title: A Proline-Rich Domain in the Genotype 4 Hepatitis E Virus ORF3 C-Terminus Is Crucial for Downstream V105DLP108 Immunoactivity.
abstract: The hepatitis E virus (HEV) is responsible for serious viral hepatitis worldwide. Animals are considered a reservoir of HEV, particularly pigs. While HEV infection in pigs and dogs is always asymptomatic, the virus causes high death rates in patients with pre-existing chronic liver disease and pregnant women in developing countries. HEV open reading frame 2 (ORF2) has been used as a diagnostic target to detect specific antibodies against HEV in serum samples. Recent research has additionally supported the potential utility of the ORF3 protein as a target in serum anti-HEV detection. However, the epitope distribution of ORF3 protein remains ambiguous. In the current study, we showed that continuous amino acid motif, VDLP, at the C-terminus of genotype 4 HEV ORF3 is a core sequence of the ORF3 protein epitope. Moreover, cooperative interaction with upstream elements is essential for its immunoactivity. Three proline residues (P99, P102 and P103) in the upstream proline-rich domain exerted significant effects on the immunocompetence of VDLP. ELISA results revealed that SAPPLPPVVDLP and SAPPLPPVVDLPQLGL peptides containing the identified VDLP epitope display weaker reactions with anti-HEV serum than the commercial ELISA kit. Our collective findings provide valuable information on the epitope distribution characteristics of HEV ORF3 and improve our understanding of the influence of the proline-rich domain on the immunoactivity of downstream amino acids in the C-terminal region.
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, China; Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, China; MOA Key Laboratory of Animal Vaccine Development, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Fangxiao
authors.initials: F
authors.lastname: Ji
authors.affiliation: MOA Key Laboratory of Animal Vaccine Development, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Huanbin
authors.initials: H
authors.lastname: Liang
authors.affiliation: MOA Key Laboratory of Animal Vaccine Development, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Honglang
authors.initials: H
authors.lastname: Gu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, China; Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Zhangyong
authors.initials: Z
authors.lastname: Ning
authors.affiliation: Key Laboratory of Comprehensive Prevention and Control for Severe Clinical Animal Diseases of Guangdong Province, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Rongchang
authors.initials: R
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province, 510642, China; MOA Key Laboratory of Animal Vaccine Development, Guangzhou, Guangdong Province, 510642, China.
authors.forename: Guihong
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D005260:Female; D005838:Genotype; D016752:Hepatitis E virus / Q000235:genetics* / Q000276:immunology*; D007106:Immune Sera / Q000276:immunology; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics*; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry; D010957:Plasmids; D011392:Proline / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000302:isolation & purification; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA; D034421:Sus scrofa; D014764:Viral Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007106:Immune Sera; D050505:Mutant Proteins; D019151:Peptide Library; D010455:Peptides; D011994:Recombinant Proteins; D014764:Viral Proteins; D011392:Proline