ZB07, IBDV TS/CJ-801 infection further enhanced pCARDs-induced IFN-β expression but decreased the Mx and PKR mRNA levels (Figure 5A–C), implying that the influenza virus and IBDV interfere with the extremely high expression of Mx and PKR. The overexpression of pigeon RIG-I caused slightly increased mRNA synthesis of IFN-β without affecting Mx and PKR expression in mock-treated DF-1 cells. Here, MX1 is linked to infection.