Table 2.

Mechanisms and outcomes of viral-derived complement modulators

Virus	Viral-derived modulator	Target	Mechanism	Outcome	Ref.
Astrovirus	Coat protein	C1	Binding of CP to the A-chain of C1q	Inhibition of complement activation Suppression of hemolytic complement activity	96
		MBL	Inhibition of C3 activation and MAC formation	Inhibition of mannan-mediated lectin pathway	97
Flaviviruses	NS1	CRP	Recruitment of CRP factor H	Decreased deposition of C3 and C5b-9 MACs on cell surfaces	101
		C4	Recruitment of C1s	Cleavage of C4	102
		C4b	Recruitment of C4BP	Inactivation of C4b	103
Nipah virus	–	C3b	Factor I-like protease activity	Cleavage of C3b	105
Hepatitis C virus	NS3/4A	C4	Proteolytic activity towards C4	Cleavage of C4	107
Hepatitis B virus	HBx	CD59	Increased CD59 activity Increased CD59 on HBx-positive cells	Resistance to complement-dependent cytotoxicity Less MAC deposition	110
Herpesvirus saimiri	CCPH	C3b and C4b C3 convertase	Promotion of factor I activity	Evasion of the classical, lectin and alternative pathways	115
	CD59 homolog	C5b-8	C5b-8-catalyzed step in MAC assembly	Decreased deposition of C5b-9 MACs on cell surfaces	114
Kaposi sarcoma- associated herpesvirus	KCP	C3b and C4b C3 convertase	Promotion of factor I activity Presence of KCP on infected cell surfaces	Evasion of complement attack	119
Rhesus rhadinovirus	RCP	C3b C3 convertase	Presence of RCP on infected cell surfaces	Evasion of complement attack	121
Herpes simplex virus 1	gC	C3, C3b, properdin and C5 C3 convertase	Binds C3 and C3 fragments Blocks the properdin- C5-C3b interaction Facilitation of C3 convertase decay	Less MAC deposition and cytotoxicity	124
Murine γ-herpesvirus-68	MHV-68 RCA	C3	Inhibition of C3 deposition	Less MAC deposition and cytotoxicity	130
Vaccinia virus	VCP	C3b and C4b	VCP binds to C3b and C4b	Reduced neutrophil infiltration (less C3a, C4a and C5a) Reduced damage secondary to SCI	136
Variola virus	SPICE	C3b and C4b C3 convertase	Facilitation of C3 convertase decay	Cleavage of C3b and C4b Less C3b deposition	144
Monkeypox virus	MOPICE	C3b and C4b	MOPICE binds to C3b and C4b Cofactor for factor I	Cleavage of C3b and C4b Less C3b deposition	147
Ectromelia virus	EMICE	C3b and C4b	Facilitation of C3 convertase decay Cofactor for factor I	Cleavage of C3b and C4b Less C3b deposition	149
Cowpox virus	IMP	C3 and C4	Cofactor for factor I	Less C3b deposition	150