Figure 1.

Ontogeny and function of lymphoid lineages. Downstream of the common lymphoid progenitor (CLP), the early innate lymphoid cell (ILC) Progenitor (EILP) initiates TCF1 expression and can differentiate into either natural killer (NK) cells or into an Id2^high common helper‐like ILC progenitor (CHILP). According to the expression or not of PLZF, it will give rise to either all helper‐like ILC subsets including CCR6⁺ ILC3, or to ILC1, ILC2 and CCR6⁻ ILC3. Environmental cytokines as well as ILC differential transcriptional factors programme their cytokine production and function.