FIG. 3.

HCV infection kinetics in DMSO-treated Huh7 cells. (A and B) Huh7 cells cultured for 6 (open square), 14 (open circle), or 20 (open diamond) days in the presence of 1% DMSO or subconfluent (closed squares) and confluent (closed triangles) non-DMSO-treated Huh7 cells were infected with JFH-1 HCV at an MOI of 0.01 FFU/cell, and the culture supernatant and intracellular RNA were collected at the indicated times postinfection. (A) Intracellular HCV RNA was analyzed by RT-QPCR and displayed as HCV RNA copies/μg total RNA. (B) Titers of supernatant infectivity, expressed as FFU/ml, were determined by indirect immunofluorescence analysis (Axiovert 200 fluorescence microscope; Zeiss, Germany) of 10-fold serially diluted culture supernatants on naïve Huh7 cells, using a 96-well plate format as described previously (43). A human monoclonal antibody with high avidity and specificity to HCV E2 (43) was used to detect positive foci (5 to 10 positive grouped cells constitute one focus). The anti-HCV E2 antibody was used in lieu of the previously reported (43) NS5A antibody, as it performs equally well in titer assays (data not shown).