Table 1.
Key mediators of NK cells
| Classification | Mediator | Host ligand | Ref. |
|---|---|---|---|
| NK cell activator | |||
| MHC-I specific receptor | KIR2DS1, 2DS3, 3DS5 | MHC I | [28] |
| Ly49c, Ly49i | MHC I | [29] | |
| NKp80 | MHC I | [30] | |
| NKG2C, NKG2E | MHC I | [31] | |
| MHC-I related receptor | NKG2D | MICA, MICB, ULBPs | [13] |
| MHC-I non-related receptor | DNAM1 | Nectin-2, CD155 | [32] |
| NKp46 (NCR1) | HS GAGs, CFP | [33] | |
| NKp44 (NCR2) | HS GAGs, MLL5, NKp44L, PCNA, BAT3, PDGF-DD, Nidogen-1 | [34] | |
| NKp30 (NCR3) | HS GAGs, B7-H6, Galectin-3 | [35] | |
| Nkp65 | Keratinocyte-associated C-type lectin | [36] | |
| LFA-1 (αLβ2 integrin) | Intercellular cell adhesion molecule 1 | [37, 38] | |
| α4 integrin | Vascular cell adhesion molecule 1 | [39] | |
| CD16 | Fc-γ | [40, 41] | |
| CD2 | CD581 | [41] | |
| TLR3 | Microbial constituents, adjuvant | [42] | |
| TLR9 | CpG | [43] | |
| NK cell inhibitor | |||
| MHC-I specific receptor | KIR3DL1 | MHC I | [44] |
| KIR2DL3, 2DL1 | MHC I | [45] | |
| NKG2A | MHC I | [46] | |
| KLRB1, LLT1 | MHC I | [47] | |
| LILRB1, LILRB2 | MHC I | [48] | |
| MHC-I non-related receptor | KLRG1 | E-, N-, and R- cadherins | [49] |
| siglec-3, siglec-7, siglec-9 | Sialic acid | [50, 51] | |
| CEACAM1 | CEACAM1, CEACAM5 | [52] | |
| 2B4 (CD244) | CD48 | [53] | |
| IRp60 | Phosphatidylserine | [54] | |
| LAIR1 | Ep-CAM | [55] | |
| CD96 | CD155 | [56] | |
| CD73 | Antibodies | [57] | |
| PD-1 | PD-L1 | [58] | |
| TIGIT | CD155 | [20] | |
| NKR-P1B | Clr-b | [59] | |
| LAG3 | MHC-II | [60] | |
Abbreviations: MHC major histocompatibility complex, KIR killer cell immunoglobulin-like receptor, MIC MHC class I chain-related, ULBP UL16-binding protein 1, DNAM1 DNAX accessory molecule 1, NCR natural cytotoxicity receptor, HS GAGs heparan sulfate glycosaminoglycans, CFP complement factor P, MLL5 mixed-lineage leukemia protein-5, PCNA proliferating cell nuclear antigen, BAT3 HLA-B-associated transcript 3, PDGF-DD platelet-derived growth factor-DD, LFA-1 lymphocyte function-associated antigen-1, TLR toll-like receptor, KLR killer cell lectin-like receptor, LLT1 lectin-like transcript 1, LILR leukocyte immunoglobulin-like receptor, Siglec sialic acid-binding immunoglobulin-like lectin, CEACAM carcinoembryonic antigen-related cell-adhesion molecule, IRp60 inhibitory receptor protein 60, LAIR1 leukocyte-associated immunoglobulin-like receptor 1, Ep-CAM epithelial cellular adhesion molecule, PD-1 programmed cell death protein 1, TIGIT T-cell immunoreceptor with Ig and ITIM domains, LAG3 lymphocyte activation gene 3