A specific and sensitive antigen capture assay for NS1 protein quantitation in Japanese encephalitis virus infection

Y. Z. Li, D. Counor, P. Lu, G. D. Liang, T. Q.H. Vu, T. N. Phan, T. K.L. Huynh, G. Sun, M. Grandadam, S. Butrapet, J. P. Lavergne, M. Flamand, Y. X. Yu, T. Solomon, P. Buchy, V. Deubel

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Japanese encephalitis virus (JEV) is a human pathogenic, mosquito-borne flavivirus that is endemic/epidemic in Asia. JEV is rarely detected or isolated from blood or cerebrospinal fluid (CSF), and detection of IgM is generally diagnostic of the infection. The flavivirus nonstructural glycoprotein NS1 is released transiently during flavivirus replication. The aim of this study was to set up a quantitative JEV NS1 antigen capture assay. A soluble hexameric form of JEV NS1 protein was produced in a stable Drosophila S2 cell clone and purified from supernatant fluids. Two IgG1 monoclonal antibodies (MAbs) with high affinity against two different epitopes of JEV NS1 antigen were used to develop an antigen-capture assay with a limit of detection of 0.2ngml -1 NS1. Up to 1μgml -1 JEV NS1 protein was released in supernatants of mammalian cells infected with JEV but <10ngml -1 was released in sera of virus-infected mice before the onset of encephalitis and death. Moreover, NS1 protein was detected at low levels (<10ngml -1) in 23.8% of sera and in 10.5% of CSF of patients diagnosed as IgM-positive for JEV. This quantitative test of NS1 protein is proposed for highly specific diagnosis of acute infection with JEV genotypes I to IV.

Original languageEnglish (US)
Pages (from-to)8-16
Number of pages9
JournalJournal of Virological Methods
Volume179
Issue number1
DOIs
StatePublished - Jan 2012
Externally publishedYes

Keywords

  • Antigen-capture
  • Flavivirus
  • Genotype
  • Japanese encephalitis
  • Monoclonal antibody
  • NS1 protein

ASJC Scopus subject areas

  • Virology

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