Bacterial fucosylation limits gut inflammation by maintaining intestinal IgA B cell response 4134

Description Loss-of-function mutation in α1,2-fucosyltransferase (Fut2) gene is associated with inflammatory bowel disease (IBD), but whether this variation links the bacterial fucosylation is unclear. We demonstrated that the status of host fucosylation influences the profile of carbohydrate metabolism and biosynthesis in gut commensal bacteria. Mice colonized with Bacteroides fragilis with lower surface fucosylation are predisposed to colitis. Immunoglobulin (Ig) A controls host-microbial homeostasis in the gut. We discovered IgA recognition of gut microbiota is mediated by dietary fucose and found that the bacterial fucosylation is critical for maintaining B cell responses in the gut. These data highlight the role of bacterial fucosylation in maintaining IgA homeostasis and immune escape mechanisms, and provide the insight into the effect of high dietary fucose in intestinal immunity. Funding Sources NIH R21AI159194, R01DK115406 and R01AA030756 Topic Categories Mucosal and Regional Immunology (MUC)