Fig. 4.

Adaptive mutations enhance the accumulation of infectious virus. One million CD81-deficient S29 cells were transfected with 4 μl of a 20-μl DNase-treated T7 transcription reaction containing indicated wild-type JFH1, JFH1 plus culture-selected mutations, or SGR-JFH1 RNA. (A) Transfected HCV core-positive cells were visualized by indirect IF with murine monoclonal anti-core followed by anti-mouse AlexaFluor 488. Green fluorescence represents HCV core and blue represents DAPI-stained nuclei as observed using the 10X objective. (B) Total extracellular and intracellular infectious virus accumulated by day 2 was measured by assays for ffu in triplicate, and means plus standard errors are plotted. The dotted line represents the cutoff of the assay, which was 10 ffu/ml. (C) Levels of extracellular and intracellular infectious virus present in the cultures of JFH1 mutant viruses (mt) were compared with that of wild-type JFH1 (wt) and the ratios were plotted. Fold increases (mt/wt) are indicated above the respective bars. Results are representative of two independent transfection experiments.