Approaches for the Development of Rapid Serological Assays for Surveillance and Diagnosis of Infections Caused by Zoonotic Flaviviruses of the Japanese Encephalitis Virus Serocomplex

Table 2

Antigen formulations to improve serological assay specificity.

Antigen	Reference	Assay Format	Serum	Sensitivity	Specificity
E protein: removal of DII cross-reactive epitopes from virus-like particles. One antigen for WNV and one antigen for SLEV	Roberson et al., 2007 [136]	IgM ELISA	Human. 134 sera including those with disease states classified as SLEV, WNV, JEV or DENV	Mutant WNV antigen: 100%*; Mutant SLEV antigen: 100%^#	Mutant WNV antigen: 88.6%* versus 70.9% for WT^§; Mutant SLEV antigen: 88.7%^#versus 69.1% for WT^§
WNV E protein subunit (r-EIII)	Beasley et al., 2004 [137]	WNV ELISA	Polyclonal mouse immune ascitic fluid- anti-WNV, -JEV, -SLEV, -MVEV, -DENV, -YFV	Strong reactivity of anti-WNV ascitic fluid with r-EIII at 1 : 64 dilution	Negligible reactivity of anti-JEV, -SLEV, -MVEV, -DENV and -YFV ascitic fluid with r-EDIII at 1 : 64 dilution.
		IgG ELISA	Human: PRNT/HI confirmed WNV pos (𝑛=11); WNV neg (𝑛=4, plus 1 SLEV pos)	100%	100%
		IgG ELISA	Horse: 57 PRNT/HI confirmed	89%^¶(𝑛=35)	87.5%^¶ (𝑛=16)
WNV E protein peptide DIII (Ep15)	Herrmann et al., 2007 [138]	IgG ELISA	Human. 66 sera including 7 WNV pos, 3 WN neg, 2 DENV pos, 54 unknown.	67%^‡	100%^‡
WNV E protein peptide DI (WN19)	Hobson-Peters et al., 2008, 2011 [60, 61]	Western Blot	Horse. VNT confirmed	69% (𝑛=11 WNV pos)[60]^†	100% ^† (𝑛=4 WNV/MVEV neg)
				80% WNV PRNT confirmed field samples (𝑛=5) [61]	Cannot differentiate MVEV-positive sera. 100% MVEV positive sera (𝑛=4) bound WN19.
JEV and DENV prM-native viral antigen	Cardosa et al., 2002 [89]	Western Blot	Human. 16 JEV pos, 22 DENV pos.	DENV assay: 95%; JEV assay: 100%	DENV assay: 100%; JEV assay: 73%
			Pig. 31 JEV pos	JEV assay: 93.5%	DENV assay: 100%
WNV prM-native viral antigen	Setoh et al., 2011 [62]	Western Blot	Horse. VNT confirmed. 16 WNV pos, 6 WNV negative (2 of these Kokobera positive)	87.5%	100%
JEV prM/M peptide	Hua et al., 2010 [139]	ELISA	Rabbit	Peptide bound by anti-JEV serum	Peptide not bound by anti-WNV and -DENV sera.

*Ability to distinguish WNV infections from other arbovirus infections.
^§WT = Wild Type.
^#Ability to distinguish SLEV infections from other arbovirus infections.
^¶After removal of 6 strong IgM positives and classifying equivocal results as false negative (for sensitivity) or false positive (for specificity).
^‡Upon comparison with commercial IgG kit.
^†Percentages based on those serum samples that did not cross-react with the scFv carrier protein.