Figure 1.

Group 3 ILC development and heterogeneity. Group 3 ILCs represent the most diverse ILC subset, comprising of CCR6⁺ LTi cells, and ILC3s that can be further divided into NCR⁻ and NCR⁺ ILC3s. Group 3 ILCs rise from a common lymphoid progenitor that lost T, B and eventually NK cell potential and depend on the transcriptional factor RORγt for their development. Depending on the environmental stimulus, ILC3s produce a variety of distinct cytokines such as IL-17, IL-22, IFNγ, and GM-CSF to mediate their functions. Interestingly, ILC3s are highly plastic cells and as such NCR⁻ ILC3s can acquire NCR expression and became NCR⁺ ILC3s in the presence of a T-bet gradient or loose completely RORγt expression to differentiate into ILC1 like ILCs and vice versa.