FIG. 3.

Effect of the combination of IFN-α and ribavirin on NV replication in HG23 cells. (A) Effect of ribavirin alone or IFN-α and ribavirin on the expression of the NV genome. One-day-old semiconfluent HG23 cells were incubated with various concentrations of ribavirin ranging from 0 (mock) to 100 μM with (+) or without (−) 2 units/ml of IFN-α. After 72 h of incubation, total RNA was prepared for real-time qRT-PCR to detect the NV genome. The reduction of NV genome by the different treatments was calculated by comparison to the NV RNA level of the control (mock treated). Error bars represent standard deviations from at least three independent experiments. The positions of molecular mass markers (in kilodaltons) are shown to the left of the blot. (B) Effect of ribavirin alone or IFN-α and ribavirin on the expression of NPT II detected by Western blot analysis. One-day-old semiconfluent HG23 cells were incubated with various concentrations of ribavirin ranging from 0 (mock) to 100 μM with or without 2 units/ml of IFN-α. After 72 h of incubation, cell lysate was prepared for Western blot analysis using antibody to neomycin phosphotransferase II. The bar graph shows relative values (the value of mock-treated cells was set at 100%) of expression of NPT II (NPT II-tVP1) in cells treated with ribavirin alone or with ribavirin and IFN-α. The intensity of each band in the blots was measured by scanning and represented the ratio of β-actin to NPT II-tVP1. RNA levels or NPT II levels for cells treated with both IFN-α and ribavirin that were significantly different (P < 0.05) from the value for cells treated with ribavirin only are indicated by asterisks.