Figure 4. HP-PRRSV nsp4 suppresses IFN responses induced by VISA.

(A–C) nsp4 and VISA expression plasmids were transfected into 3D4/21 cells together with pGL3-IFNβ-Luc (A), pGL3-IRFs-Luc (B) or pGL3-ISRE-Luc (C), and pRL-TK. pRL-TK was used as an internal control of transfection efficiency. At 24 h after transfection, cells were harvested for luciferase activity detection. Lysates of cells from panel A were subjected to Western blot analysis with anti-Flag, c-Myc and β-actin antibodies to detect VISA and nsp4 expression. Data are mean ± SD from three independent experiments with triplicate samples. Statistical analysis was performed by Student’s t test. ***P < 0.001.