Thymus epithelial cell
Synonym(s)
DefinitionThis section has been translated automatically.
Thymus-epithelial cells (mTEC) are found in the thymus both in the medulla and in the cortex. In the medulla they form the Hassall corpuscles whose function has not yet been finally clarified. mTECs play an important role in "self-tolerance" (see below tolerance; see below immune tolerance). In mTECs, in contrast to all other known cells, proteins are formed which have no special function for the cell itself. They are produced to develop self-tolerance.
With the help of proteasomes, these proteins are broken down into short fragments. These peptides are then presented to the T-cells of the thymus in the peptide binding pockets of histocompatibility antigens(MHC). It is of fundamental importance that each T cell recognises only one specific antigen. This recognition mechanism takes place via T-cell receptors that are expressed on the surface of T-cells. In a thymus epithelial cell, about 5% of all human proteins are produced purely statistically. With about 100 mTECs, the peptides of all human endogenous proteins can be presented to maturing T-lymphocytes in the thymus. These T cell receptors are generated by randomly assembled gene segments. This infinitely varied "randomness" explains the different populations of T cells. So also randomly formed T-cells with receptors that are directed against the body's own proteins. These must be eliminated.
LiteratureThis section has been translated automatically.
- Aaltonen J et al (1997) An autoimmune disease, APECED, caused by mutations in a novel gene featuring two PHD-type zinc-finger domains. Nat. gene 17: 399-403.
- Anderson M, Su M (2011). "Aire and T cell development." Curr. Opin. Immunol. 23 (2): 198-206. doi:10.1016/j.coi.2010.11.007.
- Gardner J et al (2008) Projection of an immunological self shadow within the thymus by the aire protein. Science. 298: 1395–1401
- Gardner J et al (2008) Deletional tolerance mediated by extrathymic Aire-expressing cells. Science. 321: 843-847. doi:10.1126/science.1159407. PMC 2532844. PMID 18687966.
- Liston A et al(2003) Aire regulates negative selection of organ-specific T cells. Nat Immunol 4: 350-354.
- Perniola R (2018) Twenty Years of AIRE. Front Immunol 9:98.