Physiological function and regulatory signal of intestinal type 3 innate lymphoid cell(s).

Of the three groups of innate lymphoid cells, the type 3 innate lymphoid cell(s) (ILC3) include the subgroup of enteric ILC3 that participates in many physiological functions of the organism, such as promoting the repair of damaged mucosa, maintaining the homeostasis of gut symbiotic microorganisms, and presenting specific antigens. ILC3 also includes splenic and decidual ILC3. Like other physiological processes in the organism, enteric ILC3 functions are precisely regulated at the endogenous and exogenous levels. However, there has been no review on the physiological functions and regulatory signals of intestinal ILC3. In this paper, based on the current research on the physiological functions of enteric ILC3 in animals and the human, we summarize the signals that regulate cytokine secretion, antigen presentation and the quantity of ILC3 under normal intestinal conditions. We discuss for the first time the classification of the promoting mechanism of secretagogues of ILC3 into direct and indirect types. We also propose that ILC3 can promote intestinal homeostasis, and intestinal homeostasis can ensure the physiological phenotype of ILC3. If homeostasis is disturbed, ILC3 may participate in intestinal pathological changes. Therefore, regulating ILC3 and maintaining intestinal homeostasis are critical to the body.