Stimulation of host resistance by a diet supplemented with yogurt

Our studies suggest that the beneficial anti-infective properties of yogurt could be attributed, at least partially, to the influence of the lactobacilli it contains on the host immune system. In vitro experiments conducted with human lymphocytes have shown that the addition of small quantities of yogurt is able to potentiate by 3-4 times the production and the release of Y-IFN by T lymphocytes stimulated with Con A. Bacterial adherence experiments have shown that lactobacilli bind spontaneously to CD4+ and CD8+ lymphocytes. In vivo, the addition of yogurt containing live strains of Lactobacillus bulgaricus and Streptococcus thermophilus to the standard murine diet, results after two weeks of treatment, in a different expression of the splenocyte surface antigens Thy1,2, Lyt1, Lyt2 as compared to the control group. From a functional point of view, the proliferative responses of the splenocytes to PHA, Con A and PWM were also increased significantly. With regard to Payer's patches, a significant increase in the mitogenic response of murine B lymphocytes to E. coli LPS was observed.