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Su J, Harati Taji Z, Kosinska AD, Ates Oz E, Xie Z, Bielytskyi P, Shein M, Hagen P, Esmaeili S, Steiger K, Protzer U, Schütz AK. Introducing adjuvant-loaded particulate hepatitis B core antigen as an alternative therapeutic hepatitis B vaccine component. JHEP Rep 2024; 6:100997. [PMID: 38425450 PMCID: PMC10904195 DOI: 10.1016/j.jhepr.2023.100997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 11/27/2023] [Accepted: 12/19/2023] [Indexed: 03/02/2024] Open
Abstract
Background & Aims Particulate hepatitis B core antigen (HBcoreAg) is a potent immunogen used as a vaccine carrier platform. HBcoreAg produced in E. coli encapsidates random bacterial RNA (bRNA). Using the heterologous protein-prime, viral-vector-boost therapeutic hepatitis B vaccine TherVacB, we compared the properties of different HBcoreAg forms. We explored how the content of HBcoreAg modulates antigen stability, immunogenicity, and antiviral efficacy. Methods bRNA was removed from HBcoreAg by capsid disassembly, followed by reassembly in the absence or presence of specific nucleic acid-based adjuvants poly I:C or CpG. The morphology and structure of empty, bRNA-containing and adjuvant-loaded HBcoreAg were monitored by electron microscopy and nuclear magnetic resonance spectroscopy. Empty, bRNA-containing or adjuvant-loaded HBcoreAg were applied together with HBsAg and with or without nucleic acid-based external adjuvants within the TherVacB regimen in both wild-type and HBV-carrier mice. Results While HBcoreAg retained its structure upon bRNA removal, its stability and immunogenicity decreased significantly. Loading HBcoreAg with nucleic acid-based adjuvants re-established stability of the capsid-like antigen. Immunization with poly I:C- or CpG-loaded HBcoreAg induced high antibody titers against co-administered HBsAg. When applied within the TherVacB regimen, they activated vigorous HBcoreAg- and HBsAg-specific T-cell responses in wild-type and HBV-carrier mice, requiring a significantly lower dose of adjuvant compared to externally added adjuvant. Finally, immunization with adjuvant-loaded HBcoreAg mixed with HBsAg led to long-term control of persistent HBV replication in the HBV-carrier mice. Conclusion Adjuvant-loaded HBcoreAg retained capsid integrity and stability, was as immunogenic in vivo as externally adjuvanted HBcoreAg, requiring lower adjuvant levels, and supported immunity against co-administered, non-adjuvanted HBsAg. Thus, adjuvant-loaded HBcoreAg represents a promising novel platform for vaccine development. Impact and implications Hepatitis B core antigen (HBcoreAg) recapitulates the capsid of the HBV that hosts the viral genome. Produced recombinantly, it is not infectious but emerges as a potent immunogen in vaccine development. In this preclinical study, we show that loading HBcoreAg with defined nucleic-acid-based adjuvants on the one hand stabilizes the HBcoreAg with standardized capsid content and, on the other hand, efficiently promotes the immunity of HBcoreAg and a co-administered antigen, allowing for reduced adjuvant doses. Therefore, adjuvant-loaded HBcoreAg not only serves as an encouraging option for therapeutic hepatitis B vaccines, but could also act as an efficient adjuvant delivery system for other types of vaccine.
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Affiliation(s)
- Jinpeng Su
- Institute of Virology, Technical University of Munich / Helmholtz Munich, 81675, Munich, Germany
- German Center for Infection Research (DZIF), Munich partner site, Germany
| | - Zahra Harati Taji
- Ludwig Maximilians University of Munich, 81377, Munich, Germany
- Bavarian NMR Center, Technical University of Munich, 85748, Garching, Germany
- Institute of Structural Biology, Helmholtz Munich, 85764, Neuherberg, Germany
| | - Anna D. Kosinska
- Institute of Virology, Technical University of Munich / Helmholtz Munich, 81675, Munich, Germany
- German Center for Infection Research (DZIF), Munich partner site, Germany
| | - Edanur Ates Oz
- Institute of Virology, Technical University of Munich / Helmholtz Munich, 81675, Munich, Germany
| | - Zhe Xie
- Institute of Virology, Technical University of Munich / Helmholtz Munich, 81675, Munich, Germany
| | - Pavlo Bielytskyi
- Bavarian NMR Center, Technical University of Munich, 85748, Garching, Germany
- Institute of Structural Biology, Helmholtz Munich, 85764, Neuherberg, Germany
| | - Mikhail Shein
- Ludwig Maximilians University of Munich, 81377, Munich, Germany
- Bavarian NMR Center, Technical University of Munich, 85748, Garching, Germany
- Institute of Structural Biology, Helmholtz Munich, 85764, Neuherberg, Germany
| | - Philipp Hagen
- Institute of Virology, Technical University of Munich / Helmholtz Munich, 81675, Munich, Germany
| | - Shohreh Esmaeili
- Ludwig Maximilians University of Munich, 81377, Munich, Germany
- Bavarian NMR Center, Technical University of Munich, 85748, Garching, Germany
- Institute of Structural Biology, Helmholtz Munich, 85764, Neuherberg, Germany
| | - Katja Steiger
- Comparative Experimental Pathology, Institute of Pathology, School of Medicine and Health, Technical University Munich, 81675, Munich, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich / Helmholtz Munich, 81675, Munich, Germany
- German Center for Infection Research (DZIF), Munich partner site, Germany
| | - Anne K. Schütz
- Ludwig Maximilians University of Munich, 81377, Munich, Germany
- Bavarian NMR Center, Technical University of Munich, 85748, Garching, Germany
- Institute of Structural Biology, Helmholtz Munich, 85764, Neuherberg, Germany
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