Figure 1

DENV causes infection, including entry, viral protein expression, and replication, in the microglial cell line BV2. Microglial BV2 cells were inoculated with Alexa-594 labeled (red) DENV serotype2 PL046 (MOI = 50) for 2 h. (A) Fluorescent image analysis showed microglial cells carrying fluorescent DENV 2. (B) Three-dimensional confocal images confirmed viral entry. Phalloidin (green) staining indicated actin. (C) Flow cytometry analysis demonstrated viral envelope (E) protein expression 24 h post-infection. (D) Western blotting analysis showed viral nonstructural protein1 (NS1) expression in DENV-infected cells. The relative ratio to β-actin is shown. (E) Immunocytochemistry and its relative mean fluorescence intensity (MFI) of viral dsRNA 24 h post-infection. (F) Plaque assays showed the level of viral replication. (G) Immunocytochemistry showed viral E protein expression (green) in cells infected with the four DENV serotypes. For all images and blots, representative data were selectively obtained from three individual experiments. DAPI staining indicated the nuclei (blue). For the flow cytometry analysis, the percentage of positive cells is shown. All quantitative data are shown as the means ± SD from three independent experiments. *p < 0.05, **p < 0.01, and ***p < 0.001.