Impaired maturation and Ly49 receptor expression in Eri1^−/− NK cells. B6 WT CD45.1⁺ lethally irradiated hosts were reconstituted with a 1:1 mixture of congenic WT (CD45.1⁺CD45.2⁺) and Eri1^−/− (CD45.2⁺) fetal liver cells. (A-C) Splenic and (D) BM NK cells were analyzed by flow cytometry at 8-15 weeks. (A) Cell-surface expression of activating receptors (NKp46 and NK1.1), activation markers (NKG2D and CD69), and maturation markers (CD27, NKG2A/C/E, KLRG1, CD11b, and CD49b) on WT (CD45.1⁺CD45.2⁺) and Eri1^−/− (CD45.1⁻CD45.2⁺) cells (left). Gated NK1.1⁺CD3ϵ⁻ cells are shown for all stains, except for NK1.1, which shows gating on NKp46⁺TCRβ⁻ cells. Summary of markers with significantly different expression on WT and Eri1^−/− NK cells (right). (B) Splenic NK-cell activating and inhibitory Ly49 receptors. (C) Percentage of Ly49H⁺ cells among CD11b⁺ and CD11b⁻ NK cells. (D) Percentage of Ly49H⁺ WT and Eri1^−/− NK cells at various stages of NK-cell maturation in the BM (gating shown in supplemental Figure 2A). Bar graphs and flow cytometry plots show mean ± SD (N = 3 mice). *P ≤ .05; paired Student t test.