Table 1 Expression of coinhibitory receptors and their ligands in immune cell populations
From: Blockade of novel immune checkpoints and new therapeutic combinations to boost antitumor immunity
Coinhibitory receptor | Expression in human CTLs | Expression in human NK cells | Expression in other immune cell populations | Ligand-expressing cells |
|---|---|---|---|---|
2B4 (CD244, SLAMF4) | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells | DCs, monocytes, MDSCs and basophils | CD48 (SLAMF2): Lymphocytes, DCs, monocytes, macrophages, endothelial cells and tumor cells |
BTLA | Subsets of CTLs and increased in tumor-infiltrating CTLs | Not expressed | B cells and DCs | HVEM: T cells, B cells, NK cells, DCs, monocytes and tumor cells |
CD200R | Subsets of CTLs | Subsets of NK cells | Th cells, B cells, DCs, macrophages and neutrophils | CD200: T cells, B cells, DCs, endothelial cells and tumor cells |
CD47 (IAP) | Subsets of CTLs | Subsets of NK cells | Expressed ubiquitously in human cells | SIRPα: DCs, macrophages, monocytes and granulocytes TSP1: Endothelial cells, monocytes, macrophages, granulocytes and cancer cells |
CD96 (TACTILE) | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Treg cells | PVR (CD155. Necl-5): DCs, neutrophils, macrophages and tumor cells Nectin-1 (PVRL1, CD111): DCs and tumor cells |
CTLA-4 | Subsets of CTLs and increased in tumor-infiltrating CTLs | Unclear | Th cells and Treg cells | CD80 (B7–1): B cells, T cells, DCs, macrophages and tumor cells CD86 (B7–2): B cells, T cells, DCs, macrophages and tumor cells |
ILT2 (LIR1) | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Th cells, B cells, DCs and MDSCs | HLA-G: Tumor cells HLA-I (A/B/C): Ubiquitously in human cells |
KIR-L | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Th cells | HLA-I (A/B/C): Ubiquitously in human cells |
KLRG1 | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells | Not expressed | E-cadherin: Epithelial cells and cancer cells N-cadherin: Mesenchymal cells and cancer cells R-cadherin: Neural tissue |
LAG-3 | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells | Th cells, Treg cells, B cells and DCs | HLA-II: DCs, macrophages, B cells, neutrophils, fibroblasts and tumor cells FGL-1: Tumor cells Gal-3: Fibroblasts LSECtin: Tumor cells |
NKG2A/CD94 | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Not expressed | HLA-E: Ubiquitously in human cells and increased in tumor cells |
PD-1 | Subsets of CTLs and increased in tumor-infiltrating CTLs | Expressed in tumor-infiltrating NK cells | Th cells, Treg cells, B cells, macrophages and DCs | PD-L1 (B7-H1): Treg cells, B cells, DCs, macrophages, monocytes, MDSCs and tumor cells. PD-L2 (B7-DC): DCs, macrophages, B cells and tumor cells. |
PVRIG (CD112R) | Subsets of CTLs and induced in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Not expressed | Nectin-2 (PVRL2, CD112): DCs, endothelial cells, and tumor cells |
Siglec-7/−9 | Siglec-7: Subsets of CTLs, Siglec-9: Subsets of CTLs and induced in tumor-infiltrating CTLs | Siglec-7: Subsets of NK cells, Siglec-9: Subsets of NK cells | Siglec-7: Macrophages, monocytes and mast cells Siglec-9: DCs, macrophages, monocytes and neutrophils | Sialic acid-containing ligands: Glycoproteins expressed by human cells. Hypersialylation, xenosialylation, and sialic acid alterations in tumor cells |
TIGIT | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Th cells and Treg cells | PVR (CD155, Necl-5): DCs, neutrophils, macrophages and tumor cells Nectin-2 (PVRL2, CD112): DCs, endothelial cells, and tumor cells Nectin-3 (PVRL3, CD113): DCs, endothelial cells, T cells and tumor cells |
TIM-3 | Subsets of CTLs and increased in tumor-infiltrating CTLs | Subsets of NK cells and increased in tumor-infiltrating NK cells | Th cells, Treg cells, DCs, macrophages and monocytes | Galectin-9: T cells, Treg cells, NK cells, B cells, macrophages, endothelial cells and mast cells and tumor cells. PS: Inner-cell membrane phospholipid of human cells. HMGB1: NK cells, DCs, macrophages and tumor cells CEACAM1: T cells, B cells, NK cells, neutrophils, monocytes and tumor cells |
Undiscovered B7-H3 receptor | / | / | / | B7-H3: T cells, B cells, NK cells, monocytes and tumor cells |
VISTA (PD-1H) | Subsets of CTLs and increased in tumor-infiltrating CTLs | Not expressed | Th cells, Treg cells, DCs, macrophages, monocytes, neutrophils and basophils | PSGL-1: T cells, B cells, DCs, macrophages, monocytes, endothelial cells, and neutrophils |