Editors' ChoiceImmunology

Innate Innit?

Sci. Signal.  02 Nov 2010:
Vol. 3, Issue 146, pp. ec339
DOI: 10.1126/scisignal.3146ec339

Innate lymphocytes (ILCs) are a recently described population of immune cells that produce cytokines like those associated with T helper cells but lack the recombined antigen receptors characteristic of T cells. Again, like some T helper cell lineages, a proportion of ILCs express the transcription factor RORγt. These include lymphoid tissue–inducer (LTi) cells required for fetal lymphoid tissue organogenesis and a population of natural killer (NK)–like cells that function in gut immune responses. Sawa et al. (see the Perspective by Veldhoen and Withers) wondered whether the RORγt-expressing ILCs all develop from the same progenitor population. Indeed, they found a fetal liver progenitor that gave rise to several phenotypically distinct populations. However, the LTi cells were not progenitors for the NK-like cells. It seems the trajectory of different ILC populations is developmentally regulated, and postnatally ILCs are favored that play a role in intestinal defense before the gut is fully colonized by intestinal microbiota.

S. Sawa, M. Cherrier, M. Lochner, N. Satoh-Takayama, H. J. Fehling, F. Langa, J. P. Di Santo, G. Eberl, Lineage relationship analysis of RORγt+ innate lymphoid cells. Science 330, 665–669 (2010). [Abstract] [Full Text]

M. Veldhoen, D. R. Withers, Innate lymphoid cell relations. Science 330, 594–595 (2010). [Abstract] [Full Text]