Evaluation of immunomodulatory activity of two potential probiotic Lactobacillus strains by in vivo tests

• The immunomodulatory activity of two lactobacilli strains was evaluated in vivo.
• Both strains increased spleen index & improved spleen lymphocyte transformation rate.
• Both strains enhanced sIgA production and increased the number of CD11c+CD80+ cells.
• Lactobacillus salivarius was the better strain at maintaining the Th1/Th2 balance.
• Lactobacillus plantarum was more effective in enhancing macrophage phagocytic activity.

Here we evaluate the immunomodulatory function of two potential probiotic strains, Lactobacillus salivarius CICC 23174 and Lactobacillus plantarum CGMCC 1.557. Mice were fed with each Lactobacillus strain at different doses for several consecutive days. The effects of the two probiotic strains on immune organs, immune cells and immune molecules were investigated on days 10 and 20. Both Lactobacillus strains increased the spleen index, improved the spleen lymphocyte transformation rate, enhanced sIgA production and improved the number of CD11c+ CD80+ double-positive cells. L. plantarum CGMCC 1.557 was the more active strain in enhancing the phagocytic activity of macrophages, while, L. salivarius CICC 23174 was the more effective strain at maintaining the Th1/Th2 balance. This study suggests that these two Lactobacillus strains have beneficial effects on regulation of immune responses, which has promising implications for the development of ecological agents and functional foods.