Figure 1

Schematic diagram showing the isolation of IFN-α resistant and sensitive replicon cell lines. Three different HCV 1 b sub-genomic replicon cell lines (Con-15, Con-17 and Con-24) with low ISRE-luciferase activity were cultured in growth media supplemented with G-418 (1 mg/ml) and IFN-α 2 b for more than 4 weeks. Resistant cell colonies that survived the IFN-α 2 b treatment were picked and stable resistant cell lines (R-15, R-17 and R-24 series) were established. Cured Huh-7 cell line from each replicon was prepared by repeated treatment with cyclosporine A (1 μg/ml). All of the cured Huh-7 cells were free from HCV and still maintained low level ISRE-luciferase activity after IFN-α 2 b treatment. 5/15 cell line is IFN-α sensitive HCV 1 b replicon cell line. HCV replication in this cell line was eliminated by IFN-α 2 b and used as the positive control.