Intestinal commensals: influence on immune system and tolerance to pathogens

► Commensal microbiota affects both inflammatory and regulatory processes in the gut. ► Some microbial lineages are more potent in regulation of the gut immunity than the others. ► Intestinal microbes also regulate autoimmunity and immunity to infections at distal sites. ► Commensal microbiota is involved in maintenance of tolerance to pathogens.