Immune-Signalling by Orally-Delivered Probiotic Bacteria: Effects on Common Mucosal Immunoresponses and Protection at Distal Mucosal Sites

Abstract

Probiotics – orally-delivered preparations of non-pathogenic bacterial cells – have been reported to increase anti-microbial protection in the gastrointestinal tract environment, and offer a safe and effective non-pharmaceutical means for combating infectious diseases and certain other pathologies. There is also an increasing body of evidence to suggest that immunostimulation by probiotic bacteria in the gut can enhance immune protection at distal mucosal sites, such as the urogenital and respiratory tracts. This review summarises the current information, from both clinical and animal model studies, of a role for orally-delivered probiotics in modulating mucosal immunoresponses and protection at distal sites. While it is clear that probiotics hold promise in this area, research that is targeted toward identifying the mechanism driving stimulation of the common mucosal immune system, as well as patterns of mucosal tissue homing by immunocytes following probiotic-mediated signalling in the gut, is strongly encouraged.