Fig. 3.

IFN-γ mediates the IPP-induced anti-HCV activity. The role of IFN-α and IFN-γ in the inhibition of HCV replication was analyzed by antibody-blocking assay. Rep60 cells were cultured with IPP-stimulated PBMC supernatants neutralized for either IFN-α (lanes 3 and 4) or IFN-γ (lanes 5 and 6). PBMC supernatants were pre-incubated with neutralizing antibodies for 30 min before being added to Rep60 cell cultures. Increasing doses of either IFN-α (lanes 8–10 and 11–13) or IFN-γ (lanes 14–16 and 17–19) were used to determine the neutralization ability of the mAbs to IFN-α (lanes 11–13) or IFN-γ (lanes 17–19). After 4 days of culture, the HCV RNA was analyzed by RT–PCR as described in Fig. 1(A).