ILC2 in Immunity

Group 2 innate lymphoid cells (ILC2s), previously also known as natural helper cells, nuocytes, or innate helper-2 cells) are recently identified lymphoid cells that lack antigen receptors and belong to the group of innate lymphoid cells (ILCs). Like other ILCs, ILC2s develop from the common lymphoid precursor and depend on Notch signaling and the transcription factors Id2 and GATA-3. Additionally, ILC2 development specifically requires sustained GATA-3 expression and the transcription factors RORα and Bcl11b. ILC2s are strategically distributed along barrier sites that are common sites of invasion or colonization by pathogens and commensals. ILC2s are activated by epithelial cell-derived cytokines (interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin). Analogous to Th2 cells, ILC2s produce type 2 cytokines (mainly IL-5 and IL-13) and are involved in antihelminth immunity, allergic inflammation, and epithelial repair. ILC2s have been implicated in various diseases of man and mice, including allergic asthma, chronic rhinitis, and atopic dermatitis.