Résumé
Western blot, capture-PCR, blocking ELISA and synthetic polypeptides were used to systematically study the recognition epitopes on HEV ORF2 of 23 anti-HEV monoclonal antibodies(McAbs) which were previously generated in our laboratory directed against HEV ORF2. Results showed that seven McAbs recognized linear epitopes that located at aa408-458 of HEV ORF2 and 16 conformation-dependent McAbs, most of which recognized the surface epitopes of native HEV, located at aa459-606 of HEV ORF2. The systematical study of the recognition epitopes of anti-HEV McAbs on HEV ORF2 provides important information for the investigation of virus receptor and HEV infection mechanism, as well as its vaccine and diagnostics development.
Sujets)
Animaux , Souris , Anticorps monoclonaux , Allergie et immunologie , Test ELISA , Épitopes , Anticorps de l'hépatite , Allergie et immunologie , Virus de l'hépatite E , Allergie et immunologie , Souris de lignée BALB C , Protéines virales , Allergie et immunologieRésumé
HEV is classified into H (human) group and Z (zoonosis) group according to its compatible host. H group contains genotype 1 and genotype 2 HEV isolates which infect human only; Z group contains genotype 3 and genotype 4 HEV isolates which infect both human and animals. After analysis of amino acid sequences between ORF2 aa368 and aa606, four group-conserved sites that were all located in the neutralization region of ORF2 were identified. They are aa483, aa492, aa497 and aa599. Mutation analysis and capture PCR were then performed on these sites with a group of monoclonal antibodies. Results showed that the difference of the aa497 between H and Z groups was responsible for the maintenance of their group-specific immunodominant epitopes, probably through confirmation-dependent epitope changes. Thus, aa497 and its related change on the surface structure of HEV may play important roles in host selection by H and Z groups of HEV.
Sujets)
Humains , Anticorps monoclonaux , Allergie et immunologie , Séquence nucléotidique , Génotype , Virus de l'hépatite E , Classification , Génétique , Allergie et immunologie , Épitopes immunodominants , Données de séquences moléculaires , Mutation , Tests de neutralisation , Cadres ouverts de lectureRésumé
<p><b>OBJECTIVE</b>To evaluate two commercial anti-hepatitis E virus (HEV) IgM kits used for differential diagnosis of acute enteric viral hepatitis.</p><p><b>METHODS</b>The kit for IgM capture assay, was produced with a recombinant HEV structural protein protecting primates against experimental infection by different HEV genotypes, while the other kit for indirect ELISA was produced with recombinant structural proteins from different HEV genotypes. The serum specimens were taken from 241 cases with a confirmed or presumptive diagnosis of hepatitis A and 74 cases with a confirmed or presumptive diagnosis of hepatitis E.</p><p><b>RESULTS</b>The sensitivity and specificity of the IgM capture assay kit were 97% and 100%, respectively, and the corresponding values for the other kit were 70% and 78%, respectively.</p><p><b>CONCLUSION</b>The IgM capture assay kit has higher sensitivity and specificity in diagnosing acute enteric viral hepatitis E.</p>