Fig. 1.

Increase in HCV entry under hypoxic conditions. (A) Huh7.5 cells cultured under normoxic or hypoxic conditions (1% O₂) were infected with HCVcc^JFH1 with a multiplicity of infection (MOI) of 1. At 24 h postinfection, the cells were stained with NS5A (red). (Scale bars, 50 μm.) (B) Analysis of HCV infectivity. Huh7.5 cells cultured under normoxic or hypoxic conditions were infected with serially diluted HCVcc^JFH1 for 24 h. Then HCV-infected cells stained with anti-HCV NS5A antibody were counted to obtain focus-forming units (FFU) (average ± SD; n = 3). (C) The effect of Huh7.5 cells cultured under normoxic or hypoxic conditions on HCV entry. Huh7.5 cells cultured under normoxic (white bar) or hypoxic (black bar) conditions were infected with Luc-VSV-Gpp and Luc-HCVpp (genotype 2a). At 24 h postinfection, luciferase activity was quantified (average ± SD; n = 3). Treatment with the E2 antibody (15 μg/mL) was included as a control. RLU, relative light units. ***P < 0.005 (Student’s t-test).