This is where the immune system comes in, specifically a special type of white blood cell called intraepithelial lymphocytes. These cells serve two functions: They condition and repair the thin intestinal lining, and they also serve as its first line of gut defense against pathogens.28 These lymphocytes are covered with “Ah receptors” that activate the cells.29 For years, scientists couldn’t find the key that fit into the Ah receptor lock. If we could figure out how to activate these cells, we might be able to boost our immunity.
