Fig. 4.

Impact of RBV resistance on HCV replication in vitro. (A) Three-day HCV infections in the absence or presence of high concentrations of RBV and guanosine. Cells were treated with 0 or 100 μM RBV and/or guanosine (Guo) and infected with HCV for 3 days. Titers were determined in triplicate at the end of each infection, and results are shown in focus forming units per ml (FFU/ml) with SD. Results for one of three representative experiments are shown (P = 0.002; unpaired, two-tailed, Student's t test). (B) Three-day HCV infections in the absence or presence of low RBV concentrations. Infections were performed as described for panel A, except that 0, 15, or 50 μM RBV was used.