FIG. 7.
Analysis of released HCV RNA by density gradient centrifugation. (A and B) Cell culture supernatants from two different cell lines carrying subgenomic replicons (5-15 and 9-13) (A) and two cell lines carrying sfl genomes (20-1 and 21-5) (B) were harvested 3 days postseeding and processed as described in Materials and Methods. RNA was prepared and subjected to quantitative RT-PCR. (C) For a control, supernatant from R.D.420 cells productively infected with BVDV (strain NADL) was analyzed in parallel. Copies of HCV and BVDV RNA detected per milliliter of gradient fraction (mean value of duplicates) are plotted against the density. The density of the peak fraction is given at the top of each graph.