IRF3 and viral infectious disease: During virus infection, type I IFNs are produced in infected cells via the recognition of viral PAMPs by binding to specific PRRs, such as cytosolic retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) and transmembrane Toll-like receptors (TLRs) resulting in the activation of downstream IRF3 and IRF7 pathways (7, 23).