Fig. 1.

Activation of the IFN response by PIV5-VΔC in A549/pr(IFN-β).GFP reporter cells. A549/pr(IFN-β).GFP cells were infected with PIV5 wt or PIV5-VΔC at an MOI of 5 PFU/cell. Uninfected (UI) cells were included as a negative control. Twenty-four hours post-infection, culture media were harvested and cell lysates were prepared. Lysates were subjected to immunoblotting with antibodies specific to phosphorylated (active) IRF3, GFP, ISG56, MxA, PIV5 V (C-terminus), actin and viral NP (left panel). IFN present in culture media was estimated by a CPE-reduction bio-assay and converted to IU IFN/10⁶ cells using an IFN-α standard. The mean IFN produced in three independent experiments is plotted (right panel) and error bars represent the SD for each triplicate.