Table 1.

The features and properties of T cell subsets

T cell subsets	Distinct transcription factor	Distinct cytokines	Immune functions	References
Th1	T-bet	IFN-γ	Participate in cellular immunity against intracellular microorganisms	[25–28]
Th2	GATA-3	IL-4, IL-5, IL-13	Control helminths and other extracellular pathogens	[25–28]
Th9	STAT6, IRF4	IL-9	Enhance allergic inflammation and airway hyperreactivity; promote tumour progression or anti-tumour immunity	[25–28]
Th17	RORγt	IL-17a, IL-17f, IL-21, IL-22	Clear extracellular bacteria and fungi	[25–28]
Tfh	Bcl-6	IL-4, IL-21	Regulate the maturation of B cell responses	[25–28]
Treg	Foxp3	IL-10, TGF-β	Participate in maintenance of peripheral tolerance and prevention of autoimmunity	[25–28]
DNT	IKZF2	IFN-γ, Granzyme B	Participate in regulation of adaptive and innate immunity; anti-tumour	[30]
CD8+ T		IFN-γ, TNF-α, IL-2	Clear virus and tumour cells	[24]

Th T helper, IFN Interferon, IL Interleukin, Tfh Follicular helper T, Treg Regulatory T cell, DNT Double negative T, TNF tumor necrosis factor