Development of a hepatitis C virus relapse model using genome-length hepatitis C virus ribonucleic acid-harboring cells possessing the interferon-α-resistance phenotype

Aim: The cure rate of current interferon (IFN) therapy is limited to approximately 50% and most of the relapses after therapy are caused by genotype-1. To develop a relapse model in cell culture, we attempted to obtain genome-length hepatitis C virus ribonucleic acid (HCV RNA) harboring cells possessing the IFN-α-resistance phenotype from previously established OR6 cells, which enabled the luciferase reporter assay for monitoring of HCV RNA replication. Methods: The IFN-α-resistant HCV RNA-harboring cells and control cells were obtained by the treatment of OR6 cells with and without IFN-α, respectively. Then, we examined the relapse of HCV in IFN-α-resistant HCV RNA-harboring cells. Results: Only type I IFN(αand β) showed significantly different anti-HCV activity between IFN-α-resistant HCV RNA-harboring cells and control cells. There was no significant difference in the anti-HCV activity of IFN-γ, fluvastatin, or cyclosporine A between the two types of cells. Furthermore, we showed that fluvastatin or cyclosporine A in combination with IFN-α could prevent the relapse after therapy in the IFN-α-resistant HCV RNA-harboring cells. Conclusion: We developed a HCV relapse model in cell culture using IFN-α-resistant HCV RNA-harboring cells. Thus anti-HCV reagents, which have a mechanism different from IFN-α, were shown to be useful for preventing a relapse of IFN-α-resistant HCV.