Figure 2.

MCMV infection induces early activation of microglia toward proinflammatory phenotype. (A and B) Newborn BALB/c mice were infected with MCMV. The expression of MHC-I (A) and MHC-II (B) on microglia was analyzed by flow cytometry at indicated time points p.i. Mean values ± SEM are shown (n = 3–6). The data are representative of two or three independent experiments. Unpaired two-tailed Student’s test was used. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P ≤ 0.0001. (C–E) The expression of CD80 (C), CD86 (D), and CD40 (E) on microglia was analyzed by flow cytometry on day 8 p.i. Mean values ± SEM are shown (n = 5). The data are representative of two independent experiments. Unpaired two-tailed Student’s test was used. ***, P < 0.001. Representative histograms showing expression of CD80, CD86, and CD40 are shown (C–E). (F) The expression of Stat1 was determined by qPCR on day 8 p.i. (n = 3). The data are representative of two independent experiments. (G and H) TNF-α (G) and iNOS (H) production on day 8 p.i. was analyzed by flow cytometry (n = 3 replicates, with three brains pooled per replicate). The data are representative of two independent experiments. Unpaired two-tailed Student’s test was used. (I) Newborn and adult BALB/c mice were infected with MCMV. Brains were harvested on day 8 p.i., and the virus titers were determined. Titers in organs of individual mice are shown (circles); horizontal bars indicate the median values; DL, detection limit (left). Representative histograms showing expression of MHC-II on microglia are shown (right; n = 5). The data are representative of two independent experiments. (J) Postnatal day 1 C57BL/6 mice were infected with wild-type MCMV or MULT-1MCMV. Representative histograms showing the expression of MHC-II on microglia are shown (n = 3–5). The data are representative of two independent experiments. MFI, mean fluorescence intensity.