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Hojatizadeh M, Amiri MM, Mobini M, Hassanzadeh Makoui M, Ghaedi M, Ghotloo S, Peyghami K, Jeddi-Tehrani M, Golsaz-Shirazi F, Shokri F. Cross-Reactivity of HBe Antigen-Specific Polyclonal Antibody with HBc Antigen. Viral Immunol 2023; 36:378-388. [PMID: 37294935 DOI: 10.1089/vim.2022.0196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023] Open
Abstract
Hepatitis B virus (HBV) infection is a major health problem worldwide and causes almost one million deaths annually. The HBV core gene codes for two related antigens, known as core antigen (HBcAg) and e-antigen (HBeAg), sharing 149 residues but having different amino- and carboxy-terminals. HBeAg is a soluble variant of HBcAg and a clinical marker for determining the disease severity and patients' screening. Currently available HBeAg assays have a shortcoming of showing cross-reactivity with HBcAg. In this study, for the first time, we evaluated whether HBcAg-adsorbed anti-HBe polyclonal antibodies could specifically recognize HBeAg or still show cross-reactivity with HBcAg. Recombinant HBeAg was cloned in pCold1 vector and successfully expressed in Escherichia coli and after purification by Ni-NTA resin was used to generate polyclonal anti-HBe antibodies in rabbit. Purified HBeAg was further characterized by assessing its reactivity with anti-HBe in the sera of chronically infected patients and HBeAg-immunized rabbit. Sera from patients with chronic HBV infection, containing anti-HBe, specifically reacted with recombinant HBeAg, implying antigenic similarity between the prokaryotic and native HBeAg in the serum of HBV-infected patients. In addition, the designed enzyme-linked immunosorbent assay (ELISA) with rabbit anti-HBe polyclonal antibodies could detect recombinant HBeAg with high sensitivity, while high cross-reactivity with HBcAg was observed. It is noteworthy that HBcAg-adsorbed anti-HBe polyclonal antibodies still showed high cross-reactivity with HBcAg, implying that due to the presence of highly similar epitopes in both antigens, HBcAg-adsorbed polyclonal antibodies cannot differentiate between the two antigens.
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Affiliation(s)
- Maryam Hojatizadeh
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Mehdi Amiri
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Mobini
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Hassanzadeh Makoui
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mojgan Ghaedi
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Ghotloo
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Kashan University of Medical Sciences, Kashan, Iran
| | - Kiana Peyghami
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmood Jeddi-Tehrani
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACER, Tehran, Iran
| | - Forough Golsaz-Shirazi
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fazel Shokri
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACER, Tehran, Iran
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Probing the Hepatitis B Virus E-Antigen with a Nanopore Sensor Based on Collisional Events Analysis. BIOSENSORS 2022; 12:bios12080596. [PMID: 36004992 PMCID: PMC9405897 DOI: 10.3390/bios12080596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 11/24/2022]
Abstract
Real-time monitoring, simple operation, and cheaper methods for detecting immunological proteins hold the potential for a solid influence on proteomics and human biology, as they can promote the onset of timely diagnoses and adequate treatment protocols. In this work we present an exploratory study suggesting the applicability of resistive-pulse sensing technology in conjunction with the α-hemolysin (α-HL) protein nanopore, for the detection of the chronic hepatitis B virus (HBV) e-antigen (HBeAg). In this approach, the recognition between HBeAg and a purified monoclonal hepatitis B e antibody (Ab(HBeAg)) was detected via transient ionic current spikes generated by partial occlusions of the α-HL nanopore by protein aggregates electrophoretically driven toward the nanopore’s vestibule entrance. Despite the steric hindrance precluding antigen, antibody, or antigen–antibody complex capture inside the nanopore, their stochastic bumping with the nanopore generated clear transient blockade events. The subsequent analysis suggested the detection of protein subpopulations in solution, rendering the approach a potentially valuable label-free platform for the sensitive, submicromolar-scale screening of HBeAg targets.
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Watts NR, Palmer IW, Eren E, Steven AC, Wingfield PT. Capsids of hepatitis B virus e antigen with authentic C termini are stabilized by electrostatic interactions. FEBS Lett 2019; 594:1052-1061. [PMID: 31792961 DOI: 10.1002/1873-3468.13706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/22/2022]
Abstract
The hepatitis B virus e antigen, an alternative transcript of the core gene, is a secreted protein that maintains viral persistence. The physiological form has extended C termini relative to Cp(-10)149, the construct used in many studies. To examine the role of the C termini, we expressed the constructs Cp(-10)151 and Cp(-10)154, which have additional arginine residues. Both constructs when treated with reductant formed capsids more efficiently than Cp(-10)149. These capsids were also substantially more stable, as measured by thermal denaturation and resistance to urea dissociation. Mutagenesis suggests that electrostatic interactions between the additional arginine residues and glutamate residues on adjacent subunits play a role in the extra stabilization. These findings have implications for the physiological role and biotechnological potential of this protein.
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Affiliation(s)
- Norman R Watts
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD, USA
| | - Ira W Palmer
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD, USA
| | - Elif Eren
- Laboratory of Structural Biology Research, NIAMS, National Institutes of Health, Bethesda, MD, USA
| | - Alasdair C Steven
- Laboratory of Structural Biology Research, NIAMS, National Institutes of Health, Bethesda, MD, USA
| | - Paul T Wingfield
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD, USA
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Abstract
There is no reliable cure for chronic Hepatitis B Virus (HBV). In this issue of Structure, Eren et al. (2018) show how antibody-derived proteins bind different forms of the HBV capsid protein, blocking assembly. This interaction may also affect downstream signaling. These antibody-derived molecules mark a new strategy that may ultimately contribute to a cure.
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Affiliation(s)
- Zhongchao Zhao
- Department of Molecular and Cellular Biochemistry Indiana University, Bloomington, IN 47405, USA
| | - Adam Zlotnick
- Department of Molecular and Cellular Biochemistry Indiana University, Bloomington, IN 47405, USA.
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Eren E, Watts NR, Dearborn AD, Palmer IW, Kaufman JD, Steven AC, Wingfield PT. Structures of Hepatitis B Virus Core- and e-Antigen Immune Complexes Suggest Multi-point Inhibition. Structure 2018; 26:1314-1326.e4. [PMID: 30100358 DOI: 10.1016/j.str.2018.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/13/2018] [Accepted: 06/29/2018] [Indexed: 12/22/2022]
Abstract
Hepatitis B virus (HBV) is the leading cause of liver disease worldwide. While an adequate vaccine is available, current treatment options are limited, not highly effective, and associated with adverse effects, encouraging the development of alternative therapeutics. The HBV core gene encodes two different proteins: core, which forms the viral nucleocapsid, and pre-core, which serves as an immune modulator with multiple points of action. The two proteins mostly have the same sequence, although they differ at their N and C termini and in their dimeric arrangements. Previously, we engineered two human-framework antibody fragments (Fab/scFv) with nano- to picomolar affinities for both proteins. Here, by means of X-ray crystallography, analytical ultracentrifugation, and electron microscopy, we demonstrate that the antibodies have non-overlapping epitopes and effectively block biologically important assemblies of both proteins. These properties, together with the anticipated high tolerability and long half-lives of the antibodies, make them promising therapeutics.
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Affiliation(s)
- Elif Eren
- Laboratory of Structural Biology Research, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Norman R Watts
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Altaira D Dearborn
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ira W Palmer
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joshua D Kaufman
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alasdair C Steven
- Laboratory of Structural Biology Research, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul T Wingfield
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA.
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Corti D, Benigni F, Shouval D. Viral envelope-specific antibodies in chronic hepatitis B virus infection. Curr Opin Virol 2018; 30:48-57. [PMID: 29738926 DOI: 10.1016/j.coviro.2018.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/26/2018] [Accepted: 04/02/2018] [Indexed: 12/20/2022]
Abstract
While the cellular immune response associated with acute and chronic HBV infection has been thoroughly studied, the B cell response in chronic hepatitis B and the role of antibodies raised against the HBV envelope antigens in controlling and prevention of infection requires further investigation. The detection of anti-HBs antibodies is considered as one of the biomarkers for functional cure of chronic hepatitis B virus infection, as well as for protective immunity. Indeed, vaccine-induced neutralizing anti-HBs antibodies have been shown to protect against HBV challenge. Yet, the therapeutic potential of viral envelope-specific antibodies and the mechanism involved in protection and prevention of cell-to-cell transmission warrants additional investigative efforts. In this review, we will provide a critical overview of the available preclinical and clinical literature supporting the putative role of active and passive vaccination and neutralizing envelope-specific antibodies for therapeutic intervention in combination regimens intended to cure persistent HBV infection.
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Affiliation(s)
- Davide Corti
- Humabs BioMed SA, A Subsidiary of Vir Biotechnology, 6500 Bellinzona, Switzerland.
| | - Fabio Benigni
- Humabs BioMed SA, A Subsidiary of Vir Biotechnology, 6500 Bellinzona, Switzerland
| | - Daniel Shouval
- Liver Unit, Institute for Gastroenterology and Hepatology, Hadassah-Hebrew University Hospital, P.O. Box 12000, 91120 Jerusalem, Israel.
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