ARB inhibits acute HCV infection. A: HCV core protein inhibition in ARB-pretreated Huh7.5.1 cells. Cells were pre-incubated with 8 μg/ml ARB for 24 (-24 h) or 48 (-48 h) hours prior to infection with JFH-1 (moi 0.02) for 72 hours. Cells were also treated with ARB at the time of JFH-1 infection (0 h), and treated 24 (+24 h) and 48 (+48 h) hours post-infection. Equal amounts of total protein were probed for HCV core with a monoclonal antibody. Blots were stripped and reprobed for GAPDH expression to verify equal loading of protein in all lanes. B: quantitation of HCV core protein expression. Blots in panel A were scanned and pixel intensity measured using Image J software. Data were normalized to GAPDH levels. C: Suppression of infectious JFH-1 yields in ARB-pretreated cells. Cell-free supernatants from the experiment described in panel A were quantitated for infectious virus by the focus-forming assay as described in the Materials and Methods. Green foci depict NS5A expressing cells. D: Quantitation of JFH-1 titers from panel C. Supernatants from control and ARB treated cells were serially diluted and the titer of virus determined using the focus-forming assay. Titers were calculated by counting the number of foci and correcting for the dilution factor, as described previously .