bacteria can be immunogenic and induce immunoactivation. Immunostimulatory/regulatory properties are specific for each strain and cannot be generalized to include other strains, species or genera. The differences between strains and between the administered doses make their selection difficult for the clinical use of probiotics. Moreover, the safety and efficacy of probiotic preparations require further investigation before their use in clinical trials. The long term administration of yoghurt does not affect the homeostatic balance of the immune cells in the gut since yoghurt is capable of inducing an increased in the levels of various regulatory cytokines.