title: Recognition of double-stranded RNA and activation of NF-kappaB by Toll-like receptor 3.
abstract: Toll-like receptors (TLRs) are a family of innate immune-recognition receptors that recognize molecular patterns associated with microbial pathogens, and induce antimicrobial immune responses. Double-stranded RNA (dsRNA) is a molecular pattern associated with viral infection, because it is produced by most viruses at some point during their replication. Here we show that mammalian TLR3 recognizes dsRNA, and that activation of the receptor induces the activation of NF-kappaB and the production of type I interferons (IFNs). TLR3-deficient (TLR3-/-) mice showed reduced responses to polyinosine-polycytidylic acid (poly(I:C)), resistance to the lethal effect of poly(I:C) when sensitized with d-galactosamine (d-GalN), and reduced production of inflammatory cytokines. MyD88 is an adaptor protein that is shared by all the known TLRs. When activated by poly(I:C), TLR3 induces cytokine production through a signalling pathway dependent on MyD88. Moreover, poly(I:C) can induce activation of NF-kappaB and mitogen-activated protein (MAP) kinases independently of MyD88, and cause dendritic cells to mature.
authors.affiliation: Section of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, 06520, USA.
authors.forename: L
authors.initials: L
authors.lastname: Alexopoulou
authors.forename: A C
authors.initials: AC
authors.lastname: Holt
authors.forename: R
authors.initials: R
authors.lastname: Medzhitov
authors.forename: R A
authors.initials: RA
authors.lastname: Flavell
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D029721:Drosophila Proteins; D005688:Galactosamine / Q000494:pharmacology; D006801:Humans; D007370:Interferon Type I / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008264:Macrophages / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B / Q000378:metabolism*; D011070:Poly I-C / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011971:Receptors, Immunologic; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D051196:Toll-Like Receptor 3; D051193:Toll-Like Receptors; D014777:Virus Diseases / Q000276:immunology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D016207:Cytokines; D029721:Drosophila Proteins; D007370:Interferon Type I; C507779:MYD88 protein, human; D008562:Membrane Glycoproteins; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D012330:RNA, Double-Stranded; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C495344:TLR3 protein, human; C519703:TLR3 protein, mouse; D051196:Toll-Like Receptor 3; D051193:Toll-Like Receptors; D005688:Galactosamine; D020928:Mitogen-Activated Protein Kinases; D011070:Poly I-C