FIG. 5.

Overexpression of SR-BI and SR-BII in Huh-7.5 cells enhances the glycoprotein-dependent infectivity of cell culture- and plasma-derived J6/JFH. (A) Parental and Huh-7.5 cells overexpressing human CD9, SR-BI, or SR-BII were incubated with J6/JFH derived from cell culture (J6/JFHcc; white bars) or from the plasma of infected chimeric mice (J6/JFHplasma; gray bars) for 6 h, followed by a 72-h infection. Infected cells were visualized by staining them for intracellular NS5A, and infectivity for transduced cells was expressed relative to the parental cells. J6/JFHcc and J6/JFHplasma infectivities for parental Huh-7.5 cells were 35,000 (±1,300) cells/ml and 2,250 (±700) cells/ml, respectively. The error bars indicate the standard deviation above the mean of two individual infections. (B) Comparable levels of infectious virus from the two sources were incubated with anti-E2 MAb C1 and a control anti-dengue virus MAb at 10 μg/ml for 1 h prior to infecting Huh-7.5 cells. Infectivity was measured by quantifying NS5A-positive cells, and the percent neutralization of C1 was defined by comparing infectivity in the presence of the anti-dengue virus MAb.