Analysis of NKG2D deficiency in BALB.B6-Cmv1^r mice. (A) Schematic diagram depicting the breeding scheme used to generate NKG2D-deficient mice on a BALB.B6-Cmv1^r background. C57BL/6 NKG2D KO mice were backcrossed 8 times to BALB/c mice, and the backcrossed Klrk1^+/− offspring were then backcrossed once to the congenic BALB.B6-Cmv1^r strain that carries B6 donor alleles from the NKC complex before intercrossing to generate BALB.B6-Cmv1^rKlrk1^−/− and BALB.B6-Cmv1^rKlrk1^+/+ littermates. (B) Percentages of splenic NK cells expressing Ly49A, Ly49F, and Ly49G2 from BALB.B6-Cmv1^r NKG2D-KO and BALB.B6-Cmv1^r WT littermates (gated CD3-NK1.1+). Data are mean ± SD and are representative of 2 to 3 independent experiments. (C) Percentages of c-Kit+ NK cells (upper) and CD11b/CD27 NK subsets in the spleen (middle) and BM (lower) of WT and NKG2D-KO mice. (D) Percentages of IFN-γ–producing NK cells cross-linked with ant-NK1.1 (PK136) (upper) or stimulated with IL-2 in vitro (lower). Data are expressed as mean ± SD and are representative of 3 independent experiments.