Virus replication assay

To measure completion of the viral replication cycle and production of new infectious progeny virus, replication assays were performed. The indicated MM cell lines were infected with oHSV-1 at an MOI of 0.01, corresponding to 500 PFU/mL. Human serum IgG was added between 15 and 16 h of infection. Seventy-two hours after infection, secreted virus and virus-infected MM cells were harvested, subjected to repeated freeze-thaw cycles, sonicated, and centrifuged to obtain supernatant with live viruses. The supernatant was then serially diluted and titrated on Vero cells as described earlier.15 The number of plaques formed on Vero cells 72 h after infection with the supernatant was compared with that from the initial virus titer used to infect MM cell lines, thereby determining the replication efficacy of the virus within MM cells.