A) Representative histograms showing relative proportions of splenic NK cells making IFN-γ 1.5 days p.i. MCMV based on expression of Sca-1 (left), KLRG1 (middle), or CD69 (right). B) Proportion of splenic NK cells that make IFN-γ 1.5 days p.i. MCMV based on Sca-1, KLRG1, or CD69 expression. Marker negative cells (◊) and marker expressing cells (♦). Composite data from 2 independent experiments with 3–5 mice/group. Statistical significance was determined using paired, two-tailed t-tests. C) IFN-γ production by splenic NK cells from wt B6 mice or Sca-1−/− mice 1.5 days p.i. MCMV. Composite data from 2 independent experiments with 4–5 mice/group. **p < 0.01, ***p < 0.001.