lacks_plasma_membrane_part has plasma membrane part develops from alpha-beta intraepithelial T cell CD8-positive, alpha-beta thymocyte CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell The CD8-alpha-alpha-positive, alpha-beta intraepithelial T cell, often abbreviated as CD8αα IEL, is a specialized immune cell found within the epithelial layer of mucosal surfaces, such as the intestines. CD8αα IEL have been studied extensively in mice, but equivalent cells are thought to be present in humans, albeit at lower numbers. These cells represent a subset of intraepithelial T lymphocytes characterized by the expression of both CD8-alpha-alpha homodimer and the alpha-beta variant of the T cell receptor (TCR). Other features shared with intraepithelial T lymphocytes include the expression of T-bet, a master transcription factor that controls expression of proinflammatory cytokines, natural killer cell receptors, and an activated phenotype (high expression of CD69). Functionally, CD8αα IELs are thought to play a role in maintaining epithelial integrity, local immune surveillance, and protection against microbial pathogens. Upon detecting alterations associated with infection or inflammation, these cells orchestrate immune responses to restore tissue homeostasis, primarily through the secretion of cytokines and chemokines, and directly eliminating infected cells. CD8αα IELs have been shown require β2 microglobulin-dependent MHC class I expression for their generation and/or homeostasis. They share some characteristics with natural killer cells and might have similar suppressive and regulatory roles which they perform through the production of IL-10 and TGFβ. For example, they have been shown the prevent induced colitis, indicating that by modulating immune responses, CD8αα IELs prevent excessive and damaging immune activation that can lead to chronic inflammatory conditions or autoimmunity. (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.) CD8-alpha-alpha-positive, alpha-beta intraepithelial T lymphocyte https://cellxgene.cziscience.com/cellguide/CL_0000915 An alpha-beta intraepithelial T cell with the phenotype CD8-alpha-alpha-positive located in the columnar epithelium of the gastrointestinal tract. These cells have a memory phenotype of CD2-negative and CD5-negative. CD8-alpha-alpha-positive, alpha-beta intraepithelial T-lymphocyte CD8-alpha-alpha-positive, alpha-beta intraepithelial T-cell CD2 molecule T-cell surface glycoprotein CD8 alpha chain T-cell surface glycoprotein CD5