part of part of epithelial cell epithelial cell of thymus cortical thymic epithelial cell 2010-09-23T03:17:12Z https://cellxgene.cziscience.com/cellguide/CL_0002364 Cortical thymic epithelial cells (cTECs) are a vital cell type located in the thymus, a lymphoid organ that plays a key role in the development of T cells, which are essential for the adaptive immune system. cTECs also have a role in forming barriers and lining surfaces. In the thymus, their presence contributes to the distinctive architecture of both the cortex and medulla. cTECs also play a significant part in the selection and development of T cells. During T cell maturation, these cells express both self and non-self proteins via the major histocompatibility complex (MHC) to immature T cells. cTECs then stimulate the T cells that can recognize such proteins, an important event known as positive selection. This process aids in the creation of a diverse T cell receptor (TCR) repertoire that can react to a wide range of antigens, therefore ensuring effective immunity. Apart from aiding in T cells' positive selection, cTECs also contribute to eliminating self-reactive T cells, a role essential in preventing autoimmune diseases. These cells induce an apoptosis-driven process known as "negative selection" which eliminates T cells that are too highly reactive to self-antigens. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) cTEC BTO:0004562 An epithelial cell of the cortical portion of the thymus. Epithelial cells in this region are required for positive selection of CD8-positive T cells. cortex of thymus