IFN-I directly influences Ccl3 protein expression in NK cells. (A) Scheme of the experiment. Same experiment as in Fig. 5 was performed with homozygous CCL3-EASER mice. (B) Frequency of tdTomato⁺ NK cells from WT Smith- or ∆m157-infected CCL3-EASER mice and tdTomato MFI. (C) Frequency of Venus⁺ NK cells from WT Smith- or ∆m157-infected CCL3-EASER mice and Venus MFI. Each symbol represents a single mouse. Statistical differences were analyzed by unpaired nonparametric Mann–Whitney U-test. ns, not significant. (D) Naive EASER-NK cells were cultured in the presence of mrIL-2 and stimulated for 4 h with 100 U/ml of mrIFNb as indicated. After incubation, MFI of tdTomato and Venus signals were evaluated by flow cytometry. Each symbol represents one mouse. Paired non-parametric Wilcoxon test was used: ns, not significant; *P < 0.05.