Toll-like receptors as an escape mechanism from the host defense.
Toll-like receptors (TLRs) are probably the most important class of pattern-recognition receptors. Recognition of pathogen-associated molecular patterns (PAMPs) by TLRs, either alone or in heterodimerization with other TLR or non-TLR receptors, induces the production of signals that are responsible for the activation of genes important for an effective host defense, especially those of proinflammatory cytokines. Recent studies also suggest that pathogenic microorganisms can modulate or interfere with TLR-mediated pattern recognition and can use TLRs as an escape mechanism from the host defense. Three major TLR-mediated escape mechanisms have been identified: TLR2-induced immunosuppression, especially through induction of interleukin (IL)-10 release; blockade of TLR recognition; and TLR-mediated induction of viral replication. Thus, TLR signals are not only beneficial to the host, but in certain situations the activation of particular TLR responses by microorganisms might serve as an escape mechanism from the host defense.
Department of Medicine, University Medical Center, St. Radboud, P.O. Box 9101, Geert Grooteplein 8, 6500 HB Nijmegen, The Netherlands. M.Netea@aig.umcn.nl
Mihai G
MG
Netea
Jos W M
JW
Van der Meer
Bart-Jan
BJ
Kullberg
D000818:Animals; D001419:Bacteria / Q000276:immunology / Q000472:pathogenicity*; D001424:Bacterial Infections / Q000276:immunology / Q000382:microbiology; D005658:Fungi / Q000276:immunology / Q000472:pathogenicity*; D006801:Humans; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000502:physiology; D051379:Mice; D009181:Mycoses / Q000276:immunology / Q000382:microbiology; D011956:Receptors, Cell Surface / Q000276:immunology* / Q000502:physiology; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D014777:Virus Diseases / Q000276:immunology / Q000382:microbiology; D014780:Viruses / Q000276:immunology / Q000472:pathogenicity*
D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors