Figure 2

DENV infects and activates microglia in vivo and in vitro.

(A) Representative confocal fluorescent immunostaining of Iba-1 (green), a marker for activated microglia, in DENV2 PL046-infected brains of ICR mice day 7 post-infection. DAPI is a nuclear stain (blue). (B) Representative AEC-based immunohistochemical staining of the viral NS3 protein and Iba-1 (red, arrowheads) in the serial sections of brain tissues. Hematoxylin is a nuclear counterstain (blue). (C) Representative confocal fluorescent immunostaining of Iba-1 (green) and CD31 (red) in DENV-infected brains. DAPI is a nuclear stain (blue). Murine microglial BV2 cells were inoculated with AlexaFluor 594-labeled DENV (MOI = 50) (red) for 2 h post-infection. A representative fluorescent image of viral entry is shown (D) and flow cytometric analysis was performed for quantification as a percentage (E). The MOIs of DENV infection were evaluated over a time course in BV2 cells by measuring viral NS1 protein expression (F) and by plaque assays (G). The values are the mean ± SD of three independent experiments. *P < 0.05, **P < 0.01 and ***P < 0.001, compared to mock. (H) Representative confocal fluorescent immunostaining of the viral E protein (green) in BV2 cells infected by the four serotypes of DENV. DAPI is a nuclear stain (blue).