FIG. 5.

VX-950 prevents rebound of HCV replicon upon withdrawal of inhibitor. HCV replicon cells were incubated with various concentrations of VX-950 in the absence of G418. Cells were split every 3 to 4 days, and fresh medium containing VX-950 was added at every split. After 13 days of incubation, VX-950 was withdrawn and 0.25 mg/ml G418 was added to enrich the remaining HCV replicon-positive cells that are capable of growing in the presence of G418 (rebound). The cultures were monitored for another 21 days in the presence of 0.25 mg/ml G418, and cell samples were collected whenever the cell monolayer reached confluence. The number of viable cells was determined by the ViaCount assay, and the level of HCV RNA in the cells was determined by the QRT-PCR assay. The absolute numbers of HCV replicon RNA copies per viable cell are shown. The dashed line indicates the detection limit of our QRT-PCR assay.