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Zhang J, Zheng Z, Xia N. Prophylactic Hepatitis E Vaccine. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:227-245. [PMID: 37223870 DOI: 10.1007/978-981-99-1304-6_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The hepatitis E has been increasingly recognized as an underestimated global disease burden in recent years. Subpopulations with more serious infection associated damage or death include pregnant women, patients with basic liver diseases, and elderly persons. Vaccine would be the most effective means for prevention of HEV infection. The lack of an efficient cell culture system for HEV makes the development of classic inactive or attenuated vaccine infeasible. Hence, the recombinant vaccine approaches are explored deeply. The neutralizing sites are located almost exclusively in the capsid protein, pORF2, of the virion. Based on pORF2, many vaccine candidates showed potential of protecting primate animals, two of them were tested in human and evidenced to be well-tolerated in adults and highly efficacious in preventing hepatitis E. The world's first hepatitis E vaccine, Hecolin® (HEV 239 vaccine), was licensed in China and launched in 2012.
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Affiliation(s)
- Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
| | - Zizheng Zheng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China
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2
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Fu RM, Decker CC, Dao Thi VL. Cell Culture Models for Hepatitis E Virus. Viruses 2019; 11:E608. [PMID: 31277308 PMCID: PMC6669563 DOI: 10.3390/v11070608] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/24/2019] [Accepted: 06/29/2019] [Indexed: 12/14/2022] Open
Abstract
Despite a growing awareness, hepatitis E virus (HEV) remains understudied and investigations have been historically hampered by the absence of efficient cell culture systems. As a result, the pathogenesis of HEV infection and basic steps of the HEV life cycle are poorly understood. Major efforts have recently been made through the development of HEV infectious clones and cellular systems that significantly advanced HEV research. Here, we summarize these systems, discussing their advantages and disadvantages for HEV studies. We further capitalize on the need for HEV-permissive polarized cell models to better recapitulate the entire HEV life cycle and transmission.
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Affiliation(s)
- Rebecca Menhua Fu
- Schaller Research Group at Department of Infectious Diseases and Virology, Heidelberg University Hospital, Cluster of Excellence CellNetworks, 69120 Heidelberg, Germany
- Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Charlotte Caroline Decker
- Schaller Research Group at Department of Infectious Diseases and Virology, Heidelberg University Hospital, Cluster of Excellence CellNetworks, 69120 Heidelberg, Germany
- Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Viet Loan Dao Thi
- Schaller Research Group at Department of Infectious Diseases and Virology, Heidelberg University Hospital, Cluster of Excellence CellNetworks, 69120 Heidelberg, Germany.
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3
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Abstract
Soon after the 1991 molecular cloning of hepatitis E virus (HEV), recombinant viral capsid antigens were expressed and tested in nonhuman primates for protection against liver disease and infection. Two genotype 1 subunit vaccine candidates entered clinical development: a 56 kDA vaccine expressed in insect cells and HEV 239 vaccine expressed in Escherichia coli Both were highly protective against hepatitis E and acceptably safe. The HEV 239 vaccine was approved in China in 2011, but it is not yet prequalified by the World Health Organization, a necessary step for introduction into those low- and middle-income countries where the disease burden is highest. Nevertheless, the stage is set for the final act in the hepatitis E vaccine story-policymaking, advocacy, and pilot introduction of vaccine in at-risk populations, in which it is expected to be cost-effective.
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Affiliation(s)
- Bruce L Innis
- Center for Vaccine Innovation and Access, PATH, Washington, D.C. 20001
| | - Julia A Lynch
- International Vaccine Institute, SNU Research Park, Gwanak-gu, Seoul 08826, Korea
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4
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Zhang J, Zhao Q, Xia N. Prophylactic Hepatitis E Vaccine. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 948:223-246. [PMID: 27738988 DOI: 10.1007/978-94-024-0942-0_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hepatitis E has been increasingly recognized as an underestimated global disease burden in recent years. Subpopulations with more serious infection-associated damage or death include pregnant women, patients with basic liver diseases, and elderly persons. Vaccine would be the most effective means for prevention of HEV infection. The lack of an efficient cell culture system for HEV makes the development of classic inactive or attenuated vaccine infeasible. Hence, the recombinant vaccine approaches are explored deeply. The neutralizing sites are located almost exclusively in the capsid protein, pORF2, of the virion. Based on pORF2, many vaccine candidates showed potential of protecting primate animals; two of them were tested in human and evidenced to be well tolerated in adults and highly efficacious in preventing hepatitis E. The world's first hepatitis E vaccine, Hecolin® (HEV 239 vaccine), was licensed in China and launched in 2012.
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Affiliation(s)
- Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
| | - Qinjian Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China
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5
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Behloul N, Wen J, Dai X, Dong C, Meng J. Antigenic composition and immunoreactivity differences between HEV recombinant capsid proteins generated from different genotypes. INFECTION GENETICS AND EVOLUTION 2015; 34:211-20. [PMID: 26122075 DOI: 10.1016/j.meegid.2015.06.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 12/13/2022]
Abstract
Appreciable variability has been observed in hepatitis E virus (HEV) serological diagnostics. Four recombinant proteins (p166s) were generated from position 452 to 617 aa of ORF2 of different HEV genotypes and used in an indirect ELISA to detect anti-HEV IgMs and IgGs in serially diluted sera of patients infected with different HEV genotypes (genotype 1, n=15; genotype 3, n=12; genotype 4, n=17). To evaluate the differences at a conformational level, 3D-structure models of p166s were predicted, and different bioinformatics tools were used to analyze the antigenic composition. With both anti-HEV IgMs and IgGs antibodies, there was a considerable variability between the four antigens immunoreactivities. In silico results revealed the region 483-533 aa with the highest antigenic potential and contains six key aa at positions 488, 489, 512, 533, 483 and 530. This immunoreactivity variation could affect diagnosis results and seroprevalence estimations and the identification in silico of a region highly antigenic would guide the development of efficient serological assays and epitope-based vaccines.
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Affiliation(s)
- Nouredine Behloul
- Department of Microbiology and Immunology, Southeast University School of Medicine, Nanjing, China
| | - Jiyue Wen
- Department of Microbiology and Immunology, Southeast University School of Medicine, Nanjing, China
| | - Xing Dai
- Department of Microbiology and Immunology, Southeast University School of Medicine, Nanjing, China
| | - Chen Dong
- Department of Microbiology and Immunology, Southeast University School of Medicine, Nanjing, China
| | - Jihong Meng
- Department of Microbiology and Immunology, Southeast University School of Medicine, Nanjing, China.
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Krain LJ, Nelson KE, Labrique AB. Host immune status and response to hepatitis E virus infection. Clin Microbiol Rev 2014; 27:139-65. [PMID: 24396140 PMCID: PMC3910912 DOI: 10.1128/cmr.00062-13] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatitis E virus (HEV), identified over 30 years ago, remains a serious threat to life, health, and productivity in developing countries where access to clean water is limited. Recognition that HEV also circulates as a zoonotic and food-borne pathogen in developed countries is more recent. Even without treatment, most cases of HEV-related acute viral hepatitis (with or without jaundice) resolve within 1 to 2 months. However, HEV sometimes leads to acute liver failure, chronic infection, or extrahepatic symptoms. The mechanisms of pathogenesis appear to be substantially immune mediated. This review covers the epidemiology of HEV infection worldwide, the humoral and cellular immune responses to HEV, and the persistence and protection of antibodies produced in response to both natural infection and vaccines. We focus on the contributions of altered immune states (associated with pregnancy, human immunodeficiency virus [HIV], and immunosuppressive agents used in cancer and transplant medicine) to the elevated risks of chronic infection (in immunosuppressed/immunocompromised patients) and acute liver failure and mortality (among pregnant women). We conclude by discussing outstanding questions about the immune response to HEV and interactions with hormones and comorbid conditions. These questions take on heightened importance now that a vaccine is available.
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Affiliation(s)
- Lisa J. Krain
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Kenrad E. Nelson
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Alain B. Labrique
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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7
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de Carvalho LG, Marchevsky RS, dos Santos DRL, de Oliveira JM, de Paula VS, Lopes LM, Van der Poel WHM, González JE, Munné MS, Moran J, Cajaraville ACRA, Pelajo-Machado M, Cruz OG, Pinto MA. Infection by Brazilian and Dutch swine hepatitis E virus strains induces haematological changes in Macaca fascicularis. BMC Infect Dis 2013; 13:495. [PMID: 24148233 PMCID: PMC3870956 DOI: 10.1186/1471-2334-13-495] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 10/18/2013] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Hepatitis E virus (HEV) has been described as an emerging pathogen in Brazil and seems to be widely disseminated among swine herds. An autochthonous human case of acute hepatitis E was recently reported. To obtain a better understanding of the phenotypic profiles of both human and swine HEV strains, a experimental study was conducted using the animal model, Macaca fascicularis. METHODS Six cynomolgus monkeys (Macaca fascicularis) were inoculated intravenously with swine HEV genotype 3 that was isolated from naturally and experimentally infected pigs in Brazil and the Netherlands. Two other monkeys were inoculated with HEV genotype 3 that was recovered from Brazilian and Argentinean patients with locally acquired acute and fulminant hepatitis E. The haematological, biochemical, and virological parameters of all animals were monitored for 67 days. RESULTS Subclinical hepatitis was observed in all monkeys after inoculation with HEV genotype 3 that was recovered from the infected swine and human patients. HEV RNA was detected in the serum and/or faeces of 6 out of the 8 cynomolgus monkeys between 5 and 53 days after inoculation. The mild inflammation of liver tissues and elevations of discrete liver enzymes were observed. Seroconversions to anti-HEV IgM and/or IgG were detected in 7 animals. Reactivities to anti-HEV IgA were also detected in the salivary samples of 3 animals. Interestingly, all of the infected monkeys showed severe lymphopenia and a trend toward monocytosis, which coincided with elevations in alanine aminotransferase and antibody titres. CONCLUSIONS The ability of HEV to cross the species barrier was confirmed for both the swine (Brazilian and Dutch) and human (Argentinean) strains, thus reinforcing the zoonotic risk of hepatitis E in South America. Cynomolgus monkeys that were infected with HEV genotype 3 developed subclinical hepatitis that was associated with haematological changes. Haematological approaches should be considered in future studies of HEV infection.
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Affiliation(s)
- Lilian G de Carvalho
- Centre for Laboratory Animal Breeding, Department of Primatology, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Laboratory of Technological Development in Virology, Oswaldo Cruz Institute/Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Renato S Marchevsky
- Laboratory of Neurovirulence, Institute of Technology on Immunobiologicals, Bio-Manguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Debora RL dos Santos
- Laboratory of Veterinary Viruses, Department of Veterinary Microbiology and Immunology, UFRRJ, Rio de Janeiro, Brazil
| | - Jaqueline M de Oliveira
- Laboratory of Technological Development in Virology, Oswaldo Cruz Institute/Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Vanessa S de Paula
- Laboratory of Technological Development in Virology, Oswaldo Cruz Institute/Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Leilane M Lopes
- Laboratory of Technological Development in Virology, Oswaldo Cruz Institute/Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Wilhelmus HM Van der Poel
- Central Veterinary, Institute of Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Jorge E González
- National Reference Laboratory in Viral Hepatitis, National Institute of Infectious Diseases, Buenos Aires, Argentina
| | - Maria S Munné
- National Reference Laboratory in Viral Hepatitis, National Institute of Infectious Diseases, Buenos Aires, Argentina
| | - Julio Moran
- Dr. Julio Moran Laboratories, Ebmatingen, Zurich, Switzerland
| | - Ana Carolina R A Cajaraville
- Laboratory of Virological Technology, Institute of Technology on Immunobiologicals, Bio-Manguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Marcelo Pelajo-Machado
- Laboratory of Pathology, Oswaldo Cruz Institute/Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Oswaldo G Cruz
- Programme of Scientific Computation, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Marcelo A Pinto
- Laboratory of Technological Development in Virology, Oswaldo Cruz Institute/Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
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8
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Serological diagnostics of hepatitis E virus infection. Virus Res 2011; 161:84-92. [PMID: 21704091 DOI: 10.1016/j.virusres.2011.06.006] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/03/2011] [Accepted: 06/07/2011] [Indexed: 12/15/2022]
Abstract
Development of accurate diagnostic assays for the detection of serological markers of hepatitis E virus (HEV) infection remains challenging. In the course of nearly 20 years after the discovery of HEV, significant progress has been made in characterizing the antigenic structure of HEV proteins, engineering highly immunoreactive diagnostic antigens, and devising efficient serological assays. However, many outstanding issues related to sensitivity and specificity of these assays in clinical and epidemiological settings remain to be resolved. Complexity of antigenic composition, viral genetic heterogeneity and varying epidemiological patterns of hepatitis E in different parts of the world present challenges to the refinement of HEV serological diagnostic assays. Development of antigens specially designed for the identification of serological markers specific to acute infection and of IgG anti-HEV specific to the convalescent phase of infection would greatly facilitate accurate identification of active, recent and past HEV infections.
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9
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Jiménez de Oya N, Alonso-Padilla J, Blázquez AB, Escribano-Romero E, Escribano JM, Saiz JC. Maternal transfer of antibodies to the offspring after mice immunization with insect larvae-derived recombinant hepatitis E virus ORF-2 proteins. Virus Res 2011; 158:28-32. [PMID: 21376089 DOI: 10.1016/j.virusres.2011.02.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 12/31/2022]
Abstract
Hepatitis E virus (HEV) is a major cause of acute hepatitis in humans, causing outbreaks and epidemics in regions with sub-optimal sanitary conditions, in many of which it is endemic. Nowadays there is no specific therapy or licensed vaccines against HEV infection. In this study, we have analyzed in mice the immunogenicity of HEV open-reading frame 2 (ORF-2) protein, and a truncated form of it lacking the first 111 amino acids, efficiently expressed in an improved baculovirus-based technology using insects as living biofactories. Both recombinant proteins elicited high and long-lasting specific anti HEV antibodies. Passive transfer of immunity from immunized mothers to their offspring was demonstrated to occur both by transplacental and lactation routes. These results indicate that these insect-derived immunogens constitute low-cost potential vaccine candidate to be further evaluated.
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Affiliation(s)
- Nereida Jiménez de Oya
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ctra. Coruña Km. 7.5, 28040 Madrid, Spain
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10
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A single amino acid substitution changes antigenicity of ORF2-encoded proteins of hepatitis E virus. Int J Mol Sci 2010; 11:2962-75. [PMID: 21152284 PMCID: PMC2996735 DOI: 10.3390/ijms11082962] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/25/2010] [Accepted: 08/08/2010] [Indexed: 01/29/2023] Open
Abstract
Extensive genomic diversity has been observed among hepatitis E virus (HEV) strains. However, the implication of the genetic heterogeneity on HEV antigenic properties is uncertain. In this study, monoclonal antibodies (Mabs) against truncated ORF2-encoded proteins (aa452-617, designated p166 proteins) derived from HEV strains of Burma (genotype 1a, p166Bur), Pakistan (1b, p166Pak) and Morocco (1c, p166Mor) were raised and used for identification of HEV antigenic diversity. Six Mabs reacted to these 3 p166 proteins as well as p166 proteins constructed from strains derived from Mexico (genotype 2), US (genotype 3) and China (genotype 4), indicating the existence of pan-genotypic epitopes. Two Mabs, 1B5 and 6C7, reacted with p166Bur and p166Mor, but not p166Pak or p166s derived from genotypes 2, 3, and 4, indicating that these 2 Mabs recognized strain-specific HEV epitopes. Both the common and specific epitopes could not be mapped by 23 synthetic peptides spanning the p166Bur sequence, suggesting that they are confirmation-dependent. Comparative sequence analysis showed that p166Bur and p166Mor shared an identical aa sequence along their entire lengths, whereas for p166Pak the aas occupying positions 606 and 614 are different from aas at corresponding positions of p166Bur and p166Mor. Reactivity between 1B5 and p166Bur was abrogated with mutation of p166Bur/A606V, whereas p166Pak acquired the reactivity to 1B5 with mutation of p166Pak/V606A. However, mutations of p166Bur/L614M and P166Pak/M614L did not affect the immunoreactivity. Therefore, the aa occupying position 606 plays a critical role in maintaining the antigenicity of the HEV p166 proteins.
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11
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Yang S, Wang C, Fang X, Zhai L, Dong C, Ding L, Meng J, Wang L. Fusion of C3d molecule with neutralization epitope(s) of hepatitis E virus enhances antibody avidity maturation and neutralizing activity following DNA immunization. Virus Res 2010; 151:162-9. [PMID: 20451569 DOI: 10.1016/j.virusres.2010.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Revised: 04/27/2010] [Accepted: 04/28/2010] [Indexed: 01/27/2023]
Abstract
Previous studies have identified that a hepatits E virus peptide (HEV-p179), spanning amino acids (aa) 439-617 in the 660-aa protein encoded by open reading frame 2(ORF2) of the Chinese epidemic strain (genotype 4), is the minimal size fragment of conformation-dependent neutralization epitope(s). We report here the successful immunization of mice with DNA vaccines expressing the secreted form of HEV-p179 (fused with a human tissue plasminogen activator (tPA) signal sequence) and the tPA-p179-C3d fusion protein (fused with three tandem copies of the murine complement C3d). Analysis of antibody responses in vaccinated mice revealed that immunizations with tPA-p179-C3d3 DNA vaccine dramatically increased both the level and avidity maturation of antibodies against HEV-p179 compared to p179 and tPA-p179 DNA vaccines. In addition, this increased antibody response correlated with neutralizing titers in a PCR-based cell culture neutralization assay. These results indicate that vaccination with C3d conjugated p179 DNA vaccine enhances antibody responses to HEV, and this approach may be applied to overcome the poor immunogenicity of DNA vaccines to generate HEV neutralizing antibodies.
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Affiliation(s)
- Shucai Yang
- Department of Microbiology and Immunology, Medical School of Southeast University, 87 Dingjiaqiao Rd., Nanjing, Jiangsu 210009, China.
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12
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Zhang H, Dai X, Shan X, Meng J. Characterization of antigenic epitopes of the ORF2 protein from hepatitis E virus genotype 4. Virus Res 2009; 142:140-3. [DOI: 10.1016/j.virusres.2009.02.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 02/02/2009] [Accepted: 02/03/2009] [Indexed: 10/21/2022]
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Abstract
Hepatitis E is an emerging disease in resource-poor regions of the world. It is estimated that about 2 billion people live in areas endemic for this disease. The inability to reproducibly culture hepatitis E virus makes it impossible to develop traditional live or inactivated vaccines. However, significant progress has been made in developing and testing recombinant subunit vaccines based on the viral capsid protein. This review summarizes these efforts.
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Affiliation(s)
- Rakesh Aggarwal
- Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Rae Bareilly Road, Lucknow, 226 014, India
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14
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Guo H, Zhou EM, Sun ZF, Meng X. Immunodominant Epitopes Mapped by Synthetic Peptides on the Capsid Protein of Avian Hepatitis E Virus Are Non-Protective. Viral Immunol 2008; 21:61-7. [DOI: 10.1089/vim.2007.0082] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hailong Guo
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - E. M. Zhou
- Department of Preventive Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, Shandong Province, China
| | - Z. F. Sun
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - X.J. Meng
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
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15
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Guo H, Zhou EM, Sun ZF, Meng XJ. Protection of chickens against avian hepatitis E virus (avian HEV) infection by immunization with recombinant avian HEV capsid protein. Vaccine 2007; 25:2892-9. [PMID: 17074425 DOI: 10.1016/j.vaccine.2006.09.038] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 08/30/2006] [Accepted: 09/08/2006] [Indexed: 11/30/2022]
Abstract
Avian hepatitis E virus (avian HEV) is an emerging virus associated with hepatitis-splenomegaly syndrome in chickens in North America. Avian HEV is genetically and antigenically related to human HEV, the causative agent of hepatitis E in humans. In the lack of a practical animal model, avian HEV infection in chickens has been used as a model to study human HEV replication and pathogenesis. A 32 kDa recombinant ORF2 capsid protein of avian HEV expressed in Escherichia coli was found having similar antigenic structure as that of human HEV containing major neutralizing epitopes. To determine if the capsid protein of avian HEV can be used as a vaccine, 20 chickens were immunized with purified avian HEV recombinant protein with aluminum as adjuvant and another 20 chickens were mock immunized with KLH precipitated in aluminum as controls. Both groups of chickens were subsequently challenged with avian HEV. All the tested mock-immunized control chickens developed typical avian HEV infection characterized by viremia, fecal virus shedding and seroconversion to avian HEV antibodies. Gross hepatic lesions were also found in portion of these chickens. In contrast, none of the tested chickens immunized with avian HEV capsid protein had detectable viremia, fecal virus shedding or observable gross hepatitis lesions. The results from this study suggested that immunization of chickens with avian HEV recombinant ORF2 capsid protein with aluminum as adjuvant can induce protective immunity against avian HEV infection. Chickens are a useful small animal model to study anti-HEV immunity and pathogenesis.
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Affiliation(s)
- H Guo
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
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16
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Dong C, Dai X, Meng JH. The first experimental study on a candidate combined vaccine against hepatitis A and hepatitis E. Vaccine 2006; 25:1662-8. [PMID: 17156900 DOI: 10.1016/j.vaccine.2006.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2006] [Revised: 10/16/2006] [Accepted: 11/01/2006] [Indexed: 10/23/2022]
Abstract
To test the possibility of developing a combined vaccine against hepatitis A and E, groups of mice were immunized with different formulations containing different dosages of a commercially inactivated hepatitis A vaccine and a candidate recombinant hepatitis E vaccine. Monovalent vaccine components were used as controls. The experimental results showed that the combined vaccine could induce neutralizing antibodies against both hepatitis A virus (HAV) and hepatitis E virus (HEV) effectively in mice. Moreover, the inactivated hepatitis A vaccine could increase the immunogenicity of the recombinant HEV protein, and the recombinant HEV protein had no adverse effects on the immunogenicity of the inactivated HAV vaccine. Thus, the present study demonstrates an important first step for the further development of a combined hepatitis A and E vaccine.
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Affiliation(s)
- Chen Dong
- Department of Microbiology and Immunology, School of Medicine, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009, China
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17
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Emerson SU, Clemente-Casares P, Moiduddin N, Arankalle VA, Torian U, Purcell RH. Putative neutralization epitopes and broad cross-genotype neutralization of Hepatitis E virus confirmed by a quantitative cell-culture assay. J Gen Virol 2006; 87:697-704. [PMID: 16476993 DOI: 10.1099/vir.0.81545-0] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Monolayers of Hep G2/C3A cells were inoculated with genotype 1 Hepatitis E virus (HEV) mixed with either anti-HEV or an appropriate control. After 5 or 6 days, cell monolayers were stained with anti-HEV and infected cells were identified by immunofluorescence microscopy and counted. Anti-HEV from vaccinated or infected rhesus monkeys neutralized the virus, as did mAbs that recognized epitopes on the C terminus of a recombinant vaccine protein. Antibodies were broadly cross-reactive, since convalescent serum from animals infected with any one of the four mammalian genotypes all neutralized the genotype 1 virus.
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Affiliation(s)
- Suzanne U Emerson
- Molecular Hepatitis and Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive MSC-8009, Bethesda, MD 20892-8009, USA
| | - Pilar Clemente-Casares
- Molecular Hepatitis and Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive MSC-8009, Bethesda, MD 20892-8009, USA
| | - Nasser Moiduddin
- Molecular Hepatitis and Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive MSC-8009, Bethesda, MD 20892-8009, USA
| | | | - Udana Torian
- Molecular Hepatitis and Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive MSC-8009, Bethesda, MD 20892-8009, USA
| | - Robert H Purcell
- Molecular Hepatitis and Hepatitis Viruses Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive MSC-8009, Bethesda, MD 20892-8009, USA
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18
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Zhang J, Gu Y, Ge SX, Li SW, He ZQ, Huang GY, Zhuang H, Ng MH, Xia NS. Analysis of hepatitis E virus neutralization sites using monoclonal antibodies directed against a virus capsid protein. Vaccine 2005; 23:2881-92. [PMID: 15780737 DOI: 10.1016/j.vaccine.2004.11.065] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Accepted: 11/17/2004] [Indexed: 01/08/2023]
Abstract
The dimeric form of the recombinant peptide (E2), comprising amino acid 394-606 of the capsid protein of hepatitis E virus (HEV), is strongly recognized by HEV reactive human serum, and when used as a vaccine, it protects rhesus monkeys against experimental HEV infection. In this work, the relationship of E2 to HEV has been probed using three murine monoclonal antibodies, 8C11, 13D8 and 8H3, all of which react predominantly against the E2 dimer, and can effect immune capture of the virus as well. 8C11 and 8H3 were further found to neutralize HEV infectivity in animals. Cross-blocking patterns between these antibodies discerned two spatially separate antigenic domains, one identified by 8C11 and 13D8, and the other, by 8H3. Kinetic studies using BIAcore biosensor suggest that the epitope to which 8H3 is directed is partially masked, and thus has limited access by the native antibody. However, this is not the case with the smaller Fab. Access to the 8H3 epitope was enhanced by the binding of 8C11, and inhibited by the binding of 13D8 to a distal site on the peptide. Similar to the effects of binding 8H3 to E2, 8C11 was found to enhance immune capture by 8H3, while 13D8 was inhibitory. Moreover, 8C11 and 8H3 act synergistically to neutralize HEV infectivity. The parallel cross-reaction patterns that these antibodies exhibit against the peptide and the virus, respectively, implicate two interacting conformationally dependent neutralization sites on the HEV particle. These sites might cooperate in the adsorption and penetration of the HEV virus.
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Affiliation(s)
- Jun Zhang
- The Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering, School of Life Sciences, Xiamen University, Xiamen 361005, China
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19
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Chen GB, Meng JH. Identification of 5’ capped structure and 3’ terminal sequence of hepatitis E virus isolated from Morocco. World J Gastroenterol 2004; 10:2045-9. [PMID: 15237431 PMCID: PMC4572330 DOI: 10.3748/wjg.v10.i14.2045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To examine 5’ and 3’ terminal sequences of hepatitis E virus (HEV) isolated from Morocco, to confirm 5’ methylated cap structure of the genome, and to investigate whether the 3’ UTR can be used to distinguish HEV genotypes instead of HEV complete genome sequence.
METHODS: RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) was employed to obtain the 5’ and 3’ terminal sequences of HEV Morocco strain. The 3’ UTR sequence of the Morocco strain was compared with that of the other 29 HEV strains using the DNAStar software.
RESULTS: The 5’ PCR product was obtained only from the RLM-RACE based on the capped RNA template. The 5’ UTR of the Morocco strain had 26 nucleotides, and the 3’ UTR had 65 nucleotides upstream to the polyA. The 5’ UTR between HEV strains had only point mutations of nucleotides. The phylogenetic tree based on the sequences of 3’ UTR was not the same as that based on the complete sequences.
CONCLUSION: The genome of HEV Morocco strain was methylated cap structure. The 3’ terminal sequence can not be used for distinguishing HEV genotype for all HEV strains in place of the whole HEV genome sequence.
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Affiliation(s)
- Guo-Bing Chen
- Department of Microbiology and Immunology, Southeast University School of Medicine, Nanjing 210009, Jiangsu Province, China
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20
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Abstract
Hepatitis E accounts for the major part of enterally transmitted non-A, non-B hepatitis worldwide. Its agent, the hepatitis E virus (HEV), is a small, single-stranded RNA virus. Only one serotype of HEV is recognised. Infection results in protective immunity with long-lived neutralising antibodies. In developing countries with poor sanitary conditions and high population density, hepatitis E causes water-borne epidemics with substantial mortality rates in pregnant women. In addition, more than 50% of cases of acute hepatic failure and sporadic acute hepatitis are due to hepatitis E. The overall prevalence rates of antibodies to the HEV in populations native to these areas rarely exceed 25%. Hence, many individuals remain susceptible to hepatitis E infection, making hepatitis E an important public health concern. In this context, the development of an HEV vaccine is warranted. Because HEV does not grow adequately in cell cultures the development of a vaccine based on inactivated or attenuated whole-virus particles is not feasible. HEV vaccines currently under study are based on recombinant proteins derived from immunogenic parts of the HEV capsid gene. Other approaches such as DNA-based vaccines or transgenic tomatoes have also been developed. Several recombinant protein-based vaccines elicited neutralising antibodies and protective immunity in vaccinated non-human primates. One such vaccine has passed phase I trial and is currently under further evaluation in field trials. Even so, several questions remain to be answered before vaccination programmes could be implemented.
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Affiliation(s)
- Harald Claus Worm
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University Clinic Graz, Auenbruggerplatz 15, A-8036 Graz, Austria.
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21
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Kamili S, Spelbring J, Krawczynski K. DNA vaccination against hepatitis E virus infection in cynomolgus macaques. J Gastroenterol Hepatol 2002; 17 Suppl 3:S365-9. [PMID: 12472965 DOI: 10.1046/j.1440-1746.17.s3.29.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND : The feasibility of DNA vaccination against hepatitis E in non-human primates has not been evaluated. In the present study a full-length hepatitis E virus (HEV) open reading frame (ORF)2 (Burmese strain) was assembled, cloned, and used for genetic immunization of cynomolgus macaques (cynos), which were subsequently challenged with a heterologous HEV strain (Mexico). METHODS : Four cynos were vaccinated intramuscularly with the HEV ORF2 DNA cassette and one animal was vaccinated with a mock DNA construct. RESULTS : Following vaccination anti-HEV antibodies were detected in the four HEV-DNA-vaccinated cynos, but not in the control animal. When challenged, two of the four HEV-DNA-vaccinated cynos were protected against HEV infection and had no elevated alanine aminotransferase activity, viremia, or fecal shedding. The two other DNA-vaccinated animals developed HEV infection and disease. CONCLUSION : These findings demonstrate the feasibility of DNA vaccination for the protection of HEV infection and warrant further studies to explore routes other than intramuscular for induction of a stronger and efficacious immune response.
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Affiliation(s)
- Saleem Kamili
- Division of Viral Hepatitis, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
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22
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Huang FF, Haqshenas G, Shivaprasad HL, Guenette DK, Woolcock PR, Larsen CT, Pierson FW, Elvinger F, Toth TE, Meng XJ. Heterogeneity and seroprevalence of a newly identified avian hepatitis e virus from chickens in the United States. J Clin Microbiol 2002; 40:4197-202. [PMID: 12409397 PMCID: PMC139663 DOI: 10.1128/jcm.40.11.4197-4202.2002] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We recently identified and characterized a novel virus, designated avian hepatitis E virus (avian HEV), from chickens with hepatitis-splenomegaly syndrome (HS syndrome) in the United States. Avian HEV is genetically related to but distinct from human and swine HEVs. To determine the extent of genetic variation and the seroprevalence of avian HEV infection in chicken flocks, we genetically identified and characterized 11 additional avian HEV isolates from chickens with HS syndrome and assessed the prevalence of avian HEV antibodies from a total of 1,276 chickens of different ages and breeds from 76 different flocks in five states (California, Colorado, Connecticut, Virginia, and Wisconsin). An enzyme-linked immunosorbent assay using a truncated recombinant avian HEV ORF2 antigen was developed and used to determine avian HEV seroprevalence. About 71% of chicken flocks and 30% of chickens tested in the study were positive for antibodies to avian HEV. About 17% of chickens younger than 18 weeks were seropositive, whereas about 36% of adult chickens were seropositive. By using a reverse transcription-PCR (RT-PCR) assay, we tested 21 bile samples from chickens with HS syndrome in California, Connecticut, New York, and Wisconsin for the presence of avian HEV RNA. Of the 21 bile samples, 12 were positive for 30- to 35-nm HEV-like virus particles by electron microscopy (EM). A total of 11 of the 12 EM-positive bile samples and 6 of the 9 EM-negative bile samples were positive for avian HEV RNA by RT-PCR. The sequences of a 372-bp region within the helicase gene of 11 avian HEV isolates were determined. Sequence analyses revealed that the 11 field isolates of avian HEV had 78 to 100% nucleotide sequence identities to each other, 79 to 88% identities to the prototype avian HEV, 76 to 80% identities to chicken big liver and spleen disease virus, and 56 to 61% identities to other known strains of human and swine HEV. The data from this study indicated that, like swine and human HEVs, avian HEV isolates are genetically heterogenic and that avian HEV infection is enzoonotic in chicken flocks in the United States.
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Affiliation(s)
- F F Huang
- Center for Molecular Medicine and Infectious Diseases, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0342, USA
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23
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Paraná R, Schinoni MI. Hepatite E. Rev Soc Bras Med Trop 2002. [DOI: 10.1590/s0037-86822002000300009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
O vírus da hepatite E (VHE) é o segundo vírus de transmissão fecal-oral com hepatotropismo confirmado, após o vírus da hepatite A. As grandes epidemias de hepatite das décadas de 50 e 60 na Índia foram causadas pelo VHE. Observaram-se surtos da infecção na África Central, América Latina, Oriente Médio e Repúblicas independentes da ex-União Soviética. O quadro clínico da doença assemelha-se ao de outras hepatites virais. Não há casos descritos de hepatite E crônicas. Cerca de 20% das mulheres que adquirem a doença durante a gravidez desenvolvem formas graves, com insuficiência hepática fulminante. Confirma-se o diagnóstico quando se encontra no soro anticorpos (método de ELISA) das classes IgM (fase aguda) e/ou IgG (curados). O imunoblot e o PCR-RNA podem ser usados quando necessário. Não há tratamento específico. O uso de imunoglobulina hiperimune tem sido aconselhado por alguns autores. A prevenção se faz pelos cuidados higiênicos e dietéticos habituais. Não há vacina eficaz contra a doença.
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24
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Huang FF, Haqshenas G, Guenette DK, Halbur PG, Schommer SK, Pierson FW, Toth TE, Meng XJ. Detection by reverse transcription-PCR and genetic characterization of field isolates of swine hepatitis E virus from pigs in different geographic regions of the United States. J Clin Microbiol 2002; 40:1326-32. [PMID: 11923352 PMCID: PMC140370 DOI: 10.1128/jcm.40.4.1326-1332.2002] [Citation(s) in RCA: 284] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hepatitis E virus (HEV) is an important public health concern in many developing countries. HEV is also endemic in some industrialized counties, including the United States. With our recent discovery of swine HEV in pigs that is genetically closely related to human HEV, hepatitis E is now considered a zoonotic disease. Human strains of HEV are genetically heterogenic. So far in the United States, only one strain of swine HEV has been identified and characterized from a pig. To determine the extent of genetic variations and the nature of swine HEV infections in U.S. pigs, we developed a universal reverse transcription-PCR (RT-PCR) assay that is capable of detecting genetically divergent strains of HEV. By using this universal RT-PCR assay, we tested fecal and serum samples of pigs of 2 to 4 months of age from 37 different U.S. swine farms for the presence of swine HEV RNA. Thirty-four of the 96 pigs (35%) and 20 of the 37 swine herds (54%) tested were positive for swine HEV RNA. The sequences of a 348-bp region within the ORF2 gene of 27 swine HEV isolates from different geographic regions were determined. Sequence analyses revealed that the 27 U.S. swine HEV isolates shared 88 to 100% nucleotide sequence identities with each other and 89 to 98% identities with the prototype U.S. strain of swine HEV. These U.S. swine HEV isolates are only distantly related to the Taiwanese strains of swine HEV, with about 74 to 78% nucleotide sequence identities; to most known human strains of HEV worldwide, with <79% sequence identities; and to avian HEV, with 54 to 56% sequence identities. Phylogenetic analysis showed that all the U.S. swine HEV isolates identified in this study clustered in the same genotype with the prototype U.S. swine HEV and the two U.S. strains of human HEV. The data from this study indicated that swine HEV is widespread and enzoonotic in U.S. swine herds and that, as is with human HEV, swine HEV isolates from different geographic regions of the world are also genetically heterogenic. These data further raise potential concerns for zoonosis, xenozoonosis, and food safety.
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Affiliation(s)
- F F Huang
- Center for Molecular Medicine and Infectious Diseases, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0342, USA
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25
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Abstract
Hepatitis E virus causes epidemics of acute hepatitis in many developing countries. It infrequently causes disease in developed countries, but avirulent strains might circulate. Some evidence suggests that hepatitis E might be a zoonosis. There is probably only a single serotype. A candidate vaccine consisting of baculovirus-expressed recombinant capsid protein protected macaques from hepatitis E--it passed phase I clinical trials and is currently scheduled for phase II/III clinical trials.
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Affiliation(s)
- S U Emerson
- Molecular Hepatitis and Hepatitis Viruses Sections, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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26
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Meng J, Dai X, Chang JC, Lopareva E, Pillot J, Fields HA, Khudyakov YE. Identification and characterization of the neutralization epitope(s) of the hepatitis E virus. Virology 2001; 288:203-11. [PMID: 11601892 DOI: 10.1006/viro.2001.1093] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neutralization epitope(s) of the hepatitis E virus (HEV) was studied by an in vitro neutralization assay using antibodies obtained by immunization of mice with 51 overlapping 30-mer synthetic peptides spanning the region 221-660 amino acids (aa) of the HEV open reading frame 2 encoded protein (pORF2) and 31 overlapping recombinant proteins of different sizes derived from the entire pORF2 of the HEV Burma strain. Antibodies against synthetic peptides and short recombinant proteins of approximately 100 aa did not neutralize HEV, suggesting the HEV neutralization epitope(s) is conformation-dependent. However, one recombinant protein of approximately 400 aa in length comprising the pORF2 sequence at position 274-660 aa as well as all truncated derivatives of this protein containing region 452-617 aa elicited antibodies, demonstrating HEV neutralizing activity. These findings establish for the first time that the minimal size fragment, designated pB166, that can efficiently model the neutralization epitope(s) is 166 aa in length and is located at position 452-617 aa of the HEV pORF2. Additionally, antibodies against pB166 were found to cross-neutralize three different HEV genotypes, suggesting that a common neutralization epitope(s) may exist within the different HEV genotypes. Thus, recombinant proteins constructed in this study may be considered as potential candidates for the development of an HEV subunit vaccine as well as for the development of highly sensitive and specific diagnostic tests.
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Affiliation(s)
- J Meng
- Division of Viral Hepatitis, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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27
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Tuteja R, Li TC, Takeda N, Jameel S. Augmentation of immune responses to hepatitis E virus ORF2 DNA vaccination by codelivery of cytokine genes. Viral Immunol 2001; 13:169-78. [PMID: 10892997 DOI: 10.1089/vim.2000.13.169] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
DNA vaccines encoding a viral structural protein have been shown to induce antiviral immune responses and provide protection against subsequent viral challenge. In the present study we show that DNA immunization with a plasmid expressing the hepatitis E virus ORF2 structural protein (pcDNA-ORF2) induced low levels of long-lasting antibody responses in the murine model. The use of plasmids expressing interleukin-2 (IL-2) and granulocyte-macrophage colony-stimulating-factor (GM-CSF) in conjunction with pcDNA-ORF2 enhanced the antibody responses generated by pORF-2. We further show that the immune responses generated by plasmid pcDNA-ORF2 can be boosted with virus-like particles composed of the ORF2 protein expressed through a baculovirus expression system.
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Affiliation(s)
- R Tuteja
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
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28
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Riddell MA, Li F, Anderson DA. Identification of immunodominant and conformational epitopes in the capsid protein of hepatitis E virus by using monoclonal antibodies. J Virol 2000; 74:8011-7. [PMID: 10933710 PMCID: PMC112333 DOI: 10.1128/jvi.74.17.8011-8017.2000] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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.
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Affiliation(s)
- M A Riddell
- Hepatitis Research Unit and Australian Centre for Hepatitis Virology, Macfarlane Burnet Centre for Medical Research, Fairfield 3078, Victoria, Australia
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29
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Li F, Riddell MA, Seow HF, Takeda N, Miyamura T, Anderson DA. Recombinant subunit ORF2.1 antigen and induction of antibody against immunodominant epitopes in the hepatitis E virus capsid protein. J Med Virol 2000; 60:379-86. [PMID: 10686019 DOI: 10.1002/(sici)1096-9071(200004)60:4<379::aid-jmv3>3.0.co;2-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A recombinant subunit antigen (ORF2.1), representing the carboxy-terminal 267 amino acids of the 660-amino-acid hepatitis E virus (HEV) capsid protein, was expressed in Escherichia coli and used for the immunisation of rats. Purified antigen formulated with either Aluminium Hydroxide Gel Adjuvant (Alum) or Titermax gave high and equivalent levels of antibody after three doses. Responses to two doses of 15, 75, or 150 microg antigen, formulated with Alum and given at 0 and 4 weeks, were also equivalent by 17 weeks after immunisation. Rats initially developed antibody to a wide range of linear epitopes in the ORF2.1 region, but by 27 weeks the predominant response detected by Western immunoblotting was restricted to the conformational epitope unique to ORF2.1 [Li et al. (1997) Journal of Medical Virology 52:289-300], a pattern that was also observed when comparing acute-phase patient serum samples with serum samples from convalescing patients. Antibody from immunised rats blocked the majority of patients' serum reactivity in enzyme-linked immunosorbent assay against both ORF2.1 (57-92% inhibition) and virus-like particles of HEV produced using the baculovirus system (74-97% inhibition). Together, these results suggest that the ORF2.1 subunit vaccine induces an antibody response against immunodominant, conformational epitopes in the viral capsid, which largely mimics that seen in convalescent patients, who are presumed to be immune to HEV infection.
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Affiliation(s)
- F Li
- Hepatitis Research Unit, Macfarlane Burnet Centre for Medical Research, Fairfield, Australia
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30
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Khudyakov YE, Lopareva EN, Jue DL, Crews TK, Thyagarajan SP, Fields HA. Antigenic domains of the open reading frame 2-encoded protein of hepatitis E virus. J Clin Microbiol 1999; 37:2863-71. [PMID: 10449466 PMCID: PMC85398 DOI: 10.1128/jcm.37.9.2863-2871.1999] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antigenic composition of the hepatitis E virus (HEV) protein encoded by open reading frame 2 (ORF2) was determined by using synthetic peptides. Three sets of overlapping 18-, 25-, and 30-mer peptides, with each set spanning the entire ORF2 protein of the HEV Burma strain, were synthesized. All synthetic peptides were tested by enzyme immunoassay against a panel of 32 anti-HEV-positive serum specimens obtained from acutely HEV-infected persons. Six antigenic domains within the ORF2 protein were identified. Domains 1 and 6 located at the N and C termini of the ORF2 protein, respectively, contain strong immunoglobulin G (IgG) and IgM antigenic epitopes that can be efficiently modeled with peptides of different sizes. In contrast, antigenic epitopes identified within the two central domains (3 and 4) were modeled more efficiently with 30-mer peptides than with either 18- or 25-mers. Domain 2 located at amino acids (aa) 143 to 222 was modeled best with 25-mer peptides. A few 30-mer synthetic peptides derived from domain 5 identified at aa 490 to 579 demonstrated strong IgM antigenic reactivity. Several 30-mer synthetic peptides derived from domains 1, 4, and 6 immunoreacted with IgG or IgM with more than 70% of anti-HEV-positive serum specimens. Thus, the results of this study demonstrate the existence of six diagnostically relevant antigenic domains within the HEV ORF2 protein.
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Affiliation(s)
- Y E Khudyakov
- Hepatitis Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, U. S. Department of Health and Human Services, Atlanta, Georgia 30333, USA.
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31
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Meng J, Cong ME, Dai X, Pillot J, Purdy MA, Fields HA, Khudyakov YE. Primary structure of open reading frame 2 and 3 of the hepatitis E virus isolated from Morocco. J Med Virol 1999. [DOI: 10.1002/(sici)1096-9071(199902)57:2<126::aid-jmv7>3.0.co;2-o] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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