Antiviral signaling through pattern recognition receptors.
Viral infection is detected by the host innate immune system. Innate immune cells such as dendritic cells and macrophages detect nucleic acids derived from viruses through pattern recognition receptors (PRRs). Viral recognition by PRRs initiates the activation of signaling pathways that lead to production of type I interferon and inflammatory cytokines, which are important for the elimination of viruses. Two types of PRRs that recognize viral nucleic acids, Toll-like receptors (TLR) and RIG-I-like RNA helicases (RLH), have been identified. Of the TLRs, TLR3 recognizes viral double-stranded (ds) RNA, TLR7 and human TLR8 identify viral single-stranded (ss) RNA and TLR9 detects viral DNA. TLRs are located in endosomal compartments, whereas RLH are present in the cytoplasm where they detect viral dsRNA or ssRNA. Here we review the role of TLRs and RLHs in the antiviral innate immune response.
Kawai
Taro
T
Department of Host Defense, Japan Science and Technology Agency, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Akira
Shizuo
S
D000818:Animals; D006801:Humans; D007113:Immunity, Innate; D020365:RNA Helicases / Q000276:immunology / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000276:immunology; D051192:Receptors, Pattern Recognition / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction; D051196:Toll-Like Receptor 3 / Q000276:immunology / Q000378:metabolism; D051199:Toll-Like Receptor 7 / Q000276:immunology / Q000378:metabolism; D051200:Toll-Like Receptor 8 / Q000276:immunology / Q000378:metabolism; D014777:Virus Diseases / Q000276:immunology* / Q000378:metabolism
D012330:RNA, Double-Stranded; D051192:Receptors, Pattern Recognition; D051196:Toll-Like Receptor 3; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D020365:RNA Helicases