title: Use of immuno-dominant epitope derived from genotype 4 as a diagnostic reagent for detecting the antibodies against Hepatitis E Virus.
abstract: BACKGROUND
  Despite the genotype 4 has become the dominant cause of hepatitis E disease in China, none antigen derived from genotype 4 of hepatitis E virus (HEV) was used in current commercial anti-HEV immunoassay, and the serological reactivity of antigen derive from genotype 4 is not well-charactered.
  
  
  METHODS
  We expressed and purified the 4 main immuno-dominant epitopes derived from genotype 1 and 4 including ORF2 (410-621aa) of genotype 4, ORF3 (47-114aa) of genotype 4, ORF2 (396-606aa) of genotype 1 and ORF3 (56-123aa) of genotype 4.
  
  
  RESULTS
  The ORF2 of genotype 4 displayed good diagnostics performance according to ROC analysis using in-house panel, and the immunoassays based the ORF2 of genotype 4 was then developed to detect the anti-HEV IgG antibodies and evaluated further in 530 anti-HEV IgG positive specimens and 380 negative specimens. The sensitivity and the specificity is 98.1% (520/530) and 94.7% (360/380) for immunoassay based on ORF2 of genotype 4, 96.6% (512/530) and 92.6% (352/380) for commercial immunoassay based on genotype 1. It is noted that all of the positive samples will be detected by combing two assays together. The anti-HEV immunoassays based on genotype 4 are in accordance with Chinese anti-HEV national standard,and show an good agreement of 95.8% with commercial assay (kappa=0.913, P=0.014).
  
  
  CONCLUSIONS
  The immunoassay based on ORF2G4 displays good performance, and combining assay based on genotype 1 together with genotype 4 will benefit the HEV diagnosis in large scale samples.
authors.affiliation: Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Taiping Road, Beijing 100850, P.R. China.
authors.forename: Bing-shui
authors.initials: BS
authors.lastname: Xiu
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Feng
authors.forename: Jing
authors.initials: J
authors.lastname: He
authors.forename: Kun
authors.initials: K
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Zhen-hua
authors.initials: ZH
authors.lastname: Dai
authors.forename: Xi-qin
authors.initials: XQ
authors.lastname: Yang
authors.forename: Guo-hua
authors.initials: GH
authors.lastname: Wang
authors.forename: You-chun
authors.initials: YC
authors.lastname: Wang
authors.forename: He-qiu
authors.initials: HQ
authors.lastname: Zhang
authors.forename: Xiao-guo
authors.initials: XG
authors.lastname: Song
authors.forename: Cui-xia
authors.initials: CX
authors.lastname: Zhu
mesh_terms: D000956:Antigens, Viral / Q000235:genetics; D002681:China; D003955:Diagnostic Tests, Routine / Q000379:methods*; D006508:Hepatitis Antibodies / Q000097:blood*; D016751:Hepatitis E / Q000175:diagnosis*; D016752:Hepatitis E virus / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D016056:Immunodominant Epitopes / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics; D012680:Sensitivity and Specificity; D014773:Virology / Q000379:methods*
chemical_list: D000956:Antigens, Viral; D006508:Hepatitis Antibodies; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins