Table 1.
CD8+ Treg markers and mechanisms of action.
| Subset | Natural/induced | Markers | Mechanism of action | Ref. |
|---|---|---|---|---|
| CD8+FoxP3+ (mice) | Induced | PD-1low, CD62Lhigh, CCR7low | Secretion of TGF-β | [6, 8, 21] |
| CD8, CD8α, CD25high, CD28low/high, FoxP3, CTLA-4, CD103, CD122, CXCR3, LAG-3, CD127low (mice, humans) | Natural/induced | CD25high, CD28low/high, FoxP3, CTLA-4, CD103, CD122, CXCR3, LAG-3, CD127low | Secretion of IL-10, Reduction of IFN-γ, Cell-to-cell contact dependent | [20, 22, 23, 24, 25] |
| CD8, Qa-1, NKG2A (CD94) (mice) | Natural | Qa-1 (mice), HLA-E (humans), Ly49 | Suppress T effector cells, use perforin | [23, 26, 27, 28, 29] |
| CD8, CD25, FoxP3 (humans) | Natural | CD8, CD25, FoxP3, CD127low (mice and humans) | Suppress T effector cells | [22] |
| CD8 (mice) | Natural | CD28+CD28−, CD103, CD122, ICOS+ in mice | Suppress T effector cells | [22, 30, 31, 32, 33, 34, 35, 36] |
| CD8, ILT3/ILT4 (mice) | Natural | ILT3, ILT4 | Make APCs tolerogenic | [37, 38] |
| CD8, CD103 (mice) | Induced | CD103 | CD39, attenuate glomerular endothelial cell damage | [20, 22, 23, 24, 25, 35, 39] |
| CD8, CD25, CXCR3 (CD183) CD178 (ICOS) (humans) | Natural | CD8+CD25hi, CD183+ CD178+FoxP3+ | Suppress B cells proliferation and IgG production | [40] |
| CD8, CD28 (humans) | Natural | CD8+CD28− | Inhibit T cell proliferation and cytotoxic functions | [21, 33] |
APC, antigen presenting cells; ILT, Ig-like transcript; IgG, immunoglobulin; LAG-3, lymphocyte activation gene 3; PD-1, programed death-1; ICOS, Inducible co-stimulator.