Titration of progeny viruses. Titer of progeny viruses produced from the cell was measured by TCID50 assay in 384-well plate format with 4 wells per dilution of virus. Ten (10) μL of 10-fold serial dilutions of progeny virus containing medium from respective samples (drug treated or untreated) were used to infect fresh Hep-2 cells in a 384-well format. After 6 days incubation the inhibitory effects of the compound and drug were assessed using Cell Titer Glo. A well showing a luminescence signal less than the mean of the non-infected control signal minus five times the standard deviation of the control was regarded as positive for infection.