CD8+ Tregs revisited: A heterogeneous population with different phenotypes and properties. Issue 3 (19th February 2021)

• Record Type: Journal Article
• Authors: Niederlova, Veronika; Tsyklauri, Oksana; Chadimova, Tereza; Stepanek, Ondrej
• Is Part Of: European journal of immunology. Volume 51:Issue 3(2021)
• Page Start: 512
• Page End: 530
• Publication Date: 2021-02-19
• Subjects: Autoimmunity -- CD8 T cells -- Homeostasis -- Regulatory T cells -- Tolerance; Immunology -- Periodicals; 616.079
• DOI: 10.1002/eji.202048614
• Languages: English
• ISSNs: 0014-2980

Abstract

Abstract: Regulatory T cells (Tregs) play a key role in the peripheral self‐tolerance and preventing autoimmunity. While classical CD4 + Foxp3 + Tregs are well established, their CD8 + counterparts are still controversial in many aspects including their phenotypic identity and their mechanisms of suppression. Because of these controversies and because of only a limited number of studies documenting the immunoregulatory function of CD8 + Tregs in vivo, the concept of CD8 + Tregs is still not unanimously accepted. We propose that any T‐cell subset considered as true regulatory must be distinguishable from other cell types and must suppress in vivo immune responses via a known mechanism. In this article, we revisit the concept of CD8 + Tregs by focusing on the characterization of individual CD8 + T‐cell subsets with proposed regulatory capacity separately. Therefore, we review the phenotype and function of CD8 + FOXP3 + T cells, CD8 + CD122 + T cells, CD8 + CD28 low/− T cells, CD8 + CD45RC low T cells, T cells expressing CD8αα homodimer and Qa‐1‐restricted CD8 + T cells to show whether there is sufficient evidence to establish these subsets as bona fide Tregs. Based on the intrinsic ability of CD8 + Treg subsets to promote immune tolerance in animal models, we elaborate on their potential use in clinics. Abstract : Phenotypic identity and clinical potential of CD8 + Tregs remain controversial. Here, we show that CD8 + Tregs cannot be taken as a single cell type, but rather a heterogenous group of cell subsets with diverse suppressive capacity.