Figure 3

Quercetin blocked the viral protein expression. (A) MARC-145 cells were heated (HS) or not, and 8 hours later cells were inoculated with PRRSV at an MOI of 0.1 for 1 hour. Cells without heat shock treatment were subsequently cultured with medium containing DMSO, Qct (100 μM), or no chemical (Ctrl). Cells were harvested at different times as indicated for Western blotting analysis. The levels of HSP70 and viral N protein were quantified by measuring band intensities and normalized with respect to the amount of β-actin. Data are mean ± SD, n = 3. (B) PRRSV-infected MARC-145 cells were treated with DMSO or Qct at the concentration as indicated. Mock-infected cells were untreated. IFA was performed at 24 h.p.i with anti-N antibody and Alexa Fluor 555-conjugated (red) anti-mouse secondary antibody. Nuclei were stained with Hoechst dye 33258 (blue). Bar, 200 μm.