Induction of type I IFNs by HCV -2/+1 frame mutants.

(A, B) Huh7 cells transfected with JFH1wt, JFH1Δ, JFH1Δ4, or no RNA (mock transfection control) were analyzed for IFNβ1, IFNα8, and RIG-I mRNAs or HCV RNA by qRT-PCR. (C) Cell culture media which were not concentrated were analyzed for secreted IFNβ1 by ELISA. (D) Medium harvested from the indicated viral RNA-transfected Huh7 cells were used to infect naïve Huh7 cells. Cells were then analyzed for IFNβ1 mRNA by qRT-PCR. qRT-PCR data were normalized by GAPDH mRNA and expressed as percentage of controls. Star indicates statistically significant difference (P < 0.05) from controls.