Figure 1.

Symmetry between the development of adaptive and innate lymphocytes. There are following three major T helper (Th) subsets: Th1, Th2, and Th17 cells. Transcription factors T-bet, GATA3, and RORγt are the master regulators for the differentiation of Th1, Th2, and Th17 cells, respectively, from naïve CD4 T cells. Th2 cells express high levels of GATA3 that is critical for the development and functional maintenance of Th2 cells. The importance of low GATA3 expression in Th1 and Th17 cells is not clear. During T cell development, GATA3 is critical for the development of CD4 but not CD8 T cells in the thymus. Similarly, GATA3 is indispensable for the development of all IL-7Rα-expressing helper-like innate lymphoid cells (ILCs) but not natural killer (NK) cells. While GATA3 is critical for the functional maintenance of ILC2s, it is also required for the homeostasis, function, and further maturation of other ILCs, including ILC1s and ILC3s. Although GATA3 is not necessary for the development of NK and CD8 T cells, GATA3 expression at low levels contributes to the homeostasis and maturation of these cells. EILP, early ILC progenitor that expresses TCF7; ChILP, common helper-like ILC progenitor that expresses Id2.