Since MDP pretreatment inhibited HCMV replication (Fig. 4), and its addition after infection induced the phosphorylation of TBK, IRF3 and IFN-β expression (Fig. 2C,E,F), we hypothesized that the antiviral effects of MDP pretreatment were mediated through IFN-β. This evidence concerns the gene IRF3 and infection.