Figure 3

IFN-α, IFN-β and/or IFN-γ inhibit HCMV replication in HFFs. HFFs were treated with vehicle or 100 IU/ml of IFNs 12 h prior to infection with HCMV at a MOI of 2.5: (◆) vehicle, (■) IFN-α, (●) IFN-β, (▲) IFN-γ, (□) IFN-α and IFN-γ, (○) IFN-β and IFN-γ or (◇) GCV (100 μM). On the indicated d p.i., average viral titers (n = 3) were determined by a microtiter plaque assay. HFFs were inoculated for 2 h with serially diluted lysed cultures. Plaque numbers were determined 11 d p.i. by fluorescence microscopy. At 3 d p.i., all IFN treatments significantly reduced viral titers as compared to vehicle-treated cultures (P < 0.001, one-way ANOVA and Tukey's post hoc t test). At 4 d p.i., only cells treated with GCV or combination IFN treatments inhibited viral titers as compared to vehicle-treated HFFs (P < 0.001, one-way ANOVA and Tukey's post hoc t test). Significant reduction denoted by a single asterisk. Inset: Represents HCMV titers determined over 11 d for (◆) vehicle-treated and (○) IFN-β and IFN-γ-treated HFFs. The dashed line represents the lower limit of detection of the plaque assay (20 PFU/ml) used to measure viral titers.