Fig 1.

Kinetics and rate of JEV internalization into B104 cells. (A) B104 cells were infected with JEV at 37°C. At the indicated time points after infection, extracellular virus was inactivated with proteinase K. Results are shown as a percentage of internalized viruses compared with controls (ctrl) in which PBS was substituted for proteinase K and are presented as the means ± standard deviations (SD) of three independent experiments. (B) B104 cells were incubated with JEV at 4°C for 1 h, after which the unbound virus was removed and then treated with proteinase K for 45 min at 4°C. Cells were collected in TRIzol for RNA isolation and JEV RNA copy number determination. Results are shown as a percentage of JEV RNA copy number compared with controls in which PBS was substituted for proteinase K and are presented as the means ± SD of three independent experiments. (C) B104 cells were infected with JEV at 37°C (nonpretreated infection) or at 4°C and then transferred to 37°C (pretreated infection). At the indicated times, extracellular virus was inactivated with proteinase K. Results are expressed as number of internalized PFU and are presented as the means ± SD of three independent experiments. *, P < 0.05.