Arbidol inhibits chronic HCV replication. FL-Neo replicon cells were passaged without G418 in the presence of 6 μg/ml (11 μM) ARB for 3 days (lane 3d), or 1, 2, 3 or 4 weeks (lanes 1w to 4w). Huh7 cells, as a control for non HCV-replicating cells, were treated (lane ARB +) or not (lane ARB -) at 6 μg/ml for 3 days. The rightmost lane labeled ARB- represents proteins from control FL-Neo cells, treated without ARB for 4 weeks. FL-Neo cells were separately treated with 100 U/ml IFN-α for 48 h (lane IFN +) or not (lane IFN -). Cells were then lysed and treated as described in Materials and Methods. Ten μg of total cell protein of each sample extract were submitted to SDS-PAGE, followed by western blotting with murine monoclonal antibodies to NS5A or core proteins, or polyclonal antiserum to GAPDH.