Advancement of chimeric antigen receptor-natural killer cells targeting hepatocellular carcinoma

Table 1 Activating and inhibitory receptors on human natural killer cells

	Receptor	Ligand
Activating receptors	CD16	Fc region of IgG
	NKG2D	MICA/B, ULBP1-6
	NKp30 (CD337)	B7-H6, BAT3, HCMV pp65
	NKp44 (CD336)	Viral HA and HN, PCNA, MLL5, PDGF-DD
	NKp46 (CD335)	Viral HA and HN, CFP
	NKp65	KACL
	NKp80	AICL1
	CD94-NKG2C/E/H	HLA-E (for CD94-NKG2C)
	2B4 (CD244)	CD48
	DNAM-1 (CD226)	PVR (Necl5, CD155), nectin 2 (CD112)
	Activating KIRs	HLA-A11, -Bw4
	CRTAM (CD355)	Necl-2
	Tactile (CD96)	CD155
Inhibitory receptors	Inhibitory KIRs	HLA class I
	CD94-NKG2A/B	HLA-E
	NKR-P1A	LLT1
	TIGIT	PVR (Necl5, CD155), nectin 2 (CD112)
	LIR-1 (ILT-2/CD85j/LILRB1)	HLA (α3), HCMV UL18
	IRp60 (CD300a)	PS, PE
	CEACAM1 (CD66)	CEACAM1 (CD66), TIM-3 (HAVCR2)

AICL: Activation-induced C-type lectin; BAT3: Human leukocyte antigen-B-associated transcript 3; CEACAM: Carcinoembryonic antigen-related cell adhesion molecules; CFP: Complement factor P; CRTAM: Class I-restricted T cell-associated molecule; DNAM-1: DNAX accessory molecule 1; H60: Minor histocompatibility protein 60; HA: Hemagglutinin; HAVCR2: Hepatitis A virus cellular receptor 2; HCMV: Human cytomegalovirus; HN: Hemagglutinin-neuraminidase; IgG: Immunoglobulin G; ILT-2: Immunoglobulin-like transcript 2; IRp60: Inhibitory receptor protein 60; KACL: Keratinocyte-associated C-type lectin; KIR: Killer-cell immunoglobulin-like receptor; LILRB1: Leukocyte immunoglobulin-like receptor, subfamily B member 1; LIR-1: Leukocyte immunoglobulin-like receptor 1; LLT1: Lectin-like transcript 1; MHC: Major histocompatibility complex; MIC: MHC class I chain-related protein; MLL5: Mixed lineage leukemia 5; MULT-1: Mouse UL-16- binding protein-like transcript 1; Necl: Nectin-like molecules; PCNA: Proliferating cell nuclear antigen; PDGF: Platelet-derived growth factor; PE: Phosphatidylethanolamine; PILR: Paired immunoglobulin-like type 2 receptor; PS: Phosphatidylserine; PVR: Poliovirus receptor; Rae-1: Retinoic acid early inducible 1; TIGIT: T cell immunoglobulin and immunoreceptor tyrosine-based activation motif domain; TIM-3: T cell immunoglobulin domain and mucin domain 3; ULBP: UL16 binding proteins.