Liver type 1 innate lymphoid cells develop locally via an interferon-γ-dependent loop.

Bai, Lu; Vienne, Margaux; Tang, Ling; Kerdiles, Yann; Etiennot, Marion; Escalière, Bertrand; Galluso, Justine; Wei, Haiming et al. · Science · 2021

basic_science · Level V

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Abstract

The pathways that lead to the development of tissue-resident lymphocytes, including liver type 1 innate lymphoid cells (ILC1s), remain unclear. We show here that the adult mouse liver contains Lin<sup>-</sup>Sca-1<sup>+</sup>Mac-1<sup>+</sup> hematopoietic stem cells derived from the fetal liver. This population includes Lin<sup>-</sup>CD122<sup>+</sup>CD49a<sup>+</sup> progenitors that can generate liver ILC1s but not conventional natural killer cells. Interferon-γ (IFN-γ) production by the liver ILC1s themselves promotes the development of these cells in situ, through effects on their IFN-γR<sup>+</sup> liver progenitors. Thus, an IFN-γ-dependent loop drives liver ILC1 development in situ, highlighting the contribution of extramedullary hematopoiesis to regional immune composition within the liver.

Medical subject headings