1
|
Hepatitis B and Hepatitis D Viruses: A Comprehensive Update with an Immunological Focus. Int J Mol Sci 2022; 23:ijms232415973. [PMID: 36555623 PMCID: PMC9781095 DOI: 10.3390/ijms232415973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Hepatitis B virus (HBV) and hepatitis delta virus (HDV) are highly prevalent viruses estimated to infect approximately 300 million people and 12-72 million people worldwide, respectively. HDV requires the HBV envelope to establish a successful infection. Concurrent infection with HBV and HDV can result in more severe disease outcomes than infection with HBV alone. These viruses can cause significant hepatic disease, including cirrhosis, fulminant hepatitis, and hepatocellular carcinoma, and represent a significant cause of global mortality. Therefore, a thorough understanding of these viruses and the immune response they generate is essential to enhance disease management. This review includes an overview of the HBV and HDV viruses, including life cycle, structure, natural course of infection, and histopathology. A discussion of the interplay between HDV RNA and HBV DNA during chronic infection is also included. It then discusses characteristics of the immune response with a focus on reactions to the antigenic hepatitis B surface antigen, including small, middle, and large surface antigens. This paper also reviews characteristics of the immune response to the hepatitis D antigen (including small and large antigens), the only protein expressed by hepatitis D. Lastly, we conclude with a discussion of recent therapeutic advances pertaining to these viruses.
Collapse
|
2
|
Adaptive Immune Responses, Immune Escape and Immune-Mediated Pathogenesis during HDV Infection. Viruses 2022; 14:v14020198. [PMID: 35215790 PMCID: PMC8880046 DOI: 10.3390/v14020198] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 12/13/2022] Open
Abstract
The hepatitis delta virus (HDV) is the smallest known human virus, yet it causes great harm to patients co-infected with hepatitis B virus (HBV). As a satellite virus of HBV, HDV requires the surface antigen of HBV (HBsAg) for sufficient viral packaging and spread. The special circumstance of co-infection, albeit only one partner depends on the other, raises many virological, immunological, and pathophysiological questions. In the last years, breakthroughs were made in understanding the adaptive immune response, in particular, virus-specific CD4+ and CD8+ T cells, in self-limited versus persistent HBV/HDV co-infection. Indeed, the mechanisms of CD8+ T cell failure in persistent HBV/HDV co-infection include viral escape and T cell exhaustion, and mimic those in other persistent human viral infections, such as hepatitis C virus (HCV), human immunodeficiency virus (HIV), and HBV mono-infection. However, compared to these larger viruses, the small HDV has perfectly adapted to evade recognition by CD8+ T cells restricted by common human leukocyte antigen (HLA) class I alleles. Furthermore, accelerated progression towards liver cirrhosis in persistent HBV/HDV co-infection was attributed to an increased immune-mediated pathology, either caused by innate pathways initiated by the interferon (IFN) system or triggered by misguided and dysfunctional T cells. These new insights into HDV-specific adaptive immunity will be discussed in this review and put into context with known well-described aspects in HBV, HCV, and HIV infections.
Collapse
|
3
|
Karimzadeh H, Kiraithe MM, Kosinska AD, Glaser M, Fiedler M, Oberhardt V, Salimi Alizei E, Hofmann M, Mok JY, Nguyen M, van Esch WJE, Budeus B, Grabowski J, Homs M, Olivero A, Keyvani H, Rodríguez-Frías F, Tabernero D, Buti M, Heinold A, Alavian SM, Bauer T, Schulze Zur Wiesch J, Raziorrouh B, Hoffmann D, Smedile A, Rizzetto M, Wedemeyer H, Timm J, Antes I, Neumann-Haefelin C, Protzer U, Roggendorf M. Amino Acid Substitutions within HLA-B*27-Restricted T Cell Epitopes Prevent Recognition by Hepatitis Delta Virus-Specific CD8 + T Cells. J Virol 2018; 92:JVI.01891-17. [PMID: 29669837 PMCID: PMC6002722 DOI: 10.1128/jvi.01891-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/22/2018] [Indexed: 02/07/2023] Open
Abstract
Virus-specific CD8 T cell response seems to play a significant role in the outcome of hepatitis delta virus (HDV) infection. However, the HDV-specific T cell epitope repertoire and mechanisms of CD8 T cell failure in HDV infection have been poorly characterized. We therefore aimed to characterize HDV-specific CD8 T cell epitopes and the impacts of viral mutations on immune escape. In this study, we predicted peptide epitopes binding the most frequent human leukocyte antigen (HLA) types and assessed their HLA binding capacities. These epitopes were characterized in HDV-infected patients by intracellular gamma interferon (IFN-γ) staining. Sequence analysis of large hepatitis delta antigen (L-HDAg) and HLA typing were performed in 104 patients. The impacts of substitutions within epitopes on the CD8 T cell response were evaluated experimentally and by in silico studies. We identified two HLA-B*27-restricted CD8 T cell epitopes within L-HDAg. These novel epitopes are located in a relatively conserved region of L-HDAg. However, we detected molecular footprints within the epitopes in HLA-B*27-positive patients with chronic HDV infections. The variant peptides were not cross-recognized in HLA-B*27-positive patients with resolved HDV infections, indicating that the substitutions represent viral escape mutations. Molecular modeling of HLA-B*27 complexes with the L-HDAg epitope and its potential viral escape mutations indicated that the structural and electrostatic properties of the bound peptides differ considerably at the T cell receptor interface, which provides a possible molecular explanation for the escape mechanism. This viral escape from the HLA-B*27-restricted CD8 T cell response correlates with a chronic outcome of hepatitis D infection. T cell failure resulting from immune escape may contribute to the high chronicity rate in HDV infection.IMPORTANCE Hepatitis delta virus (HDV) causes severe chronic hepatitis, which affects 20 million people worldwide. Only a small number of patients are able to clear the virus, possibly mediated by a virus-specific T cell response. Here, we performed a systematic screen to define CD8 epitopes and investigated the role of CD8 T cells in the outcome of hepatitis delta and how they fail to eliminate HDV. Overall the number of epitopes identified was very low compared to other hepatotropic viruses. We identified, two HLA-B*27-restricted epitopes in patients with resolved infections. In HLA-B*27-positive patients with chronic HDV infections, however, we detected escape mutations within these identified epitopes that could lead to viral evasion of immune responses. These findings support evidence showing that HLA-B*27 is important for virus-specific CD8 T cell responses, similar to other viral infections. These results have implications for the clinical prognosis of HDV infection and for vaccine development.
Collapse
Affiliation(s)
- Hadi Karimzadeh
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
- Institute of Virology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany
| | - Muthamia M Kiraithe
- University Hospital Freiburg, Department of Medicine II, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Anna D Kosinska
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich and Hannover Sites, Braunschweig, Germany
| | - Manuel Glaser
- Center for Integrated Protein Science Munich at the Department of Biosciences, Technische Universität München, Freising, Germany
| | - Melanie Fiedler
- Institute of Virology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany
| | - Valerie Oberhardt
- University Hospital Freiburg, Department of Medicine II, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Elahe Salimi Alizei
- University Hospital Freiburg, Department of Medicine II, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Maike Hofmann
- University Hospital Freiburg, Department of Medicine II, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | | | | | | | - Bettina Budeus
- Department of Bioinformatics, University of Duisburg-Essen, Essen, Germany
| | - Jan Grabowski
- German Center for Infection Research (DZIF), Munich and Hannover Sites, Braunschweig, Germany
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Maria Homs
- CIBERehd and Departments of Biochemistry/Microbiology and Hepatology, Vall d'Hebron Hospital, University Autònoma de Barcelona (UAB), Barcelona, Spain
| | | | - Hossein Keyvani
- Department of Virology, Iran University of Medical Sciences, Tehran, Iran
| | - Francisco Rodríguez-Frías
- CIBERehd and Departments of Biochemistry/Microbiology and Hepatology, Vall d'Hebron Hospital, University Autònoma de Barcelona (UAB), Barcelona, Spain
| | - David Tabernero
- CIBERehd and Departments of Biochemistry/Microbiology and Hepatology, Vall d'Hebron Hospital, University Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Maria Buti
- CIBERehd and Departments of Biochemistry/Microbiology and Hepatology, Vall d'Hebron Hospital, University Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Andreas Heinold
- Institute of Transfusion Medicine, University of Duisburg-Essen, University Hospital, Essen, Germany
| | - Seyed Moayed Alavian
- Baqiyatallah Research Center for Gastroenterology and Liver Diseases, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Tanja Bauer
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich and Hannover Sites, Braunschweig, Germany
| | - Julian Schulze Zur Wiesch
- Department of Medicine, Section of Infectious Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bijan Raziorrouh
- University Hospital Munich-Grosshadern, Department of Medicine II, Munich, Germany
| | - Daniel Hoffmann
- Department of Bioinformatics, University of Duisburg-Essen, Essen, Germany
| | - Antonina Smedile
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Mario Rizzetto
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Heiner Wedemeyer
- German Center for Infection Research (DZIF), Munich and Hannover Sites, Braunschweig, Germany
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - Jörg Timm
- Institute of Virology, Heinrich-Heine-University, University Hospital, Duesseldorf, Germany
| | - Iris Antes
- Center for Integrated Protein Science Munich at the Department of Biosciences, Technische Universität München, Freising, Germany
| | - Christoph Neumann-Haefelin
- University Hospital Freiburg, Department of Medicine II, University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich and Hannover Sites, Braunschweig, Germany
| | - Michael Roggendorf
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
- Institute of Virology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany
- German Center for Infection Research (DZIF), Munich and Hannover Sites, Braunschweig, Germany
| |
Collapse
|
4
|
Guo Z, King T. Therapeutic Strategies and New Intervention Points in Chronic Hepatitis Delta Virus Infection. Int J Mol Sci 2015; 16:19537-52. [PMID: 26295228 PMCID: PMC4581312 DOI: 10.3390/ijms160819537] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 12/18/2022] Open
Abstract
Chronic hepatitis delta virus infection (CHD) is a condition arising from super-infection of hepatitis B virus (HBV)-infected patients, resulting in a more rapid advance in liver pathology and hepatocellular carcinoma than is observed for HBV mono-infection. Although hepatitis delta virus (HDV) is structurally simple, its life cycle involves the complex participation of host enzymes, HBV-derived surface antigen (HBsAg), and HDV-auto-ribozyme and hepatitis delta antigen (HDAg) activities. Unsatisfactory clinical trial results with interferon-based therapies are motivating researchers to adjust and redirect the approach to CHD drug development. This new effort will likely require additional structural and functional studies of the viral and cellular/host components involved in the HDV replication cycle. This review highlights recent work aimed at new drug interventions for CHD, with interpretation of key pre-clinical- and clinical trial outcomes and a discussion of promising new technological approaches to antiviral drug design.
Collapse
Affiliation(s)
- Zhimin Guo
- Huron Peak Ave., Superior, CO 80027, USA.
| | - Thomas King
- Allevagen, LLC, 4105 Perry St., Denver, CO 80212, USA.
| |
Collapse
|
5
|
Prime/boost immunization with DNA and adenoviral vectors protects from hepatitis D virus (HDV) infection after simultaneous infection with HDV and woodchuck hepatitis virus. J Virol 2013; 87:7708-16. [PMID: 23637419 DOI: 10.1128/jvi.00645-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis D virus (HDV) superinfection of hepatitis B virus (HBV) carriers causes severe liver disease and a high rate of chronicity. Therefore, a vaccine protecting HBV carriers from HDV superinfection is needed. To protect from HDV infection an induction of virus-specific T cells is required, as antibodies to the two proteins of HDV, p24 and p27, do not neutralize the HBV-derived envelope of HDV. In mice, HDV-specific CD8(+) and CD4(+) T cell responses were induced by a DNA vaccine expressing HDV p27. In subsequent experiments, seven naive woodchucks were immunized with a DNA prime and adenoviral boost regimen prior to simultaneous woodchuck hepatitis virus (WHV) and HDV infection. Five of seven HDV-immunized woodchucks were protected against HDV infection, while acute self-limiting WHV infection occurred as expected. The two animals with the breakthrough had a shorter HDV viremia than the unvaccinated controls. The DNA prime and adenoviral vector boost vaccination protected woodchucks against HDV infection in the setting of simultaneous infection with WHV and HDV. In future experiments, the efficacy of this protocol to protect from HDV infection in the setting of HDV superinfection will need to be proven.
Collapse
|
6
|
Abstract
Hepatitis delta virus (HDV) infection may occur as coinfection with hepatitis B virus (HBV) or as superinfection of a chronically HBV-infected patient. A strong antibody response is mounted, which persists for many years; however, it is not able to modulate the course of infection. In most cases the superinfection takes a chronic course. In patients with inactive disease (HDV PCR negative) an oligospecific T-helper cell immune response and a cytotoxic T-cell response were found, which were absent in patients with persistent viremia. The role of the cellular immune response in liver injury during acute infection has not been investigated. Vaccination strategies tested in the woodchuck model induced specific B- and T-cell responses but failed to protect from HDV infection.
Collapse
Affiliation(s)
- M Fiedler
- Institute of Virology, University Clinic Essen, Germany
| | | |
Collapse
|
7
|
Shiau YT, Huang YH, Wu JC, Tao MH, Syu W, Chang FY, Lee SD. Analysis of humoral immunity of hepatitis D virus DNA vaccine generated in mice by using different dosage, gene gun immunization, and in vivo electroporation. J Chin Med Assoc 2006; 69:7-13. [PMID: 16447920 DOI: 10.1016/s1726-4901(09)70104-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Hepatitis D virus (HDV) DNA vaccine can produce Th1 and cytotoxic T-cell immune responses but only a low anti-HDV antibody titer is generated with a large hepatitis D antigen (L-HDAg) construct. In contrast, DNA vaccine expressing small hepatitis D antigen (S-HDAg) can generate a high titer of anti-HDV antibodies. Whether the low humoral immunity of L-HDAg DNA vaccine is due to inadequate dosage or can be ameliorated by other modes of immunization needs further evaluation. METHODS Plasmid (p25L) encoding L-HDAg and plasmid (pS/p25L) coexpressing hepatitis B surface antigen (HBsAg) and L-HDAg were used in this study. We compared the humoral response generated in mice using different plasmid DNA dosages and modes of immunization, including gene gun and in vivo electroporation (EP). RESULTS Intramuscular injection with a high dose of plasmid DNA (10 mg/kg) produced strong antibodies to HBsAg earlier than the usual dose did, but did not augment the anti-HDV response. Gene gun DNA immunization could not provide a better humoral immune response to HDV. EP DNA immunization had a higher anti-HDV seroconversion rate of 80%, but the anti-HDV antibody responses were generally weak (titer < or = 400:1). CONCLUSION The low humoral immunogenicity of DNA vaccine with L-HDAg cannot be ameliorated by different dosage, gene gun immunization, or in vivo EP intramuscular injection. DNA vaccine with a L-HDAg construct may not be a candidate HDV vaccine to generate anti-HDV humoral immunity.
Collapse
Affiliation(s)
- Yih-Tsong Shiau
- Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taiwan, ROC
| | | | | | | | | | | | | |
Collapse
|
8
|
Seizer P, Riedl P, Reimann J, Schirmbeck R. Different sources of ?help? facilitate the antibody response to hepatitis D virus ? antigen. J Mol Med (Berl) 2004; 83:225-34. [PMID: 15776288 DOI: 10.1007/s00109-004-0598-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Accepted: 09/02/2004] [Indexed: 12/18/2022]
Abstract
Repeated injections of hepatitis D antigen (HDAg) delivered either as a recombinant protein, or expressed from a DNA vaccine elicited no (or only very low) antibody responses in inbred mouse strains. Codelivery of oligonucleotides (ODN) with immune-stimulating sequences (ISS) with the protein antigen, or ISS in DNA vaccines (encoding HDAg) did not overcome the low intrinsic immunogenicity of this small viral antigen for B cells. In contrast, codelivery of immunogenic, heterologous proteins (either mixed to recombinant HDAg as recombinant proteins, or fused to HDAg sequences as chimeric antigens expressed from DNA vaccines) provided specific, CD4+ T cell-dependent "help" that supported efficient priming of antibody responses to HDAg. Chimeric proteins in which selected HDAg fragments were fused in frame with immunogenic, heterologous protein fragments produced by DNA vaccines allowed the mapping of antibody-binding HDAg domains of the viral antigen. The described approach thus facilitates induction of serum antibody responses against native viral antigens with low immunogenicity for B cells.
Collapse
Affiliation(s)
- Peter Seizer
- Institute for Medical Microbiology and Immunology, University of Ulm, Albert Einstein Allee 11, 89081, Ulm, Germany
| | | | | | | |
Collapse
|
9
|
Huang YH, Tao MH, Hu CP, Syu WJ, Wu JC. Identification of novel HLA-A*0201-restricted CD8+ T-cell epitopes on hepatitis delta virus. J Gen Virol 2004; 85:3089-3098. [PMID: 15448372 DOI: 10.1099/vir.0.80183-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis delta virus (HDV) superinfection causes a poor prognosis in hepatitis B virus-infected patients and effective therapy is lacking. Cytotoxic T-lymphocyte (CTL) responses play an important role in the pathogenesis of chronic viral hepatitis; however, the CD8+ T-cell epitopes of HDV have never been defined. Potential HLA-A*0201-restricted HDV peptides were selected from the SYFPEITHI database and screened by T2 cell-stabilization assay. HLA-A*0201 transgenic mice on a C57BL/6 background were injected intramuscularly with an HDV DNA vaccine. Splenocytes were stained directly ex vivo with HLA-A*0201-peptide tetramers after immunization. Epitope-specific CTL responses were confirmed by cytotoxic assays. HLA-A2, chronically infected HDV patients were also enrolled, to assess the existence of HDV-specific CD8+ T cells, based on findings in animals. Following HDV DNA vaccination, nearly 0.9 % of the total splenic CD8+ T cells were specific for peptides HDV 26-34 and HDV 43-51 in HLA-A*0201 transgenic mice, which was significantly higher than the number found in non-transgenic mice or in transgenic mice that had been immunized with control plasmid. HDV 26-34- and 43-51-specific CTL lines were able to produce CTL responses to each peptide. Interestingly, HDV 26-34- and HDV 43-51-specific CD8+ T cells were also detectable in two chronically infected HDV patients in the absence of active HDV replication. In conclusion, HDV 26-34 and 43-51 are novel HLA-A*0201-restricted CTL epitopes on genotype I HDV. HDV 26-34- and 43-51-specific CTLs have been detected in chronic hepatitis delta patients without active disease. Evoking CTL responses to HDV may be an alternative approach to controlling HDV viraemia in patients with chronic hepatitis delta.
Collapse
Affiliation(s)
- Yi-Hsiang Huang
- Institute of Clinical Medicine, National Yang-Ming University, Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, 201 Shih-Pai Road, Sec. 2, Taipei 112, Taiwan, Republic of China
| | - Mi-Hua Tao
- Division of Cancer Research, Institute of Biomedical Science, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Cheng-Po Hu
- Department of Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
| | - Wan-Jr Syu
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Jaw-Ching Wu
- Institute of Clinical Medicine, National Yang-Ming University, Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, 201 Shih-Pai Road, Sec. 2, Taipei 112, Taiwan, Republic of China
| |
Collapse
|
10
|
Huang YH, Wu JC, Hsu SC, Syu WJ. Varied immunity generated in mice by DNA vaccines with large and small hepatitis delta antigens. J Virol 2004; 77:12980-5. [PMID: 14645554 PMCID: PMC296071 DOI: 10.1128/jvi.77.24.12980-12985.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Whether the hepatitis delta virus (HDV) DNA vaccine can induce anti-HDV antibodies has been debatable. The role of the isoprenylated motif of hepatitis delta antigens (HDAg) in the generation of immune responses following DNA-based immunization has never been studied. Plasmids p2577L, encoding large HDAg (L-HDAg), p2577S, expressing small HDAg (S-HDAg), and p25L-211S, encoding a mutant form of L-HDAg with a cysteine-to-serine mutation at codon 211, were constructed in this study. Mice were intramuscularly injected with the plasmids. The anti-HDV antibody titers, T-cell proliferation responses, T-helper responses, and HDV-specific, gamma interferon (IFN-gamma)-producing CD8(+) T cells were analyzed. Animals immunized with p2577S showed a strong anti-HDV antibody response. Conversely, only a low titer of anti-HDV antibodies was detected in mice immunized with p2577L. Epitope mapping revealed that the anti-HDV antibodies generated by p2577L vaccination hardly reacted with epitope amino acids 174 to 194, located at the C terminus of S-HDAg. All of the HDAg-encoding plasmids could induce significant T-cell proliferation responses and generate Th1 responses and HDV-specific, IFN-gamma-producing CD8(+) T cells. In conclusion, HDAg-specific antibodies definitely exist following DNA vaccination. The magnitudes of the humoral immune responses generated by L-HDAg- and S-HDAg-encoding DNA vaccines are different. The isoprenylated motif can mask epitope amino acids 174 to 195 of HDAg but does not interfere with cellular immunity following DNA-based immunization. These findings are important for the choice of a candidate HDV DNA vaccine in the future.
Collapse
Affiliation(s)
- Yi-Hsiang Huang
- Institute
of Clinical Medicine, Institute of Microbiology and
Immunology, School of Medicine, National
Yang-Ming University, Division of Gastroenterology,
Department of Medicine, Taipei Veterans General
Hospital, Taipei, Taiwan, Republic of
China
| | - Jaw-Ching Wu
- Institute
of Clinical Medicine, Institute of Microbiology and
Immunology, School of Medicine, National
Yang-Ming University, Division of Gastroenterology,
Department of Medicine, Taipei Veterans General
Hospital, Taipei, Taiwan, Republic of
China
- Corresponding
author. Mailing address: Institute of Clinical Medicine, National
Yang-Ming University, and Division of Gastroenterology, Department of
Medicine, Taipei Veterans General Hospital, 201 Shih-Pai Rd., Sec. 2,
Taipei 112, Taiwan. Phone: 886-2-28712121, ext. 3218. Fax:
886-2-28749437. E-mail:
| | - Sheng-Chieh Hsu
- Institute
of Clinical Medicine, Institute of Microbiology and
Immunology, School of Medicine, National
Yang-Ming University, Division of Gastroenterology,
Department of Medicine, Taipei Veterans General
Hospital, Taipei, Taiwan, Republic of
China
| | - Wan-Jr Syu
- Institute
of Clinical Medicine, Institute of Microbiology and
Immunology, School of Medicine, National
Yang-Ming University, Division of Gastroenterology,
Department of Medicine, Taipei Veterans General
Hospital, Taipei, Taiwan, Republic of
China
| |
Collapse
|