Regulation of innate immune responses by Toll-like receptors.
Innate immune response in Drosophila is mediated by signaling through Toll receptors. In mammals, Toll-like receptors (TLRs), comprising a large family, recognize a specific pattern of microbial components. So far, the roles of TLR2, TLR4, TLR5, TLR6, and TLR9 have been revealed. The recognition of microbial components by TLRs leads to activation of innate immunity, which provokes inflammatory responses and finally the development of adaptive immunity. The inflammatory response depends on a TLR-mediated MyD88-dependent cascade. However, there seems to exist additional cascades in TLR signaling. In the case of TLR4 signaling, an MyD88-independent pathway is now being characterized. In addition to the activation of innate immune responses, TLR-mediated signaling leads to suppression of the activity of innate immune cells, represented by "lipopolysaccharide (LPS) tolerance". Progress in elucidating the molecular mechanisms for LPS tolerance has been made through the analysis of TLR-mediated signaling pathways. Thus, the activity for innate immune responses is known to be finely regulated by TLRs.
Takeda
K
K
Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.
Akira
S
S
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology*; D004330:Drosophila / Q000276:immunology; D029721:Drosophila Proteins; D007113:Immunity, Innate; D008070:Lipopolysaccharides / Q000276:immunology*; D008322:Mammals / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000502:physiology; D053594:Myeloid Differentiation Factor 88; D011956:Receptors, Cell Surface / Q000276:immunology* / Q000502:physiology; D011971:Receptors, Immunologic / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D051193:Toll-Like Receptors
D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D029721:Drosophila Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; C499312:Myd88 protein, Drosophila; D053594:Myeloid Differentiation Factor 88; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D051193:Toll-Like Receptors; C495341:tehao protein, Drosophila