Figure 2.

Antiviral activity of ASA against BUNV. Vero cells were absorbed 1 h with BUNV at an MOI of 1 PFU/cell, exposed to increasing concentrations of ASA for 8 h and processed by immunofluorescence. (A–D) Fluorescence microscopy of infected cells untreated (A) and treated with 5, 10 and 15 mM ASA (B–D). Nuclei are labeled with DAPI (blue) and viral infection with an antibody specific for BUNV nucleoprotein (N) (green). (E) Percentage of infected cells measured by immunofluorescence in the absence of ASA treatment and with three different concentrations of ASA. Data are shown as mean ± s.e.m. of three independent experiments. (F) Dose–response curve (red line) of ASA was determined by nonlinear regression. Cytotoxic effect on Vero cells exposed to increasing concentrations of the drug in the absence of virus is also shown (black line). IC₅₀ and CC₅₀ were determined from dose–response curves based on treatment with seven different concentrations. IC₅₀ was calculated from the percentage of infected cells, and CC₅₀ was determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability assay. ND, no drug. Scale bars: 50 μm.