title: Generation and characterization of a new mammalian cell line continuously expressing virus-like particles of Japanese encephalitis virus for a subunit vaccine candidate.
abstract: BACKGROUND
  Japanese encephalitis virus (JEV) is the most important cause of epidemic encephalitis in most Asian regions. There is no specific treatment available for Japanese encephalitis, and vaccination is the only effective way to prevent JEV infection in humans and domestic animals. The purpose of this study is to establish a new mammalian cell line stably and efficiently expressing virus-like particle of JEV for potential use of JEV subunit vaccine.
  
  
  RESULTS
  We generated a new cell clone (BJ-ME cells) that stably produces a secreted form of Japanese encephalitis virus (JEV) virus-like particle (VLP). The BJ-ME cells were engineered by transfecting BHK-21 cells with a code-optimized cDNA encoding JEV prM and E protein expression plasmid. Cell line BJ-ME can stably produces a secreted form of Japanese encephalitis virus virus-like particle (JEV-VLP) which contains the JEV envelope glycoprotein (E) and membrane protein (M). The amount of JEV-VLP antigen released into the culture fluid of BJ-ME cells was as high as 15-20 μg/ml. JEV-VLP production was stable after multiple cell passages and 100% cell expression was maintained without detectable cell fusion or apoptosis. Cell culture fluid containing the JEV-VLP antigen could be harvested five to seven times continuously at intervals of 4-6 days while maintaining the culture. Mice immunized with the JEV-VLP antigen with or without adjuvant developed high titers of neutralizing antibodies and 100% protection against lethal JEV challenge.
  
  
  CONCLUSIONS
  These results suggest that the recombinant JEV-VLP antigen produced by the BJ-ME cell line is an effective, safe and affordable subunit Japanese encephalitis vaccine candidate, especially for domestic animals such as pig and horse.
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Maduan Street, Harbin 150001, PR China. huaronghong@163.com.
authors.forename: Rong-Hong
authors.initials: RH
authors.lastname: Hua
authors.forename: Ye-Nan
authors.initials: YN
authors.lastname: Li
authors.forename: Zhen-Shi
authors.initials: ZS
authors.lastname: Chen
authors.forename: Li-Ke
authors.initials: LK
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Huo
authors.forename: Xiao-Lei
authors.initials: XL
authors.lastname: Wang
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Guo
authors.forename: Nan
authors.initials: N
authors.lastname: Shen
authors.forename: Jing-Fei
authors.initials: JF
authors.lastname: Wang
authors.forename: Zhi-Gao
authors.initials: ZG
authors.lastname: Bu
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D004664:Encephalitis Virus, Japanese / Q000378:metabolism*; D005260:Female; D022321:Japanese Encephalitis Vaccines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D058425:Vaccines, Virus-Like Particle / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D057134:Antibodies, Neutralizing; D022321:Japanese Encephalitis Vaccines; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D058425:Vaccines, Virus-Like Particle; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; C080628:glycoprotein E, Japanese encephalitis virus