An Id2(RFP)-Reporter Mouse Redefines Innate Lymphoid Cell Precursor Potentials

Innate lymphoid cell (ILC) development proposes that ILC precursors (ILCPs) segregate along natural killer (NK) cell versus helper cell (ILC1, ILC2, ILC3) pathways, the latter depending on expression of Id2, Zbtb16, and Gata3. We have developed an Id2-reporter strain expressing red fluorescent protein (RFP) in the context of normal Id2 expression to re-examine ILCP phenotype and function. We show that bone-marrow ILCPs were heterogeneous and harbored extensive NK-cell potential in vivo and in vitro. By multiplexing Id2(RFP) with Zbtb16(CreGFP) and Bcl11b(tdTomato) strains, we made a single-cell dissection of the ILCP compartment. In contrast with the current model, we have demonstrated that Id2(+)Zbtb16(+) ILCPs included multi-potent ILCPs that retained NK-cell potential. Late-stage ILC2P and ILC3P compartments could be defined by differential Zbtb16 and Bcl11b expression. We suggest a revised model for ILC differentiation that redefines the cell-fate potential of helper-ILC-restricted Zbtb16(+) ILCPs.