Fig. 4. (A) An infectivity assay using the media supernatant collected from the Huh7.5 cells transfected with either wild type J6/JFH1 or mutant J6/JFH1-79A82A RNAs at 6 days post-transfection. Media supernatant was collected from the cells transfected with either wild type or mutant J6/JFH1-79A82A RNAs, and these collected media supernatant were inoculated on top of naïve Huh7.5 cells. The HCV-infected cells were staining with a mouse anti-core antibody and an anti-mouse Alexa 488 antibody at 3 days post-transfection. Nucleus in each cell was stained with DAPI. (B) Quantitation of the relative virus RNA levels in the media supernatant collected from the Huh7.5 cells transfected with either wild type J6/JFH1 or mutant J6/JFH1-79A82A RNAs at 6 days post-transfection by real-time RT-PCR analysis. Average values from triplicate experiments and standard deviations were noted (*p<0.01). (C) A STAT3 reporter lucifersase plasmid was cotransfected either alone or with J6/JFH1-WT or J6/JFH1-79A82A RNAs plus renilla luciferase plasmid in the absence or presence of exogenous 5 ng/ml IL-6. Average percentages of firefly and renilla luicferase activity ratio with standard deviation were plotted.