Intracellular localization of Stat1 in WT or F170S HPIV1-infected Vero cells following IFN treatment.

<p>Vero cells were mock-infected or infected with WT or F170S HPIV1 at an MOI of 1 TCID₅₀/cell, and 48 h later were mock-treated (-IFN) or treated (+IFN) with 1000 IU/ml of IFN-β for 1 h. Cells were fixed, permeabilized, immunostained with antibodies for HPIV1 surface proteins (green) and Stat1 (red), stained with DAPI to visualize nuclei (blue), and analyzed by confocal microscopy. Representative fields are shown. Overall, 2% of the WT HPIV1-infected cells and 82% of the F170S HPIV1-infected cells showed nuclear Stat1 following IFN-β treatment.