1
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Shawky H, Tabll AA, Elshenawy RM, Helmy NM, Moustafa RI, Elesnawy YK, Abdelghany MM, El-Abd YS. Glycylglycine promotes the solubility and antigenic utility of recombinant HCV structural proteins in a point-of-care immunoassay for detection of active viremia. Microb Cell Fact 2024; 23:25. [PMID: 38238770 PMCID: PMC10795219 DOI: 10.1186/s12934-024-02297-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/04/2024] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Although E. coli is generally a well-opted platform for the overproduction of recombinant antigens as heterologous proteins, the optimization of expression conditions to maximize the yield of functional proteins remains empirical. Herein, we developed an optimized E. coli (BL21)-based system for the overproduction of soluble immunoreactive HCV core/envelope proteins that were utilized to establish a novel immunoassay for discrimination of active HCV infection. METHODS The core/E1-E2 genes were amplified and expressed in E. coli BL21 (DE3) in the absence/presence of glycylglycine. The antigenic performance of soluble proteins was assessed against 63 HCV-seronegative (Ab-) sera that included normal and interferent sera (HBV and/or chronic renal failure), and 383 HCV-seropositive (Ab+) samples that included viremic (chronic/relapsers) and recovered patients' sera. The color intensity (OD450) and S/Co values were estimated. RESULTS The integration of 0.1-0.4M glycylglycine in the growth media significantly enhanced the solubility/yield of recombinant core and envelope proteins by ~ 225 and 242 fold, respectively. This was reflected in their immunoreactivity and antigenic performance in the developed immunoassay, where the soluble core/E1/E2 antigen mixture showed 100% accuracy in identifying HCV viremic sera with a viral RNA load as low as 3800 IU/mL, without cross-reactivity against normal/interferent HCV-Ab-sera. The ideal S/Co threshold predicting active viremia (> 2.75) showed an AUC value of 0.9362 (95% CI: 0.9132 to 0.9593), with 87.64, 91.23% sensitivity and specificity, and 94.14, 82.11% positive and negative predictive values, respectively. The different panels of samples assayed with our EIA showed a good concordance with the viral loads and also significant correlations with the golden standards of HCV diagnosis in viremic patients. The performance of the EIA was not affected by the immunocompromised conditions or HBV co-infection. CONCLUSION The applicability of the proposed platform would extend beyond the reported approach, where glycylglycine, low inducer concentration and post-induction temperature, combined with the moderately-strong constitutive promoter enables the stable production of soluble/active proteins, even those with reported toxicity. Also, the newly developed immunoassay provides a cost-effective point-of-care diagnostic tool for active HCV viremia that could be useful in resource-limited settings.
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Affiliation(s)
- Heba Shawky
- Therapeutic Chemistry Department, Pharmaceutical Industries and Drug Research Institute, National Research Centre, Dokki, Cairo, 12622, Egypt
| | - Ashraf A Tabll
- Microbial Biotechnology Department, Biotechnology Research Institute, National Research Centre, Dokki, Cairo, 12622, Egypt
| | - Reem M Elshenawy
- Microbial Biotechnology Department, Biotechnology Research Institute, National Research Centre, Dokki, Cairo, 12622, Egypt
| | - Naiera M Helmy
- Microbial Biotechnology Department, Biotechnology Research Institute, National Research Centre, Dokki, Cairo, 12622, Egypt
| | - Rehab I Moustafa
- Microbial Biotechnology Department, Biotechnology Research Institute, National Research Centre, Dokki, Cairo, 12622, Egypt
| | | | - Marwa M Abdelghany
- National Committee for Control of Viral Hepatitis (NCCVH), Ministry of Health and Population, Cairo, Egypt
| | - Yasmine S El-Abd
- Microbial Biotechnology Department, Biotechnology Research Institute, National Research Centre, Dokki, Cairo, 12622, Egypt.
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2
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Toth EA, Andrianov AK, Fuerst TR. Prospects for developing an Hepatitis C virus E1E2-based nanoparticle vaccine. Rev Med Virol 2023; 33:e2474. [PMID: 37565536 PMCID: PMC10626635 DOI: 10.1002/rmv.2474] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/12/2023]
Abstract
Globally, more than 58 million people are chronically infected with Hepatitis C virus (HCV) with 1.5 million new infections occurring each year. An effective vaccine for HCV is therefore a major unmet medical and public health need. Since HCV rapidly accumulates mutations, vaccines must elicit the production of broadly neutralising antibodies (bnAbs) in a reproducible fashion. Decades of research have generated a number of HCV vaccine candidates. Based on the available data and research through clinical development, a vaccine antigen based on the E1E2 glycoprotein complex appears to be the best choice, but robust induction of humoral and cellular responses leading to virus neutralisation has not yet been achieved. One issue that has arisen in developing an HCV vaccine (and many other vaccines as well) is the platform used for antigen delivery. The majority of viral vaccine trials have employed subunit vaccines. However, subunit vaccines often have limited immunogenicity, as seen for HCV, and thus multiple formats must be examined in order to elicit a robust anti-HCV immune response. Nanoparticle vaccines are gaining prominence in the field due to their ability to facilitate a controlled multivalent presentation and trafficking to lymph nodes, where they can interact with both arms of the immune system. This review discusses the potential for development of a nanoparticle-based HCV E1E2 vaccine, with an emphasis on the potential benefits of such an approach along with the major challenges facing the incorporation of E1E2 into nanoparticulate delivery systems and how those challenges can be addressed.
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Affiliation(s)
- Eric A. Toth
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
| | - Alexander K. Andrianov
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
| | - Thomas R. Fuerst
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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3
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Gomez-Escobar E, Roingeard P, Beaumont E. Current Hepatitis C Vaccine Candidates Based on the Induction of Neutralizing Antibodies. Viruses 2023; 15:v15051151. [PMID: 37243237 DOI: 10.3390/v15051151] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
The introduction of direct-acting antivirals (DAAs) has revolutionized hepatitis C treatment. Short courses of treatment with these drugs are highly beneficial to patients, eliminating hepatitis C virus (HCV) without adverse effects. However, this outstanding success is tempered by the continuing difficulty of eradicating the virus worldwide. Thus, access to an effective vaccine against HCV is strongly needed to reduce the burden of the disease and contribute to the elimination of viral hepatitis. The recent failure of a T-cell vaccine based on the use of viral vectors expressing the HCV non-structural protein sequences to prevent chronic hepatitis C in drug users has pointed out that the induction of neutralizing antibodies (NAbs) will be essential in future vaccine candidates. To induce NAbs, vaccines must contain the main target of this type of antibody, the HCV envelope glycoproteins (E1 and E2). In this review, we summarize the structural regions in E1 and E2 proteins that are targeted by NAbs and how these proteins are presented in the vaccine candidates currently under development.
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Affiliation(s)
- Elsa Gomez-Escobar
- Inserm U1259 MAVIVH, Université de Tours and CHRU de Tours, 37000 Tours, France
| | - Philippe Roingeard
- Inserm U1259 MAVIVH, Université de Tours and CHRU de Tours, 37000 Tours, France
| | - Elodie Beaumont
- Inserm U1259 MAVIVH, Université de Tours and CHRU de Tours, 37000 Tours, France
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4
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Poumbourios P, Langer C, Boo I, Zakir T, Center RJ, Akerman A, Milogiannakis V, Aggarwal A, Johnstone BA, Ha J, Coulibaly F, Turville SG, Drummer HE. Enhanced stability of the SARS CoV-2 spike glycoprotein following modification of an alanine cavity in the protein core. PLoS Pathog 2023; 19:e1010981. [PMID: 37200378 PMCID: PMC10231827 DOI: 10.1371/journal.ppat.1010981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 05/31/2023] [Accepted: 04/24/2023] [Indexed: 05/20/2023] Open
Abstract
The spike (S) glycoprotein of SARS CoV-2 is the target of neutralizing antibodies (NAbs) that are crucial for vaccine effectiveness. The S1 subunit binds ACE2 while the S2 subunit mediates virus-cell membrane fusion. S2 is a class I fusion glycoprotein subunit and contains a central coiled coil that acts as a scaffold for the conformational changes associated with fusion function. The coiled coil of S2 is unusual in that the 3-4 repeat of inward-facing positions are mostly occupied by polar residues that mediate few inter-helical contacts in the prefusion trimer. We examined how insertion of bulkier hydrophobic residues (Val, Leu, Ile, Phe) to fill a cavity next to Ala1016 and Ala1020 in the 3-4 repeat affects the stability and antigenicity of S trimers. Substitution of Ala1016 with bulkier hydrophobic residues in the context of a prefusion-stabilized S trimer, S2P-FHA, was associated with increased thermal stability. S glycoprotein membrane fusion function was retained with Ala1016/Ala1020 cavity-filling mutations associated with improved recombinant S2P-FHA thermostability, however 2 mutants, A1016L and A1016V/A1020I, lacked ability to mediate entry of S-HIV-1 pseudoparticles into 293-ACE2 cells. When assessed as immunogens, two thermostable S2P-FHA mutants derived from the ancestral isolate, A1016L (16L) and A1016V/A1020I (VI) elicited neutralizing antibody with 50%-inhibitory dilutions (ID50s) in the range 2,700-5,110 for ancestral and Delta-derived viruses, and 210-1,744 for Omicron BA.1. The antigens elicited antibody specificities directed to the receptor-binding domain (RBD), N-terminal domain (NTD), fusion peptide and stem region of S2. The VI mutation enabled the production of intrinsically stable Omicron BA.1 and Omicron BA.4/5 S2P-FHA-like ectodomain oligomers in the absence of an external trimerization motif (T4 foldon), thus representing an alternative approach for stabilizing oligomeric S glycoprotein vaccines.
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Affiliation(s)
- Pantelis Poumbourios
- Burnet Institute, Melbourne, Australia
- Department of Microbiology, Monash University, Clayton, Australia
| | | | - Irene Boo
- Burnet Institute, Melbourne, Australia
| | | | - Rob J. Center
- Burnet Institute, Melbourne, Australia
- Department of Microbiology at The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Australia
| | - Anouschka Akerman
- Kirby Institute, University of New South Wales, Kensington, Australia
| | | | - Anupriya Aggarwal
- Kirby Institute, University of New South Wales, Kensington, Australia
| | - Bronte A. Johnstone
- Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Jungmin Ha
- Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - Fasséli Coulibaly
- Infection Program, Biomedicine Discovery Institute, Monash University, Clayton, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | | | - Heidi E. Drummer
- Burnet Institute, Melbourne, Australia
- Department of Microbiology, Monash University, Clayton, Australia
- Department of Microbiology at The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Australia
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5
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Pedroza-Escobar D, Castillo-Maldonado I, González-Cortés T, Delgadillo-Guzmán D, Ruíz-Flores P, Cruz JHS, Espino-Silva PK, Flores-Loyola E, Ramirez-Moreno A, Avalos-Soto J, Téllez-López MÁ, Velázquez-Gauna SE, García-Garza R, Vertti RDAP, Torres-León C. Molecular Bases of Protein Antigenicity and Determinants of Immunogenicity, Anergy, and Mitogenicity. Protein Pept Lett 2023; 30:719-733. [PMID: 37691216 DOI: 10.2174/0929866530666230907093339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/03/2023] [Accepted: 08/03/2023] [Indexed: 09/12/2023]
Abstract
BACKGROUND The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune system components exhibit antigenicity and are defined as antigens. The antigens exhibiting immunogenicity can induce innate or adaptive immune responses and give rise to humoral or cell-mediated immunity. The antigens exhibiting mitogenicity can cross-link cell membrane receptors on B and T lymphocytes leading to cell proliferation. All antigens vary greatly in physicochemical features such as biochemical nature, structural complexity, molecular size, foreignness, solubility, and so on. OBJECTIVE Thus, this review aims to describe the molecular bases of protein-antigenicity and those molecular bases that lead to an immune response, lymphocyte proliferation, or unresponsiveness. CONCLUSION The epitopes of an antigen are located in surface areas; they are about 880-3,300 Da in size. They are protein, carbohydrate, or lipid in nature. Soluble antigens are smaller than 1 nm and are endocytosed less efficiently than particulate antigens. The more the structural complexity of an antigen increases, the more the antigenicity increases due to the number and variety of epitopes. The smallest immunogens are about 4,000-10,000 Da in size. The more phylogenetically distant immunogens are from the immunogen-recipient, the more immunogenicity increases. Antigens that are immunogens can trigger an innate or adaptive immune response. The innate response is induced by antigens that are pathogen-associated molecular patterns. Exogenous antigens, T Dependent or T Independent, induce humoral immunogenicity. TD protein-antigens require two epitopes, one sequential and one conformational to induce antibodies, whereas, TI non-protein-antigens require only one conformational epitope to induce low-affinity antibodies. Endogenous protein antigens require only one sequential epitope to induce cell-mediated immunogenicity.
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Affiliation(s)
- David Pedroza-Escobar
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Irais Castillo-Maldonado
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Tania González-Cortés
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Dealmy Delgadillo-Guzmán
- Facultad de Medicina, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Pablo Ruíz-Flores
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Jorge Haro Santa Cruz
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Perla-Karina Espino-Silva
- Centro de Investigacion Biomedica, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | - Erika Flores-Loyola
- Facultad de Ciencias Biologicas, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27276, Mexico
| | - Agustina Ramirez-Moreno
- Facultad de Ciencias Biologicas, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27276, Mexico
| | - Joaquín Avalos-Soto
- Cuerpo Academico Farmacia y Productos Naturales, Facultad de Ciencias Quimicas, Universidad Juarez del Estado de Durango, Gomez Palacio, Mexico
| | - Miguel-Ángel Téllez-López
- Cuerpo Academico Farmacia y Productos Naturales, Facultad de Ciencias Quimicas, Universidad Juarez del Estado de Durango, Gomez Palacio, Mexico
| | | | - Rubén García-Garza
- Facultad de Medicina, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Coahuila, 27000, Mexico
| | | | - Cristian Torres-León
- Centro de Investigacion y Jardin Etnobiologico, Universidad Autonoma de Coahuila, Viesca, Coahuila, 27480, Mexico
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6
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Zhang L, Wang X, Ming A, Tan W. Pseudotyped Virus for Flaviviridae. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:313-327. [PMID: 36920705 DOI: 10.1007/978-981-99-0113-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Members of Flaviviridae are enveloped single positive-stranded RNA viruses including hepacivirus, pestivirus, pegivirus, and mosquito-transmitted flavivirus, which are important pathogens of infectious diseases and pose serious threats to human health. Pseudotyped virus is an artificially constructed virus-like particle, which could infect host cells similar to a live virus but cannot produce infectious progeny virus. Therefore, pseudotyped virus has the advantages of a wide host range, high transfection efficiency, low biosafety risk, and accurate and objective quantification. It has been widely used in biological characteristics, drug screening, detection methods, and vaccine evaluation of Flaviviridae viruses like hepatitis C virus, Japanese encephalitis virus, dengue virus, and Zika virus.
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Affiliation(s)
- Leiliang Zhang
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Xiao Wang
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Annan Ming
- Department of Pathogen Biology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Wenjie Tan
- NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
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7
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Induction of cross-neutralizing antibodies by a permuted hepatitis C virus glycoprotein nanoparticle vaccine candidate. Nat Commun 2022; 13:7271. [PMID: 36434005 PMCID: PMC9700739 DOI: 10.1038/s41467-022-34961-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 11/14/2022] [Indexed: 11/27/2022] Open
Abstract
Hepatitis C virus (HCV) infection affects approximately 58 million people and causes ~300,000 deaths yearly. The only target for HCV neutralizing antibodies is the highly sequence diverse E1E2 glycoprotein. Eliciting broadly neutralizing antibodies that recognize conserved cross-neutralizing epitopes is important for an effective HCV vaccine. However, most recombinant HCV glycoprotein vaccines, which usually include only E2, induce only weak neutralizing antibody responses. Here, we describe recombinant soluble E1E2 immunogens that were generated by permutation of the E1 and E2 subunits. We displayed the E2E1 immunogens on two-component nanoparticles and these nanoparticles induce significantly more potent neutralizing antibody responses than E2. Next, we generated mosaic nanoparticles co-displaying six different E2E1 immunogens. These mosaic E2E1 nanoparticles elicit significantly improved neutralization compared to monovalent E2E1 nanoparticles. These results provide a roadmap for the generation of an HCV vaccine that induces potent and broad neutralization.
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8
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Prentoe J, Janitzek CM, Velázquez-Moctezuma R, Soerensen A, Jørgensen T, Clemmensen S, Soroka V, Thrane S, Theander T, Nielsen MA, Salanti A, Bukh J, Sander AF. Two-component vaccine consisting of virus-like particles displaying hepatitis C virus envelope protein 2 oligomers. NPJ Vaccines 2022; 7:148. [DOI: 10.1038/s41541-022-00570-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 10/31/2022] [Indexed: 11/16/2022] Open
Abstract
AbstractDevelopment of B-cell-based hepatitis C virus (HCV) vaccines that induce broadly neutralizing antibodies (bNAbs) is hindered by extensive sequence diversity and low immunogenicity of envelope glycoprotein vaccine candidates, most notably soluble E2 (sE2). To overcome this, we employed two-component approaches using self-assembling virus-like particles (cVLPs; component 1), displaying monomeric or oligomeric forms of HCV sE2 (sE2mono or sE2oligo; component 2). Immunization studies were performed in BALB/c mice and the neutralizing capacity of vaccine-induced antibodies was tested in cultured-virus-neutralizations, using HCV of genotypes 1–6. sE2-cVLP vaccines induced significantly higher levels of NAbs (p = 0.0065) compared to corresponding sE2 vaccines. Additionally, sE2oligo-cVLP was superior to sE2mono-cVLP in inducing bNAbs. Interestingly, human monoclonal antibody AR2A had reduced binding in ELISA to sE2oligo-cVLP compared with sE2mono-cVLP and competition ELISA using mouse sera from vaccinated animals indicated that sE2oligo-cVLP induced significantly less non-bNAbs AR2A (p = 0.0043) and AR1B (p = 0.017). Thus, cVLP-displayed oligomeric sE2 shows promise as an HCV vaccine candidate.
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9
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Donnison T, McGregor J, Chinnakannan S, Hutchings C, Center RJ, Poumbourios P, Klenerman P, Drummer HE, Barnes E. A pan-genotype hepatitis C virus viral vector vaccine generates T cells and neutralizing antibodies in mice. Hepatology 2022; 76:1190-1202. [PMID: 35313015 PMCID: PMC9790311 DOI: 10.1002/hep.32470] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS A prophylactic vaccine targeting multiple HCV genotypes (gt) is urgently required to meet World Health Organization elimination targets. Neutralizing antibodies (nAbs) and CD4+ and CD8+ T cells are associated with spontaneous clearance of HCV, and each may contribute to protective immunity. However, current vaccine candidates generate either nAbs or T cells targeting genetically variable epitopes and have failed to show efficacy in human trials. We have previously shown that a simian adenovirus vector (ChAdOx1) encoding conserved sequences across gt1-6 (ChAd-Gt1-6), and separately gt-1a E2 protein with variable regions deleted (E2Δ123HMW ), generates pan-genotypic T cells and nAbs, respectively. We now aim to develop a vaccine to generate both viral-specific B- and T-cell responses concurrently. APPROACH AND RESULTS We show that vaccinating with ChAd-Gt1-6 and E2Δ123HMW sequentially in mice generates T-cell and antibody (Ab) responses comparable to either vaccine given alone. We encoded E2Δ123 in ChAdOx1 (ChAd-E2Δ123) and show that this, given with an E2Δ123HMW protein boost, induces greater CD81-E2 inhibitory and HCV-pseudoparticle nAb titers compared to the E2Δ123HMW prime boost. We developed bivalent viral vector vaccines (ChAdOx1 and modified vaccinia Ankara [MVA]) encoding both Gt1-6 and E2Δ123 immunogens (Gt1-6-E2Δ123) generating polyfunctional CD4+ and CD8+ T cells and nAb titers in prime/boost strategies. This approach generated nAb responses comparable to monovalent E2Δ123 ChAd/MVA vaccines and superior to three doses of recombinant E2Δ123HMW protein, while also generating high-magnitude T-cell responses. CONCLUSIONS These data are an important step forward for the development of a pan-genotype HCV vaccine to elicit T cells and nAbs for future assessment in humans.
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Affiliation(s)
- Timothy Donnison
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Joey McGregor
- Burnet Institute, Melbourne, Victoria, Australia.,Department of Microbiology and Immunology at The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria, Australia
| | - Senthil Chinnakannan
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Claire Hutchings
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Rob J Center
- Burnet Institute, Melbourne, Victoria, Australia.,Department of Microbiology and Immunology at The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria, Australia
| | - Pantelis Poumbourios
- Burnet Institute, Melbourne, Victoria, Australia.,Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Paul Klenerman
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Heidi E Drummer
- Burnet Institute, Melbourne, Victoria, Australia.,Department of Microbiology and Immunology at The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, Victoria, Australia.,Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Eleanor Barnes
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK.,Nuffield Department of Medicine, Jenner Institute, University of Oxford, Oxford, UK
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10
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Barnes E, Cooke GS, Lauer GM, Chung RT. Implementation of a controlled human infection model for evaluation of HCV vaccine candidates. Hepatology 2022; 77:1757-1772. [PMID: 35736236 DOI: 10.1002/hep.32632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 12/08/2022]
Abstract
Hepatitis C virus (HCV) remains a major global health concern. Directly acting antiviral (DAA) drugs have transformed the treatment of HCV. However, it has become clear that, without an effective HCV vaccine, it will not be possible to meet the World Health Organization targets of HCV viral elimination. Promising new vaccine technologies that generate high magnitude antiviral T and B cell immune responses and significant new funding have recently become available, stimulating the HCV vaccine pipeline. In the absence of an immune competent animal model for HCV, the major block in evaluating new HCV vaccine candidates will be the assessment of vaccine efficacy in humans. The development of a controlled human infection model (CHIM) for HCV could overcome this block, enabling the head-to-head assessment of vaccine candidates. The availability of highly effective DAA means that a CHIM for HCV is possible for the first time. In this review, we highlight the challenges and issues with currently available strategies to assess HCV vaccine efficacy including HCV "at-risk" cohorts and animal models. We describe the development of CHIM in other infections that are increasingly utilized by trialists and explore the ethical and safety concerns specific for an HCV CHIM. Finally, we propose an HCV CHIM study design including the selection of volunteers, the development of an infectious inoculum, the evaluation of host immune and viral parameters, and the definition of study end points for use in an HCV CHIM. Importantly, the study design (including number of volunteers required, cost, duration of study, and risk to volunteers) varies significantly depending on the proposed mechanism of action (sterilizing/rapid viral clearance vs. delayed viral clearance) of the vaccine under evaluation. We conclude that an HCV CHIM is now realistic, that safety and ethical concerns can be addressed with the right study design, and that, without an HCV CHIM, it is difficult to envisage how the development of an HCV vaccine will be possible.
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Affiliation(s)
- Eleanor Barnes
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, Oxford, UK
| | - Graham S Cooke
- Department of Infectious Disease, Imperial College London, Oxford, UK
| | - Georg M Lauer
- Liver Center, GI Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Raymond T Chung
- Liver Center, GI Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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11
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Virus-Like Particles Containing the E2 Core Domain of Hepatitis C Virus Generate Broadly Neutralizing Antibodies in Guinea Pigs. J Virol 2022; 96:e0167521. [PMID: 34986001 PMCID: PMC8906423 DOI: 10.1128/jvi.01675-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A vaccine to prevent hepatitis C virus (HCV) infection is urgently needed for use alongside direct-acting antiviral drugs to achieve elimination targets. We have previously shown that a soluble recombinant form of the glycoprotein E2 ectodomain (residues 384 to 661) that lacks three variable regions (Δ123) is able to elicit a higher titer of broadly neutralizing antibodies (bNAbs) than the parental form (receptor-binding domain [RBD]). In this study, we engineered a viral nanoparticle that displays HCV glycoprotein E2 on a duck hepatitis B virus (DHBV) small surface antigen (S) scaffold. Four variants of E2-S virus-like particles (VLPs) were constructed: Δ123-S, RBD-S, Δ123A7-S, and RBDA7-S; in the last two, 7 cysteines were replaced with alanines. While all four E2-S variant VLPs display E2 as a surface antigen, the Δ123A7-S and RBDA7-S VLPs were the most efficiently secreted from transfected mammalian cells and displayed epitopes recognized by cross-genotype broadly neutralizing monoclonal antibodies (bNMAbs). Both Δ123A7-S and RBDA7-S VLPs were immunogenic in guinea pigs, generating high titers of antibodies reactive to native E2 and able to prevent the interaction between E2 and the cellular receptor CD81. Four out of eight animals immunized with Δ123A7-S elicited neutralizing antibodies (NAbs), with three of those animals generating bNAbs against 7 genotypes. Immune serum generated by animals with NAbs mapped to major neutralization epitopes located at residues 412 to 420 (epitope I) and antigenic region 3. VLPs that display E2 glycoproteins represent a promising vaccine platform for HCV and could be adapted to large-scale manufacturing in yeast systems. IMPORTANCE There is currently no vaccine to prevent hepatitis C virus infection, which affects more than 71 million people globally and is a leading cause of progressive liver disease, including cirrhosis and cancer. Broadly neutralizing antibodies that recognize the E2 envelope glycoprotein can protect against heterologous viral infection and correlate with viral clearance in humans. However, broadly neutralizing antibodies are difficult to generate due to conformational flexibility of the E2 protein and epitope occlusion. Here, we show that a VLP vaccine using the duck hepatitis B virus S antigen fused to HCV glycoprotein E2 assembles into virus-like particles that display epitopes recognized by broadly neutralizing antibodies and elicit such antibodies in guinea pigs. This platform represents a novel HCV vaccine candidate amenable to large-scale manufacture at low cost.
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Bukh J. Vaccines against hepatitis C: a travel into neutralisation space. Gut 2021; 70:1609-1610. [PMID: 33495269 DOI: 10.1136/gutjnl-2020-323377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 12/23/2020] [Indexed: 12/08/2022]
Affiliation(s)
- Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Structural and Biophysical Characterization of the HCV E1E2 Heterodimer for Vaccine Development. Viruses 2021; 13:v13061027. [PMID: 34072451 PMCID: PMC8227786 DOI: 10.3390/v13061027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/07/2023] Open
Abstract
An effective vaccine for the hepatitis C virus (HCV) is a major unmet medical and public health need, and it requires an antigen that elicits immune responses to multiple key conserved epitopes. Decades of research have generated a number of vaccine candidates; based on these data and research through clinical development, a vaccine antigen based on the E1E2 glycoprotein complex appears to be the best choice. One bottleneck in the development of an E1E2-based vaccine is that the antigen is challenging to produce in large quantities and at high levels of purity and antigenic/functional integrity. This review describes the production and characterization of E1E2-based vaccine antigens, both membrane-associated and a novel secreted form of E1E2, with a particular emphasis on the major challenges facing the field and how those challenges can be addressed.
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Andrianov AK, Fuerst TR. Immunopotentiating and Delivery Systems for HCV Vaccines. Viruses 2021; 13:v13060981. [PMID: 34070543 PMCID: PMC8227888 DOI: 10.3390/v13060981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 05/16/2021] [Accepted: 05/19/2021] [Indexed: 12/13/2022] Open
Abstract
Development of preventive vaccines against hepatitis C virus (HCV) remains one of the main strategies in achieving global elimination of the disease. The effort is focused on the quest for vaccines capable of inducing protective cross-neutralizing humoral and cellular immune responses, which in turn dictate the need for rationally designed cross-genotype vaccine antigens and potent immunoadjuvants systems. This review provides an assessment of the current state of knowledge on immunopotentiating compounds and vaccine delivery systems capable of enhancing HCV antigen-specific immune responses, while focusing on the synergy and interplay of two modalities. Structural, physico-chemical, and biophysical features of these systems are discussed in conjunction with the analysis of their in vivo performance. Extreme genetic diversity of HCV-a well-known hurdle in the development of an HCV vaccine, may also present a challenge in a search for an effective immunoadjuvant, as the effort necessitates systematic and comparative screening of rationally designed antigenic constructs. The progress may be accelerated if the preference is given to well-defined molecular immunoadjuvants with greater formulation flexibility and adaptability, including those capable of spontaneous self-assembly behavior, while maintaining their robust immunopotentiating and delivery capabilities.
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Affiliation(s)
- Alexander K. Andrianov
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA;
- Correspondence:
| | - Thomas R. Fuerst
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA;
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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Brasher NA, Adhikari A, Lloyd AR, Tedla N, Bull RA. Hepatitis C Virus Epitope Immunodominance and B Cell Repertoire Diversity. Viruses 2021; 13:v13060983. [PMID: 34070572 PMCID: PMC8229270 DOI: 10.3390/v13060983] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 12/02/2022] Open
Abstract
Despite the advent of effective, curative treatments for hepatitis C virus (HCV), a preventative vaccine remains essential for the global elimination of HCV. It is now clear that the induction of broadly neutralising antibodies (bNAbs) is essential for the rational design of such a vaccine. This review details the current understanding of epitopes on the HCV envelope, characterising the potency, breadth and immunodominance of antibodies induced against these epitopes, as well as describing the interactions between B-cell receptors and HCV infection, with a particular focus on bNAb heavy and light chain variable gene usage. Additionally, we consider the importance of a public repertoire for antibodies against HCV, compiling current knowledge and suggesting that further research in this area may be critical to the rational design of an effective HCV vaccine.
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Affiliation(s)
- Nicholas A. Brasher
- Faculty of Medicine, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (N.A.B.); (A.A.); (N.T.)
- The Kirby Institute, Faculty of Medicine, UNSW Sydney, Sydney, NSW 2052, Australia;
| | - Anurag Adhikari
- Faculty of Medicine, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (N.A.B.); (A.A.); (N.T.)
- The Kirby Institute, Faculty of Medicine, UNSW Sydney, Sydney, NSW 2052, Australia;
- Department of Infection and Immunology, Kathmandu Research Institute for Biological Sciences, Lalitpur 44700, Nepal
| | - Andrew R. Lloyd
- The Kirby Institute, Faculty of Medicine, UNSW Sydney, Sydney, NSW 2052, Australia;
| | - Nicodemus Tedla
- Faculty of Medicine, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (N.A.B.); (A.A.); (N.T.)
| | - Rowena A. Bull
- Faculty of Medicine, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (N.A.B.); (A.A.); (N.T.)
- The Kirby Institute, Faculty of Medicine, UNSW Sydney, Sydney, NSW 2052, Australia;
- Correspondence:
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Structure-Based and Rational Design of a Hepatitis C Virus Vaccine. Viruses 2021; 13:v13050837. [PMID: 34063143 PMCID: PMC8148096 DOI: 10.3390/v13050837] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 12/11/2022] Open
Abstract
A hepatitis C virus (HCV) vaccine is a critical yet unfulfilled step in addressing the global disease burden of HCV. While decades of research have led to numerous clinical and pre-clinical vaccine candidates, these efforts have been hindered by factors including HCV antigenic variability and immune evasion. Structure-based and rational vaccine design approaches have capitalized on insights regarding the immune response to HCV and the structures of antibody-bound envelope glycoproteins. Despite successes with other viruses, designing an immunogen based on HCV glycoproteins that can elicit broadly protective immunity against HCV infection is an ongoing challenge. Here, we describe HCV vaccine design approaches where immunogens were selected and optimized through analysis of available structures, identification of conserved epitopes targeted by neutralizing antibodies, or both. Several designs have elicited immune responses against HCV in vivo, revealing correlates of HCV antigen immunogenicity and breadth of induced responses. Recent studies have elucidated the functional, dynamic and immunological features of key regions of the viral envelope glycoproteins, which can inform next-generation immunogen design efforts. These insights and design strategies represent promising pathways to HCV vaccine development, which can be further informed by successful immunogen designs generated for other viruses.
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To Include or Occlude: Rational Engineering of HCV Vaccines for Humoral Immunity. Viruses 2021; 13:v13050805. [PMID: 33946211 PMCID: PMC8146105 DOI: 10.3390/v13050805] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/16/2021] [Accepted: 04/28/2021] [Indexed: 02/07/2023] Open
Abstract
Direct-acting antiviral agents have proven highly effective at treating existing hepatitis C infections but despite their availability most countries will not reach the World Health Organization targets for elimination of HCV by 2030. A prophylactic vaccine remains a high priority. Whilst early vaccines focused largely on generating T cell immunity, attention is now aimed at vaccines that generate humoral immunity, either alone or in combination with T cell-based vaccines. High-resolution structures of hepatitis C viral glycoproteins and their interaction with monoclonal antibodies isolated from both cleared and chronically infected people, together with advances in vaccine technologies, provide new avenues for vaccine development.
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Immuno-Informatics Analysis of Pakistan-Based HCV Subtype-3a for Chimeric Polypeptide Vaccine Design. Vaccines (Basel) 2021; 9:vaccines9030293. [PMID: 33801143 PMCID: PMC8004085 DOI: 10.3390/vaccines9030293] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) causes chronic and acute hepatitis infections. As there is extreme variability in the HCV genome, no approved HCV vaccine has been available so far. An effective polypeptide vaccine based on the functionally conserved epitopes will be greatly helpful in curing disease. For this purpose, an immuno-informatics study is performed based on the published HCV subtype-3a from Pakistan. First, the virus genome was translated to a polyprotein followed by a subsequent prediction of T-cell epitopes. Non-allergenic, IFN-γ producer, and antigenic epitopes were shortlisted, including 5 HTL epitopes and 4 CTL, which were linked to the final vaccine by GPGPG and AAY linkers, respectively. Beta defensin was included as an adjuvant through the EAAAK linker to improve the immunogenicity of the polypeptide. To ensure its safety and immunogenicity profile, antigenicity, allergenicity, and various physiochemical attributes of the polypeptide were evaluated. Molecular docking was conducted between TLR4 and vaccine to evaluate the binding affinity and molecular interactions. For stability assessment and binding of the vaccine-TLR4 docked complex, molecular dynamics (MD) simulation and MMGBSA binding free-energy analyses were conducted. Finally, the candidate vaccine was cloned in silico to ensure its effectiveness. The current vaccine requires future experimental confirmation to validate its effectiveness. The vaccine construct produced might be useful in providing immune protection against HCV-related infections.
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Optimized Hepatitis C Virus (HCV) E2 Glycoproteins and their Immunogenicity in Combination with MVA-HCV. Vaccines (Basel) 2020; 8:vaccines8030440. [PMID: 32764419 PMCID: PMC7563715 DOI: 10.3390/vaccines8030440] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/22/2020] [Accepted: 07/25/2020] [Indexed: 12/20/2022] Open
Abstract
Hepatitis C virus (HCV) represents a major global health challenge and an efficient vaccine is urgently needed. Many HCV vaccination strategies employ recombinant versions of the viral E2 glycoprotein. However, recombinant E2 readily forms disulfide-bonded aggregates that might not be optimally suited for vaccines. Therefore, we have designed an E2 protein in which we strategically changed eight cysteines to alanines (E2.C8A). E2.C8A formed predominantly monomers and virtually no aggregates. Furthermore, E2.C8A also interacted more efficiently with broadly neutralizing antibodies than conventional E2. We used mice to evaluate different prime/boost immunization strategies involving a modified vaccinia virus Ankara (MVA) expressing the nearly full-length genome of HCV (MVA-HCV) in combination with either the E2 aggregates or the E2.C8A monomers. The combined MVA-HCV/E2 aggregates prime/boost strategy markedly enhanced HCV-specific effector memory CD4+ T cell responses and antibody levels compared to MVA-HCV/MVA-HCV. Moreover, the aggregated form of E2 induced higher levels of anti-E2 antibodies in vaccinated mice than E2.C8A monomers. These antibodies were cross-reactive and mainly of the IgG1 isotype. Our findings revealed how two E2 viral proteins that differ in their capacity to form aggregates are able to enhance to different extent the HCV-specific cellular and humoral immune responses, either alone or in combination with MVA-HCV. These combined protocols of MVA-HCV/E2 could serve as a basis for the development of a more effective HCV vaccine.
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Hepatitis C virus vaccine design: focus on the humoral immune response. J Biomed Sci 2020; 27:78. [PMID: 32631318 PMCID: PMC7338099 DOI: 10.1186/s12929-020-00669-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/26/2020] [Indexed: 02/06/2023] Open
Abstract
Despite the recent development of safe and highly effective direct-acting antivirals, hepatitis C virus (HCV) infection remains a significant health problem. In 2016, the World Health Organization set out to reduce the rate of new HCV infections by 90% by 2030. Still, global control of the virus does not seem to be achievable in the absence of an effective vaccine. Current approaches to the development of a vaccine against HCV include the production of recombinant proteins, synthetic peptides, DNA vaccines, virus-like particles, and viral vectors expressing various antigens. In this review, we focus on the development of vaccines targeting the humoral immune response against HCV based on the cumulative evidence supporting the important role of neutralizing antibodies in protection against HCV infection. The main targets of HCV-specific neutralizing antibodies are the glycoproteins E1 and E2. Recent advances in the knowledge of HCV glycoprotein structure and their epitopes, as well as the possibility of getting detailed information on the human antibody repertoire generated by the infection, will allow rational structure-based antigen design to target specific germline antibodies. Although obtaining a vaccine capable of inducing sterilizing immunity will be a difficult task, a vaccine that prevents chronic hepatitis C infections, a more realistic goal in the short term, would have a considerable health impact.
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