CD8+ T regulatory cell (CD8+ Treg)

CD8+ T regulatory cells (CD8+ Tregs) are a specialized subset of T lymphocytes that play a crucial role in maintaining immune homeostasis and self-tolerance by suppressing excessive or autoreactive immune responses [1.3.1, 1.3.2]. Unlike the more widely studied CD4+ Tregs, CD8+ Tregs are characterized by the expression of the CD8 glycoprotein and various markers such as CD122, CD25, and sometimes FoxP3, Helios, or Eomes [1.3.1, 1.3.4]. They function through multiple mechanisms, including the secretion of immunosuppressive cytokines like IL-10 and TGF-beta, direct cytotoxicity against activated CD4+ helper T cells (often via HLA-E or Qa-1 recognition), and the modulation of antigen-presenting cells [1.3.1, 1.3.2]. In the context of cancer, CD8+ Tregs can accumulate in the tumor microenvironment and contribute to immune evasion, making them targets for depletion or inhibition to restore anti-tumor immunity [1.3.1]. Conversely, in autoimmune diseases and transplantation, therapeutic strategies aim to expand or activate these cells to restore tolerance and prevent tissue damage [1.1.1, 1.2.1]. Emerging therapies, such as bispecific antibodies (e.g., MTX-101) and low-dose cytokine treatments, are being developed to specifically modulate CD8+ Treg activity for clinical benefit in gastrointestinal and other autoimmune disorders [1.2.1, 1.2.3].

Other names

CD8+ suppressor T cellCD8+ FoxP3+ T cellCD8+CD28- T cellCD8+CD122+ T cellCD8+CD103+ T cellQa-1-restricted CD8+ T cellHLA-E-restricted CD8+ T cell

Modulation of CD8+ Treg activity occurs through several mechanisms: agonism of inhibitory receptors (e.g., KIR2DL) to restore suppressive function, expansion of the cell population via low-dose cytokine signaling (e.g., IL-2, IL-15), and induction of a regulatory phenotype through T-cell receptor (TCR) modulation (e.g., anti-CD3 antibodies). In oncology, mechanisms focus on the depletion or inhibition of these cells to enhance anti-tumor immunity, often via checkpoint blockade or targeting specific surface markers like CCR4 or CCR8 [1.2.1, 1.2.3, 1.3.1].