ETS1 influences NK cell terminal differentiation and function. (A-B) Flow cytometric expression of the indicated receptors on gated NK cells from d21 control (ctrl) and ETS1 p27 cultures (mean ± SEM; n = 5-15). (C) d18 to d21 NK cells were stimulated with an equal number of K562 target cells, and CD107a expression was determined (mean ± SEM; n = 8). (D) The cytotoxic capacity of sorted d18 to d21 NK cells against K562 targets was determined in a ⁵¹chromium release assay. Data are expressed as the percent specific lysis as a function of the effector:target ratio (mean ± SEM; n = 6). (E) The mean fluorescence intensity (MFI) of perforin and granzyme B (GzmB) expression in ctrl and ETS1 p27 NK cells (n = 6). (F) Fas ligand expression of NK cells that were unstimulated (US) or stimulated for 2 hours with K562 cells (n = 5). (G) Cells from d21 ctrl and ETS1 p27 cultures were stimulated with K562 cells for 6 hours, or with IL-12/IL-18 or IL-12/IL-15/IL-18 for 24 hours, and IFN-γ production was determined by flow cytometry in gated NK cells (mean ± SEM; n = 4-12). (H) Sorted d21 NK cells were stimulated with IL-12/IL-18 or IL-12/IL-15/IL-18 for 24 hours, and secreted IFN-γ was measured by using enzyme-linked immunosorbent assay. The relative IFN-γ production compared with ctrl is shown (mean ± SEM; n = 6-7). Significant difference compared with ctrl, *P < .05, **P < .01, and ***P < .001 (Student t test).