Involvement of gastrointestinal tract associated microbiota in direct and indirect immunomodulation: An overview

Abstract

Gastrointestinal Tract (GIT) associated microbiota is a diverse community of trillions of microorganisms, which homeostatically co-exist with the host in normal conditions and interact actively with the physiological processes of the host. Among them, some microorganisms impart beneficial effects on the host while pathogens and opportunistic pathogens always tend to invade host body cells. Many studies have now established that probiotic bacterial strains can modulate our overall immunity and play crucial roles in digestion, metabolism, brain-gut communication, etc. Talk about immunomodulation by probiotics, studies have revealed that many bacterial strains regulate innate and adaptive immunity either directly engaging immune cells of the host body or indirectly by blocking the entry of pathogens and viruses into the host body. In this overview, we will talk about how probiotics affect immunity by promoting the creation of tight junctions (TJs), raising mucin secretion, and improving the cytotoxicity of macrophages and Natural Killer (NK) cells. The discussion will give us a holistic idea about immunomodulation by gut microbiota (GM) and provide an opportunity to use the information for human welfare.