These NK cells express p44 in the case of humans and the IL-23R. It is reasoned that dendritic cells, upon activation following exposure to harmful infectious agents, synthesize IL-23, which binds to the IL-23R on NK cells. These activated NK cells synthesize IL-22. The gastrointestinal epithelial cells express the receptor for IL-22 and, upon ligation, synthesize IL-10, which supposedly downregulates the degree of inflammation and homeostasis is maintained.
NK: Natural killer; R: Receptor.