TGFB1 and colitis: An elaborately-designed study illustrated that a complex mixture of 46 strains of Clostridium, in particular Clostridium clusters IV and XIVa, could induce TGF-β in intestinal epithelial cells to intensify the subsequent accumulation of IL-10-producing induced T regulatory (iTreg) cells, which were known to suppress colitis in a DSS-challenged colitis model [72].