title: A specific and sensitive antigen capture assay for NS1 protein quantitation in Japanese encephalitis virus infection.
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.
authors.affiliation: Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institute for Biological Sciences, 411 Hefei Road, Shanghai 200025, China.
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Li
authors.forename: D
authors.initials: D
authors.lastname: Counor
authors.forename: P
authors.initials: P
authors.lastname: Lu
authors.forename: G D
authors.initials: GD
authors.lastname: Liang
authors.forename: T Q H
authors.initials: TQ
authors.lastname: Vu
authors.forename: T N
authors.initials: TN
authors.lastname: Phan
authors.forename: T K L
authors.initials: TK
authors.lastname: Huynh
authors.forename: G
authors.initials: G
authors.lastname: Sun
authors.forename: M
authors.initials: M
authors.lastname: Grandadam
authors.forename: S
authors.initials: S
authors.lastname: Butrapet
authors.forename: J P
authors.initials: JP
authors.lastname: Lavergne
authors.forename: M
authors.initials: M
authors.lastname: Flamand
authors.forename: Y X
authors.initials: YX
authors.lastname: Yu
authors.forename: T
authors.initials: T
authors.lastname: Solomon
authors.forename: P
authors.initials: P
authors.lastname: Buchy
authors.forename: V
authors.initials: V
authors.lastname: Deubel
mesh_terms: D054366:Agouti Signaling Protein; D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral / Q000032:analysis*; D001774:Blood Chemical Analysis; D002135:Calcium-Binding Proteins; D002460:Cell Line; D002555:Cerebrospinal Fluid / Q000737:chemistry; D019411:Clinical Laboratory Techniques / Q000379:methods*; D017869:Cyclic GMP-Dependent Protein Kinases; D004330:Drosophila; D029721:Drosophila Proteins; D004672:Encephalitis, Japanese / Q000175:diagnosis*; D005260:Female; D018177:Flavivirus Infections; D019204:GTP-Binding Proteins; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G; D008565:Membrane Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D017361:Viral Nonstructural Proteins / Q000097:blood* / Q000134:cerebrospinal fluid*; D014773:Virology / Q000379:methods*
chemical_list: C090181:Acam protein, Drosophila; D054366:Agouti Signaling Protein; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D002135:Calcium-Binding Proteins; D029721:Drosophila Proteins; D007074:Immunoglobulin G; D008565:Membrane Proteins; C100315:NS1 protein, Flavivirus; D017361:Viral Nonstructural Proteins; C409458:a protein, Drosophila; C515183:a protein, mouse; C098676:in protein, Drosophila; D017869:Cyclic GMP-Dependent Protein Kinases; C528566:for protein, Drosophila; D019204:GTP-Binding Proteins; C548058:nucleostemin 1, Drosophila