The immunomodulatory effects of lactic acid bacteria for improving immune functions and benefits

Probiotics have a number of beneficial health effects in humans and animals, such as reducing lactose intolerance symptoms and enhancing the bioavailability of nutrients. Probiotics help regulate intestinal microflora and immunomodulatory properties. Probiotics also decrease the prevalence of allergies in susceptible individuals, inhibit the inflammatory responses in the gut, and have antagonistic effects against intestinal and food-borne pathogens. Bacteria typically colonize the intestinal tract first and then reinforce the host defense systems by inducing generalized mucosal immune responses, including modulation of DC/NK interaction, a balanced T-helper cell response, self-limited inflammatory response, and the secretion of polymeric IgA. A lot of reports showed that lactic acid bacteria (LAB) as Lactobacillus and Bifidobacterium and their fermented products are effective at enhancing innate and adaptive immunity, prevent gastric mucosal lesion development, alleviate allergies, and put up defense against intestinal pathogen infection. In this review paper, we compared the influence of immunomodulatory effects on the function and efficacy of lactobacillus products with different strains. We also discuss the beneficial effects of several LAB strain and its derivative products for human immunity and related diseases.