IFIH1 and infection: As shown in Figure 2, the transcript and protein levels of IFN-α, IFN-β, RIG-I, MDA5, MAVS, and TRAF3 in the PRRSV-infected cell group and poly (I: C)-stimulated cell group were significantly elevated at 12 h and 24 h post-infection compared to those in the mock-infected cell group (Figure 2a–h,k–o).