Fig. 1: Impact of the gut microbiota on the intestinal mucosal immune system.
From: Modulation of oral vaccine efficacy by the gut microbiota
Chemical and physical barriers exist that can spatially isolate the gut microbiota and host immune cells to prevent excessive immune responses. Chemical barrier molecules include antimicrobial peptides and Reg3 family proteins. The physical barriers include the mucus layer, the glycocalyx on IECs, and the tight and adhesion junctions of the epithelium. The gut microbiota plays a pivotal role in affecting the intestinal mucus and epithelial barriers. The gut microbiota and their metabolites impact DC maturation, antigen uptake and presentation. The gut microbiota was confirmed to be beneficial for the development of B and T cells and the production of sIgA. Changes in the gut microbiota directly influence the Th1/Th2 and Th17/Treg balance. SIgA, secretory immunoglobulin A; MHC, major histocompatibility complex; TCR, T-cell receptor; DC, dendritic cell; Treg, regulatory T cell. (Created with Adobe illustrator).
