FIG 2.

ΔUS3 PRV shows reduced epithelial spread and viral passage across the basement membrane (BM) at 48 hpi, and inhibition of PAK activity reduces epithelial spread and BM passage of WT PRV. Porcine respiratory mucosa explants were inoculated with WT, ΔUS3, or US3R PRV in the absence or presence of the PAK inhibitor IPA3. At 48 hpi, plaque width and viral passage across the BM were analyzed by fluorescence microscopy. (A to F) Representative confocal micrographs showing viral antigens (green) and collagen IV (red) for the three different virus strains in the absence (A to C) or presence (D to F) of IPA3. The dashed line indicates localization of the BM, and arrows indicate viral passage across the BM. Scale bar, 250 μm. (G and H) Quantification of plaque width (G) and the percentage of plaques with viral passage across the BM (H) for the three virus strains in the absence (blue bars) or presence (red bars) of IPA3. Data represent means + SD from triplicate independent biological replicates. Different letters indicate statistically significant differences between conditions.