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Thymic epithelial cells (TECs) are specialized cells with high degree of anatomic, phenotypic and functional heterogeneity that are located in the outer layer (epithelium) of the thymic stroma. The thymus , as a primary lymphoid organ , mediates T cell development and maturation.
The thymus (pl.: thymuses or thymi) is a specialized primary lymphoid organ of the immune system.Within the thymus, thymus cell lymphocytes or T cells mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders.
T cells are grouped into a series of subsets based on their function. CD4 and CD8 T cells are selected in the thymus, but undergo further differentiation in the periphery to specialized cells which have different functions. T cell subsets were initially defined by function, but also have associated gene or protein expression patterns.
Cortical thymic epithelial cells (cTECs) form unique parenchyma cell population of the thymus which critically contribute to the development of T cells. Thymus tissue is compartmentalized into cortex and medulla and each of these two compartments comprises its specific thymic epithelial cell subset. cTECs reside in the outer part- cortex, which ...
In 1989, two scientific groups came up with the hypothesis that the thymus expresses genes which are in the periphery, strictly expressed by specific tissues (e.g.: Insulin produced by β cells of the pancreas) to subsequently present these so-called "tissue-restricted antigens" (TRAs) from almost all parts of the body to developing T cells in order to test which TCRs recognize self-tissues ...
The thymic epithelial cells display self antigen to the T cells to test their affinity for self. Transcriptional regulators AIRE and Fezf2 play important roles in the expression of self tissue antigens on the thymic epithelial cells in the thymus.
In immunology, a naive T cell (T h 0 cell) is a T cell that has differentiated in the thymus, and successfully undergone the positive and negative processes of central selection in the thymus. Among these are the naive forms of helper T cells ( CD4 + ) and cytotoxic T cells ( CD8 + ).
Inappropriate reactivity toward normal self-antigen that was not eliminated in the thymus can occur, since the T cells that leave the thymus are relatively but not completely safe. Some will have receptors that can respond to self-antigens that: are present in such high concentration outside the thymus that they can bind to "weak" receptors.