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Abstract |
The innate immune system is the first line of defence against invading microorganisms. The system consists of cells: neutrophils, monocytes/macrophages, dendritic cells and natural killer cells, and soluble elements such as cytokines and components of the complement system.
Detection of these microorganisms is mediated by pattern recognition receptors (PRR) expressed on the cells of the innate immune system. The most important components of PRR are Toll-like receptors (TLR). TLR recognise structures common to many pathogens, so-called pathogen associated molecular patterns (PAMP). PAMP are parts of endotoxins, peptidoglycans and other microbial molecules of clinical relevance in infectious diseases.
Apart from distinguishing self from invading microorganisms, TLR also play a role in the recognition of molecules associated with tissue damage and remodelling. It is therefore likely that defects in the TLR-PRR system underlie many diseases, including diseases in the oral cavity.
