Table 2.

Viral interference with IFN

Function/activity	Gene/protein	Virus	Mechanism	Refs
Inhibition of JAK/STAT pathway	EIA	Adenovirus	Decreases the levels of STAT1 and p48	1, 7, 42
	EBNA-2	EBV	Downregulates IFN-induced transcription	1, 7
	Unknown	HCMV	Reduces levels of JAK1 and p48; involvement of proteasome	7
	Unknown	HPIV-2	Targets STAT2 for degradation	7
	Unknown	HPIV-3, SeV	Block STAT1 phosphorylation	7
	E7	HPV-16	Binds to p48	7
	T antigen	MPV	Binds to and inactivates JAK1	7
	V protein	SV5	Targets STAT1 for proteasome-mediated degradation	7
IFN-induced transcription	IRF homolog	HHV-8	Represses transcriptional responses to IFNs	1, 7
	Capsid protein	HBV	Inhibits MxA gene expression	7
Inhibition of PKR activity	σ3, NSP3, E3L, OV20.0L, NS1	Reovirus, rotavirus, VV, OV, influenza virus	Bind dsRNA and prevent PKR activation	2, 5, 6, 7
	VAI RNA, EBER RNA, TAR RNA	Adenovirus, EBV, HIV	RNA that binds to, but fails to activate, PKR	5, 7, 42
	PK2, NS5A and E2, US11, Tat	Baculovirus, HCV, HSV, HIV	Bind to and inhibit PKR	5, 7
	Unknown	Poliovirus	Induced degradation of PKR	5, 7
	Unknown	Influenza virus	Induction of p58IPK, a cellular inhibitor of PKR	5, 7
Inhibition of eIF-2α phosphorylation and translational arrest	K3L	VV	eIF-2α homolog, prevents eIF-2α phosphorylation, also inhibits PKR	2, 5, 6, 7
	ICP34.5	HSV	Redirects protein phosphatase 1 to dephosphorylate and re-activate eIF-2α	7
Inhibition of 2′5′OS/RNase L system	σ3,NSP3, E3L, OV20.0L, NS1	Reovirus, rotavirus, VV, OV, influenza virus	Bind dsRNA and prevent activation of 2′5′OS/RNase L	2, 6, 7
	Unknown	EMCV, HIV	Induce RNase L inhibitor, which antagonizes 2′5′OA binding to RNase L	7
	Unknown	HSV	Synthesis of 2′5′OA antagonists	7