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The remaining cells exit the thymus as mature naive T cells, also known as recent thymic emigrants. [13] This process is an important component of central tolerance and serves to prevent the formation of self-reactive T cells that are capable of inducing autoimmune diseases in the host.
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.
Regulatory T cells are another type of T cell that mature in the thymus. Selection of T reg cells occurs in the thymic medulla and is accompanied by the transcription of FOXP3. T reg cells are important for regulating autoimmunity by suppressing the immune system when it should not be active. [8]
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 ...
The remaining 96–98% of T cells die by apoptosis and are phagocytosed by macrophages in the thymus. So many thymocytes (T cells) die during the maturation process because there is intensive screening to make sure each thymocyte can recognize self-peptide:self-MHC complex [12] and for self-tolerance. Having experienced apoptosis, the thymocyte ...
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.
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 ...
In studying the development of the avian immune system, the embryo offers several advantages such as the availability of many embryos at precise stages of development and distinct B and T cell systems. Each population differentiates from a primary lymphoid organ: T cells in the thymus and B cells in the Bursa of Fabricius.