Table 1.

A summary of immune checkpoint molecules

Molecules	Full name	Alternate name	Binding partners	Expressed cells	References
CTLA-4	Cytotoxic T lymphocyte-associated protein-4	CD152	CD80 (B7-1) CD86 (B7-2)	T cells	5,139
PD-1	Programmed cell-death protein-1	CD279	PD-L1 (B7-H1 or CD274) PD-L2 (B7-DC or CD273)	T cells, NKT cells, B cells, monocytes, Langerhans’ cells	16,140
LAG-3	Lymphocyte activation gene-3	CD223	MHC-II FGL1 galectin-3 (LGALS3) LSECtin α-synuclein	T cells, B cells, Tregs, NK cells, NKT cells, pDCs	5,141,142
TIGIT	T-cell immunoglobulin and ITIM domain	WUCAM Vstm3 Vsig9	CD155 (PVR, Necl-5) CD112 (nectin-2, PRR2, PVRL2)	T cells, Tregs, NK cells,	143–145
TIM-3	T-cell immunoglobulin and mucin-domain containing-3	HAVCR2 CD366	Galectin-9 Ceacam-1 HMGB-1 PtdSer	T cells, Tregs, DCs, NK cells, monocytes, macrophages	5,18,144–146
BTLA	B and T cell lymphocyte attenuator	CD272	HVEM	B cells, T cells, macrophages, DCs	147,148
VISTA	V-domain Ig suppressor of T cell activation	PD-1H DD1α Gi24 Dies1 B7-H5	VSIG-3	APCs, T cells, Tregs	5,149
B7-H3	B7 homolog 3 protein	CD276	IL20RA TLT2 (putative)	T cells, B cells, APCs, NK cells, DCs, monocytes, fibroblasts, epithelial cells, tumor cells	5,145,150–153
B7-H4	B7 homolog 4 protein	VTC1 B7x B7S1	unknown	T cells, B cells, monocytes, DCs	145,154,155
KIR	Killer-cell immunoglobulin-like receptor	CD158	MHC class I molecules	NK cells, T cells	111,156
CD160	Cluster of differentiation 160	–	HVEM	NK cells, T cells, intraepithelial lymphocytes	157
CD73	Cluster of differentiation 73	ecto-5’- nucleotidase	Dephosphorylating extracellular AMP to generate adenosine	Tumor cells, Th cells, Tregs, T cells, B cells, macrophages, DCs	158,159
CD96	Cluster of differentiation 96	–	CD111 CD155	T cells, NK cells, NKT cells	160,161