NK cells affect the frequency of activated CD4⁺IFN-γ⁺ T cells. Ly49H⁻, Ly49H⁺, and Ly49H⁺ NK1.1-depleted mice were infected with MCMV (5 × 10³ PFU). (A) The frequencies of CD4⁺IFN-γ⁺ T cells in the liver at days 6 and 10 pi are shown. The frequencies of IFN-γ⁺ cells are shown as a percentage of TCR⁺CD4⁺ cells. Density plots are representative of results from three independent experiments using three mice per time point, except the NK depletion which was performed once. Frequencies of cells in each boxed region are shown as arithmetic means with standard errors. (B) The numbers of CD4⁺IFN-γ⁺ T cells in the liver at days 6 and 10 pi are shown as arithmetic means with standard errors. The experiments were performed in BALB/c (Ly49H⁻) and BALB.B6-CT8 (Ly49H⁺) mice.