TLR 2

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This article is a rough translation of an article in German.
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toll-like receptor 2
Identifiers
Symbol	TLR2
HUGO	11848
Entrez	7097
OMIM	603028
RefSeq	NM_003264
UniProt	O60603
Other data
Locus	Chr. 4 q32

TLR-2 is the name for a biomolecule, which plays a role in the human immune system. It is a membrane protein, a receptor, which sits on the surface of certain cells and which can recognize own body or foreign substances, and passes on appropriate signals to the cell and/or the nervous system.

The TLR-2 discussed here is member of a large family of homologous Toll-like receptors (TLRs).

[edit] Impact

TLR-2 is a membrane receptor found at the surface of immunce system cells and recognises many bacterial, fungal, viral and endogenous substances. Phagocytosis of bound materials takes place in Endosome/Phagosome and a cellular activation, so that the elements of the innate immune system take over such as macrophages, PMN and dendritic cells tasks of the nonspecific immune defense, B1a and form MZB first anti-bodies and uses in the process the specific anti-body formation. Here cytokine is involved e.g. Tumor necrosis factor-alpha(TNF α) and different interleukins (IL-1alpha, IL-1beta, IL-6, IL-8, IL-12). Before TLRs were discovered, some the materials specified below were grouped under the term so-called Moduline. By that rather Th1 appropriate Cytokine pattern is seen in most experimental models an immune deviation this way, away of the Th2-expression. Conjugates are developed as vaccines or already used without a priori knowledge.

One only 2006 recognized characteristic is the Expression of the TLR-2 on the Tregs (special form of the T-cells), which is brought equally to TCR determined Proliferation and functional inactivity. Thereby, a disinhibiting (Disinhibition) of the early inflammation phase and the specific anti-body formation is reached. After reduction of the exciter number many exciter-specific Tregs are present, which, now without TLR-2-Signal, become active and the specific like the inflammatory immune reaction to restrain (see also TGF beta, Interleukin 10). Older literature, which attributes a direct immune stimulation effect over TLR-2 to a given substance, must be interpreted under circumstances that the used TLR-2-knockouts has regularly quite few Tregs.

Functionally relevant Polymorphisme is described, which reduced to a function restriction and thus usually survival rate with infections/Sepsis with Gram-positive bacteria leads in particular.

The signal transduction is represented in the article toll like Receptor.

[edit] Occurrence

TLR-2 is expressed on microglia, Schwann cells, monocytes, macrophages, dendritic cells, polymorphonuclear leukocytes, B-cells (B1a, MZB, B2), T-cells including regulatory T cells (CD4, CD25) (squeezed out). This than heterodimer (combined molecule) with e.g. partly happens. TLR-1 or TLR-6. TLR-2 is likewise in the epithelium of the bronchial tube, the alveoli, to find the kidney small channels and the Bowman's capsule of the kidney. Within the range of the skin it's found on keratinocytes and tallow glands, here sbc1 induces itself, whereby a bactericidal tallow can be formed.