ItpkB^−/− NK cells express an immature NKR repertoire that persists in IL-2 or IL-15 culture but is normalized upon ectopic ItpkB expression. (A-D) CD94-coupled (NKG2A/C/E) and Ly49 NKRs were assessed on splenic NK cells by flow cytometry. (A) Top, representative dot plots indicating the percentage of cells in the respective quadrants. Center and bottom, bar graphs depicting mean ± SEM, percentages or total numbers of splenic NK cells expressing the indicated NKRs in WT (open bars) or ItpkB^−/− (black bars) mice (n = 5). (B) Pie charts showing the percentage of immature (CD11b⁻; top) or mature (CD11b⁺; bottom) splenic NK cells expressing the indicated Ly49D/H combinations in ItpkB^+/+ or ItpkB^−/− mice, respectively. Results shown are representative of at least 4 independent experiments. (C) Retrovirally transduced BM chimeras were generated as in Figure 2A. Shown is Ly49D/H expression on GFP⁻ versus GFP⁺ItpkB^−/− donor-derived splenic NK cells transduced with empty (top) or WT ItpkB (bottom) expressing retroviruses. (D) Ly49D/H expression on purified WT and ItpkB^−/− splenic NK cells cultured for 7 days in IL-2 (1000 U/mL; top) or IL-15 (100 ng/mL; bottom).