Table 1.

The characteristics of CD4⁺ T subsets.

CD4+ T subset	Activation by cytokine	Signaling	Master transcriptional factor	Produced cytokine	Function
Th1	IL-12 and IL-10	SOCS1, STAT1, and STAT4	T-bet	IFN-γ, IL-10, and IL-12	Mediating chronic inflammatory response
Th2	N/A	NF-κB, STAT6, and PI(3)K	GATA-3	IL-4	Anti-helminth immunity, atopic asthma, IgE synthesis, and eosinophilia
Th17	IL-1β, IL6, IL-23, and TGF-β	SOCS1, SMAD7, and STAT3	RORγt	IL-17 and IL-21	Eliminating pathogens in host defense reactions and inducing tissue inflammation
Tfh	N/A	PI3K-mTOR, KLF2, PTEN, and ICOS-ICOSL	BCL6	IL-6 and IL-21	Supporting GC B cell differentiation into plasma cells and memory B cells
Treg	IL-2 and TGF-β	SOCS1, SMAD3, STAT3, STAT5, and mTOR	FOXP3	TGF-β	Maintaining immune homeostasis and self-tolerance