scholarly journals Identification of Immunodominant and Conformational Epitopes in the Capsid Protein of Hepatitis E Virus by Using Monoclonal Antibodies

2000 ◽  
Vol 74 (17) ◽  
pp. 8011-8017 ◽  
Author(s):  
Michaela A. Riddell ◽  
Fan Li ◽  
David A. Anderson
Keyword(s):  
Monoclonal Antibodies ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Antigenic Structure ◽  
Conformational Epitopes ◽  
Baculovirus System ◽  
Cross Inhibition ◽  
Murine Monoclonal Antibodies ◽  
Immunodominant Epitopes

ABSTRACT Antibody to the capsid (PORF2) protein of hepatitis E virus (HEV) is sufficient to confer immunity, but knowledge of B-cell epitopes in the intact capsid is limited. A panel of murine monoclonal antibodies (MAbs) was generated following immunization with recombinant ORF2.1 protein, representing the C-terminal 267 amino acids (aa) of the 660-aa capsid protein. Two MAbs reacted exclusively with the conformational ORF2.1 epitope (F. Li, J. Torresi, S. A. Locarnini, H. Zhuang, W. Zhu, X. Guo, and D. A. Anderson, J. Med. Virol. 52:289–300, 1997), while the remaining five demonstrated reactivity with epitopes in the regions aa 394 to 414, 414 to 434, and 434 to 457. The antigenic structures of both the ORF2.1 protein expressed in Escherichia coli and the virus-like particles (VLPs) expressed using the baculovirus system were examined by competitive enzyme-linked immunosorbent assays (ELISAs) using five of these MAbs and HEV patient sera. Despite the wide separation of epitopes within the primary sequence, all the MAbs demonstrated some degree of cross-inhibition with each other in ORF2.1 and/or VLP ELISAs, suggesting a complex antigenic structure. MAbs specific for the conformational ORF2.1 epitope and a linear epitope within aa 434 to 457 blocked convalescent patient antibody reactivity against VLPs by approximately 60 and 35%, respectively, while MAbs against epitopes within aa 394 to 414 and 414 to 434 were unable to block patient serum reactivity. These results suggest that sequences spanning aa 394 to 457 of the capsid protein participate in the formation of strongly immunodominant epitopes on the surface of HEV particles which may be important in immunity to HEV infection.

Characterization of monoclonal antibodies to hepatitis E virus (HEV) capsid protein and identification of binding activity

2007 ◽  
Vol 14 (5) ◽  
pp. 555-563 ◽  
Author(s):  
Junkun He ◽  
Robert A. Kuschner ◽  
Vincent Dewar ◽  
Pierre Voet ◽  
Ludmila V. Asher ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Binding Activity

scholarly journals Characterization of Two Novel Linear B-Cell Epitopes in the Capsid Protein of Avian Hepatitis E Virus (HEV) That Are Common to Avian, Swine, and Human HEVs

2015 ◽  
Vol 89 (10) ◽  
pp. 5491-5501 ◽  
Author(s):  
Xinjie Wang ◽  
Qin Zhao ◽  
Lu Dang ◽  
Yani Sun ◽  
Jiming Gao ◽  
...  
Keyword(s):  
Amino Acid ◽  
B Cell ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Antigenic Structure ◽  
B Cell Epitopes ◽  
Avian Hepatitis E Virus ◽  
Avian Hev ◽  
Linear B

ABSTRACTAntisera raised against the avian hepatitis E virus (HEV) capsid protein are cross-reactive with human and swine HEV capsid proteins. In this study, two monoclonal antibodies (MAbs) against the avian HEV capsid protein, namely, 3E8 and 1B5, were shown to cross-react with the swine HEV capsid protein. The motifs involved in binding both MAbs were identified and characterized using phage display biopanning, peptide synthesis, and truncated or mutated protein expression, along with indirect enzyme-linked immunosorbent assay (ELISA) and Western blotting. The results showed that the I/VPHD motif is a necessary core sequence and that P and H are two key amino acids for recognition by MAb 3E8. The VKLYM/TS motif is the minimal amino acid sequence necessary for recognition by MAb 1B5. Cross-reactivity between the two epitopes and antibodies against avian, swine, and human HEVs in sera showed that both epitopes are common to avian, swine, and human HEVs. In addition, amino acid sequence alignment of the capsid proteins revealed that the key motifs of both novel epitopes are the same in HEVs from different animal species, predicting that they may be common to HEV isolates from boars, rabbits, rats, ferrets, mongooses, deer, and camels as well. Protein modeling analysis showed that both epitopes are at least partially exposed on the surface of the HEV capsid protein. Protective capacity analysis demonstrated that the two epitopes are nonprotective against avian HEV infection in chickens. Collectively, these studies characterize two novel linear B-cell epitopes common to avian, swine, and human HEVs, which furthers the understanding of HEV capsid protein antigenic structure.IMPORTANCEMore and more evidence indicates that the host range diversity of hepatitis E virus (HEV) is a global public health concern. A better understanding of the antigenic structure of the HEV capsid protein may improve disease diagnosis and prevention. In this study, binding site mapping and localization as well as the antigenic biology of two novel linear B-cell epitopes common to several different species of HEV were characterized. These findings partially reveal the antigenic structure of the HEV capsid protein and provide potential applications for the development of diagnostics and interventions for HEV infection.

Production of monoclonal antibodies against hepatitis E virus capsid protein and evaluation of their neutralizing activity in a cell culture system

2008 ◽  
Vol 153 (4) ◽  
pp. 657-666 ◽  
Author(s):  
Masaharu Takahashi ◽  
Yu Hoshino ◽  
Toshinori Tanaka ◽  
Hideyuki Takahashi ◽  
Tsutomu Nishizawa ◽  
...  
Keyword(s):  
Cell Culture ◽  
Monoclonal Antibodies ◽  
Capsid Protein ◽  
Culture System ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Cell Culture System ◽  
Virus Capsid ◽  
A Cell ◽  
Virus Capsid Protein

Analysis of epitopes in the capsid protein of avian hepatitis E virus by using monoclonal antibodies

2011 ◽  
Vol 171 (2) ◽  
pp. 374-380 ◽  
Author(s):  
Shiwei Dong ◽  
Qin Zhao ◽  
Mingzhe Lu ◽  
Peiming Sun ◽  
Hongkai Qiu ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Avian Hepatitis E Virus

Analysis of hepatitis E virus neutralization sites using monoclonal antibodies directed against a virus capsid protein

Vaccine ◽  
2005 ◽  
Vol 23 (22) ◽  
pp. 2881-2892 ◽  
Author(s):  
Jun Zhang ◽  
Ying Gu ◽  
Sheng X. Ge ◽  
Shao W. Li ◽  
Zhi Q. He ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Virus Neutralization ◽  
Virus Capsid ◽  
Virus Capsid Protein

scholarly journals Characterization of Three Novel Linear Neutralizing B-Cell Epitopes in the Capsid Protein of Swine Hepatitis E Virus

2018 ◽  
Vol 92 (13) ◽  
pp. e00251-18 ◽  
Author(s):  
Yiyang Chen ◽  
Baoyuan Liu ◽  
Yani Sun ◽  
Huixia Li ◽  
Taofeng Du ◽  
...  
Keyword(s):  
B Cell ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Disease Diagnosis ◽  
Antigenic Structure ◽  
Human Populations ◽  
Genotype 3 ◽  
Genotype 4 ◽  
B Cell Epitopes

ABSTRACTHepatitis E virus (HEV) causes liver disease in humans and is thought to be a zoonotic infection, with domestic animals, including swine and rabbits, being a reservoir. One of the proteins encoded by the virus is the capsid protein. This is likely the major immune-dominant protein and a target for vaccination. Four monoclonal antibodies (MAbs), three novel, 1E4, 2C7, and 2G9, and one previously characterized, 1B5, were evaluated for binding to the capsid protein from genotype 4 swine HEV. The results indicated that625DFCP628,458PSRPF462, and407EPTV410peptides on the capsid protein comprised minimal amino acid sequence motifs recognized by 1E4, 2C7, and 2G9, respectively. The data suggested that 2C7 and 2G9 epitopes were partially exposed on the surface of the capsid protein. Truncated genotype 4 swine HEV capsid protein (sp239, amino acids 368 to 606) can exist in multimeric forms. Preincubation of swine HEV with 2C7, 2G9, or 1B5 before addition to HepG2 cells partially blocked sp239 cell binding and inhibited swine HEV infection. The study indicated that 2C7, 2G9, and 1B5 partially blocked swine HEV infection of rabbits better than 1E4 or normal mouse IgG. The cross-reactivity of antibodies suggested that capsid epitopes recognized by 2C7 and 2G9 are common to HEV strains infecting most host species. Collectively, MAbs 2C7, 2G9, and 1B5 were shown to recognize three novel linear neutralizing B-cell epitopes of genotype 4 HEV capsid protein. These results enhance understanding of HEV capsid protein structure to guide vaccine and antiviral design.IMPORTANCEGenotype 3 and 4 HEVs are zoonotic viruses. Here, genotype 4 HEV was studied due to its prevalence in human populations and pig herds in China. To improve HEV disease diagnosis and prevention, a better understanding of the antigenic structure and neutralizing epitopes of HEV capsid protein are needed. In this study, the locations of three novel linear B-cell recognition epitopes within genotype 4 swine HEV capsid protein were characterized. Moreover, the neutralizing abilities of three MAbs specific for this protein, 2C7, 2G9, and 1B5, were studiedin vitroandin vivo. Collectively, these findings reveal structural details of genotype 4 HEV capsid protein and should facilitate development of applications for the design of vaccines and antiviral drugs for broader prevention, detection, and treatment of HEV infection of diverse human and animal hosts.

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