Differential roles of ROR gamma-t in the development of NKp46+ spleen (LTIL) cells and NKp46+ NK cells in gut and skin

Natural killer (NK) cells are NKp46+CD3- lymphocytes that can perform granule-dependent cytotoxicity and produce interferon-gamma, when isolated from blood, lymphoid organs, lung, liver and uterus. Here we identify in dermis, gut lamina propria and cryptopatches, very distinct populations of NKp46+CD3- cells with reduced ability to degranulate and to produce interferon-gamma. In gut, the transcription factor RORgamma-t and CD127 (IL-7R alpha) defined a novel subset of NKp46+CD3- that is reminiscent of lymphoid tissue inducer (LTi)-like cells. Gut ROR gamma t+NKp46+ cells produced IL-22 in contrast to ROR-gamma t-independent lamina propria and dermis NK cells. These data show that LTi-like cells and NK cells share unanticipated similarities and reveal the heterogeneity of NKp46+CD3- cells in innate immunity, lymphoid organization and local tissue repair. A total of 6 samples were included in this study. Duplicate samples of natural killer cells from mouse skin, spleen, and intestine were analyzed.