Figure 2.

A new model for layered ontogeny of ILC2s along with fetal and postnatal waves of γδ T cells. Like most tissue-resident cells, the developmental timepoint in which ILC2s arise and colonize tissues coincides with γδ T cells early in life (based on layered ontogeny in B6 mice). Taken together with TCR locus sequence tracing data and pulse-labeling lineage tracing studies, it is highly likely that tissue-resident ILC2s arise perinatally from developing DN2s that have ineffectively rearranged their γ/δ loci, rather than from progenitors in the BM. These cells then take up residence at their designated tissue sites and self-renew locally.