– Zymosan A, a polysaccharide from Saccharomyces cerevisiae (brewer’s yeast), is a TLR2 agonist that promotes regeneration of ISCs from intestinal stem cells after radiation injury by up-regulating ASCL2 through the TLR2 signaling pathway and the Wnt signaling pathway.Zymosan A stimulates immune responses and induces inflammation , anorexia and elevated body temperature, and also inhibits the gap junction protein connexin 43 in human corneal fibroblasts and causes corneal stromal damage.