Figure 3

Probiotics impact mucosal/surface immunity. Probiotics can provide local or mucosal immunity and protection from many pathogens in a diversified manner. They can affect the adhesion of different pathogens to host cell surface by competitive exclusion. The binding of probiotics can induce the host cells to secrete anti-inflammatory cytokines which will decrease the inflammation at the tissue surface. Probiotics can also secrete antimicrobials to inhibit the growth of pathogens. The metabolites of probiotics like lactic acid from lactobacillus bacterium can result in alteration of pH in lumen or at surface, which can ultimately inhibit the growth of certain pH sensitive pathogens. Probiotics can also bind to toxin released by pathogens resulting in neutralization of the toxins. Similar types of protection can be provided by symbiota associated with other organs i.e. oral cavity, skin, respiratory tract and urogenital tract.