Detection of Human Anti-Flavivirus Antibodies with a West Nile Virus Recombinant Antigen Microsphere Immunoassay

Susan J. Wong, Valerie L. Demarest, Rebekah H. Boyle, Tian Wang, Michel Ledizet, Kalipada Kar, Laura D. Kramer, Erol Fikrig, Raymond A. Koski

Research output: Contribution to journalArticlepeer-review

109 Scopus citations


We report a new, suspended-microsphere diagnostic test to detect antibodies to West Nile (WN) virus in human serum and cerebrospinal fluid (CSF). The microsphere immunofluorescence assay can be performed in less than 3 h on specimens of ≤30 μl. A recombinant WN virus envelope (E) protein antigen is covalently coupled to fluorescent polystyrene microspheres. After incubation with diluted serum or CSF, antibodies bound to the E protein antigen are detected with fluorescently labeled anti-human immunoglobulin antibody and flow analysis in a dual-laser Luminex 100 instrument. Retrospective testing of 833 sera from New York patients with suspected viral encephalitis demonstrated concordance with results obtained with the traditional enzyme-linked immunosorbent assay for immunoglobulin G (IgG) antibodies to WN virus (kappa = 0.85). One hundred eighty-eight (22.4%) of the samples, which were collected from June to November 2002, tested positive for antibodies to WN virus in the microsphere assay. Specimens depleted of IgG with anti-IgG antibody were reassayed to measure anti-E protein IgM antibodies and to provide an indication of current or recent WN virus infection. The assay also detects antibodies to E proteins from related flaviviruses, including St. Louis encephalitis, Japanese encephalitis, and dengue viruses. The new microsphere immunoassay provides a sensitive and rapid alternative to traditional enzyme-linked immunosorbent assays that detect antibodies to flavivirus E proteins. This assay can aid physicians and public health workers in the management of outbreaks of WN virus and related flaviviruses.

Original languageEnglish (US)
Pages (from-to)65-72
Number of pages8
JournalJournal of Clinical Microbiology
Issue number1
StatePublished - Jan 2004
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology (medical)


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