TABLE 2.

NK cells directly recognize virus-encoded ligands or cellular ligands that are modulated by virus infection ^a

Species	Virus	Viral ligand or virus-modulated cellular ligands	NK cell receptor
Human	HCMV	HLA-E	CD94/NKG2C
		Cell stress ligands: MICA/B, ULBP1-4^b	NKG2D
		pp65	NKp30
		UL18	LILRB1
		???	KIR2DS4, KIR2DS2, KIR3DS1
	HSV	Unknown but associated with ICP0 expression	NKp30, NKp40, NKp46
	EBV	HLA-C	KIR2DS1
	Ectromelia virus	HA	NKp30, NKp46
	Vaccinia virus	HA	NKp30, NKp46
	Dengue virus	Envelope-protein	NKp44
	West Nile virus	Envelope-protein, HA-neuraminidase	NKp44
	Influenza A virus	HA, HA-neuraminidase	NKp44, NKp46
	Human parainfluenza virus	HA-neuraminidase	NKp46
	Sendai virus	HA, HA-neuraminidase	NKp44, NKp46
	Newcastle disease virus	HA, HA-neuraminidase	NKp44, NKp46
	Ebola virus	???	NKp30
	HCV	???	NKp30, NKp46, CD94/NKG2C
	HCV	E2	CD81
	HIV	HLA-B	KIR3DS1
		???	NKp44, NKp46
		Vpu reduces NTB-A^c	NTB-A
Mouse	MCMV	m157	Ly49H/DAP12 (C57BL/6)
		m157	Ly49I (129)
		H-2D^k with m04	Ly49P/DAP12
		Virus-induced cell stress ligands: Rae1, H60a–c, Mult1^b	NKG2D
		ml54 reduces CD48^c	2B4
	Ectromelia virus	Qa-1^b	CD94/NKG2E
	Influenza A virus	HA	NKp46

Please see these reviews of NK cell recognition of viral ligands.^28,269

Cell stress ligands are induced when cells are infected.

This cellular ligand is downregulated by a viral protein leading to less NK cell activation.