Immunoassay targeting nonstructural protein 5 to differentiate West Nile virus infection from dengue and St. Louis encephalitis virus infections and from flavivirus vaccination.
West Nile virus (WNV) is an emerging flavivirus that has caused frequent epidemics since 1996. Besides natural transmission by mosquitoes, WNV can also be transmitted through blood transfusion and organ transplantation, thus heightening the urgency of development of a specific and rapid serologic assay of WNV infection. The current immunoassays lack specificity because they are based on detection of antibodies against WNV structural proteins and immune responses to structural proteins among flaviviruses cross-react to each other. Here, we describe microsphere immunoassays that detect antibodies to nonstructural proteins 3 and 5 (NS3 and NS5). In contrast to immunoassays based on viral envelope and NS3 proteins, the NS5-based assay (i) reliably discriminates between WNV infections and dengue virus or St. Louis encephalitis virus infections, (ii) differentiates between flavivirus vaccination and natural WNV infection, and (iii) indicates recent infections. These unique features of the NS5-based immunoassay will be very useful for both clinical and veterinary diagnosis of WNV infection.
Wong
Susan J
SJ
Wadsworth Center, New York State Department of Health, and Department of Biomedical Sciences, University at Albany, State University of New York, Albany, New York 12201, USA. ship@wadsworth.org
Boyle
Rebekah H
RH
Demarest
Valerie L
VL
Woodmansee
Anh N
AN
Kramer
Laura D
LD
Li
Hongmin
H
Drebot
Michael
M
Koski
Raymond A
RA
Fikrig
Erol
E
Martin
Denise A
DA
Shi
Pei-Yong
PY
D003715:Dengue / Q000175:diagnosis*; D004674:Encephalitis, St. Louis / Q000175:diagnosis*; D005416:Flavivirus / Q000276:immunology*; D006801:Humans; D007118:Immunoassay; D043583:Nucleoside-Triphosphatase / Q000378:metabolism; D020365:RNA Helicases; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D012697:Serine Endopeptidases; D014611:Vaccination; D017361:Viral Nonstructural Proteins / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D043583:Nucleoside-Triphosphatase; D020365:RNA Helicases; D012324:RNA-Dependent RNA Polymerase; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; D014765:Viral Vaccines; C060028:NS3 protein, flavivirus; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C096041:NS5 protein, flavivirus