Table 6.

Viral interference with MHC functions

Function/Activity	Gene/Protein	Virus	Mechanism	Refs
Effect on MHC class I	E3/19K	Adenovirus	Binding and retention of class I in ER	1, 11, 32, 33, 42
	US3	HCMV	Binding and retention of class I in ER	1, 11, 32, 33, 34
	US2, US11	HCMV	Relocation of heavy chain into ER for degradation	1, 11, 32, 33, 34, 49
	m4	MCMV	Binds class I molecules	1, 11, 32, 33, 34
	m6	MCMV	Binding of class I molecules and transport to lysosomes for degradation	1, 11, 32, 33, 34
	m152	MCMV	Retains class I in ER–Golgi intermediate compartment	1, 11, 32, 33, 34, 35
	K3, K5	HHV-8, MHV-68	Downregulation of class I molecules	36, 37, 38
	Nef	HIV	Endocytosis of surface class I and CD4	1, 11, 32, 33, 49
	Vpu	HIV	Destabilization of class I, targets CD4 to proteasome	1, 11, 32, 33, 49
Effect on MHC class II	E1A	Adenovirus	Interferes with class II upregulation (IFN-γ signal transduction cascade)	1, 11, 32, 33
	Unknown	HSV	Interference with class II function	1, 11, 32, 33
	Unknown	HCMV, MCMV	Interference with class II upregulation (IFN-γ signal transduction cascade)	1, 11, 32, 33, 34
	US2	HCMV	Targets class II DR, DM α chain for degradation	1, 11, 32, 33, 34
	ORF14	HSV	Class II binding	1, 11, 32, 33
	E5, E6	HPV, BPV	Interference with class II processing, E5 acidification of endosomes, E6 interaction with AP complex	1, 11, 32, 33
	Nef	HIV	Interference with class II processing	1, 11, 32, 33
Effect on TAP	ICP-47	HSV	Prevents peptide binding to TAP in cytosol	1, 11, 32, 33
	US6	HCMV	Prevents peptide transport through TAP pore	1, 11, 32, 33, 34
Effect on antigen processing	EBNA-1	EBV	A Gly–Ala repeat motif prevents proteasomal degradation	1, 11, 32, 33
	pp65	HCMV	Modulates processing of another HCMV protein	1, 11, 32, 33, 34
Effect on NK cells	UL18, m144, r144	HCMV, MCMV, RCMV	Class I homolog, inhibits NK cell lysis	1, 11, 32, 33, 34
	MC80	MCV	Class I homolog, function unknown	1, 11, 32, 33
	UL40	HCMV	UL40 peptide causes HLA-E upregulation	39, 40