Administration of IL-25 to mice elicited the release of high levels of IL-5 and IL-13 from a population Acalabrutinib of RAG-independent, γ-common-chain dependent, non-T, non-B innate lymphoid cells in the gut. Later studies identified several cell populations with similar, but not identical, phenotypes in various organs. These cell populations were lineage negative (Lin−) Sca-1+IL-7R+Thy1+T1/ST2+, and served as critical mediators

of parasite expulsion in the murine intestine [[15, 61, 62]]. Transcriptional analysis revealed a number of transcription factors, including Id2, Notch1, Notch2, RORα and GATA3 [[6, 15, 61, 63]] that could potentially control the development and function of these cells. Like NK cells and RORγt-dependent ILCs, development of type 2 ILCs depends on the transcriptional repressor Id2 [[4, 15]], suggesting, as discussed above, that they are derived from a common precursor; however, type 2 ILCs develop independently of RORγt, as Rorγt−/− mice exhibit numbers of type 2 ILCs comparable to those in wt mice [[15]]. Recently, it was reported that ILC2s could be generated from a bone marrow Lin−IL7Rα+Flt3+ CLP, differentiating under the influence

of Notch1 signaling [[6, 64]] ILC2s failed to differentiate in mice with a spontaneous deletion in the gene for RORα, the so called staggerer (Rorasg/sg) mice [[6]]. In line with this observation, staggerer mice either injected with IL-25 or infected with the helminth parasite N. brasiliensis failed to either generate ILC2s or expel the parasites respectively. GATA3 is highly BMN 673 molecular weight expressed by ILC2s [[15, 63, 65]], and mice

in which GATA3 was deleted only in IL-13-producing cells, of which the majority were ILC2s during N. brasiliensis infection, are phenocopies of IL13-deficient mice [[66]]. Fludarabine cost These mice exhibited reduced worm clearance, suggesting that GATA3 is critical for IL-13 production in ILC2s. Together, these findings emphasize the striking similarity between Th2 cells and ILC2s, with both cell types relying on GATA3 for their function. Collectively, the studies described in this section indicate that the development and function of ILC2s are controlled by several transcription factors including Id2, RORα, Notch1 and GATA3. ILC-related transcription factors are potential targets for therapy in those diseases in which ILCs play either a prominent detrimental or beneficiary role. Two recent papers describe the potent effects of RORγt antagonism in inhibiting Th17-cell differentiation and reducing the severity of experimental auto-immune encephalomyelitis (EAE)[[67, 68]]. First, Huh et al reported that digoxin, and the two synthetic, non-toxic, derivatives 20,22-dihydrodigoxin-21,23-diol and digoxin-21-salicylidene, inhibit the differentiation of mouse and human Th17 cells[[67]]. Digoxin was shown to specifically inhibit RORγt transcriptional activity.