Figure 5

Cell culture adaptation affects the inhibition of IFN-β signaling by the P, C, and V proteins of MeV. Vero cells were transfected with a plasmid constitutively expressing renilla luciferase, a plasmid expressing firefly luciferase under the control of an IFN-α/β-responsive promoter and the plasmids as indicated in the three panels. Forty-eight hours after transfection, cells were stimulated with IFN-β for six hours, lysed and tested for luciferase activity. VC-indicates cells transfected with pCAGGS empty vector but not stimulated while VC+ indicates cells transfected with pCAGGS empty vector and stimulated with IFN-β. Results are expressed as a ratio of firefly to renilla luciferase luminescence taken as a percentage of the luminescence obtained using IFN-stimulated, empty pCAGGS vector (VC+). (A) results of IFN-β signaling assay with P proteins from D87-wt and D-CEF, (B, C) inhibition of IFN-β signaling by the C and V proteins, respectively. The data shown are an average of three experiments done with triplicate samples. Error bars denote one standard deviation. Bars marked with a are significantly different from VC+ with a P ≤ 0.05. (*: P ≤ 0.01, **: P ≤ 0.001)