T cells in pancreatic cancer stroma

Table 1 T cell phenotype and functions

T cell phenotype	Surface markers	Immune response	Effector functions
Cytotoxic T cell
CTLs	CD8	Tumour killing	IFN-γ, TNF-α cytokines, granzymes, FasL
Helper T cell
Th1	CD4 STAT4 T-bet	Tumour killing	IFN-γ, IL-2 cytokines, increase CTL activity
Th2	CD4 STAT6 GATA3	Tumour tolerance	IL-4, IL-5, IL-13 cytokines, decrease CTL activity
Th17	STAT3 RORγt	Tumour tolerance	IL-17 cytokine
γδ T cells	TCRγ/δ	Tumour tolerance	IL-4, IL-10, TGF-β cytokines and CTL activity
Regulatory T cell
Tregs	CD4 CD25 FOXP3	Tumour tolerance	IL-10, TGF-β cytokines, CTLA-4

CTL: Cytotoxic lymphocyte; IFN-γ: Interferon-γ; TNF-α: Tumour necrosis factor α; IL: Interleukin; TGF-β: Transforming growth factor β.