Table 1.

Regulation of effector T cells by molecules on tumor cells.

Tumor cells	Effector T cells	Effector function	Function in CSCs
MHC class I & II	TCR	activation	[[37], [38], [39], [40], [41],43,44,[48], [49], [50],132,133]
CD80/B7-1	CD28/TP44	activation	[45]
CD86/B7-2	CD152/CTLA-4 PD-L1	inhibition
CD274/PD-L1/B7–H1	CD279/PD-1	inhibition	[130,141,143,[151], [152], [153], [154], [155], [156], [157], [158], [159], [160], [161], [162], [163],166,167,169]
CD273/PD-L2/B7-DC
CD275/ICOS-L/B7–H2	CD278/ICOS/AILIM	activation	?
CD276/B7–H3	?	?	?
VTCN1/B7–S1/B7–H4	?	?	?
VISTA/GI24/B7–H5	CD28H/IGPR1/TMIGD2	inhibition?	?
HHLA2/B7–H7
NCR3LG1/B7–H6	CD337/NKp30/NCR3a	activation	[[78], [79], [80]]
MHC class II	CD223/LAG3	activation	[33,186,187]
FGL1, galectin-3, LSECtin		inhibition
CEACAM1, galectin-9, HMGB1	TIM3	inhibition	?
CD200	CD200R	inhibition	[[179], [180], [181], [182]]

AILIM, activation-inducible lymphocyte immunomodulatory molecule; CEACAM1, carcinoembryonic antigen-related cell adhesion molecule 1; CTLA-4, cytotoxic T-cell-associated antigen-4; FGL1, fibrinogen-like protein 1; HHLA2, human endogenous retrovirus-H long terminal repeat-associating protein 2; HMGB1, high-mobility group box-1; ICOS, inducible T-cell co-stimulator; ICOS-L, ICOS ligand; IGPR1, immunoglobulin and proline-rich receptor-1; LAG3, lymphocyte activation gene 3; LSECtin, liver and lymph node sinusoidal endothelial cell C-type lectin; MHC, major histocompatibility complex; NCR3, natural cytotoxicity triggering receptor 3; NCR3LG1, NCR3 ligand 1; PD-1, programmed cell death-1; PD-L1/2, PD-1 ligand 1/2; TCR, T-cell receptor; TIM3, T-cell immunoglobulin and mucin domain 3; TMIGD2, transmembrane and immunoglobulin domain containing 2; VISTA, V-domain immunoglobulin suppressor of T-cell activation; VTCN1, V-set domain-containing T-cell activation inhibitor 1.

^aExpressed on NK cells.