FIG. 2.
M36 is required for MCMV replication in macrophages and in vivo. (A) Comparable growth of M36Rev and WT-MCMV in macrophages. Triplicate cultures of IC-21 macrophages were infected at an MOI of 1 with the viruses indicated. (B) Comparable growth of M36Rev and WT-MCMV in vivo. BALB/c mice were infected i.p. with 5 × 105 PFU of the indicated viruses. Infectious virus in lung homogenates was quantitated by plaque assay on day 5. Circles represent individual mice and horizontal bars mark the median values. DL, detection limit of the virus plaque assay. For group comparisons of interest, P values (Wilcoxon-Mann-Whitney rank sum test, two-tailed) are indicated. Differences are considered as significant and not significant for P < 0.01 and P > 0.05, respectively. (C) Caspase inhibition rescues ΔM36 growth. IC-21 macrophages were infected as described above. Cells were exposed to 30 μM zVAD-fmk (□) or left untreated (□). Infectious virus in SN harvested on day 6 was titrated by plaque assay on MEFs. Histograms indicate mean values; error bars indicate standard deviations.