The antiviral activity of the IRF9-Stat fusion constructs in an IFN resistant cell line containing HCV 2a sub-genomic RNA (R4-GFP). (A) GFP expression levels in R4-GFP cells transfected with IRF9, IRF9-S1C and IRF9-S2C at 72 hrs post-transfection. (B) Flow cytometric analysis of mean fluorescence intensity of R4-GFP transfected cells at 72 hrs. S3-GFP and R4-GFP cells treated with and without IFN-α were used as controls. The error bars represent the SEM from three experiments. The Student's t-test was used to compare R4-GFP transfected cells to R4-GFP cells plus IFN-α. P-values < 0.05 were considered significant.