. 2023 Dec 17;15(24):5877. doi: 10.3390/cancers15245877

Table 1.

Extracellular markers, transcription factors, and mechanisms of actions of various Treg subtypes.

T_reg Subset	Origin	Markers	Transcription Factors	Suppressive Mechanism	References
tT_regs	Generating in the thymus	CD4⁺, CD25^hi, CD27^lo, CTLA-4⁺, LAG-3⁺, TIGIT⁺, TIM-3⁺, PD-1+	FOXP3pos	Cell-contact-dependent immunosuppression via receptors like CTLA-4 and PD-1	[33]
pT_regs	Differentiating from peripheral naive CD4+ T cells	CD4⁺, CD25^hi, CD27^lo, CTLA-4+, LAG-3+, TIGIT+, Tim-3+, PD-1+	FOXP3pos	Inhibitory function via soluble factors such as TGF-β1 and IL-10	[33]
Tr1 T_regs	Differentiating from peripheral naive CD4+ T cells	CD4⁺, CD25, CD49b⁺, LAG-3⁺ [3]	Tbet, Blimp-1, FOXP3neg [1]	Inhibitory function via IL-10 production	[34,35]
Th3 T_regs	Differentiating from peripheral naive CD4+ T cells	CD4⁺, CD25⁺, CD69⁺, LAP⁺	TGF-β, FOXP3neg	Inhibitory function via TGF-β production	[36]
CD8⁺ T_regs	Differentiating from peripheral naive CD8+ T cells	CD8⁺, CD25⁺, CD122+, CD49d+	FOXP3pos, Eomes, Helios, TGF-β	TGF-dependent control of Helios and homeostatic cytokine IL-15 [4]	[37,38]

tTregs: thymus-derived Tregs, pTregs: peripherally derived Tregs, Tr1 Tregs: Type 1 Tregs, Th3 Tregs: T helper T cells, CTLA-4: Cytotoxic T-lymphocyte-associated protein 4, LAG-3: Lymphocyte-activation gene 3, TIGIT: T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains, TIM3: T-cell immunoglobulin and mucin domain-containing protein 3, PD-1: Programmed cell death protein 1, FOXP3: Forkhead box P3, TGF-β: Transforming Growth Factor β 1, IL-10: Interleukin-10, Tbet: T-box expressed in T cells, Blimp-1: B lymphocyte-induced maturation protein 1, LAP: Latency-associated peptide positive, Eomes: Eomesodermin, IL-15: Interleukin-15.