We have previously successfully established knockouts (KOs) of various components of the cell-intrinsic antiviral signaling system in A549 cells, such as RIG-I [19,20,22], MAVS [20], and IRF3 [21], and could demonstrate that such KOs completely abrogate IFN production upon RIG-I stimulation by virus infection or dsRNA transfection. This evidence concerns the gene IFNA1 and viral infectious disease.