Regulatory T cell (CD4+CD25+Foxp3+) (Treg)

Regulatory T cells characterized by the expression of CD4, CD25 (the alpha chain of the IL‑2 receptor), and the transcription factor FOXP3 are a specialized subset of lymphocytes essential for maintaining immune homeostasis and self-tolerance. These cells suppress inappropriate or excessive immune responses, thereby preventing autoimmune diseases and limiting chronic inflammation. They achieve this through multiple mechanisms including secretion of immunoregulatory cytokines, metabolic disruption such as competition for IL‑2, induction of apoptosis in effector lymphocytes, modulation of antigen-presenting cell function, and production of extracellular vesicles that promote tolerance[1][5]. There are two main subtypes based on origin: Natural regulatory T cells develop in the thymus and primarily maintain tolerance to self-antigens; induced regulatory T cells arise from conventional naïve CD4+ T cells in peripheral tissues under specific conditions such as exposure to transforming growth factor beta. Both subtypes require FOXP3 for their development and suppressive function. Deficiency or dysfunction in these regulatory mechanisms can result in severe autoimmune syndromes such as IPEX syndrome. Conversely, an overabundance or hyperactivity can contribute to tumor progression by dampening anti-tumor immunity within the tumor microenvironment[1][2][6]. Therapeutic strategies targeting these cells include expansion with low-dose IL‑2 for treating autoimmune diseases or depletion/inhibition approaches being explored for cancer immunotherapy. However, manipulating this population carries risks related to loss-of-control over infections or malignancy due to broad immunosuppression[5]. In summary, CD4+CD25+Foxp3+ regulatory T cells are a critical cellular target at the intersection between autoimmunity control and cancer therapy due to their central role in modulating immune responses across health and disease contexts.

Other names

CD4+CD25+Foxp3+ regulatory T cellTreg cellNatural regulatory T cell (nTreg)Induced regulatory T cell (iTreg)

Immunosuppression via cytokine secretion, metabolic disruption, and direct suppression of effector cells[1][5]