Fig 2.

EV71 antagonized the antiviral effect of IFN-α treatment. (A) RD cells were infected with EV71 at an MOI of 1. IFN-α treatment (100 U/ml, frames c to g; or 1,000 U/ml, frames h to l) was performed before or after viral infection as indicated on the figure. Cells uninfected or infected without IFN treatment are shown in frames a or b, respectively. Photomicrographs were taken at 20 h postinfection (original magnification, ×100). (B) Cellular viral loads were quantified by qRT-PCR at 20 h p.i. The cells infected with EV71 but without IFN treatment were set as controls. (C) RD cells were infected with EV71 at an MOI of 10. At 9 h after infection, cells were stimulated with IFN-α2b for another 2 h (Virus+IFN). Cellular RNA was extracted, and expression levels of relative ISGs were measured by qRT-PCR. The expression level of each gene was calculated relative to GAPDH gene expression and normalized to mock-treated cells. Data are shown as mean ± SD of three independent experiments; each was done in triplicate. *, P < 0.05, versus the control; **, P < 0.001, versus the control; #, P < 0.001, Virus+IFN versus Con+IFN.