title: Comprehensive mapping of a novel NS1 epitope conserved in flaviviruses within the Japanese encephalitis virus serocomplex.
abstract: Nonstructural protein-1 (NS1) of the Japanese encephalitis virus (JEV) is an immunogenic protein that is a potential candidate for the development of vaccines and diagnostic reagents. NS1 is known to be more specific than the E protein in serological testing of flavivirus infections. However, NS1 exhibits cross-reactivity among flaviviruses even within the same genus and more so within a serocomplex. However, the cross-reactive epitopes on JEV NS1 are poorly characterized. The present study describes the full mapping of a linear B-cell epitope that is common and specific to the JEV serocomplex of Flaviviridae. We generated an NS1-specific monoclonal antibody that cross-reacts with the West Nile virus (WNV) NS1 protein by immunizing mice with recombinant JEV NS1. For epitope mapping, 51 partially overlapping peptides spanning the entire NS1 protein were expressed with a glutathione S-transferase (GST) tag and screened using monoclonal antibodies. Two linear epitope-containing peptides were identified using enzyme-linked immunosorbent assay (ELISA). By sequentially removing amino acid residues from the carboxy and amino terminal of peptides, we successfully identified the smallest unit of the linear epitope required to react with the monoclonal antibody. The linear epitope was located in amino acids residues ²²⁷ETHTLW²³². Furthermore, results of the sequence alignment revealed that the epitope was highly conserved among JEV strains. Notably, the epitope is highly conserved among viruses of the JEV serocomplex. Furthermore, the homologous regions on NS1 proteins from dengue viruses showed no cross-reactivity with the monoclonal antibodies. The epitope was recognized by antisera against the WNV but not against the dengue virus. This novel JEV serocomplex-specific linear B-cell epitope of NS1 would be helpful in the development of new vaccines and diagnostic assays.
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China. Electronic address: huaronghong@163.com.
authors.forename: Rong-Hong
authors.initials: RH
authors.lastname: Hua
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Li-Ke
authors.initials: LK
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Huo
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Ye-Nan
authors.initials: YN
authors.lastname: Li
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
authors.forename: Xiao-Lei
authors.initials: XL
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Cheng-Feng
authors.initials: CF
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, PR China. Electronic address: buzhigao@caas.cn.
authors.forename: Zhi-Gao
authors.initials: ZG
authors.lastname: Bu
mesh_terms: D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000276:immunology; D017124:Conserved Sequence; D003429:Cross Reactions; D004664:Encephalitis Virus, Japanese / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D004672:Encephalitis, Japanese / Q000821:virology*; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D005416:Flavivirus / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D018985:Epitopes, B-Lymphocyte; C100315:NS1 protein, Flavivirus; D017361:Viral Nonstructural Proteins
keywords: Japanese encephalitis virus serocomplex; Linear B-cell epitope; NS1 protein