T cells with suppressive properties are summarized
| Regulatory/suppressor T cells . | ||
|---|---|---|
| Cell type . | Phenotype . | Suggested immunosuppressive mechanisms . |
| CD4+ | ||
| nTreg | CD25 + FOXP3 + 45RO+ CTLA-4+ GITR+CD134+CD62L+CD103+ lymphocyte activation gene-3+ CD127lo CD26+ | Cell-to-cell contact-dependent in vitro (CTLA-4) Cell-to-cell contact- and cytokine-dependent in vivo (IL-10 and TGF-β) |
| iTreg | ||
| Th3 | CD25±FOXP3±45RO+ CTLA-4+ | Cytokine-mediated (TGF-β production > > IL-10) |
| Tr1 | CD25±FOXP3±45RO+ CTLA-4− | Cell-to-cell contact Cytokine-mediated (IL-10 > > TGF-β, IL-5, IFN-γ production) |
| TGF-β/IL-10 double-positive Treg | CD25− FOXP3− | Cytokine-mediated (IL-10 and TGF-β production) |
| CD8+ | ||
| T suppressor cells (Ts) | ||
| Naturally occurring | FOXP3+ 45RO+CD25+CTLA-4+GITR+ | Cell-to-cell contact-dependent (CTLA-4) Cytokine-mediated (TGF-β production) |
| Non–antigen specific | CD28−Foxp3−CD56− | Cytokine-mediated (IL-10 production) |
| Inducible | CD25+Foxp3+CD28+GITR+CTLA-4+ | Cell-to-cell contact |
| γ/δ T cells | Cell-to-cell contact Cytokine-mediated (IL-2, IL-10, IL-17, IFN-γ, TGF-β, TNF-α production) | |
| CD4−CD8− αβ T cells | CD25+30+45+69+LFA-1+CTLA-4+ | Cell-to-cell contact Produce IFN-γ and TNF-α |
| NKT cells | CD161 | Cytokine-mediated, produce both Th-1 (IFN-γ and TNF-α) and Th-2 cytokines (IL-4, -10,-13) |
| Regulatory/suppressor T cells . | ||
|---|---|---|
| Cell type . | Phenotype . | Suggested immunosuppressive mechanisms . |
| CD4+ | ||
| nTreg | CD25 + FOXP3 + 45RO+ CTLA-4+ GITR+CD134+CD62L+CD103+ lymphocyte activation gene-3+ CD127lo CD26+ | Cell-to-cell contact-dependent in vitro (CTLA-4) Cell-to-cell contact- and cytokine-dependent in vivo (IL-10 and TGF-β) |
| iTreg | ||
| Th3 | CD25±FOXP3±45RO+ CTLA-4+ | Cytokine-mediated (TGF-β production > > IL-10) |
| Tr1 | CD25±FOXP3±45RO+ CTLA-4− | Cell-to-cell contact Cytokine-mediated (IL-10 > > TGF-β, IL-5, IFN-γ production) |
| TGF-β/IL-10 double-positive Treg | CD25− FOXP3− | Cytokine-mediated (IL-10 and TGF-β production) |
| CD8+ | ||
| T suppressor cells (Ts) | ||
| Naturally occurring | FOXP3+ 45RO+CD25+CTLA-4+GITR+ | Cell-to-cell contact-dependent (CTLA-4) Cytokine-mediated (TGF-β production) |
| Non–antigen specific | CD28−Foxp3−CD56− | Cytokine-mediated (IL-10 production) |
| Inducible | CD25+Foxp3+CD28+GITR+CTLA-4+ | Cell-to-cell contact |
| γ/δ T cells | Cell-to-cell contact Cytokine-mediated (IL-2, IL-10, IL-17, IFN-γ, TGF-β, TNF-α production) | |
| CD4−CD8− αβ T cells | CD25+30+45+69+LFA-1+CTLA-4+ | Cell-to-cell contact Produce IFN-γ and TNF-α |
| NKT cells | CD161 | Cytokine-mediated, produce both Th-1 (IFN-γ and TNF-α) and Th-2 cytokines (IL-4, -10,-13) |
Suppressive T cells are mostly present in CD4+ cell population. However, some CD8+, double-negative, and NKT cells also have suppressive functions. Some of these T cells demonstrate their suppressive activity by cell-cell contact manners, whereas others release cytokines and inhibit effector immune system cells.
CTLA-4 indicates cytotoxic T-lymphocyte antigen-4; GITR, glucocorticoid-induced TNFR-related protein; iTreg, inducible regulatory T cells, NKT cells, batural killer T cells; nTreg, natural regulatory T cells; Tr1, regulatory T cells type 1; and Th3, T helper 3.