Figure 3. ST2 and IL-33 augment expansion of naïve and memory Ly49H⁺ NK cells and control of MCMV.

(A and B) WT and Il1rl1^−/− Ly49H⁺ NK cells from mixed BM chimeric mice were transferred into Ly49H-deficient mice and infected with 1 × 10⁵ pfu MCMV. The number of Ly49H⁺ NK cells in the spleen (A) and liver (B) on day 7 pi is shown. Data are pooled from 2 experiments (n = 6 mice). (C) WT and Il33^−/− mice were infected with 5 × 10⁵ pfu MCMV. The number of Ly49H⁺ NK cells in the blood on day 7 pi is shown. Data are pooled from 2 experiments (n = 4 mice). (D and E) WT and Il1rl1^−/− Ly49H⁺ NK cells were transferred into Ly49H-deficient mice and infected with MCMV. (D) The number of Ly49H⁺ NK cells in the blood is represented as the ratio relative to the number of Ly49H⁺ NK cells in the blood on day 0 (before infection). (E) Y-axis represents the number of memory Ly49H⁺ NK cells detected in the spleen on day 29 pi compared with the number of naïve Ly49H⁺ NK cells adoptively transferred into recipient mice on day 0. Data are pooled from 3 experiments (n = 8 mice). (F) Phenotype of WT and Il1rl1^−/− memory Ly49H⁺ NK cells on day 29 pi in the spleen. Bold and thin lines represent memory WT and Il1rl1^−/− Ly49H⁺ NK cells, respectively. Dark grey-shaded and light grey-shaded histograms represent naïve WT and Il1rl1^−/− Ly49H⁺ NK cells, respectively. Data are representative of 2 experiments (n = 2-3 mice per experiment). (G) Memory Ly49H⁺ NK cells were isolated 29 days after infection, transferred into naïve Ly49H-deficient mice, and infected with 1 × 10⁵ pfu MCMV. Expansion of memory Ly49H⁺ NK cells in the spleen on day 7 after secondary infection is represented as the fold expansion relative to the number of memory Ly49H⁺ NK cells detected in the spleen of mice adoptively transferred with memory Ly49H⁺ NK cells but not infected. Data are pooled from 3 experiments (n = 9 mice). *p <0.05, **p <0.01 vs. Il1rl1^−/− or Il33^−/−. (H-J) WT and Il1rl1^−/− memory NK cells were purified 25–32 days after infection, and WT and Il1rl1^−/− naïve NK cells were purified from BM chimeric mice. WT and Il1rl1^−/− naïve and memory Ly49H⁺ NK cells were transferred separately into Ly49H-deficient or DAP12-deficient mice and infected with 1 × 10⁵ pfu MCMV. The copy number of MCMV IE1 gene in the blood (H) on day 4 pi, and in the spleen (I) and liver (J) on day 7 pi was analyzed by q-PCR. (H) Data were pooled from 4 experiments (n = 7-11 mice per group) and (I and J) data were pooled from 2 experiments (n = 4 mice per group). *p <0.05, ***p <0.005.