Mammalian toll-like receptors.
OBJECTIVE
To review the role of mammalian Toll-like receptors (TLRs) in host defense.


METHODS
MEDLINE search and current literature.


RESULTS
First, TLRs participate in the recognition of molecular patterns present on microorganisms. Second, TLRs are expressed at the interface with the environment, the site of microbial invasion. Third, activation of TLRs induces expression of costimulatory molecules and the release of cytokines that instruct the adaptive immune response. Fourth, activation of TLRs leads to direct antimicrobial effector pathways that can result in elimination of the foreign invader.


CONCLUSIONS
Maintained throughout evolution, mammalian TLRs are proteins that participate in innate immunity to microbial pathogens. Insights into TLR activation pathways provide new therapeutic targets for intervention in infectious and immunologic disease.
Modlin
Robert L
RL
Department of Medicine, Molecular Biology Institute, UCLA School of Medicine, Los Angeles, California 90095, USA. rmodlin@mednet.ucla.edu
D000818:Animals; D001424:Bacterial Infections / Q000276:immunology; D016207:Cytokines / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins; D006801:Humans; D007113:Immunity, Innate; D008070:Lipopolysaccharides / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D011956:Receptors, Cell Surface / Q000378:metabolism / Q000502:physiology*; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors
D016207:Cytokines; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors