Fig 8.

Measuring biologically active type I IFN in the plasma of RRV-infected RMs. Biologically active IFN-α was measured in plasma from WT_BAC RRV-infected RMs (A) or vIRF-ko RRV-infected RMs (B) using a luciferase reporter assay. At the time points indicated, plasma was added to cells constitutively expressing firefly luciferase under an ISRE promoter, tRF-ISRE. Baseline readings (preinfection) were subtracted from readings at all subsequent time points. Data were normalized to constitutively expressed Renilla luciferase. The number of animals with measured IFN responses was calculated at each time point, and the dichotomous data set (no response = 0, response = 1) was compared using logistical regression. Using responses from the WT_BAC RRV-infected animals as the reference (WT = 0, vIRF-ko = 1), virus (P = 0.0014; OR, 5.07; 95% CI, 1.87 to 13.72) and dpi (P = 0.0085; OR, 1.17; 95% CI, 1.04 to 1.32) were set as independent variables. ISRE, interferon-stimulated response element; RLU, relative luciferase units.