Fig. 2

Prebiotics, probiotics, and postbiotics each have specific associations with immune cells in the lamina propria. Aryl hydrocarbon receptor (AHR) ligands, which are present in food antigens, promote mucosal healing via IL-22 production from group 3 innate lymphoid cells (ILC3). SFB also promote IL-22 production from ILC3 and activate lamina propria DCs and macrophages to induce Th17 cells through the production of SAA from IECs. C. rodentium and epithelial cell (EC)-adhesive bacteria induce Th17 differentiation by reactive oxygen species (ROS), adenosine triphosphate (ATP), and others. C. butyricum induce intestinal IL-10-producing macrophages, while polysaccharide A (PSA)-positive B. fragilis stimulate DCs to produce IL-10. PSA itself directly promotes the development of the activation of Foxp3-positive Treg cells in a similar way to SCFA, such as propionate and butyrate. Clostridium clusters IV and XIVa also promote Treg cell accumulation via TGF-β production from IEC