1
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Falkenhagen A, Panajotov J, Johne R. Colon-derived Caco-2 cells support replication of hepatitis E virus genotype 1 strain Sar55 generated by reverse genetics. Virus Res 2024; 347:199427. [PMID: 38917940 PMCID: PMC11261143 DOI: 10.1016/j.virusres.2024.199427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/20/2024] [Accepted: 06/22/2024] [Indexed: 06/27/2024]
Abstract
The hepatitis E virus (HEV) is infecting over 20 million people annually with a high morbidity especially in pregnant women and immune-suppressed individuals. While HEV genotype 1 (HEV-1) infects only humans, genotype 3 (HEV-3) is zoonotic and commonly transmitted from infected animals to humans. Whereas a few reverse genetics systems enabling targeted genome manipulations exist for HEV-3, those for HEV-1 are still very limited, mainly because of inefficient cell culture replication. Here, the generation of HEV-1 strain Sar55 and HEV-3 strain 47832mc by transfecting in vitro-transcribed and capped virus genomes into different cell lines was attempted. Culture supernatants of colon-derived colorectal adenocarcinoma cell line Caco-2 contained HEV-1 and HEV-3 capable of infecting Caco-2 cells. Density gradient centrifugation analyses of culture supernatants confirmed that HEV-1 particles were quasi-enveloped in analogy to HEV-3 and that non-virion-associated capsid protein was secreted from cells. Following transfection or infection of Caco-2 cells, HEV-1 consistently reached higher titers than HEV-3 in culture supernatants, but HEV-1 generated by transfection of Caco-2 cells was unable to efficiently infect hepatoma cell lines PLC/PRF/5 or HuH7-Lunet BLR. Taken together, our results indicate that HEV-1 is able to exert a complete replication cycle in Caco-2 cells. An efficient cell culture system for this genotype will be useful for studying species tropism, but further research is required to determine the significance of HEV-1 replication in colon-derived cells.
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Affiliation(s)
- Alexander Falkenhagen
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany.
| | - Jessica Panajotov
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
| | - Reimar Johne
- Department of Biological Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
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2
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Wißing MH, Meister TL, Nocke MK, Gömer A, Masovic M, Knegendorf L, Brüggemann Y, Bader V, Siddharta A, Bock CT, Ploss A, Kenney SP, Winklhofer KF, Behrendt P, Wedemeyer H, Steinmann E, Todt D. Genetic determinants of host- and virus-derived insertions for hepatitis E virus replication. Nat Commun 2024; 15:4855. [PMID: 38844458 PMCID: PMC11156872 DOI: 10.1038/s41467-024-49219-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 05/24/2024] [Indexed: 06/09/2024] Open
Abstract
Hepatitis E virus (HEV) is a long-neglected RNA virus and the major causative agent of acute viral hepatitis in humans. Recent data suggest that HEV has a very heterogeneous hypervariable region (HVR), which can tolerate major genomic rearrangements. In this study, we identify insertions of previously undescribed sequence snippets in serum samples of a ribavirin treatment failure patient. These insertions increase viral replication while not affecting sensitivity towards ribavirin in a subgenomic replicon assay. All insertions contain a predicted nuclear localization sequence and alanine scanning mutagenesis of lysine residues in the HVR influences viral replication. Sequential replacement of lysine residues additionally alters intracellular localization in a fluorescence dye-coupled construct. Furthermore, distinct sequence patterns outside the HVR are identified as viral determinants that recapitulate the enhancing effect. In conclusion, patient-derived insertions can increase HEV replication and synergistically acting viral determinants in and outside the HVR are described. These results will help to understand the underlying principles of viral adaptation by viral- and host-sequence snatching during the clinical course of infection.
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Affiliation(s)
| | - Toni Luise Meister
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
- Institute for Infection Research and Vaccine Development (IIRVD), Centre for Internal Medicine, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany
- Department for Clinical Immunology of Infectious Diseases, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Centre for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Maximilian Klaus Nocke
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
| | - André Gömer
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
| | - Mejrema Masovic
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
| | - Leonard Knegendorf
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
- Hannover Medical School, Institute for Medical Microbiology and Hospital Epidemiology, Hannover, Germany
| | - Yannick Brüggemann
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
| | - Verian Bader
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Anindya Siddharta
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Claus-Thomas Bock
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Scott P Kenney
- Center for Food Animal Health, Departments of Animal Sciences and Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, 43210, USA
| | - Konstanze F Winklhofer
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Cluster of Excellence RESOLV, Bochum, Germany
| | - Patrick Behrendt
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- German Center for Infectious Disease Research (DZIF); Partner Sites Hannover-Braunschweig, Braunschweig, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- German Center for Infectious Disease Research (DZIF); Partner Sites Hannover-Braunschweig, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany, Braunschweig, Germany
| | - Eike Steinmann
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany.
- German Centre for Infection Research (DZIF), External Partner Site, Bochum, Germany.
| | - Daniel Todt
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany.
- European Virus Bioinformatics Center (EVBC), Jena, Germany.
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3
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Zhang L, Xiao K, Kong L. A computational method for small molecule-RNA binding sites identification by utilizing position specificity and complex network information. Biosystems 2024; 235:105094. [PMID: 38056591 DOI: 10.1016/j.biosystems.2023.105094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/08/2023]
Abstract
Some computational methods have been given for small molecule-RNA binding site identification due to that it plays a significant role in revealing biology function researches. However, it is still challenging to design an accurate model, especially for MCC. We designed a feature extraction technology from two aspects (position specificity and complex network information). Specifically, complex network was employed to express the space topological structure and sequence position information for improving prediction effect. Then, the features fused position specificity and complex network information were input into random forest classifier for model construction. The AUC of 88.22%, 77.92% and 81.46% were obtained on three independent datasets (RB19, CS71, RB78). Compared with the existing method, the best MCC were obtained on three datasets, which were 8.19%, 0.59% and 4.35% higher than the state-of-the-art prediction methods, respectively. The outstanding performances show that our method is a powerful tool to identify RNA binding sites, helping to the design RNA-targeting small molecule drugs. The data and resource codes are available at https://github.com/Kangxiaoneuq/PCN_RNAsite.
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Affiliation(s)
- Lichao Zhang
- School of Mathematics and Statistics, Northeastern University at Qinhuangdao, Qinhuangdao, 066000, PR China; Hebei Innovation Center for Smart Perception and Applied Technology of Agricultural Data, Qinhuangdao, 066000, PR China.
| | - Kang Xiao
- School of Mathematics and Statistics, Northeastern University at Qinhuangdao, Qinhuangdao, 066000, PR China.
| | - Liang Kong
- Hebei Innovation Center for Smart Perception and Applied Technology of Agricultural Data, Qinhuangdao, 066000, PR China; School of Mathematics and Information Science & Technology, Hebei Normal University of Science & Technology, Qinhuangdao, 066000, PR China.
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4
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Biedermann P, Klink P, Nocke MK, Papp CP, Harms D, Kebelmann M, Thürmer A, Choi M, Altmann B, Todt D, Hofmann J, Bock CT. Insertions and deletions in the hypervariable region of the hepatitis E virus genome in individuals with acute and chronic infection. Liver Int 2023; 43:794-804. [PMID: 36617681 DOI: 10.1111/liv.15517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/30/2022] [Accepted: 01/04/2023] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND AIMS Hepatitis E virus is a major cause of acute hepatitis worldwide and can progress to chronicity in immunocompromised individuals. Various virus-host recombination events have been reported in the hypervariable region of the hepatitis E virus genome, but the patterns of assembly and selection remain unclear. METHODS To gain further insight into viral evolution, we assessed the presence of low abundance variants in 16 samples from individuals with acute or chronic infection using a targeted next-generation sequencing approach. RESULTS In seven samples, different variants with insertions and/or deletions were identified. Among them, eight insertions originating either from human genes or from the hepatitis E virus genome. Five different deletions could be identified. The amino acid composition of sequences with insertions showed a higher frequency of lysine and a lower abundance of proline, and additionally acetylation and ubiquitination sites were more frequent than in hepatitis E virus wild-type sequences. CONCLUSIONS These findings suggest that the nucleotide composition of insertions and sites for post-translational modification may contribute to recombination events. Although the impact of low-level hepatitis E virus variants is uncertain, our results highlight the importance of a highly sensitive next-generation sequencing approach to capture the full diversity of hypervariable region.
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Affiliation(s)
- Paula Biedermann
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
- German Centre for Infection Research, Institute of Virology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Patrycja Klink
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Maximilian K Nocke
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Christian-Patrick Papp
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
- German Centre for Infection Research, Institute of Virology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Dominik Harms
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Marianne Kebelmann
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Andrea Thürmer
- Genome Sequencing, Methodology and Research Infrastructure, Robert Koch Institute, Berlin, Germany
| | - Mira Choi
- Department of Nephrology and Intensive Medical Care, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Britta Altmann
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Daniel Todt
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
| | - Jörg Hofmann
- German Centre for Infection Research, Institute of Virology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
- Labor Berlin, Charité-Vivantes GmbH, Berlin, Germany
| | - Claus-Thomas Bock
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
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5
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Gremmel N, Keuling O, Becher P, Baechlein C. Isolation of 15 hepatitis E virus strains lacking ORF1 rearrangements from wild boar and pig organ samples and efficient replication in cell culture. Transbound Emerg Dis 2022; 69:e2617-e2628. [PMID: 35678772 DOI: 10.1111/tbed.14608] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/03/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
As a zoonotic pathogen, the hepatitis E virus (HEV) leads to numerous infections in humans with different clinical manifestations. Especially genotype 3, as causative agent of a foodborne zoonosis, is transmitted to humans by ingestion of undercooked or raw meat containing liver from HEV-infected animals. Although the virus' prevalence and dissemination in hosts like wild boar and pig have been well characterized, HEV is greatly understudied on a molecular level and reliable cell culture models are lacking. For this reason, the present study concentrated on the isolation and subsequent characterization of porcine HEV from tissue samples derived from wild boar and domestic pigs: 222 wild boars hunted in Northern Germany were investigated for the presence of HEV RNA with a detection rate of 5.9%. Three additional HEV-positive wild boar liver samples as well as an HEV-positive spleen and a positive kidney from domestic pigs were included. After inoculation of positive samples onto the human hepatoma cell line PLC/PRF/5, cells were grown for several weeks. Successful isolation was confirmed by RT-qPCR, virus passage, immunofluorescence staining and titration. Overall, 15 strains from a total of 18 RNA-positive organ samples could be obtained and viral loads >109 RNA copies/ml were measured in cell culture supernatants. Accordingly, 83.3% of the HEV RNA-positive samples contained infectious hepatitis E viral particles and therefore must be considered as a potential source for human infections. Phylogenetic analyses revealed that all isolated strains belong to genotype 3. Further genetic characterization showed a high degree of sequence variability, but no sequence insertions, in the hypervariable region within the open reading frame 1.
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Affiliation(s)
- Nele Gremmel
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany
| | - Oliver Keuling
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine, Hannover, Germany
| | - Paul Becher
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany
| | - Christine Baechlein
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany.,Present address: Lower Saxony State Office for Consumer Protection and Food Safety, Food and Veterinary Institute Braunschweig/Hannover, Hannover, Germany
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6
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Cierniak F, Ulrich RG, Groschup MH, Eiden M. A Modular Hepatitis E Virus Replicon System for Studies on the Role of ORF1-Encoded Polyprotein Domains. Pathogens 2022; 11:pathogens11030355. [PMID: 35335679 PMCID: PMC8948863 DOI: 10.3390/pathogens11030355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/04/2022] [Accepted: 03/13/2022] [Indexed: 12/02/2022] Open
Abstract
Zoonotic hepatitis E virus (HEV) infection is an emerging cause of acute viral hepatitis in developed countries. Known reservoirs of zoonotic genotype 3 (HEV-3) are mainly pigs and wild boar, and to a lesser extent rabbits and deer. Rabbit hepatitis E virus (HEV-3ra) is prevalent in rabbits worldwide and represents a particular risk for zoonotic infection. Current understanding of the molecular mechanisms of HEV pathogenesis is incomplete, particularly due to the limited availability of efficient and reliable cell culture systems. In order to identify genomic regions responsible for HEV propagation in cell culture, we developed a modular chimeric reporter replicon system based on cell culture-adapted (Kernow-C1/p6 and 47832mc) and rabbit-derived HEV strains. Replication in HepG2 cells was monitored on the basis of a Gaussia luciferase reporter gene that was inserted in place of the open reading frame (ORF) 2 of the HEV genome. Luciferase activity of rabbit HEV-derived replicons was significantly lower than that of Kernow-C1/p6 and 47832mc replicons. Serial exchanges of defined ORF1 segments within the Kernow-C1/p6 replicon backbone indicated that HEV replication in HepG2 cells is not determined by a single domain but rather by an interplay of longer segments of the ORF1-derived nonstructural polyprotein. This implies that a specific combination of viral factors is required for efficient HEV propagation in cell culture.
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Affiliation(s)
- Filip Cierniak
- Institute of Novel and Emerging Infectious Diseases (INNT), Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany; (F.C.); (R.G.U.); (M.H.G.)
| | - Rainer G. Ulrich
- Institute of Novel and Emerging Infectious Diseases (INNT), Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany; (F.C.); (R.G.U.); (M.H.G.)
- Partner Site Hamburg-Lübeck-Borstel-Riems, German Centre for Infection Research (DZIF), 17493 Greifswald-Insel Riems, Germany
| | - Martin H. Groschup
- Institute of Novel and Emerging Infectious Diseases (INNT), Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany; (F.C.); (R.G.U.); (M.H.G.)
- Partner Site Hamburg-Lübeck-Borstel-Riems, German Centre for Infection Research (DZIF), 17493 Greifswald-Insel Riems, Germany
| | - Martin Eiden
- Institute of Novel and Emerging Infectious Diseases (INNT), Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany; (F.C.); (R.G.U.); (M.H.G.)
- Correspondence:
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7
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Cancela F, Noceti O, Arbiza J, Mirazo S. Structural aspects of hepatitis E virus. Arch Virol 2022; 167:2457-2481. [PMID: 36098802 PMCID: PMC9469829 DOI: 10.1007/s00705-022-05575-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/04/2022] [Indexed: 12/14/2022]
Abstract
Hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide. Hepatitis E is an enterically transmitted zoonotic disease that causes large waterborne epidemic outbreaks in developing countries and has become an increasing public-health concern in industrialized countries. In this setting, the infection is usually acute and self-limiting in immunocompetent individuals, although chronic cases in immunocompromised patients have been reported, frequently associated with several extrahepatic manifestations. Moreover, extrahepatic manifestations have also been reported in immunocompetent individuals with acute HEV infection. HEV belongs to the alphavirus-like supergroup III of single-stranded positive-sense RNA viruses, and its genome contains three partially overlapping open reading frames (ORFs). ORF1 encodes a nonstructural protein with eight domains, most of which have not been extensively characterized: methyltransferase, Y domain, papain-like cysteine protease, hypervariable region, proline-rich region, X domain, Hel domain, and RNA-dependent RNA polymerase. ORF2 and ORF3 encode the capsid protein and a multifunctional protein believed to be involved in virion release, respectively. The novel ORF4 is only expressed in HEV genotype 1 under endoplasmic reticulum stress conditions, and its exact function has not yet been elucidated. Despite important advances in recent years, the biological and molecular processes underlying HEV replication remain poorly understood, primarily due to a lack of detailed information about the functions of the viral proteins and the mechanisms involved in host-pathogen interactions. This review summarizes the current knowledge concerning HEV proteins and their biological properties, providing updated detailed data describing their function and focusing in detail on their structural characteristics. Furthermore, we review some unclear aspects of the four proteins encoded by the ORFs, highlighting the current key information gaps and discussing potential novel experimental strategies for shedding light on those issues.
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Affiliation(s)
- Florencia Cancela
- grid.11630.350000000121657640Sección Virología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Ofelia Noceti
- grid.414402.70000 0004 0469 0889Programa Nacional de Trasplante Hepático y Unidad Docente Asistencial Centro Nacional de Tratamiento Hepatobiliopancreatico. Hospital Central de las Fuerzas Armadas, Montevideo, Uruguay
| | - Juan Arbiza
- grid.11630.350000000121657640Sección Virología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Santiago Mirazo
- grid.11630.350000000121657640Sección Virología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay ,grid.11630.350000000121657640Departamento de Bacteriología y Virología, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay ,Av. Alfredo Navarro 3051, PC 11600 Montevideo, Uruguay
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8
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Cell Culture Isolation and Whole Genome Characterization of Hepatitis E Virus Strains from Wild Boars in Germany. Microorganisms 2021; 9:microorganisms9112302. [PMID: 34835427 PMCID: PMC8624179 DOI: 10.3390/microorganisms9112302] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 11/16/2022] Open
Abstract
Infection with hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. The HEV genotype 3 can be zoonotically transmitted from animals to humans, with wild boars representing an important reservoir species. Cell culture isolation of HEV is generally difficult and mainly described for human isolates so far. Here, five sera and five liver samples from HEV-RNA-positive wild boar samples were inoculated onto PLC/PRF/5 cells, incubated for 3 months and thereafter passaged for additional 6 weeks. As demonstrated by RT-qPCR, immunofluorescence and immune electron microscopy, virus was successfully isolated from two liver samples, which originally contained high HEV genome copy numbers. Both isolates showed slower growth than the culture-adapted HEV strain 47832c. In contrast to this strain, the isolated strains had no insertions in their hypervariable genome region. Next generation sequencing using an HEV sequence-enriched library enabled full genome sequencing. Strain Wb108/17 belongs to subtype 3f and strain Wb257/17 to a tentative novel subtype recently described in Italian wild boars. The results indicate that HEV can be successfully isolated in cell culture from wild boar samples containing high HEV genome copy numbers. The isolates may be used further to study the zoonotic potential of wild boar-derived HEV subtypes.
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