Fig. 1: ΔM27-MCMV replicates to low levels at early times post-infection.

BALB/c mice were infected i.p. with wt-MCMV or ΔM27-MCMV. At 3 and 21 days post-infection (dpi), the indicated organs were collected and frozen. The virus titers were determined from organ homogenates by plaque titration. Titrations were performed in quadruplicates. Pooled data of three independent experiments are shown. Bars depict the geometric mean, dots show the titers of individual mice (n = 13). DL detection limit. a Virus titer in the salivary gland. b Virus titer in spleen. c–f Newborn C57BL/6 mice were i.p. injected with 500 PFU of WT- or ΔM27-MCMV at ~24 h postpartum, and viral titers were determined in indicated organs at 9 dpi by plaque assay. Titers of individual mice (dots) and median values (bars) are shown (n = 11–12). g As in C, but surface expression of MHC-II by live CD45^int CD11b⁺ microglia cells was determined by cytometry. The gating strategy is shown in Supplementary Fig. 1. Median fluorescence intensity (MFI) values of MHC-II expression were normalized to mock control samples (n = 10). Significance was calculated by heteroscedastic unpaired one-tailed t-test. *p < 0.05. ***p < 0.001.