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Rutkowska DA, Du Plessis LH, Suleman E, O’Kennedy MM, Thimiri Govinda Raj DB, Lemmer Y. Development of a Plant-Expressed Subunit Vaccine against Brucellosis. Microorganisms 2024; 12:1047. [PMID: 38930429 PMCID: PMC11205566 DOI: 10.3390/microorganisms12061047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/28/2024] Open
Abstract
Brucellosis is an important bacterial disease of livestock and the most common zoonotic disease. The current vaccines are effective but unsafe, as they result in animal abortions and are pathogenic to humans. Virus-like particles are being investigated as molecular scaffolds for foreign antigen presentation to the immune system. Here, we sought to develop a new-generation vaccine by presenting selected Brucella melitensis T cell epitopes on the surface of Orbivirus core-like particles (CLPs) and transiently expressing these chimeric particles in Nicotiana benthamiana plants. We successfully demonstrated the assembly of five chimeric CLPs in N. benthamiana plants, with each CLP presenting a different T cell epitope. The safety and protective efficacy of three of the highest-yielding CLPs was investigated in a mouse model of brucellosis. All three plant-expressed chimeric CLPs were safe when inoculated into BALB/c mice at specific antigen doses. However, only one chimeric CLP induced protection against the virulent Brucella strain challenge equivalent to the protection induced by the commercial Rev1 vaccine. Here, we have successfully shown the assembly, safety and protective efficacy of plant-expressed chimeric CLPs presenting B. melitensis T cell epitopes. This is the first step in the development of a safe and efficacious subunit vaccine against brucellosis.
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Affiliation(s)
- Daria A. Rutkowska
- Advanced Agriculture and Food Cluster, Council for Scientific and Industrial Research, Pretoria 0001, South Africa;
| | - Lissinda H. Du Plessis
- Centre of Excellence for Pharmaceutical Sciences (PharmacenTM), North-West University, Potchefstroom 2520, South Africa;
| | - Essa Suleman
- Advanced Agriculture and Food Cluster, Council for Scientific and Industrial Research, Pretoria 0001, South Africa;
| | - Martha M. O’Kennedy
- Future Production and Chemicals Cluster, Council for Scientific and Industrial Research, Pretoria 0001, South Africa; (M.M.O.); (Y.L.)
| | - Deepak B. Thimiri Govinda Raj
- Synthetic Biology and Precision Medicine Centre, Future Production and Chemicals Cluster, Council for Scientific and Industrial Research, Pretoria 0001, South Africa;
| | - Yolandy Lemmer
- Future Production and Chemicals Cluster, Council for Scientific and Industrial Research, Pretoria 0001, South Africa; (M.M.O.); (Y.L.)
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2
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Bekker S, Potgieter CA, van Staden V, Theron J. Investigating the Role of African Horse Sickness Virus VP7 Protein Crystalline Particles on Virus Replication and Release. Viruses 2022; 14:2193. [PMID: 36298748 PMCID: PMC9608501 DOI: 10.3390/v14102193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/19/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022] Open
Abstract
African horse sickness is a deadly and highly infectious disease of equids, caused by African horse sickness virus (AHSV). AHSV is one of the most economically important members of the Orbivirus genus. AHSV is transmitted by the biting midge, Culicoides, and therefore replicates in both insect and mammalian cell types. Structural protein VP7 is a highly conserved major core protein of orbiviruses. Unlike any other orbivirus VP7, AHSV VP7 is highly insoluble and forms flat hexagonal crystalline particles of unknown function in AHSV-infected cells and when expressed in mammalian or insect cells. To examine the role of AHSV VP7 in virus replication, a plasmid-based reverse genetics system was used to generate a recombinant AHSV that does not form crystalline particles. We characterised the role of VP7 crystalline particle formation in AHSV replication in vitro and found that soluble VP7 interacted with viral proteins VP2 and NS2 similarly to wild-type VP7 during infection. Interestingly, soluble VP7 was found to form uncharacteristic tubule-like structures in infected cells which were confirmed to be as a result of unique VP7-NS1 colocalisation. Furthermore, it was found that VP7 crystalline particles play a role in AHSV release and yield. This work provides insight into the role of VP7 aggregation in AHSV cellular pathogenesis and contributes toward the understanding of the possible effects of viral protein aggregation in other human virus-borne diseases.
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Affiliation(s)
- Shani Bekker
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0083, South Africa
| | - Christiaan A. Potgieter
- Deltamune (Pty) Ltd., 3 Bauhinia Street, Unit 34 Oxford Office Park, Highveld Techno Park, Centurion 0169, South Africa
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University, Potchefstroom 2520, South Africa
| | - Vida van Staden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0083, South Africa
| | - Jacques Theron
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0083, South Africa
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3
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Bekker S, Huismans H, van Staden V. Generation of a Soluble African Horse Sickness Virus VP7 Protein Capable of Forming Core-like Particles. Viruses 2022; 14:1624. [PMID: 35893692 PMCID: PMC9331310 DOI: 10.3390/v14081624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/12/2022] [Accepted: 07/21/2022] [Indexed: 02/06/2023] Open
Abstract
A unique characteristic of the African horse sickness virus (AHSV) major core protein VP7 is that it is highly insoluble, and spontaneously forms crystalline particles in AHSV-infected cells and when expressed in vitro. The aggregation of AHSV VP7 into these crystals presents many problems in AHSV vaccine development, and it is unclear whether VP7 aggregation affects AHSV assembly or contributes to AHSV pathogenesis. Here, we set out to abolish VP7 self-assembly by targeting candidate amino acid regions on the surface of the VP7 trimer via site-directed mutagenesis. It was found that the substitution of seven amino acids resulted in the complete disruption of AHSV VP7 self-assembly, which abolished the formation of VP7 crystalline particles and converted VP7 to a fully soluble protein still capable of interacting with VP3 to form core-like particles. This work provides further insight into the formation of AHSV VP7 crystalline particles and the successful development of AHSV vaccines. It also paves the way for future research by drawing comparisons with similar viral phenomena observed in human virology.
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Affiliation(s)
| | | | - Vida van Staden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0083, South Africa; (S.B.); (H.H.)
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4
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Fearon SH, Dennis SJ, Hitzeroth II, Rybicki EP, Meyers AE. Plant expression systems as an economical alternative for the production of iELISA coating antigen AHSV VP7. N Biotechnol 2022; 68:48-56. [DOI: 10.1016/j.nbt.2022.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/28/2021] [Accepted: 01/28/2022] [Indexed: 10/19/2022]
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5
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Fearon SH, Dennis SJ, Hitzeroth II, Rybicki EP, Meyers AE. Humoral and cell-mediated immune responses to plant-produced African horse sickness virus VP7 quasi-crystals. Virus Res 2021; 294:198284. [PMID: 33421520 DOI: 10.1016/j.virusres.2020.198284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/22/2020] [Accepted: 12/26/2020] [Indexed: 11/26/2022]
Abstract
African horse sickness (AHS) is a devastating viral disease affecting equines and has resulted in many disastrous epizootics. To date, no successful therapeutic treatment exists for AHS, and commercially used live-attenuated vaccines have various undesirable side effects. Previous studies have shown that mice inoculated with insoluble African horse sickness virus (AHSV) VP7 crystals are protected from live challenge with a lethal dose of AHSV. This study investigates the humoral and cell-mediated immune responses in guinea-pigs to a safer monovalent vaccine alternative based on AHSV-5 VP7 quasi-crystals produced in plants. Guinea-pigs received prime- and boost-inoculations of between 10 and 50 μg of purified plant-produced AHSV VP7. Western immunoblot analysis of the humoral response showed stimulation of high titres of anti-VP7 antibodies 28 days after the boost-inoculation in sera from three of the five experimental animals. In addition, RNA-seq transcriptome profiling of guinea-pig spleen-derived RNA highlighted thirty significantly (q ≤ 0.05) differentially expressed genes involved in innate and adaptive immunity. Differential expression of genes involved in Th1, Th2 and Th17 cell differentiation suggest a cell-mediated immune response to AHSV-5 VP7. Upregulation of several important cytokines and cytokine receptors were noted, including TNFSF14, CX3CR1, IFNLR1 and IL17RA. Upregulation of IL17RA suggests a Th17 response which has been reported as a key component in AHSV immunity. While further investigation is needed to validate these findings, these results suggest that AHSV-5 VP7 quasi-crystals produced in N. benthamiana are immunogenic and induce both humoral and cell-mediated responses.
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Affiliation(s)
- Shelley H Fearon
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7700, South Africa
| | - Susan J Dennis
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7700, South Africa
| | - Inga I Hitzeroth
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7700, South Africa
| | - Edward P Rybicki
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7700, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Rondebosch, Cape Town 7700, South Africa
| | - Ann E Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7700, South Africa.
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Luciani M, Armillotta G, Ciarelli A, Ulisse S, Teodori L, Bortone G, Giamboi A, Monaco F, Tittarelli M, Di Ventura M, Iannetti L, Podaliri Vulpiani M, Di Febo T. Production of monoclonal antibodies binding to the VP7 protein of African horse sickness virus. J Virol Methods 2019; 270:131-136. [PMID: 31095974 DOI: 10.1016/j.jviromet.2019.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 04/08/2019] [Accepted: 05/13/2019] [Indexed: 11/30/2022]
Abstract
Monoclonal antibodies (MAbs) against AHSV were produced by immunising BALB/c mice with AHSV serotype 9 and six clones able to recognize specifically the VP7-AHSV with a strong reactivity were selected. The specificity of the MAbs was assessed in i-ELISA against a commercial VP7-AHSV and in immunoblot against a home-made VP7-AHSV, expressed by a Baculovirus expression system; potential cross-reactions with related orbiviruses (Bluetongue virus and Epizootic Haemorrhagic Disease virus) were investigated as well. One of the six MAbs selected, MAb 7F11E14, was tested in direct immunofluorescence and reacted with all nine AHSV serotypes, but didn't cross-react with BTV and EHDV. MAb 7F11E14 was also used to develop a competitive ELISA and was able to detect AHSV antibodies in the sera of AHS infected animals.
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Affiliation(s)
- Mirella Luciani
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy.
| | - Gisella Armillotta
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Antonella Ciarelli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Simonetta Ulisse
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Liana Teodori
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Grazia Bortone
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Alessandro Giamboi
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Federica Monaco
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Manuela Tittarelli
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Mauro Di Ventura
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Luigi Iannetti
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | | | - Tiziana Di Febo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
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Analysis of the three-dimensional structure of the African horse sickness virus VP7 trimer by homology modelling. Virus Res 2017; 232:80-95. [DOI: 10.1016/j.virusres.2017.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 01/27/2017] [Accepted: 02/02/2017] [Indexed: 01/21/2023]
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8
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Wall GV, Rutkowska DA, Mizrachi E, Huismans H, van Staden V. A Dual Laser Scanning Confocal and Transmission Electron Microscopy Analysis of the Intracellular Localization, Aggregation and Particle Formation of African Horse Sickness Virus Major Core Protein VP7. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:56-68. [PMID: 28112080 DOI: 10.1017/s143192761601268x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The bulk of the major core protein VP7 in African horse sickness virus (AHSV) self-assembles into flat, hexagonal crystalline particles in a process appearing unrelated to viral replication. Why this unique characteristic of AHSV VP7 is genetically conserved, and whether VP7 aggregation and particle formation have an effect on cellular biology or the viral life cycle, is unknown. Here we investigated how different small peptide and enhanced green fluorescent protein (eGFP) insertions into the VP7 top domain affected VP7 localization, aggregation, and particle formation. This was done using a dual laser scanning confocal and transmission electron microscopy approach in conjunction with analyses of the solubility, aggregation, and fluorescence profiles of the proteins. VP7 top domain modifications did not prevent trimerization, or intracellular trafficking, to one or two discrete sites in the cell. However, modifications that resulted in a misfolded and insoluble VP7-eGFP component blocked trafficking, and precluded protein accumulation at a single cellular site, perhaps by interfering with normal trimer-trimer interactions. Furthermore, the modifications disrupted the stable layering of the trimers into characteristic AHSV VP7 crystalline particles. It was concluded that VP7 trafficking is driven by a balance between VP7 solubility, trimer forming ability, and trimer-trimer interactions.
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Affiliation(s)
- Gayle V Wall
- Department of Genetics,University of Pretoria,Pretoria,0002,South Africa
| | - Daria A Rutkowska
- Department of Genetics,University of Pretoria,Pretoria,0002,South Africa
| | - Eshchar Mizrachi
- Department of Genetics,University of Pretoria,Pretoria,0002,South Africa
| | - Henk Huismans
- Department of Genetics,University of Pretoria,Pretoria,0002,South Africa
| | - Vida van Staden
- Department of Genetics,University of Pretoria,Pretoria,0002,South Africa
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9
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Maree S, Maree FF, Putterill JF, de Beer TA, Huismans H, Theron J. Synthesis of empty african horse sickness virus particles. Virus Res 2016; 213:184-194. [DOI: 10.1016/j.virusres.2015.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 11/05/2015] [Accepted: 12/07/2015] [Indexed: 11/30/2022]
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10
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Factors that affect the intracellular localization and trafficking of African horse sickness virus core protein, VP7. Virology 2014; 456-457:279-91. [DOI: 10.1016/j.virol.2014.03.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/26/2014] [Accepted: 03/29/2014] [Indexed: 11/21/2022]
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11
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Venter E, van der Merwe CF, Buys AV, Huismans H, van Staden V. Comparative ultrastructural characterization of African horse sickness virus-infected mammalian and insect cells reveals a novel potential virus release mechanism from insect cells. J Gen Virol 2014; 95:642-651. [PMID: 24347494 DOI: 10.1099/vir.0.060400-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
African horse sickness virus (AHSV) is an arbovirus capable of successfully replicating in both its mammalian host and insect vector. Where mammalian cells show a severe cytopathic effect (CPE) following AHSV infection, insect cells display no CPE. These differences in cell death could be linked to the method of viral release, i.e. lytic or non-lytic, that predominates in a specific cell type. Active release of AHSV, or any related orbivirus, has, however, not yet been documented from insect cells. We applied an integrated microscopy approach to compare the nanomechanical and morphological response of mammalian and insect cells to AHSV infection. Atomic force microscopy revealed plasma membrane destabilization, integrity loss and structural deformation of the entire surface of infected mammalian cells. Infected insect cells, in contrast, showed no morphological differences from mock-infected cells other than an increased incidence of circular cavities present on the cell surface. Transmission electron microscopy imaging identified a novel large vesicle-like compartment within infected insect cells, not present in mammalian cells, containing viral proteins and virus particles. Extracellular clusters of aggregated virus particles were visualized adjacent to infected insect cells with intact plasma membranes. We propose that foreign material is accumulated within these vesicles and that their subsequent fusion with the cell membrane releases entrapped viruses, thereby facilitating a non-lytic virus release mechanism different from the budding previously observed in mammalian cells. This insect cell-specific defence mechanism contributes to the lack of cell damage observed in AHSV-infected insect cells.
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Affiliation(s)
- E. Venter
- Department of Genetics, University of Pretoria, Pretoria 0002, South Africa
| | - C. F. van der Merwe
- Laboratory for Microscopy and Microanalysis, University of Pretoria, South Africa
| | - A. V. Buys
- Laboratory for Microscopy and Microanalysis, University of Pretoria, South Africa
| | - H. Huismans
- Department of Genetics, University of Pretoria, Pretoria 0002, South Africa
| | - V. van Staden
- Department of Genetics, University of Pretoria, Pretoria 0002, South Africa
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Pushko P, Pumpens P, Grens E. Development of Virus-Like Particle Technology from Small Highly Symmetric to Large Complex Virus-Like Particle Structures. Intervirology 2013; 56:141-65. [DOI: 10.1159/000346773] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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