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Liu H, Hong X, Xi J, Menne S, Hu J, Wang JCY. Cryo-EM structures of human hepatitis B and woodchuck hepatitis virus small spherical subviral particles. SCIENCE ADVANCES 2022; 8:eabo4184. [PMID: 35930632 PMCID: PMC9355357 DOI: 10.1126/sciadv.abo4184] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
The loss of detectable hepatitis B surface antigen (HBsAg) is considered a functional cure in chronic hepatitis B. Naturally, HBsAg can be incorporated into the virion envelope or assembled into subviral particles (SVPs) with lipid from host cells. Until now, there has been no detailed structure of HBsAg, and the published SVP structures are controversial. Here, we report the first subnanometer-resolution structures of spherical SVP from hepatitis B virus (HBV) and the related woodchuck hepatitis virus (WHV) determined by cryo-electron microscopy in combination with AlphaFold2 prediction. Both structures showed unique rhombicuboctahedral symmetry with 24 protruding spikes comprising dimer of small HBsAg with four helical domains. The lipid moiety in the SVP is organized in a noncanonical lipid patch instead of a lipid bilayer, which can accommodate the exposed hydrophobic surface and modulate particle stability. Together, these findings advance our knowledge of viral membrane organization and the structures of HBV and WHV spherical SVPs.
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Affiliation(s)
- Haitao Liu
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Xupeng Hong
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Ji Xi
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Stephan Menne
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington DC 20007, USA
| | - Jianming Hu
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Joseph Che-Yen Wang
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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2
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Vaillant A. HBsAg, Subviral Particles, and Their Clearance in Establishing a Functional Cure of Chronic Hepatitis B Virus Infection. ACS Infect Dis 2021; 7:1351-1368. [PMID: 33302622 DOI: 10.1021/acsinfecdis.0c00638] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In diverse viral infections, the production of excess viral particles containing only viral glycoproteins (subviral particles or SVP) is commonly observed and is a commonly evolved mechanism for immune evasion. In hepatitis B virus (HBV) infection, spherical particles contain the hepatitis B surface antigen, outnumber infectious virus 10 000-100 000 to 1, and have diverse inhibitory effects on the innate and adaptive immune response, playing a major role in the chronic nature of HBV infection. The current goal of therapies in development for HBV infection is a clinical outcome called functional cure, which signals a persistent and effective immune control of the infection. Although removal of spherical SVP (and the HBsAg they carry) is an important milestone in achieving functional cure, this outcome is rarely achieved with current therapies due to distinct mechanisms for assembly, secretion, and persistence of SVP, which are poorly targeted by direct acting antivirals or immunotherapies. In this Review, the current understanding of the distinct mechanisms involved in the production and persistence of spherical SVP in chronic HBV infection and their immunoinhibitory activity will be reviewed as well as current therapies in development with the goal of clearing spherical SVP and achieving functional cure.
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Affiliation(s)
- Andrew Vaillant
- Replicor Inc., 6100 Royalmount Avenue, Montreal, Quebec H8Y 3E6, Canada
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3
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Hepatitis B Virus Exploits ERGIC-53 in Conjunction with COPII to Exit Cells. Cells 2020; 9:cells9081889. [PMID: 32806600 PMCID: PMC7464876 DOI: 10.3390/cells9081889] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/05/2020] [Accepted: 08/10/2020] [Indexed: 12/20/2022] Open
Abstract
Several decades after its discovery, the hepatitis B virus (HBV) still displays one of the most successful pathogens in human populations worldwide. The identification and characterization of interactions between cellular and pathogenic components are essential for the development of antiviral treatments. Due to its small-sized genome, HBV highly depends on cellular functions to produce and export progeny particles. Deploying biochemical-silencing methods and molecular interaction studies in HBV-expressing liver cells, we herein identified the cellular ERGIC-53, a high-mannose-specific lectin, and distinct components of the endoplasmic reticulum (ER) export machinery COPII as crucial factors of viral trafficking and egress. Whereas the COPII subunits Sec24A, Sec23B and Sar1 are needed for both viral and subviral HBV particle exit, ERGIC-53 appears as an exclusive element of viral particle propagation, therefore interacting with the N146-glycan of the HBV envelope in a productive manner. Cell-imaging studies pointed to ER-derived, subcellular compartments where HBV assembly initiates. Moreover, our findings provide evidence that HBV exploits the functions of ERGIC-53 and Sec24A after the envelopment of nucleocapsids at these compartments in conjunction with endosomal sorting complexes required for transport (ESCRT) components. These data reveal novel insights into HBV assembly and trafficking, illustrating therapeutic prospects for intervening with the viral life cycle.
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Michalak TI. Diverse Virus and Host-Dependent Mechanisms Influence the Systemic and Intrahepatic Immune Responses in the Woodchuck Model of Hepatitis B. Front Immunol 2020; 11:853. [PMID: 32536912 PMCID: PMC7267019 DOI: 10.3389/fimmu.2020.00853] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 04/14/2020] [Indexed: 12/15/2022] Open
Abstract
Woodchuck infected with woodchuck hepatitis virus (WHV) represents the pathogenically nearest model of hepatitis B and associated hepatocellular carcinoma (HCC). This naturally occurring animal model also is highly valuable for development and preclinical evaluation of new anti-HBV agents and immunotherapies against chronic hepatitis (CH) B and HCC. Studies in this system uncovered a number of molecular and immunological processes which contribute or likely contribute to the immunopathogenesis of liver disease and modulation of the systemic and intrahepatic innate and adaptive immune responses during hepadnaviral infection. Among them, inhibition of presentation of the class I major histocompatibility complex on chronically infected hepatocytes and a role of WHV envelope proteins in this process, as well as augmented hepatocyte cytotoxicity mediated by constitutively expressed components of CD95 (Fas) ligand- and perforin-dependent pathways, capable of eliminating cells brought to contact with hepatocyte surface, including activated T lymphocytes, were uncovered. Other findings pointed to a role of autoimmune response against hepatocyte asialoglycoprotein receptor in augmenting severity of liver damage in hepadnaviral CH. It was also documented that WHV in the first few hours activates intrahepatic innate immunity that transiently decreases hepatic virus load. However, this activation is not translated in a timely manner to induction of virus-specific T cell response which appears to be hindered by defective activation of antigen presenting cells and presentation of viral epitopes to T cells. The early WHV infection also induces generalized polyclonal activation of T cells that precedes emergence of virus-specific T lymphocyte reactivity. The combination of these mechanisms hinder recognition of virus allowing its dissemination in the initial, asymptomatic stages of infection before adaptive cellular response became apparent. This review will highlight a range of diverse mechanisms uncovered in the woodchuck model which affect effectiveness of the anti-viral systemic and intrahepatic immune responses, and modify liver disease outcomes. Further exploration of these and other mechanisms, either already discovered or yet unknown, and their interactions should bring more comprehensive understanding of HBV pathogenesis and help to identify novel targets for therapeutic and preventive interventions. The woodchuck model is uniquely positioned to further contribute to these advances.
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Affiliation(s)
- Tomasz I Michalak
- Molecular Virology and Hepatology Research Group, Division of BioMedical Sciences, Faculty of Medicine, Health Sciences Centre, Memorial University of Newfoundland, St. John's, NL, Canada
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5
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Yang F. Post-translational Modification Control of HBV Biological Processes. Front Microbiol 2018; 9:2661. [PMID: 30443247 PMCID: PMC6222169 DOI: 10.3389/fmicb.2018.02661] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/18/2018] [Indexed: 12/11/2022] Open
Abstract
Hepatitis B virus infection remains a global healthy issue that needs to be urgently solved. Novel strategies for anti-viral therapy are based on exploring the effective diagnostic markers and therapeutic targets of diseases caused by hepatitis B virus (HBV) infection. It is well-established that not only viral proteins themselves but also key factors from the host control the biological processes associated with HBV, including replication, transcription, packaging, and secretion. Protein post-translational modifications (PTMs), such as phosphorylation, acetylation, methylation, and ubiquitination, have been shown to control protein activity, regulate protein stability, promote protein interactions and alter protein subcellular localization, leading to the modulation of crucial signaling pathways and affected cellular processes. This review focuses on the functions and effects of diverse PTMs in regulating important processes in the HBV life cycle. The potential roles of PTMs in the pathogenesis of HBV-associated liver diseases are also discussed.
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Affiliation(s)
- Fan Yang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Affiliation(s)
- David J. Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Biological Sciences and the Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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7
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Bathula C, Ghosh S, Hati S, Tripathy S, Singh S, Chakrabarti S, Sen S. Bioisosteric modification of known fucosidase inhibitors to discover a novel inhibitor of α-l-fucosidase. RSC Adv 2017. [DOI: 10.1039/c6ra24939f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hydantoin, thiohydantoin and pyridone analogs as α-l-fucosidase inhibitors through bioisosteric modification of known bovine α-l-fucosidase inhibitors.
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Affiliation(s)
| | - Shreemoyee Ghosh
- Structural Biology and Bio-Informatics Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata
- India
| | - Santanu Hati
- Department of Chemistry
- School of Natural Sciences
- Shiv Nadar University
- India
| | - Sayantan Tripathy
- Department of Life Sciences
- School of Natural Sciences
- Shiv Nadar University
- India
| | - Shailja Singh
- Department of Life Sciences
- School of Natural Sciences
- Shiv Nadar University
- India
| | - Saikat Chakrabarti
- Structural Biology and Bio-Informatics Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata
- India
| | - Subhabrata Sen
- Department of Chemistry
- School of Natural Sciences
- Shiv Nadar University
- India
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8
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Mulrooney-Cousins PM, Michalak TI. Asymptomatic Hepadnaviral Persistence and Its Consequences in the Woodchuck Model of Occult Hepatitis B Virus Infection. J Clin Transl Hepatol 2015; 3:211-9. [PMID: 26623268 PMCID: PMC4663203 DOI: 10.14218/jcth.2015.00020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/20/2015] [Accepted: 07/21/2015] [Indexed: 02/06/2023] Open
Abstract
Woodchuck hepatitis virus (WHV) is molecularly and pathogenically closely related to hepatitis B virus (HBV). Both viruses display tropism towards hepatocytes and cells of the immune system and cause similar liver pathology, where acute hepatitis can progress to chronic hepatitis and to hepatocellular carcinoma (HCC). Two forms of occult hepadnaviral persistence were identified in the woodchuck-WHV model: secondary occult infection (SOI) and primary occult infection (POI). SOI occurs after resolution of a serologically apparent infection with hepatitis or after subclinical serologically evident virus exposure. POI is caused by small amounts of virus and progresses without serological infection markers, but the virus genome and its replication are detectable in the immune system and with time in the liver. SOI can be accompanied by minimal hepatitis, while the hallmark of POI is normal liver morphology. Nonetheless, HCC develops in about 20% of animals with SOI or POI within 3 to 5 years. The virus persists throughout the lifespan in both SOI and POI at serum levels rarely greater than 100 copies/mL, causes hepatitis and HCC when concentrated and administered to virus-naïve woodchucks. SOI is accompanied by virus-specific T and B cell immune responses, while only virus-specific T cells are detected in POI. SOI coincides with protection against reinfection, while POI does not and hepatitis develops after challenge with liver pathogenic doses >1000 virions. Both SOI and POI are associated with virus DNA integration into the liver and the immune system genomes. Overall, SOI and POI are two distinct forms of silent hepadnaviral persistence that share common characteristics. Here, we review findings from the woodchuck model and discuss the relevant observations made in human occult HBV infection (OBI).
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Affiliation(s)
| | - Tomasz I. Michalak
- Correspondence to: Tomasz I. Michalak, Molecular Virology and Hepatology Research Group, Faculty of Medicine, Health Sciences Centre, Memorial University, St. John’s, NL A1B 3V6, Canada. Tel: +1-709-777-7301, Fax: +1-709-777-8279, E-mail:
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9
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Wu Q, Liu HO, Liu YD, Liu WS, Pan D, Zhang WJ, Yang L, Fu Q, Xu JJ, Gu JX. Decreased expression of hepatocyte nuclear factor 4α (Hnf4α)/microRNA-122 (miR-122) axis in hepatitis B virus-associated hepatocellular carcinoma enhances potential oncogenic GALNT10 protein activity. J Biol Chem 2015; 290:1170-85. [PMID: 25422324 PMCID: PMC4294483 DOI: 10.1074/jbc.m114.601203] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/16/2014] [Indexed: 12/19/2022] Open
Abstract
MicroRNA-122 (miR-122), a mammalian liver-specific miRNA, has been reported to play crucial roles in the control of diverse aspects of hepatic function and dysfunction, including viral infection and hepatocarcinogenesis. In this study, we explored the clinical significance, transcriptional regulation, and direct target of miR-122 in hepatitis B virus (HBV)-associated hepatocellular carcinoma. Reduced expression of miR-122 in patients with HBV-associated hepatocellular carcinoma was correlated with venous invasion and poor prognosis. Furthermore, UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase-10 (GALNT10) was identified as a bona fide target of miR-122 in hepatoma cells. Ectopic expression and knockdown studies showed that GALNT10 indeed promotes proliferation and apoptosis resistance of hepatoma cells in a glycosyltransferase-dependent manner. Critically, adverse correlation between miR-122 and GALNT10, a poor prognosticator of clinical outcome, was demonstrated in hepatoma patients. Hepatocyte nuclear factor 4α (Hnf4α), a liver-enriched transcription factor that activates miR-122 gene transcription, was suppressed in HBV-infected hepatoma cells. Chromatin immunoprecipitation assay showed significantly reduced association of Hnf4α with the miR-122 promoter in HBV-infected hepatoma cells. Moreover, GALNT10 was found to intensify O-glycosylation following signal activation of the epidermal growth factor receptor. In addition, in a therapeutic perspective, we proved that GALNT10 silencing increases sensitivity to sorafenib and doxorubicin challenge. In summary, our results reveal a novel Hnf4α/miR-122/GALNT10 regulatory pathway that facilitates EGF miR-122 activation and hepatoma growth in HBV-associated hepatocarcinogenesis.
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Affiliation(s)
- Qian Wu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Hai-Ou Liu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Yi-Dong Liu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Wei-Si Liu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Deng Pan
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Wei-Juan Zhang
- Department of Immunology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Liu Yang
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Qiang Fu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Jie-Jie Xu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
| | - Jian-Xin Gu
- From the Key Laboratory of Glycoconjugate Research, Ministry of Health, Department of Biochemistry and Molecular Biology and
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10
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Kosinska AD, Zhang E, Johrden L, Liu J, Seiz PL, Zhang X, Ma Z, Kemper T, Fiedler M, Glebe D, Wildner O, Dittmer U, Lu M, Roggendorf M. Combination of DNA prime--adenovirus boost immunization with entecavir elicits sustained control of chronic hepatitis B in the woodchuck model. PLoS Pathog 2013; 9:e1003391. [PMID: 23785279 PMCID: PMC3681757 DOI: 10.1371/journal.ppat.1003391] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 04/15/2013] [Indexed: 12/21/2022] Open
Abstract
A potent therapeutic T-cell vaccine may be an alternative treatment of chronic hepatitis B virus (HBV) infection. Previously, we developed a DNA prime-adenovirus (AdV) boost vaccination protocol that could elicit strong and specific CD8+ T-cell responses to woodchuck hepatitis virus (WHV) core antigen (WHcAg) in mice. In the present study, we first examined whether this new prime-boost immunization could induce WHcAg-specific T-cell responses and effectively control WHV replication in the WHV-transgenic mouse model. Secondly, we evaluated the therapeutic effect of this new vaccination strategy in chronically WHV-infected woodchucks in combination with a potent antiviral treatment. Immunization of WHV-transgenic mice by DNA prime-AdV boost regimen elicited potent and functional WHcAg-specific CD8+ T-cell response that consequently resulted in the reduction of the WHV load below the detection limit in more than 70% of animals. The combination therapy of entecavir (ETV) treatment and DNA prime-AdV boost immunization in chronic WHV carriers resulted in WHsAg- and WHcAg-specific CD4+ and CD8+ T-cell responses, which were not detectable in ETV-only treated controls. Woodchucks receiving the combination therapy showed a prolonged suppression of WHV replication and lower WHsAg levels compared to controls. Moreover, two of four immunized carriers remained WHV negative after the end of ETV treatment and developed anti-WHs antibodies. These results demonstrate that the combined antiviral and vaccination approach efficiently elicited sustained immunological control of chronic hepadnaviral infection in woodchucks and may be a new promising therapeutic strategy in patients. Chronic hepatitis B virus (HBV) infection is one of the major causes of liver cirrhosis and liver cancer worldwide. Recommended treatment regimens of chronic hepatitis B based on interferon alpha and nucleot(s)ide analogues do not lead to the satisfactory results. Over the last 20 years, continuous efforts have been undertaken to develop new immunotherapeutic approaches for the treatment of chronic hepatitis B, however, without satisfactory results. We proposed here that the combination of potent antivirals with a prime-boost vaccination protocol that is inducing appropriate virus-specific T-cell responses may restore immune control over HBV. To test this hypothesis we performed a proof-of-principle experiment using woodchucks, a widely accepted animal model of chronic HBV infection. We pretreated animals with entecavir to suppress viral replication and immunized them by a prime-boost regimen with DNA vaccines expressing woodchuck hepatitis virus (WHV) surface and core antigens and adenoviral vectors expressing WHV core antigen. Consistent with our hypothesis, the combination therapy achieved a stronger antiviral effect than the monotherapy alone, leading to sustained immunological control of chronic WHV infection and viral clearance in some animals. These data are encouraging and implicate the feasibility and usefulness of the immunotherapeutic strategies for the treatment of chronically HBV-infected patients.
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MESH Headings
- Adenoviridae
- Animals
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Cells, Cultured
- Disease Models, Animal
- Hepatitis B Vaccines/genetics
- Hepatitis B Vaccines/immunology
- Hepatitis B Vaccines/pharmacology
- Hepatitis B, Chronic/genetics
- Hepatitis B, Chronic/immunology
- Hepatitis B, Chronic/prevention & control
- Humans
- Immunity, Cellular/drug effects
- Immunity, Cellular/genetics
- Immunity, Cellular/immunology
- Immunization, Secondary
- Marmota
- Mice
- Mice, Transgenic
- Vaccines, DNA/genetics
- Vaccines, DNA/microbiology
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Affiliation(s)
- Anna D. Kosinska
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Ejuan Zhang
- Institute of Virology, University Hospital of Essen, Essen, Germany
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, People's Republic of China
| | - Lena Johrden
- Department of Molecular and Medical Virology, Institute of Microbiology and Hygiene, Ruhr-University Bochum, Bochum, Germany
| | - Jia Liu
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Pia L. Seiz
- Institute of Medical Virology, National Reference Centre for Hepatitis B and D Viruses, Justus-Liebig University, Giessen, Germany
| | - Xiaoyong Zhang
- Institute of Virology, University Hospital of Essen, Essen, Germany
- Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China
| | - Zhiyong Ma
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Thekla Kemper
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Melanie Fiedler
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Dieter Glebe
- Institute of Medical Virology, National Reference Centre for Hepatitis B and D Viruses, Justus-Liebig University, Giessen, Germany
| | - Oliver Wildner
- Paul-Ehrlich-Institut, Division of Medical Biotechnology, Langen, Germany
| | - Ulf Dittmer
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Mengji Lu
- Institute of Virology, University Hospital of Essen, Essen, Germany
| | - Michael Roggendorf
- Institute of Virology, University Hospital of Essen, Essen, Germany
- * E-mail:
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Niedre-Otomere B, Bogdanova A, Bruvere R, Ose V, Gerlich WH, Pumpens P, Glebe D, Kozlovska T. Posttranslational modifications and secretion efficiency of immunogenic hepatitis B virus L protein deletion variants. Virol J 2013; 10:63. [PMID: 23442390 PMCID: PMC3598826 DOI: 10.1186/1743-422x-10-63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 02/20/2013] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Subviral particles of hepatitis B virus (HBV) composed of L protein deletion variants with the 48 N-terminal amino acids of preS joined to the N-terminus of S protein (1-48preS/S) induced broadly neutralizing antibodies after immunization of mice with a Semliki Forest virus vector. A practical limitation for use as vaccine is the suboptimal secretion of such particles. The role of the N-terminal preS myristoylation in the cellular retention of full-length L protein is described controversially in the literature and the relation of these data to the truncated L protein was unknown. Thus, we studied the effect of preS myristoylation signal suppression on 1-48preS/S secretion efficiency, glycosylation and subcellular distribution. FINDINGS The findings are that 1-48preS/S is secreted, and that removal of the N-terminal myristoylation signal in its G2A variant reduced secretion slightly, but significantly. The glycosylation pattern of 1-48preS/S was not affected by the removal of the myristoylation signal (G2A mutant) but was different than natural L protein, whereby N4 of the preS and N3 of the S domain were ectopically glycosylated. This suggested cotranslational translocation of 1-48preS in contrast to natural L protein. The 1-48preS/S bearing a myristoylation signal was localized in a compact, perinuclear pattern with strong colocalization of preS and S epitopes, while the non-myristoylated mutants demonstrated a dispersed, granular cytoplasmic distribution with weaker colocalization. CONCLUSIONS The large deletion in 1-48preS/S in presence of the myristoylation site facilitated formation and secretion of protein particles with neutralizing preS1 epitopes at their surface and could be a useful feature for future hepatitis B vaccines.
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12
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Ochoa-Callejero L, Otano I, Vales A, Olagüe C, Sarobe P, Lasarte JJ, Prieto J, Menne S, González-Aseguinolaza G. Identification of CD4+ and CD8+ T cell epitopes of woodchuck hepatitis virus core and surface antigens in BALB/c mice. Vaccine 2010; 28:5323-31. [PMID: 20665977 DOI: 10.1016/j.vaccine.2010.05.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A therapeutic vaccine against chronic hepatitis B virus (HBV) infection requires the development of a strong and multispecific Th1 cell immune response. Woodchucks chronically infected with the woodchuck hepatitis virus (WHV) closely resemble HBV infection and represent the best animal model for this hepadnavirus-induced disease. Using the BIMAS "HLA Peptide Binding Predictions" program, we have identified and further characterized novel H-2 d-restricted CD8+ epitopes within the WHV core (peptides C#12-21, C#18-32, C#19-27, C#61-69) and surface antigens (peptides preS2#10-18, preS2#27-35, S#76-84, S#133-140 and S#257-265), respectively. These peptides bind to H-2 d with high efficiency and upon immunization of mice with peptide and Freund's adjuvant they induce the development of IFN-gamma producing T cells. More importantly, WHV core peptides C#19-27 and C#61-69 and WHV surface peptides S#133-140 and S#257-265 were also recognized by CD8+ T cells after immunization of mice with DNA/PEI nanoparticles. Direct stimulation of splenocytes obtained from such DNA-immunized mice with peptides C#18-32, S#76-84, and S#257-265 resulted in significant production of IFN-gamma. Thus, we have identified T cell determinants in mice from WHV core and surface antigens that have important value for designing and evaluating an effective vaccine against hepadnavirus infection.
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Affiliation(s)
- L Ochoa-Callejero
- Laboratory of Gene Therapy of Viral Hepatitis, Division of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), Pamplona, Navarra, Spain
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13
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Patient R, Hourioux C, Roingeard P. Morphogenesis of hepatitis B virus and its subviral envelope particles. Cell Microbiol 2009; 11:1561-70. [PMID: 19673892 DOI: 10.1111/j.1462-5822.2009.01363.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
After cell hijacking and intracellular amplification, non-lytic enveloped viruses are usually released from the infected cell by budding across internal membranes or through the plasma membrane. The enveloped human hepatitis B virus (HBV) is an example of virus using an intracellular compartment to form new virions. Four decades after its discovery, HBV is still the primary cause of death by cancer due to a viral infection worldwide. Despite numerous studies on HBV genome replication little is known about its morphogenesis process. In addition to viral neogenesis, the HBV envelope proteins have the capability without any other viral component to form empty subviral envelope particles (SVPs), which are secreted into the blood of infected patients. A better knowledge of this process may be critical for future antiviral strategies. Previous studies have speculated that the morphogenesis of HBV and its SVPs occur through the same mechanisms. However, recent data clearly suggest that two different processes, including constitutive Golgi pathway or cellular machinery that generates internal vesicles of multivesicular bodies (MVB), independently form these two viral entities.
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14
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Short JM, Chen S, Roseman AM, Butler PJG, Crowther RA. Structure of hepatitis B surface antigen from subviral tubes determined by electron cryomicroscopy. J Mol Biol 2009; 390:135-41. [PMID: 19414021 DOI: 10.1016/j.jmb.2009.04.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 04/17/2009] [Accepted: 04/28/2009] [Indexed: 10/20/2022]
Abstract
Hepatitis B virus consists of an icosahedral core containing the double-stranded DNA genome, enveloped by a membrane with embedded surface proteins. The crystal structure of the core protein has been solved but little information about the structure of the surface proteins has so far been available. There are three sizes of surface protein, small (S), medium (M) and large (L), which form disulfide-bonded homo- and heterodimers. The three proteins, expressed from different start sites in the coding sequence, share the common C-terminal S region; the M protein contains an additional preS2 sequence N-terminal to S, and the L protein a further preS1 sequence N-terminal to M. In infected individuals, the surface proteins are produced in huge excess over the amount needed for viral envelopment and are secreted as a heterogeneous mixture of isometric and tubular subviral particles. We have used electron cryomicroscopy to study tubular particles extracted from human serum. Helical Fourier-Bessel analysis was used to calculate a low-resolution map, although it showed that the tubes were quite disordered. From the symmetry derived from this analysis, we used single-particle methods to improve the resolution. We found that the tubes had a diameter of approximately 250 A, with spike-like features projecting from the membrane. In the plane of the membrane the proteins appear to be close packed. We propose a model for the packing arrangement of surface protein dimers in the tubes.
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15
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Correlation of virus and host response markers with circulating immune complexes during acute and chronic woodchuck hepatitis virus infection. J Virol 2008; 83:1579-91. [PMID: 19052077 DOI: 10.1128/jvi.01934-08] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Woodchuck hepatitis virus (WHV) is an established model for human hepatitis B virus. The kinetics of virus and host responses in serum and liver during acute, self-limited WHV infection in adult woodchucks were studied. Serum WHV DNA and surface antigen (WHsAg) were detected as early as 1 to 3 weeks following experimental infection and peaked between 1 and 5 weeks postinfection. Thereafter, serum WHsAg levels declined rapidly and became undetectable, while WHV DNA levels became undetectable much later, between 4 and 20 weeks postinfection. Decreasing viremia correlated with transient liver injury marked by an increase in serum sorbitol dehydrogenase (SDH) levels. Clearance of WHV DNA from serum was associated with the normalization of serum SDH. Circulating immune complexes (CICs) of WHsAg and antibodies against WHsAg (anti-WHs) that correlated temporarily with the peaks in serum viremia and WHs antigenemia were detected. CICs were no longer detected in serum once free anti-WHs became detectable. The detection of CICs around the peak in serum viremia and WHs antigenemia in resolving woodchucks suggests a critical role for the humoral immune response against WHsAg in the early elimination of viral and subviral particles from the peripheral blood. Individual kinetic variation during WHV infections in resolving woodchucks infected with the same WHV inoculum and dose is likely due to the outbred nature of the animals, indicating that the onset and magnitude of the individual immune response determine the intensity of virus inhibition and the timing of virus elimination from serum.
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16
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Lu M, Yao X, Xu Y, Lorenz H, Dahmen U, Chi H, Dirsch O, Kemper T, He L, Glebe D, Gerlich WH, Wen Y, Roggendorf M. Combination of an antiviral drug and immunomodulation against hepadnaviral infection in the woodchuck model. J Virol 2008; 82:2598-603. [PMID: 18160442 PMCID: PMC2258919 DOI: 10.1128/jvi.01613-07] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 12/14/2007] [Indexed: 12/29/2022] Open
Abstract
The essential role of multispecific immune responses for the control of hepatitis B virus (HBV) infection implies the need of multimodal therapeutic strategies for chronic HBV infection, including antiviral chemotherapy and immunomodulation. This hypothesis was tested in the woodchuck model by a combination of lamivudine pretreatment and subsequent immunizations of woodchucks chronically infected with woodchuck hepatitis virus. The immunizations were performed with DNA vaccines or antigen-antibody immune complexes (IC)/DNA vaccines. Immunizations with IC/DNA vaccines led to an anti-woodchuck hepatitis virus surface antibody response and significant reductions of viral load and antigenemia, suggesting that such a strategy may be effective against chronic HBV infection.
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Affiliation(s)
- Mengji Lu
- Institut für Virologie, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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17
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Abstract
Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds. All members of this family can cause acute and chronic hepatic infection, which in the case of human hepatitis B virus (HBV) constitutes a major global health problem. Although our knowledge about the molecular biology of these highly liver-specific viruses has profoundly increased in the last two decades, the mechanisms of attachment and productive entrance into the differentiated host hepatocytes are still enigmatic. The difficulties in studying hepadnaviral entry were primarily caused by the lack of easily accessible in vitro infection systems. Thus, for more than twenty years, differentiated primary hepatocytes from the respective species were the only in vitro models for both orthohepadnaviruses (e.g. HBV) and avihepadnaviruses (e.g. duck hepatitis B virus [DHBV]). Two important discoveries have been made recently regarding HBV: (1) primary hepatocytes from tree-shrews; i.e., Tupaia belangeri, can be substituted for primary human hepatocytes, and (2) a human hepatoma cell line (HepaRG) was established that gains susceptibility for HBV infection upon induction of differentiation in vitro. A number of potential HBV receptor candidates have been described in the past, but none of them have been confirmed to function as a receptor. For DHBV and probably all other avian hepadnaviruses, carboxypeptidase D (CPD) has been shown to be indispensable for infection, although the exact role of this molecule is still under debate. While still restricted to the use of primary duck hepatocytes (PDH), investigations performed with DHBV provided important general concepts on the first steps of hepadnaviral infection. However, with emerging data obtained from the new HBV infection systems, the hope that DHBV utilizes the same mechanism as HBV only partially held true. Nevertheless, both HBV and DHBV in vitro infection systems will help to: (1) functionally dissect the hepadnaviral entry pathways, (2) perform reverse genetics (e.g. test the fitness of escape mutants), (3) titrate and map neutralizing antibodies, (4) improve current vaccines to combat acute and chronic infections of hepatitis B, and (5) develop entry inhibitors for future clinical applications.
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Affiliation(s)
- Dieter Glebe
- Institute of Medical Virology, Justus-Liebig University of Giessen, Frankfurter Strasse 107, D-35392 Giessen, Germany.
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18
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update covering the period 1999-2000. MASS SPECTROMETRY REVIEWS 2006; 25:595-662. [PMID: 16642463 DOI: 10.1002/mas.20080] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
This review describes the use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates and continues coverage of the field from the previous review published in 1999 (D. J. Harvey, Matrix-assisted laser desorption/ionization mass spectrometry of carbohydrates, 1999, Mass Spectrom Rev, 18:349-451) for the period 1999-2000. As MALDI mass spectrometry is acquiring the status of a mature technique in this field, there has been a greater emphasis on applications rather than to method development as opposed to the previous review. The present review covers applications to plant-derived carbohydrates, N- and O-linked glycans from glycoproteins, glycated proteins, mucins, glycosaminoglycans, bacterial glycolipids, glycosphingolipids, glycoglycerolipids and related compounds, and glycosides. Applications of MALDI mass spectrometry to the study of enzymes acting on carbohydrates (glycosyltransferases and glycosidases) and to the synthesis of carbohydrates, are also covered.
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Affiliation(s)
- David J Harvey
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, United Kingdom.
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19
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Schmitt S, Glebe D, Tolle TK, Lochnit G, Linder D, Geyer R, Gerlich WH. Structure of pre-S2 N- and O-linked glycans in surface proteins from different genotypes of hepatitis B virus. J Gen Virol 2004; 85:2045-2053. [PMID: 15218190 DOI: 10.1099/vir.0.79932-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The middle-sized (M) surface proteins of hepatitis B virus (HBV) and other orthohepadnaviruses contain a conserved N-glycan in their pre-S2 domain, which is essential for the secretion of viral particles. Recently, we also found O-glycans in the pre-S2 domain of M protein from woodchuck hepatitis virus (WHV) and HBV genotype D. Since the O-glycosylation motif is not conserved in all genotypes of HBV, the glycosylation patterns of HBV genotypes A and C were analysed. Pre-S2 (glyco)peptides were released from HBV-carrier-derived HBV subviral particles by tryptic digestion, purified by reversed-phase HPLC and identified by amino acid and amino-terminal sequence analysis as well as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Pre-S2 N-glycans were characterized by anion-exchange chromatography, methylation analysis and on-target sequential exoglycosidase digestions in combination with MALDI-TOF-MS, demonstrating the presence of partially sialylated diantennary complex-type oligosaccharides in all genotypes examined. Pre-S2 O-glycans were characterized by on-target sequential exoglycosidase digestions in combination with MALDI-TOF-MS. The pre-S2 domain of M protein and, to a minor extent, of L (large) protein from HBV genotype C and D was partially O-glycosylated by Neu5Ac(alpha2-3)Gal(beta1-3)GalNAcalpha- or Gal(beta1-3)GalNAcalpha-units at Thr-37 within a conserved sequence context. Genotype A, containing no Thr at position 37 or 38, was not O-glycosylated. Analytical data further revealed that M protein is mostly amino-terminally acetylated in all examined genotypes and that the terminal methionine is partially oxidized. The findings may be relevant for the secretion and the immunogenicity of HBV.
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Affiliation(s)
- Sigrid Schmitt
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
| | - Dieter Glebe
- Institute of Medical Virology, University of Giessen, Frankfurter Strasse 107, D-35392 Giessen, Germany
| | - Tanja K Tolle
- Institute of Medical Virology, University of Giessen, Frankfurter Strasse 107, D-35392 Giessen, Germany
| | - Günter Lochnit
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
| | - Dietmar Linder
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
| | - Rudolf Geyer
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
| | - Wolfram H Gerlich
- Institute of Medical Virology, University of Giessen, Frankfurter Strasse 107, D-35392 Giessen, Germany
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20
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Structure of pre-S2 N- and O-linked glycans in surface proteins from different genotypes of hepatitis B virus. J Gen Virol 2004. [DOI: 10.1099/vir.0.79932-0#] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The middle-sized (M) surface proteins of hepatitis B virus (HBV) and other orthohepadnaviruses contain a conserved N-glycan in their pre-S2 domain, which is essential for the secretion of viral particles. Recently, we also found O-glycans in the pre-S2 domain of M protein from woodchuck hepatitis virus (WHV) and HBV genotype D. Since the O-glycosylation motif is not conserved in all genotypes of HBV, the glycosylation patterns of HBV genotypes A and C were analysed. Pre-S2 (glyco)peptides were released from HBV-carrier-derived HBV subviral particles by tryptic digestion, purified by reversed-phase HPLC and identified by amino acid and amino-terminal sequence analysis as well as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Pre-S2 N-glycans were characterized by anion-exchange chromatography, methylation analysis and on-target sequential exoglycosidase digestions in combination with MALDI-TOF-MS, demonstrating the presence of partially sialylated diantennary complex-type oligosaccharides in all genotypes examined. Pre-S2 O-glycans were characterized by on-target sequential exoglycosidase digestions in combination with MALDI-TOF-MS. The pre-S2 domain of M protein and, to a minor extent, of L (large) protein from HBV genotype C and D was partially O-glycosylated by Neu5Ac(α2–3)Gal(β1–3)GalNAcα- or Gal(β1–3)GalNAcα-units at Thr-37 within a conserved sequence context. Genotype A, containing no Thr at position 37 or 38, was not O-glycosylated. Analytical data further revealed that M protein is mostly amino-terminally acetylated in all examined genotypes and that the terminal methionine is partially oxidized. The findings may be relevant for the secretion and the immunogenicity of HBV.
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21
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Schildgen O, Roggendorf M, Lu M. Identification of a glycosylation site in the woodchuck hepatitis virus preS2 protein and its role in protein trafficking. J Gen Virol 2004; 85:787-793. [PMID: 15039521 DOI: 10.1099/vir.0.19672-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The middle surface antigen (M-sAg) of hepadnaviruses is one of three envelope proteins that share a common C-terminal S domain. M-sAg contains the preS2 domain in addition to the S region. The preS2 region of woodchuck hepatitis virus (WHV) contains a potential glycosylation site Asn-Gln-Thr at amino acid (aa) positions 3-5. In this study, we mutated this site by site-directed mutagenesis and confirmed that glycosylation occurs here. In in vitro translation assays, the mutation Thr to Asn at aa 5 significantly impaired glycosylation of M-sAg. The mutated M-sAg formed abnormal clustered structures in transfected cells as determined by immunofluorescent staining. Confocal microscopic analysis showed that an enrichment of this glycosylation-deficient protein in the Golgi apparatus occurred, which is not typical for the wild-type protein. These results are consistent with earlier findings that incorrect glycosylation of viral proteins may interfere with virus assembly.
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Affiliation(s)
- O Schildgen
- Institut für Virologie, Universitätsklinikum Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - M Roggendorf
- Institut für Virologie, Universitätsklinikum Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - M Lu
- Institut für Virologie, Universitätsklinikum Essen, Hufelandstraße 55, 45122 Essen, Germany
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22
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Glebe D, Aliakbari M, Krass P, Knoop EV, Valerius KP, Gerlich WH. Pre-s1 antigen-dependent infection of Tupaia hepatocyte cultures with human hepatitis B virus. J Virol 2003; 77:9511-21. [PMID: 12915565 PMCID: PMC187384 DOI: 10.1128/jvi.77.17.9511-9521.2003] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2003] [Accepted: 06/03/2003] [Indexed: 12/17/2022] Open
Abstract
The susceptibility of the tree shrew Tupaia belangeri to human hepatitis B virus (HBV) has been demonstrated both in vivo and in vitro. In this study, we show that purified HBV infects primary T. belangeri hepatocyte cultures in a very specific manner, as detected by HBV covalently closed circular DNA, mRNA, HBV e antigen, and HBsAg production. A monoclonal antibody (MAb), MA18/7, directed against the pre-S1 domain of the large HBs protein, which has been shown to neutralize infectivity of HBV for primary human hepatocytes, also blocked infection of primary Tupaia hepatocytes. MAbs against the pre-S2 domain of HBs inhibited infection only partially, whereas an S MAb and polyvalent anti-HBs antibodies neutralized infection completely. Thus, both pre-S1 and S antigens are necessary for infection in the tupaia. Using subviral particles, >70% of primary Tupaia hepatocytes are capable of specific binding of pre-S1-rich HBsAg, showing localization in distinct membrane areas. The data show that the early steps of HBV infection in Tupaia hepatocyte cultures are comparable to those in the human system.
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Affiliation(s)
- Dieter Glebe
- Institute of Medical Virology. Institute of Anatomy and Cell Biology, Justus Liebig University Giessen, 35392 Giessen, Germany.
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23
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Lu M, Klaes R, Menne S, Gerlich W, Stahl B, Dienes HP, Drebber U, Roggendorf M. Induction of antibodies to the PreS region of surface antigens of woodchuck hepatitis virus (WHV) in chronic carrier woodchucks by immunizations with WHV surface antigens. J Hepatol 2003; 39:405-13. [PMID: 12927927 DOI: 10.1016/s0168-8278(03)00241-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND/AIMS One goal of therapeutic vaccinations against chronic hepatitis B virus infection is to stimulate the B-cell responses to viral surface antigens in chronic carriers. Here we investigated the induction of antibody responses to hepadnaviral surface antigens in the woodchuck model, with emphasis on the vaccination of woodchucks chronically infected with woodchuck hepatitis virus (WHV). METHODS Naive and chronically WHV-infected woodchucks were immunized with plasma-derived WHV surface antigens (p-WHsAg) containing the S and PreS sequences. Antibody responses to WHsAg and the WHV PreS region and viral load in immunized woodchucks were monitored. RESULTS After repeated immunizations with WHsAg, 17 of 18 chronic WHV carriers developed a persistent antibody response to WHsAg. These antibodies were mainly directed to epitopes within the PreS region and detectable by Western blotting. However, neither WHV DNA nor WHsAg concentrations in these woodchucks changed significantly by immunizations and during the follow up. Sequence analysis of WHV genomes showed that no WHV mutants emerged after the induction of anti-WHs/anti-WHpreS antibodies. No immunopathological changes in livers of immunized animals were recognized thus far. CONCLUSIONS Our study demonstrated that the immunological unresponsiveness of chronically WHV-infected woodchucks to WHsAg can be partially overcome by repeated immunizations with WHsAg.
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Affiliation(s)
- Mengji Lu
- Institut für Virologie, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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24
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Tai PC, Suk FM, Gerlich WH, Neurath AR, Shih C. Hypermodification and immune escape of an internally deleted middle-envelope (M) protein of frequent and predominant hepatitis B virus variants. Virology 2002; 292:44-58. [PMID: 11878907 DOI: 10.1006/viro.2001.1239] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Naturally occurring deletions within the human hepatitis B virus (HBV) preS2 region have frequently been identified in patients with hepatocellular carcinoma (HCC), while chronic carriers without cirrhosis and HCC contain no detectable preS2 deletion variants. We have characterized two different preS2 internal deletion variants from two patients. In addition to several weak phenotypes, our study revealed three unexpected strong phenotypes: (1) a paradoxical "hypermodification" phenomenon was observed with significantly increased size heterogeneity and molecular weights of the secreted middle (M) envelope proteins containing a preS2 internal deletion. This phenomenon was observed in transient transfection with a human hepatoma Huh7 cell line as well as in stable transfection with a rodent hepatoma cell line 7777. (2) A significantly increased intracellular accumulation of all three envelope proteins (large, middle, and small) was detected by both Western blot analysis and immunofluorescence microscopy. (3) The middle envelope proteins with a preS2 internal deletion were not recognized in vitro by a putative neutralizing antiserum, suggesting that these variants can evade immune recognition in vivo. To our knowledge, this is the first identification and characterization of the M deletion variant protein in HBV natural infection.
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Affiliation(s)
- Pei-Ching Tai
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, 77555-0609, USA
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25
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Waters JA, O'Neill C, Abdul-Gader A, Goldin R, Karayiannis P, Monjardino J. Purification of woodchuck hepatitis surface antigen using a monoclonal antibody raised against the antigen. J Virol Methods 2001; 93:97-103. [PMID: 11311348 DOI: 10.1016/s0166-0934(00)00300-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Woodchuck hepatitis virus (WHV) is closely related to the human hepatitis B virus (HBV) and infection of woodchucks with WHV creates a useful model for studies of immunity, pathogenesis and therapy of HBV infection. To increase the usefulness of this model, monoclonal antibodies were raised to woodchuck hepatitis surface antigen (WHsAg) and one of these antibodies was used to purify the antigen by affinity chromatography from serum, a simpler and quicker method of purification than the current ultracentrifugation methods. The bands found by SDS-polyacrylamide gel electophoresis of WHsAg were the major 25 and 29 kilodalton (kDa) bands and a triplet of 45, 51 and 55 kDa which are thought to be the glycosylated and unglycosylated middle and large WHsAg. Both the antibody and the antigen are valuable reagents for the study of WHV infection.
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Affiliation(s)
- J A Waters
- Department of Medicine, Imperial College School of Science, Technology and Medicine, St Mary's Campus, Norfolk Place, London W2 1PG, UK.
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26
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Lu X, Hazboun T, Block T. Limited proteolysis induces woodchuck hepatitis virus infectivity for human HepG2 cells. Virus Res 2001; 73:27-40. [PMID: 11163642 DOI: 10.1016/s0168-1702(00)00218-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Previous work from our laboratory has shown that digestion of hepatitis B virus (HBV) with V8 protease rendered the virus infectious for human hepatoblastoma cell line (HepG2). It was hypothesized that the cleavage exposes a 16 amino acid region that includes a consensus 'fusion' motif necessary to mediate infectivity. Since woodchuck hepatitis virus (WHV) and HBV possess significant homology in this region of their envelope proteins, including the V8 protease cleavage site, the possibility that WHV infectivity for HepG2 cells could be induced by V8 digestion was explored. WHV isolated from the serum of chronically infected woodchucks, digested with V8 protease, was shown to loose its preS domain. V8 digested WHV eluted from gel filtration columns with a size similar to that of undigested virus, suggesting that digestion with V8 protease did not cause significant changes in virion size. The amount of progeny virus secreted into the culture medium following infection of HepG2 cells with V8 digested WHV reached 2.5 pg/ml, after 8 days. Moreover, WHV DNA replicative intermediates could be detected in the cells following infection with protease digested, but not undigested, viruses. These data suggest that protease modification of WHV, a non-human virus, induced infectivity for human tissue culture cells. These results are consistent with the hypothesis that exposure of an amino acid region of the envelope polypeptide that contains a consensus fusion motif is important in Hepadnavirus entry.
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Affiliation(s)
- X Lu
- Jefferson Center for Medical Research at DVC, Thomas Jefferson University, Doylestown, PA 18901, USA.
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27
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Sobotta D, Sominskaya I, Jansons J, Meisel H, Schmitt S, Heermann KH, Kaluza G, Pumpens P, Gerlich WH. Mapping of immunodominant B-cell epitopes and the human serum albumin-binding site in natural hepatitis B virus surface antigen of defined genosubtype. J Gen Virol 2000; 81:369-78. [PMID: 10644835 DOI: 10.1099/0022-1317-81-2-369] [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: 12/12/2022] Open
Abstract
Twelve MAbs were generated by immunization of BALB/c mice with plasma-derived hepatitis B virus surface spherical antigen particles subtype ayw2 (HBsAg/ayw2 genotype D). Their epitopes were mapped by analysis of reactivity with plasma-derived HBsAg/ayw2 and HBsAg/adw2 (genotype A) in enzyme immunoassays and blots. Mapping was supported by nested sets of truncated preS2 proteins and preS2 peptides. Five antibodies were S domain-specific, seven were preS2-specific and 11 had a preference for genotype D. According to our data, group I of the three known epitope groups of preS2 has to be divided into IA and IB. Three preS2-specific MAbs forming the new group IA reacted with genotype D residues 3-15 which have not yet been described as an epitope region. IA antibodies strongly inhibited the binding of polymerized human serum albumin. Two antibodies (group II) reacted with the glycosylated N-terminal region of preS2 in plasma-derived HBsAg, but not with a preparation from transfected murine cells. One group III antibody was subtype-specific and reacted with the highly variable preS2 sequence 38-48. Only one antibody (group IB) mapped to the region (old group I) which was believed to be immunodominant and genotype-independent. Geno(sub)type-specific epitopes of preS2 are obviously the immunodominant components of natural HBsAg in BALB/c mice, but these epitopes may be masked by serum albumins in humans. The data may explain why it is difficult to detect anti-preS2 antibodies in human recipients of preS2-containing vaccines, in spite of the preS2 immunodominance in mice.
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Affiliation(s)
- D Sobotta
- Institute of Medical Virology, Clinics of the Justus-Liebig-University, Frankfurter Str. 107, D-35392 Giessen, Germany
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28
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Schmitt S, Glebe D, Alving K, Tolle TK, Linder M, Geyer H, Linder D, Peter-Katalinic J, Gerlich WH, Geyer R. Analysis of the pre-S2 N- and O-linked glycans of the M surface protein from human hepatitis B virus. J Biol Chem 1999; 274:11945-57. [PMID: 10207016 DOI: 10.1074/jbc.274.17.11945] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The surface antigen of hepatitis B virus comprises a nested set of small (S), middle (M), and large (L) proteins, all of which are partially glycosylated in their S domains. The pre-S2 domain, present only in M and L proteins, is further N-glycosylated at Asn-4 exclusively in the M protein. Since the pre-S2 N-glycan appears to play a crucial role in the secretion of viral particles, the M protein may be considered as a potential target for antiviral therapy. For characterization of the pre-S2 glycosylation, pre-S2 (glyco)peptides were released from native, patient-derived hepatitis B virus subviral particles by tryptic digestion, separated from remaining particles, purified by reversed-phase high performance liquid chromatography, and identified by amino acid and N-terminal sequence analysis as well as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Pre-S2 N-glycans were characterized by anion exchange chromatography, methylation analysis, and on target sequential exoglycosidase digestions in combination with MALDI-TOF-MS, demonstrating the presence of partially sialylated diantennary complex-type oligosaccharides. In addition, the pre-S2 domain of M protein, but not that of L protein, was found to be partially O-glycosylated by a Gal(beta1-3)GalNAcalpha-, Neu5Ac(alpha2-3)Gal(beta1-3)GalNAcalpha-, or GalNAcalpha-residue. The respective O-glycosylation site was assigned to Thr-37 by digestion with carboxypeptidases in combination with MALDI-TOF-MS and by quadrupole time-of-flight electrospray mass spectrometry. Analytical data further revealed that about 90% of M protein is N-terminally acetylated.
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Affiliation(s)
- S Schmitt
- Institute of Biochemistry, University of Giessen, Friedrichstrasse 24, D-35392 Giessen, Germany
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