Background of the antigen
The innate immune system detects viral infection by recognizing various viral components and triggers antiviral responses. Like the toll-like receptor 3 (TLR3), the cytoplasmic helicase retinoic acid inducible gene protein 1 (RIG1/DDX58) recognizes double-stranded (ds) RNA, a molecular pattern associated with viral infection. Unlike TLR3 however, RIG1/DDX58 activates the kinases TBK1 and IKKe through the adaptor protein IPS1. These kinases then phosphorylate the transcription factors IRF3 and IRF7 which are essential for the expression of type-I interferons. RIG1/DDX58 is required for the production of interferons in response to RNA viruses including paramyxoviruses, influenza virus, and Japanese encephalitis virus.