Intestinal barrier: A gentlemen’s agreement between microbiota and immunity

Figure 1 First line of defense of the intestinal barrier shapes the gut microbiota. Antimicrobial peptides are produced by Paneth cells, such as alpha-defensins, lysozyme C, phospholipases and C-type lectin, primarily regenerating islet-derived 3-gamma (RegIIIγ) or by enterocytes (RegIIIγ). In the adaptive immunity scenario, system effectors are secreted into the intestinal lumen, restricting bacterial penetration into the host mucus and mucosal tissue.