Table I.

Activating and inhibitory natural killer cell receptors.

Receptor	Ligand(s)
Activating receptors
Activating KIR	HLA-A11,-Bw4, -C
NKG2D	MICA/B, ULBP1 to -6
DNAM-1 (CD226)	PVR (Necl5, CD155), nectin 2 (CD112)
CRTAM (CD355)	Necl-2
NKp80	AICL1
NKp65	KACL
NKp46 (CD335)	Viral HA/HN, CFP (properdin)
NKp44 (CD336)	Viral HA/HN, PCNA, MLL5, PDGF-DD
NKp30 (CD337)	B7-H6, BAT3, HCMV pp65
CD16	IgG (Fc portion)
2B4 (CD244)	CD48
NKG2C/E/H	HLA-E (for NKG2C)
CD96	CD155
Inhibitory receptors
Inhibitory KIR	MHC class I
NKR-P1A	LLT1
NKG2A/B	HLA-E
TIGIT	PVR (Necl5, CD155), nectin 2 (CD112)
LIR-1 (ILT-2/CD85j/LILRB1)	HLA (a3), HCMV UL18
IRp60 (CD300a)	PS, PE
CEACAM1 (CD66)	CEACAM1 (CD66), TIM-3 (HAVCR2)

KIR, killer-cell immunoglobulin-like receptor; HLA, human leucocyte antigen; MIC, major histocompatibility complex (MHC) class I chain-related protein; ULBP, UL16-binding proteins; DNAM-1, DNAX accessory molecule 1; PVR, poliovirus receptor; Necl, nectinlike molecules; CRTAM, class I-restricted T cell-associated molecule; AICL, activation-induced C-type lectin; KACL, keratinocyte-associated C-type lectin; HA, haemagglutinin; HN, haemagglutinin-neuraminidase; CFP, complement factor P; PCNA, proliferating cell nuclear antigen; MLL5, mixed lineage leukaemia 5; PDGF, plateletderived growth factor; IRp60, inhibitory receptor protein 60; BAT3, HLA-B-associated transcript 3; HCMV, human cytomegalovirus; IgG, immunoglobulin G; LLT1, lectin-like transcript 1; TIGIT, T cell immunoglobulin and immunoreceptor tyrosine-based activation motif (ITIM) domain; LIR-1, leucocyte immunoglobulin-like receptor 1; PS, phosphatidylserine; PE, phosphatidylethanolamine; CEACAM, carcinoembryonic antigen-related cell adhesion molecules; TIM-3, T-cell immunoglobulin domain and mucin domain 3; HAVCR2, hepatitis A virus cellular receptor 2.