Enhanced numbers of NK cells were determined in persistently mCMV infected compared to naïve mice. IFNγ production by a) CD3-, DX5+, NK1.1+, b) Ly49H+ CD3-, DX5+ NK1.1+ and c) Ly49H- CD3-, DX5+, NK1.1+ cells were determined in spleens of naïve or day 4.5 post FV infection in naïve (white bar) and persistently mCMV (black bar) infected mice. d-f) NK cells were characterized in the spleen of naïve and persistently mCMV infected mice. d) Absolute numbers of NK cells were determined by gating of NK1.1+ DX5+ CD3- cells. Absolute numbers of CD62Llow (e) and MFI of KLRG-1 (f) gated on NK1.1+ DX5+ CD3- cells were analyzed between the different groups. Data are pooled from d) 4–5 independent experiments with 9–16 mice per group, e,f) 3 independent experiments with 8–16 mice per group. Statistical analysis: unpaired t-test. Statistically significant differences between the groups are indicated by * p < 0.05, ** for p < 0.001, *** for p < 0.0001.