capable of regulatory T cell FMA:84070 BTO:0004520 suppressor T-lymphocyte suppressor T cell regulatory T-lymphocyte https://cellxgene.cziscience.com/cellguide/CL_0000815 Regulatory T cells, or Tregs, represent a vital component of the immune system, functioning to maintain immune tolerance and homeostasis. Tregs prevent excessive immune responses and autoimmunity by suppressing or downregulating proliferation or activation of other immune cells. Originating in the thymus, Tregs belong to a larger group of T cells that express CD4 protein on their surface. They can be identified by their expression of the forkhead/winged-helix transcription factor Foxp3, which is a crucial intracellular marker that controls their development and function. Tregs are key players in preventing autoimmune diseases, allergies, and graft-versus-host disease, a potential complication of bone marrow transplantation. By suppressing the immune response, Tregs ensure that the immune system doesn't mistakenly attack the body's own healthy tissues, or harmless substances such as pollen, or transplanted tissue. Abnormalities in Treg number or function can result in a profound dysregulation of immune homeostasis, leading to the development of various immune-mediated diseases. However, Tregs also appear to contribute to tumor development. Developmentally, while Tregs may emerge directly from the thymus, Tregs may also arise peripherally from conventional T cells. Thymic or "natural" Tregs likely arise from thymocytes that strongly recognize self-antigen and contribute to self-tolerance. Peripherally induced Tregs likely recognize foreign antigen and are likely important in maintaining tolerance to non-host antigens, such as intestinal microbiota or food allergens. Understanding the precise functions and mechanisms of regulatory T cells is a continually evolving field, with potential implications for combating autoimmunity, enhancing cancer therapy, and preventing transplant rejection. (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.) This cell type may express FoxP3 and CD25 and secretes IL-10 and TGF-beta. regulatory T-cell MESH:D050378 regulatory T lymphocyte suppressor T lymphocyte Treg A T cell which regulates overall immune responses as well as the responses of other T cell subsets through direct cell-cell contact and cytokine release. suppressor T-cell mature T cell negative regulation of immune response Homo sapiens