1
|
Buyel JF. Towards a seamless product and process development workflow for recombinant proteins produced by plant molecular farming. Biotechnol Adv 2024; 75:108403. [PMID: 38986726 DOI: 10.1016/j.biotechadv.2024.108403] [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: 03/25/2024] [Revised: 06/25/2024] [Accepted: 07/06/2024] [Indexed: 07/12/2024]
Abstract
Plant molecular farming (PMF) has been promoted as a fast, efficient and cost-effective alternative to bacteria and animal cells for the production of biopharmaceutical proteins. Numerous plant species have been tested to produce a wide range of drug candidates. However, PMF generally lacks a systematic, streamlined and seamless workflow to continuously fill the product pipeline. Therefore, it is currently unable to compete with established platforms in terms of routine, throughput and horizontal integration (the rapid translation of product candidates to preclinical and clinical development). Individual management decisions, limited funding and a lack of qualified production capacity can hinder the execution of such projects, but we also lack suitable technologies for sample handling and data management. This perspectives article will highlight current bottlenecks in PMF and offer potential solutions that combine PMF with existing technologies to build an integrated facility of the future for product development, testing, manufacturing and clinical translation. Ten major bottlenecks have been identified and are discussed in turn: automated cloning and simplified transformation options, reproducibility of bacterial cultivation, bioreactor integration with automated cell handling, options for rapid mid-scale candidate and product manufacturing, interconnection with (group-specific or personalized) clinical trials, diversity of (post-)infiltration conditions, development of downstream processing platforms, continuous process operation, compliance of manufacturing conditions with biosafety regulations, scaling requirements for cascading biomass.
Collapse
Affiliation(s)
- J F Buyel
- University of Natural Resources and Life Sciences, Vienna (BOKU), Department of Biotechnology (DBT), Institute of Bioprocess Science and Engineering (IBSE), Muthgasse 18, A-1190 Vienna, Austria.
| |
Collapse
|
2
|
Hamel L, Comeau M, Tardif R, Poirier‐Gravel F, Paré M, Lavoie P, Goulet M, Michaud D, D'Aoust M. Heterologous expression of influenza haemagglutinin leads to early and transient activation of the unfolded protein response in Nicotiana benthamiana. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:1146-1163. [PMID: 38038125 PMCID: PMC11022800 DOI: 10.1111/pbi.14252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/06/2023] [Accepted: 11/16/2023] [Indexed: 12/02/2023]
Abstract
The unfolded protein response (UPR) allows cells to cope with endoplasmic reticulum (ER) stress induced by accumulation of misfolded proteins in the ER. Due to its sensitivity to Agrobacterium tumefaciens, the model plant Nicotiana benthamiana is widely employed for transient expression of recombinant proteins of biopharmaceutical interest, including antibodies and virus surface proteins used for vaccine production. As such, study of the plant UPR is of practical significance, since enforced expression of complex secreted proteins often results in ER stress. After 6 days of expression, we recently reported that influenza haemagglutinin H5 induces accumulation of UPR proteins. Since up-regulation of corresponding UPR genes was not detected at this time, accumulation of UPR proteins was hypothesized to be independent of transcriptional induction, or associated with early but transient UPR gene up-regulation. Using time course sampling, we here show that H5 expression does result in early and transient activation of the UPR, as inferred from unconventional splicing of NbbZIP60 transcripts and induction of UPR genes with varied functions. Transient nature of H5-induced UPR suggests that this response was sufficient to cope with ER stress provoked by expression of the secreted protein, as opposed to an antibody that triggered stronger and more sustained UPR activation. As up-regulation of defence genes responding to H5 expression was detected after the peak of UPR activation and correlated with high increase in H5 protein accumulation, we hypothesize that these immune responses, rather than the UPR, were responsible for onset of the necrotic symptoms on H5-expressing leaves.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Marie‐Claire Goulet
- Centre de recherche et d'innovation sur les végétaux, Département de phytologieUniversité LavalQuébecQuebecCanada
| | - Dominique Michaud
- Centre de recherche et d'innovation sur les végétaux, Département de phytologieUniversité LavalQuébecQuebecCanada
| | | |
Collapse
|
3
|
Wagner N, Musiychuk K, Shoji Y, Tottey S, Streatfield SJ, Fischer R, Yusibov V. Basic leucine zipper transcription activators - tools to improve production and quality of human erythropoietin in Nicotiana benthamiana. Biotechnol J 2024; 19:e2300715. [PMID: 38797727 DOI: 10.1002/biot.202300715] [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: 12/19/2023] [Revised: 04/02/2024] [Accepted: 04/25/2024] [Indexed: 05/29/2024]
Abstract
Human erythropoietin (hEPO) is one of the most in-demand biopharmaceuticals, however, its production is challenging. When produced in a plant expression system, hEPO results in extensive plant tissue damage and low expression. It is demonstrated that the modulation of the plant protein synthesis machinery enhances hEPO production. Co-expression of basic leucine zipper transcription factors with hEPO prevents plant tissue damage, boosts expression, and increases hEPO solubility. bZIP28 co-expression up-regulates genes associated with the unfolded protein response, indicating that the plant tissue damage caused by hEPO expression is due to the native protein folding machinery being overwhelmed and that this can be overcome by co-expressing bZIP28.
Collapse
Affiliation(s)
- Nazgul Wagner
- Biotechnology Division, Fraunhofer USA Inc., Center Mid-Atlantic, Newark, Delaware, USA
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Konstantin Musiychuk
- Biotechnology Division, Fraunhofer USA Inc., Center Mid-Atlantic, Newark, Delaware, USA
| | - Yoko Shoji
- Biotechnology Division, Fraunhofer USA Inc., Center Mid-Atlantic, Newark, Delaware, USA
| | - Stephen Tottey
- Biotechnology Division, Fraunhofer USA Inc., Center Mid-Atlantic, Newark, Delaware, USA
| | - Stephen J Streatfield
- Biotechnology Division, Fraunhofer USA Inc., Center Mid-Atlantic, Newark, Delaware, USA
| | - Rainer Fischer
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Vidadi Yusibov
- Biotechnology Division, Fraunhofer USA Inc., Center Mid-Atlantic, Newark, Delaware, USA
| |
Collapse
|
4
|
Zahmanova G, Aljabali AAA, Takova K, Minkov G, Tambuwala MM, Minkov I, Lomonossoff GP. Green Biologics: Harnessing the Power of Plants to Produce Pharmaceuticals. Int J Mol Sci 2023; 24:17575. [PMID: 38139405 PMCID: PMC10743837 DOI: 10.3390/ijms242417575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/11/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
Plants are increasingly used for the production of high-quality biological molecules for use as pharmaceuticals and biomaterials in industry. Plants have proved that they can produce life-saving therapeutic proteins (Elelyso™-Gaucher's disease treatment, ZMapp™-anti-Ebola monoclonal antibodies, seasonal flu vaccine, Covifenz™-SARS-CoV-2 virus-like particle vaccine); however, some of these therapeutic proteins are difficult to bring to market, which leads to serious difficulties for the manufacturing companies. The closure of one of the leading companies in the sector (the Canadian biotech company Medicago Inc., producer of Covifenz) as a result of the withdrawal of investments from the parent company has led to the serious question: What is hindering the exploitation of plant-made biologics to improve health outcomes? Exploring the vast potential of plants as biological factories, this review provides an updated perspective on plant-derived biologics (PDB). A key focus is placed on the advancements in plant-based expression systems and highlighting cutting-edge technologies that streamline the production of complex protein-based biologics. The versatility of plant-derived biologics across diverse fields, such as human and animal health, industry, and agriculture, is emphasized. This review also meticulously examines regulatory considerations specific to plant-derived biologics, shedding light on the disparities faced compared to biologics produced in other systems.
Collapse
Affiliation(s)
- Gergana Zahmanova
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (K.T.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Alaa A. A. Aljabali
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Yarmouk University, Irbid 21163, Jordan;
| | - Katerina Takova
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (K.T.)
| | - George Minkov
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (K.T.)
| | - Murtaza M. Tambuwala
- Lincoln Medical School, University of Lincoln, Brayford Pool Campus, Lincoln LN6 7TS, UK;
| | - Ivan Minkov
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria
| | | |
Collapse
|
5
|
Parthiban S, Vijeesh T, Gayathri T, Shanmugaraj B, Sharma A, Sathishkumar R. Artificial intelligence-driven systems engineering for next-generation plant-derived biopharmaceuticals. FRONTIERS IN PLANT SCIENCE 2023; 14:1252166. [PMID: 38034587 PMCID: PMC10684705 DOI: 10.3389/fpls.2023.1252166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/17/2023] [Indexed: 12/02/2023]
Abstract
Recombinant biopharmaceuticals including antigens, antibodies, hormones, cytokines, single-chain variable fragments, and peptides have been used as vaccines, diagnostics and therapeutics. Plant molecular pharming is a robust platform that uses plants as an expression system to produce simple and complex recombinant biopharmaceuticals on a large scale. Plant system has several advantages over other host systems such as humanized expression, glycosylation, scalability, reduced risk of human or animal pathogenic contaminants, rapid and cost-effective production. Despite many advantages, the expression of recombinant proteins in plant system is hindered by some factors such as non-human post-translational modifications, protein misfolding, conformation changes and instability. Artificial intelligence (AI) plays a vital role in various fields of biotechnology and in the aspect of plant molecular pharming, a significant increase in yield and stability can be achieved with the intervention of AI-based multi-approach to overcome the hindrance factors. Current limitations of plant-based recombinant biopharmaceutical production can be circumvented with the aid of synthetic biology tools and AI algorithms in plant-based glycan engineering for protein folding, stability, viability, catalytic activity and organelle targeting. The AI models, including but not limited to, neural network, support vector machines, linear regression, Gaussian process and regressor ensemble, work by predicting the training and experimental data sets to design and validate the protein structures thereby optimizing properties such as thermostability, catalytic activity, antibody affinity, and protein folding. This review focuses on, integrating systems engineering approaches and AI-based machine learning and deep learning algorithms in protein engineering and host engineering to augment protein production in plant systems to meet the ever-expanding therapeutics market.
Collapse
Affiliation(s)
- Subramanian Parthiban
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India
| | - Thandarvalli Vijeesh
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India
| | - Thashanamoorthi Gayathri
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India
| | - Balamurugan Shanmugaraj
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India
| | - Ashutosh Sharma
- Tecnologico de Monterrey, School of Engineering and Sciences, Centre of Bioengineering, Queretaro, Mexico
| | - Ramalingam Sathishkumar
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India
| |
Collapse
|
6
|
Strasser R. Plant glycoengineering for designing next-generation vaccines and therapeutic proteins. Biotechnol Adv 2023; 67:108197. [PMID: 37315875 DOI: 10.1016/j.biotechadv.2023.108197] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/16/2023]
Abstract
Protein glycosylation has a huge impact on biological processes in all domains of life. The type of glycan present on a recombinant glycoprotein depends on protein intrinsic features and the glycosylation repertoire of the cell type used for expression. Glycoengineering approaches are used to eliminate unwanted glycan modifications and to facilitate the coordinated expression of glycosylation enzymes or whole metabolic pathways to furnish glycans with distinct modifications. The formation of tailored glycans enables structure-function studies and optimization of therapeutic proteins used in different applications. While recombinant proteins or proteins from natural sources can be in vitro glycoengineered using glycosyltransferases or chemoenzymatic synthesis, many approaches use genetic engineering involving the elimination of endogenous genes and introduction of heterologous genes to cell-based production systems. Plant glycoengineering enables the in planta production of recombinant glycoproteins with human or animal-type glycans that resemble natural glycosylation or contain novel glycan structures. This review summarizes key achievements in glycoengineering of plants and highlights current developments aiming to make plants more suitable for the production of a diverse range of recombinant glycoproteins for innovative therapies.
Collapse
Affiliation(s)
- Richard Strasser
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
| |
Collapse
|
7
|
Esqueda A, Sun H, Bonner J, Lai H, Jugler C, Kibler KV, Steinkellner H, Chen Q. A Monoclonal Antibody Produced in Glycoengineered Plants Potently Neutralizes Monkeypox Virus. Vaccines (Basel) 2023; 11:1179. [PMID: 37514995 PMCID: PMC10416152 DOI: 10.3390/vaccines11071179] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/28/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
The 2022 global outbreaks of monkeypox virus (MPXV) and increased human-to-human transmission calls for the urgent development of countermeasures to protect people who cannot benefit from vaccination. Here, we describe the development of glycovariants of 7D11, a neutralizing monoclonal IgG antibody (mAb) directed against the L1 transmembrane protein of the related vaccinia virus, in a plant-based system as a potential therapeutic against the current MPVX outbreak. Our results indicated that 7D11 mAb quickly accumulates to high levels within a week after gene introduction to plants. Plant-produced 7D11 mAb assembled correctly into the tetrameric IgG structure and can be easily purified to homogeneity. 7D11 mAb exhibited a largely homogeneous N-glycosylation profile, with or without plant-specific xylose and fucose residues, depending on the expression host, namely wild-type or glycoengineered plants. Plant-made 7D11 retained specific binding to its antigen and displayed a strong neutralization activity against MPXV, as least as potent as the reported activity against vaccinia virus. Our study highlights the utility of anti-L1 mAbs as MPXV therapeutics, and the use of glycoengineered plants to develop mAb glycovariants for potentially enhancing the efficacy of mAbs to combat ever-emerging/re-emerging viral diseases.
Collapse
Affiliation(s)
- Adrian Esqueda
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Haiyan Sun
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - James Bonner
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Huafang Lai
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Collin Jugler
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Karen V. Kibler
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Herta Steinkellner
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1180 Vienna, Austria
| | - Qiang Chen
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| |
Collapse
|
8
|
Margolin E, Schäfer G, Allen JD, Gers S, Woodward J, Sutherland AD, Blumenthal M, Meyers A, Shaw ML, Preiser W, Strasser R, Crispin M, Williamson AL, Rybicki EP, Chapman R. A plant-produced SARS-CoV-2 spike protein elicits heterologous immunity in hamsters. FRONTIERS IN PLANT SCIENCE 2023; 14:1146234. [PMID: 36959936 PMCID: PMC10028082 DOI: 10.3389/fpls.2023.1146234] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/17/2023] [Indexed: 06/16/2023]
Abstract
Molecular farming of vaccines has been heralded as a cheap, safe and scalable production platform. In reality, however, differences in the plant biosynthetic machinery, compared to mammalian cells, can complicate the production of viral glycoproteins. Remodelling the secretory pathway presents an opportunity to support key post-translational modifications, and to tailor aspects of glycosylation and glycosylation-directed folding. In this study, we applied an integrated host and glyco-engineering approach, NXS/T Generation™, to produce a SARS-CoV-2 prefusion spike trimer in Nicotiana benthamiana as a model antigen from an emerging virus. The size exclusion-purified protein exhibited a characteristic prefusion structure when viewed by transmission electron microscopy, and this was indistinguishable from the equivalent mammalian cell-produced antigen. The plant-produced protein was decorated with under-processed oligomannose N-glycans and exhibited a site occupancy that was comparable to the equivalent protein produced in mammalian cell culture. Complex-type glycans were almost entirely absent from the plant-derived material, which contrasted against the predominantly mature, complex glycans that were observed on the mammalian cell culture-derived protein. The plant-derived antigen elicited neutralizing antibodies against both the matched Wuhan and heterologous Delta SARS-CoV-2 variants in immunized hamsters, although titres were lower than those induced by the comparator mammalian antigen. Animals vaccinated with the plant-derived antigen exhibited reduced viral loads following challenge, as well as significant protection from SARS-CoV-2 disease as evidenced by reduced lung pathology, lower viral loads and protection from weight loss. Nonetheless, animals immunized with the mammalian cell-culture-derived protein were better protected in this challenge model suggesting that more faithfully reproducing the native glycoprotein structure and associated glycosylation of the antigen may be desirable.
Collapse
Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Georgia Schäfer
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Observatory, Cape Town, Cape Town, South Africa
| | - Joel D Allen
- School of Biological Sciences and Institute of Life Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Jeremy Woodward
- Electron Microscope Unit, University of Cape Town, Cape Town, South Africa
| | - Andrew D Sutherland
- Division of Medical Virology, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, Cape Town, South Africa
| | - Melissa Blumenthal
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Observatory, Cape Town, Cape Town, South Africa
| | - Ann Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Megan L Shaw
- Department of Medical Biosciences, University of the Western Cape, Cape Town, South Africa
| | - Wolfgang Preiser
- Division of Medical Virology, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, Cape Town, South Africa
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Max Crispin
- School of Biological Sciences and Institute of Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward P Rybicki
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
9
|
Jugler C, Sun H, Nguyen K, Palt R, Felder M, Steinkellner H, Chen Q. A novel plant-made monoclonal antibody enhances the synergetic potency of an antibody cocktail against the SARS-CoV-2 Omicron variant. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:549-559. [PMID: 36403203 PMCID: PMC9946148 DOI: 10.1111/pbi.13970] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/06/2022] [Accepted: 11/12/2022] [Indexed: 06/01/2023]
Abstract
This study describes a novel, neutralizing monoclonal antibody (mAb), 11D7, discovered by mouse immunization and hybridoma generation, against the parental Wuhan-Hu-1 RBD of SARS-CoV-2. We further developed this mAb into a chimeric human IgG and recombinantly expressed it in plants to produce a mAb with human-like, highly homogenous N-linked glycans that has potential to impart greater potency and safety as a therapeutic. The epitope of 11D7 was mapped by competitive binding with well-characterized mAbs, suggesting that it is a Class 4 RBD-binding mAb that binds to the RBD outside the ACE2 binding site. Of note, 11D7 maintains recognition against the B.1.1.529 (Omicron) RBD, as well neutralizing activity. We also provide evidence that this novel mAb may be useful in providing additional synergy to established antibody cocktails, such as Evusheld™ containing the antibodies tixagevimab and cilgavimab, against the Omicron variant. Taken together, 11D7 is a unique mAb that neutralizes SARS-CoV-2 through a mechanism that is not typical among developed therapeutic mAbs and by being produced in ΔXFT Nicotiana benthamiana plants, highlights the potential of plants to be an economic and safety-friendly alternative platform for generating mAbs to address the evolving SARS-CoV-2 crisis.
Collapse
Affiliation(s)
- Collin Jugler
- The Biodesign InstituteArizona State UniversityTempeArizonaUSA
- School of Life SciencesArizona State UniversityTempeArizonaUSA
| | - Haiyan Sun
- The Biodesign InstituteArizona State UniversityTempeArizonaUSA
| | - Katherine Nguyen
- School of Molecular SciencesArizona State UniversityTempeArizonaUSA
| | - Roman Palt
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life SciencesViennaAustria
| | | | - Herta Steinkellner
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Qiang Chen
- The Biodesign InstituteArizona State UniversityTempeArizonaUSA
- School of Life SciencesArizona State UniversityTempeArizonaUSA
| |
Collapse
|
10
|
Plant-Produced Mouse-Specific Zona Pellucida 3 Peptide Induces Immune Responses in Mice. Vaccines (Basel) 2023; 11:vaccines11010153. [PMID: 36679998 PMCID: PMC9866649 DOI: 10.3390/vaccines11010153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/04/2023] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
Contraceptive vaccines are designed to stimulate autoimmune responses to molecules involved in the reproductive process. A mouse-specific peptide from zona pellucida 3 (mZP3) has been proposed as a target epitope. Here, we employed a plant expression system for the production of glycosylated mZP3 and evaluated the immunogenicity of plant-produced mZP3-based antigens in a female BALB/c mouse model. In the mZP3-1 antigen, mZP3 fused with a T-cell epitope of tetanus toxoid, a histidine tag, and a SEKDEL sequence. A fusion antigen (GFP-mZP3-1) and a polypeptide antigen containing three repeats of mZP3 (mZP3-3) were also examined. Glycosylation of mZP3 should be achieved by targeting proteins to the endoplasmic reticulum. Agrobacterium-mediated transient expression of antigens resulted in successful production of mZP3 in Nicotiana benthamiana. Compared with mZP3-1, GFP-mZP3-1 and mZP3-3 increased the production of the mZP3 peptide by more than 20 and 25 times, respectively. The glycosylation of the proteins was indicated by their size and their binding to a carbohydrate-binding protein. Both plant-produced GFP-mZP3-1 and mZP3-3 antigens were immunogenic in mice; however, mZP3-3 generated significantly higher levels of serum antibodies against mZP3. Induced antibodies recognized native zona pellucida of wild mouse, and specific binding of antibodies to the oocytes was observed in immunohistochemical studies. Therefore, these preliminary results indicated that the plants can be an efficient system for the production of immunogenic mZP3 peptide, which may affect the fertility of wild mice.
Collapse
|
11
|
Song S, Kim H, Jang EY, Jeon H, Diao H, Khan MRI, Lee M, Lee YJ, Nam J, Kim S, Kim Y, Sohn E, Hwang I, Choi J. SARS-CoV-2 spike trimer vaccine expressed in Nicotiana benthamiana adjuvanted with Alum elicits protective immune responses in mice. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:2298-2312. [PMID: 36062974 PMCID: PMC9538723 DOI: 10.1111/pbi.13908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/30/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
The ongoing coronavirus disease 2019 (COVID-19) pandemic has spurred rapid development of vaccines as part of the public health response. However, the general strategy used to construct recombinant trimeric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) proteins in mammalian cells is not completely adaptive to molecular farming. Therefore, we generated several constructs of recombinant S proteins for high expression in Nicotiana benthamiana. Intramuscular injection of N. benthamiana-expressed Sct vaccine (NSct Vac) into Balb/c mice elicited both humoral and cellular immune responses, and booster doses increased neutralizing antibody titres. In human angiotensin-converting enzyme knock-in mice, two doses of NSct Vac induced anti-S and neutralizing antibodies, which cross-neutralized Alpha, Beta, Delta and Omicron variants. Survival rates after lethal challenge with SARS-CoV-2 were up to 80%, without significant body weight loss, and viral titres in lung tissue fell rapidly, with no infectious virus detectable at 7-day post-infection. Thus, plant-derived NSct Vac could be a candidate COVID-19 vaccine.
Collapse
Affiliation(s)
- Shi‐Jian Song
- Department of Life SciencePohang University of Science and TechnologyPohangKorea
| | - Heeyeon Kim
- Division of Acute Viral Disease, Center for Emerging Virus ResearchNational Institute of Infectious Diseases, Korea National Institute of HealthCheongjuKorea
| | - Eun Young Jang
- Division of Vaccine Research, Vaccine Research CenterNational Institute of Infectious Diseases, Korea National Institute of HealthCheongjuKorea
| | - Hyungmin Jeon
- Department of Life SciencePohang University of Science and TechnologyPohangKorea
| | - Hai‐Ping Diao
- Department of Life SciencePohang University of Science and TechnologyPohangKorea
| | - Md Rezaul Islam Khan
- Department of Life SciencePohang University of Science and TechnologyPohangKorea
| | - Mi‐Seon Lee
- Division of Infectious Diseases InspectionJeju Special Self‐Governing Province Institute of Environment ResearchJejuKorea
| | - Young Jae Lee
- Division of Vaccine Research, Vaccine Research CenterNational Institute of Infectious Diseases, Korea National Institute of HealthCheongjuKorea
| | - Jeong‐hyun Nam
- Division of Vaccine Research, Vaccine Research CenterNational Institute of Infectious Diseases, Korea National Institute of HealthCheongjuKorea
| | - Seong‐Ryeol Kim
- Division of Acute Viral Disease, Center for Emerging Virus ResearchNational Institute of Infectious Diseases, Korea National Institute of HealthCheongjuKorea
| | - Young‐Jin Kim
- Department of Life SciencePohang University of Science and TechnologyPohangKorea
| | - Eun‐Ju Sohn
- BioApplications Inc.Pohang Technopark ComplexPohangSouth Korea
| | - Inhwan Hwang
- Department of Life SciencePohang University of Science and TechnologyPohangKorea
| | - Jang‐Hoon Choi
- Division of Acute Viral Disease, Center for Emerging Virus ResearchNational Institute of Infectious Diseases, Korea National Institute of HealthCheongjuKorea
| |
Collapse
|
12
|
Kim DB, Lee SM, Geem KR, Kim J, Kim EH, Lee DW. In planta Production and Validation of Neuraminidase Derived from Genotype 4 Reassortant Eurasian Avian-like H1N1 Virus as a Vaccine Candidate. PLANTS (BASEL, SWITZERLAND) 2022; 11:2984. [PMID: 36365437 PMCID: PMC9655071 DOI: 10.3390/plants11212984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Influenza viruses are a major public health threat that causes repetitive outbreaks. In recent years, genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 (G4 EA H1N1) has garnered attention as a potential novel pandemic strain. The necessity of developing vaccines against G4 EA H1N1 is growing because of the increasing cases of human infection and the low cross-reactivity of the strain with current immunity. In this study, we produced a G4 EA H1N1-derived neuraminidase (G4NA) as a vaccine candidate in Nicotiana benthamiana. The expressed G4NA was designed to be accumulated in the endoplasmic reticulum (ER). The M-domain of the human receptor-type tyrosine-protein phosphatase C was incorporated into the expression cassette to enhance the translation of G4NA. In addition, the family 3 cellulose-binding module and Brachypodium distachyon small ubiquitin-like modifier sequences were used to enable the cost-effective purification and removal of unnecessary domains after purification, respectively. The G4NA produced in plants displayed high solubility and assembled as a tetramer, which is required for the efficacy of an NA-based vaccine. In a mouse immunization model, the G4NA produced in plants could induce significant humoral immune responses. The plant-produced G4NA also stimulated antigen-specific CD4 T cell activation. These G4NA vaccine-induced immune responses were intensified by the administration of the antigen with a vaccine adjuvant. These results suggest that G4NA produced in plants has great potential as a vaccine candidate against G4 EA H1N1.
Collapse
Affiliation(s)
- Da Been Kim
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Korea
| | - Sun Min Lee
- Viral Immunology Laboratory, Institut Pasteur Korea, Seongnam 13488, Korea
| | - Kyoung Rok Geem
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 61186, Korea
| | - Jitae Kim
- Bio-Energy Research Center, Chonnam National University, Gwangju 61186, Korea
| | - Eui Ho Kim
- Viral Immunology Laboratory, Institut Pasteur Korea, Seongnam 13488, Korea
| | - Dong Wook Lee
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Korea
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju 61186, Korea
- Bio-Energy Research Center, Chonnam National University, Gwangju 61186, Korea
| |
Collapse
|
13
|
Gaobotse G, Venkataraman S, Mmereke KM, Moustafa K, Hefferon K, Makhzoum A. Recent Progress on Vaccines Produced in Transgenic Plants. Vaccines (Basel) 2022; 10:1861. [PMID: 36366370 PMCID: PMC9698746 DOI: 10.3390/vaccines10111861] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 01/15/2024] Open
Abstract
The development of vaccines from plants has been going on for over two decades now. Vaccine production in plants requires time and a lot of effort. Despite global efforts in plant-made vaccine development, there are still challenges that hinder the realization of the final objective of manufacturing approved and safe products. Despite delays in the commercialization of plant-made vaccines, there are some human vaccines that are in clinical trials. The novel coronavirus (SARS-CoV-2) and its resultant disease, coronavirus disease 2019 (COVID-19), have reminded the global scientific community of the importance of vaccines. Plant-made vaccines could not be more important in tackling such unexpected pandemics as COVID-19. In this review, we explore current progress in the development of vaccines manufactured in transgenic plants for different human diseases over the past 5 years. However, we first explore the different host species and plant expression systems during recombinant protein production, including their shortcomings and benefits. Lastly, we address the optimization of existing plant-dependent vaccine production protocols that are aimed at improving the recovery and purification of these recombinant proteins.
Collapse
Affiliation(s)
- Goabaone Gaobotse
- Department of Biological Sciences & Biotechnology, Botswana International University of Science & Technology, Palapye, Botswana
| | - Srividhya Venkataraman
- Virology Laboratory, Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Kamogelo M. Mmereke
- Department of Biological Sciences & Biotechnology, Botswana International University of Science & Technology, Palapye, Botswana
| | - Khaled Moustafa
- The Arabic Preprint Server/Arabic Science Archive (ArabiXiv)
| | - Kathleen Hefferon
- Department of Microbiology, Cornell University, Ithaca, NY 14850, USA
| | - Abdullah Makhzoum
- Department of Biological Sciences & Biotechnology, Botswana International University of Science & Technology, Palapye, Botswana
| |
Collapse
|
14
|
Bolaños-Martínez OC, Strasser R. Plant-made poliovirus vaccines - Safe alternatives for global vaccination. FRONTIERS IN PLANT SCIENCE 2022; 13:1046346. [PMID: 36340406 PMCID: PMC9630729 DOI: 10.3389/fpls.2022.1046346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Human polioviruses are highly infectious viruses that are spread mainly through the fecal-oral route. Infection of the central nervous system frequently results in irreversible paralysis, a disease called poliomyelitis. Children under five years are mainly affected if they have not acquired immunity through natural infection or via vaccination. Current polio vaccines comprise the injectable inactivated polio vaccine (IPV, also called the Salk vaccine) and the live-attenuated oral polio vaccine (OPV, also called the Sabin vaccine). The main limitations of the IPV are the reduced protection at the intestinal mucosa, the site of virus replication, and the high costs for manufacturing due to use of live viruses. While the OPV is more effective and stimulates mucosal immunity, it is manufactured using live-attenuated strains that can revert into pathogenic viruses resulting in major safety concerns and vaccine-derived outbreaks. During the last fifteen years, plant-based poliovirus vaccines have been explored by several groups as a safe and low-cost alternative, and promising results in protection against challenges with viruses and induction of neutralizing antibodies have been obtained. However, low yields and a high frequency in dose administration highlight the need for improvements in polioviral antigen production. In this review, we provide insights into recent efforts to develop plant-made poliovirus candidates, with an emphasis on strategies to optimize the production of viral antigens.
Collapse
Affiliation(s)
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| |
Collapse
|
15
|
Margolin E, Allen JD, Verbeek M, Chapman R, Meyers A, van Diepen M, Ximba P, Motlou T, Moore PL, Woodward J, Strasser R, Crispin M, Williamson AL, Rybicki EP. Augmenting glycosylation-directed folding pathways enhances the fidelity of HIV Env immunogen production in plants. Biotechnol Bioeng 2022; 119:2919-2937. [PMID: 35781691 PMCID: PMC9544252 DOI: 10.1002/bit.28169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 11/25/2022]
Abstract
Heterologous glycoprotein production relies on host glycosylation-dependent folding. When the biosynthetic machinery differs from the usual expression host, there is scope to remodel the assembly pathway to enhance glycoprotein production. Here we explore the integration of chaperone coexpression with glyco-engineering to improve the production of a model HIV-1 envelope antigen. Calreticulin was coexpressed to support protein folding together with Leishmania major STT3D oligosaccharyltransferase, to improve glycan occupancy, RNA interference to suppress the formation of truncated glycans, and Nicotiana benthamiana plants lacking α1,3-fucosyltransferase and β1,2-xylosyltransferase was used as an expression host to prevent plant-specific complex N-glycans forming. This approach reduced the formation of undesired aggregates, which predominated in the absence of glyco-engineering. The resulting antigen also exhibited increased glycan occupancy, albeit to a slightly lower level than the equivalent mammalian cell-produced protein. The antigen was decorated almost exclusively with oligomannose glycans, which were less processed compared with the mammalian protein. Immunized rabbits developed comparable immune responses to the plant-produced and mammalian cell-derived antigens, including the induction of autologous neutralizing antibodies when the proteins were used to boost DNA and modified vaccinia Ankara virus-vectored vaccines. This study demonstrates that engineering glycosylation-directed folding offers a promising route to enhance the production of complex viral glycoproteins in plants.
Collapse
Affiliation(s)
- Emmanuel Margolin
- Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Joel D Allen
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Matthew Verbeek
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Ann Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Michiel van Diepen
- Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Phindile Ximba
- Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Thopisang Motlou
- National Institute for Communicable Diseases of the National Health Laboratory Service, Centre for HIV and STIs, Johannesburg, South Africa
- MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Penny L Moore
- National Institute for Communicable Diseases of the National Health Laboratory Service, Centre for HIV and STIs, Johannesburg, South Africa
- MRC Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Congella, Durban, South Africa
| | - Jeremy Woodward
- Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton, UK
| | - Anna-Lise Williamson
- Department of Pathology, Division of Medical Virology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward P Rybicki
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
16
|
Hou HW, Bishop CA, Huckauf J, Broer I, Klaus S, Nausch H, Buyel JF. Seed- and leaf-based expression of FGF21-transferrin fusion proteins for oral delivery and treatment of non-alcoholic steatohepatitis. FRONTIERS IN PLANT SCIENCE 2022; 13:998596. [PMID: 36247628 PMCID: PMC9557105 DOI: 10.3389/fpls.2022.998596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 08/29/2022] [Indexed: 06/16/2023]
Abstract
Non-alcoholic steatohepatitis (NASH) is a global disease with no effective medication. The fibroblast growth factor 21 (FGF21) can reverse this liver dysfunction, but requires targeted delivery to the liver, which can be achieved via oral administration. Therefore, we fused FGF21 to transferrin (Tf) via a furin cleavage site (F), to promote uptake from the intestine into the portal vein, yielding FGF21-F-Tf, and established its production in both seeds and leaves of commercial Nicotiana tabacum cultivars, compared their expression profile and tested the bioavailability and bioactivity in feeding studies. Since biopharmaceuticals need to be produced in a contained environment, e.g., greenhouses in case of plants, the seed production was increased in this setting from 239 to 380 g m-2 a-1 seed mass with costs of 1.64 € g-1 by side branch induction, whereas leaves yielded 8,193 g m-2 a-1 leave mass at 0.19 € g-1. FGF21-F-Tf expression in transgenic seeds and leaves yielded 6.7 and 5.6 mg kg-1 intact fusion protein, but also 4.5 and 2.3 mg kg-1 additional Tf degradation products. Removing the furin site and introducing the liver-targeting peptide PLUS doubled accumulation of intact FGF21-transferrin fusion protein when transiently expressed in Nicotiana benthamiana from 0.8 to 1.6 mg kg-1, whereas truncation of transferrin (nTf338) and reversing the order of FGF21 and nTf338 increased the accumulation to 2.1 mg kg-1 and decreased the degradation products to 7% for nTf338-FGF21-PLUS. Application of partially purified nTf338-FGF21-PLUS to FGF21-/- mice by oral gavage proved its transfer from the intestine into the blood circulation and acutely affected hepatic mRNA expression. Hence, the medication of NASH via oral delivery of nTf338-FGF21-PLUS containing plants seems possible.
Collapse
Affiliation(s)
- Hsuan-Wu Hou
- Department Bioprocess Engineering, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Chair for Agrobiotechnology, University of Rostock, Rostock, Germany
| | - Christopher A. Bishop
- Department of Physiology of Energy Metabolism, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Jana Huckauf
- Chair for Agrobiotechnology, University of Rostock, Rostock, Germany
| | - Inge Broer
- Chair for Agrobiotechnology, University of Rostock, Rostock, Germany
| | - Susanne Klaus
- Department of Physiology of Energy Metabolism, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany
- Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - Henrik Nausch
- Department Bioprocess Engineering, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Johannes F. Buyel
- Department Bioprocess Engineering, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute of Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
- Department of Biotechnology (DBT), Institute of Bioprocess Science and Engineering (IBSE), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| |
Collapse
|
17
|
Abstract
The idea of producing vaccines in plants originated in the late 1980s. Initially, it was contemplated that this notion could facilitate the concept of edible vaccines, making them more cost effective and easily accessible. Initial studies on edible vaccines focussed on the use of a variety of different transgenic plant host species for the production of vaccine antigens. However, adequate expression levels of antigens, the difficulties predicted with administration of consistent doses, and regulatory rules required for growth of transgenic plants gave way to the development of vaccine candidates that could be purified and administered parenterally. The field has subsequently advanced with improved expression techniques including a shift from using transgenic to transient expression of antigens, refinement of purification protocols, a deeper understanding of the biological processes and a wealth of evidence of immunogenicity and efficacy of plant-produced vaccine candidates, all contributing to the successful practice of what is now known as biopharming or plant molecular farming. The establishment of this technology has resulted in the development of many different types of vaccine candidates including subunit vaccines and various different types of nanoparticle vaccines targeting a wide variety of bacterial and viral diseases. This has brought further acceptance of plants as a suitable platform for vaccine production and in this review, we discuss the most recent advances in the production of vaccines in plants for human use.
Collapse
Affiliation(s)
- Jennifer Stander
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa
| | - Sandiswa Mbewana
- Biopharming Research Unit, Department of Molecular and Cell Biology, 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.
| |
Collapse
|
18
|
Rosenberg YJ, Jiang X, Lees JP, Urban LA, Mao L, Sack M. Enhanced HIV SOSIP Envelope yields in plants through transient co-expression of peptidyl-prolyl isomerase B and calreticulin chaperones and ER targeting. Sci Rep 2022; 12:10027. [PMID: 35705669 PMCID: PMC9200074 DOI: 10.1038/s41598-022-14075-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 05/09/2022] [Indexed: 11/12/2022] Open
Abstract
High yield production of recombinant HIV SOSIP envelope (Env) trimers has proven elusive as numerous disulfide bonds, proteolytic cleavage and extensive glycosylation pose high demands on the host cell machinery and stress imposed by accumulation of misfolded proteins may ultimately lead to cellular toxicity. The present study utilized the Nicotiana benthamiana/p19 (N.b./p19) transient plant system to assess co-expression of two ER master regulators and 5 chaperones, crucial in the folding process, to enhance yields of three Env SOSIPs, single chain BG505 SOSIP.664 gp140, CH505TF.6R.SOSIP.664.v4.1 and CH848-10.17-DT9. Phenotypic changes in leaves induced by SOSIP expression were employed to rapidly identify chaperone-assisted improvement in health and expression. Up to 15-fold increases were obtained by co-infiltration of peptidylprolvl isomerase (PPI) and calreticulin (CRT) which were further enhanced by addition of the ER-retrieval KDEL tags to the SOSIP genes; levels depending on individual SOSIP type, day of harvest and chaperone gene dosage. Results are consistent with reducing SOSIP misfolding and cellular stress due to increased exposure to the plant host cell's calnexin/calreticulin network and accelerating the rate-limiting cis-trans isomerization of Xaa-Pro peptide bonds respectively. Plant transient co-expression facilitates rapid identification of host cell factors and will be translatable to other complex glycoproteins and mammalian expression systems.
Collapse
|
19
|
Geddes-McAlister J, Prudhomme N, Gutierrez Gongora D, Cossar D, McLean MD. The emerging role of mass spectrometry-based proteomics in molecular pharming practices. Curr Opin Chem Biol 2022; 68:102133. [DOI: 10.1016/j.cbpa.2022.102133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/02/2022] [Accepted: 02/23/2022] [Indexed: 12/11/2022]
|
20
|
Ruocco V, Strasser R. Transient Expression of Glycosylated SARS-CoV-2 Antigens in Nicotiana benthamiana. PLANTS (BASEL, SWITZERLAND) 2022; 11:1093. [PMID: 35448821 PMCID: PMC9033091 DOI: 10.3390/plants11081093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 12/14/2022]
Abstract
The current COVID-19 pandemic very dramatically shows that the world lacks preparedness for novel viral diseases. In addition to newly emerging viruses, many known pathogenic viruses such as influenza are constantly evolving, leading to frequent outbreaks with severe diseases and deaths. Hence, infectious viruses are a recurrent burden to our daily life, and powerful strategies to stop the spread of human pathogens and disease progression are of utmost importance. Transient plant-based protein expression is a technology that allows fast and highly flexible manufacturing of recombinant viral proteins and, thus, can contribute to infectious disease detection and prevention. This review highlights recent progress in the transient production of viral glycoproteins in N. benthamiana with a focus on SARS-CoV-2-derived viral antigens.
Collapse
Affiliation(s)
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria;
| |
Collapse
|
21
|
Improving Protein Quantity and Quality—The Next Level of Plant Molecular Farming. Int J Mol Sci 2022; 23:ijms23031326. [PMID: 35163249 PMCID: PMC8836236 DOI: 10.3390/ijms23031326] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 12/15/2022] Open
Abstract
Plants offer several unique advantages in the production of recombinant pharmaceuticals for humans and animals. Although numerous recombinant proteins have been expressed in plants, only a small fraction have been successfully put into use. The hugely distinct expression systems between plant and animal cells frequently cause insufficient yield of the recombinant proteins with poor or undesired activity. To overcome the issues that greatly constrain the development of plant-produced pharmaceuticals, great efforts have been made to improve expression systems and develop alternative strategies to increase both the quantity and quality of the recombinant proteins. Recent technological revolutions, such as targeted genome editing, deconstructed vectors, virus-like particles, and humanized glycosylation, have led to great advances in plant molecular farming to meet the industrial manufacturing and clinical application standards. In this review, we discuss the technological advances made in various plant expression platforms, with special focus on the upstream designs and milestone achievements in improving the yield and glycosylation of the plant-produced pharmaceutical proteins.
Collapse
|
22
|
Plant-Derived Recombinant Vaccines against Zoonotic Viruses. Life (Basel) 2022; 12:life12020156. [PMID: 35207444 PMCID: PMC8878793 DOI: 10.3390/life12020156] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 12/12/2022] Open
Abstract
Emerging and re-emerging zoonotic diseases cause serious illness with billions of cases, and millions of deaths. The most effective way to restrict the spread of zoonotic viruses among humans and animals and prevent disease is vaccination. Recombinant proteins produced in plants offer an alternative approach for the development of safe, effective, inexpensive candidate vaccines. Current strategies are focused on the production of highly immunogenic structural proteins, which mimic the organizations of the native virion but lack the viral genetic material. These include chimeric viral peptides, subunit virus proteins, and virus-like particles (VLPs). The latter, with their ability to self-assemble and thus resemble the form of virus particles, are gaining traction among plant-based candidate vaccines against many infectious diseases. In this review, we summarized the main zoonotic diseases and followed the progress in using plant expression systems for the production of recombinant proteins and VLPs used in the development of plant-based vaccines against zoonotic viruses.
Collapse
|
23
|
Margolin E, Verbeek M, de Moor W, Chapman R, Meyers A, Schäfer G, Williamson AL, Rybicki E. Investigating Constraints Along the Plant Secretory Pathway to Improve Production of a SARS-CoV-2 Spike Vaccine Candidate. FRONTIERS IN PLANT SCIENCE 2022; 12:798822. [PMID: 35058959 PMCID: PMC8764404 DOI: 10.3389/fpls.2021.798822] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/29/2021] [Indexed: 05/10/2023]
Abstract
Given the complex maturation requirements of viral glycoproteins and the challenge they often pose for expression in plants, the identification of host constraints precluding their efficient production is a priority for the molecular farming of vaccines. Building on previous work to improve viral glycoprotein production in plants, we investigated the production of a soluble SARS-CoV-2 spike comprising the ectopic portion of the glycoprotein. This was successfully transiently expressed in N. benthamiana by co-expressing the human lectin-binding chaperone calreticulin, which substantially increased the accumulation of the glycoprotein. The spike was mostly unprocessed unless the protease furin was co-expressed which resulted in highly efficient processing of the glycoprotein. Co-expression of several broad-spectrum protease inhibitors did not improve accumulation of the protein any further. The protein was successfully purified by affinity chromatography and gel filtration, although the purified product was heterogenous and the yields were low. Immunogenicity of the antigen was tested in BALB/c mice, and cellular and antibody responses were elicited after low dose inoculation with the adjuvanted protein. This work constitutes an important proof-of-concept for host plant engineering in the context of rapid vaccine development for SARS-CoV-2 and other emerging viruses.
Collapse
Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Matthew Verbeek
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Warren de Moor
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Ann Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Georgia Schäfer
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Observatory, Cape Town, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward Rybicki
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
24
|
Song SJ, Diao HP, Moon B, Yun A, Hwang I. The B1 Domain of Streptococcal Protein G Serves as a Multi-Functional Tag for Recombinant Protein Production in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:878677. [PMID: 35548280 PMCID: PMC9083265 DOI: 10.3389/fpls.2022.878677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/21/2022] [Indexed: 05/17/2023]
Abstract
Plants have long been considered a cost-effective platform for recombinant production. A recently recognized additional advantage includes the low risk of contamination of human pathogens, such as viruses and bacterial endotoxins. Indeed, a great advance has been made in developing plants as a "factory" to produce recombinant proteins to use for biopharmaceutical purposes. However, there is still a need to develop new tools for recombinant protein production in plants. In this study, we provide data showing that the B1 domain of Streptococcal protein G (GB1) can be a multi-functional domain of recombinant proteins in plants. N-terminal fusion of the GB1 domain increased the expression level of various target proteins ranging from 1.3- to 3.1-fold at the protein level depending on the target proteins. GB1 fusion led to the stabilization of the fusion proteins. Furthermore, the direct detection of GB1-fusion proteins by the secondary anti-IgG antibody eliminated the use of the primary antibody for western blot analysis. Based on these data, we propose that the small GB1 domain can be used as a versatile tag for recombinant protein production in plants.
Collapse
|
25
|
Chung YH, Church D, Koellhoffer EC, Osota E, Shukla S, Rybicki EP, Pokorski JK, Steinmetz NF. Integrating plant molecular farming and materials research for next-generation vaccines. NATURE REVIEWS. MATERIALS 2021; 7:372-388. [PMID: 34900343 DOI: 10.1038/s41578-021-00399-395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 05/28/2023]
Abstract
Biologics - medications derived from a biological source - are increasingly used as pharmaceuticals, for example, as vaccines. Biologics are usually produced in bacterial, mammalian or insect cells. Alternatively, plant molecular farming, that is, the manufacture of biologics in plant cells, transgenic plants and algae, offers a cheaper and easily adaptable strategy for the production of biologics, in particular, in low-resource settings. In this Review, we discuss current vaccination challenges, such as cold chain requirements, and highlight how plant molecular farming in combination with advanced materials can be applied to address these challenges. The production of plant viruses and virus-based nanotechnologies in plants enables low-cost and regional fabrication of thermostable vaccines. We also highlight key new vaccine delivery technologies, including microneedle patches and material platforms for intranasal and oral delivery. Finally, we provide an outlook of future possibilities for plant molecular farming of next-generation vaccines and biologics.
Collapse
Affiliation(s)
- Young Hun Chung
- Department of Bioengineering, University of California, San Diego, La Jolla, CA USA
| | - Derek Church
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
| | - Edward C Koellhoffer
- Department of Radiology, University of California, San Diego Health, La Jolla, CA USA
| | - Elizabeth Osota
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
- Biomedical Science Program, University of California, San Diego, La Jolla, CA USA
| | - Sourabh Shukla
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
| | - Edward P Rybicki
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Jonathan K Pokorski
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
- Institute for Materials Discovery and Design, University of California, San Diego, La Jolla, CA USA
- Center for Nano-Immuno Engineering, University of California, San Diego, La Jolla, CA USA
| | - Nicole F Steinmetz
- Department of Bioengineering, University of California, San Diego, La Jolla, CA USA
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
- Department of Radiology, University of California, San Diego Health, La Jolla, CA USA
- Institute for Materials Discovery and Design, University of California, San Diego, La Jolla, CA USA
- Center for Nano-Immuno Engineering, University of California, San Diego, La Jolla, CA USA
- Moores Cancer Center, University of California, San Diego, La Jolla, CA USA
| |
Collapse
|
26
|
Chung YH, Church D, Koellhoffer EC, Osota E, Shukla S, Rybicki EP, Pokorski JK, Steinmetz NF. Integrating plant molecular farming and materials research for next-generation vaccines. NATURE REVIEWS. MATERIALS 2021; 7:372-388. [PMID: 34900343 PMCID: PMC8647509 DOI: 10.1038/s41578-021-00399-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 05/04/2023]
Abstract
Biologics - medications derived from a biological source - are increasingly used as pharmaceuticals, for example, as vaccines. Biologics are usually produced in bacterial, mammalian or insect cells. Alternatively, plant molecular farming, that is, the manufacture of biologics in plant cells, transgenic plants and algae, offers a cheaper and easily adaptable strategy for the production of biologics, in particular, in low-resource settings. In this Review, we discuss current vaccination challenges, such as cold chain requirements, and highlight how plant molecular farming in combination with advanced materials can be applied to address these challenges. The production of plant viruses and virus-based nanotechnologies in plants enables low-cost and regional fabrication of thermostable vaccines. We also highlight key new vaccine delivery technologies, including microneedle patches and material platforms for intranasal and oral delivery. Finally, we provide an outlook of future possibilities for plant molecular farming of next-generation vaccines and biologics.
Collapse
Affiliation(s)
- Young Hun Chung
- Department of Bioengineering, University of California, San Diego, La Jolla, CA USA
| | - Derek Church
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
| | - Edward C. Koellhoffer
- Department of Radiology, University of California, San Diego Health, La Jolla, CA USA
| | - Elizabeth Osota
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
- Biomedical Science Program, University of California, San Diego, La Jolla, CA USA
| | - Sourabh Shukla
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
| | - Edward P. Rybicki
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Jonathan K. Pokorski
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
- Institute for Materials Discovery and Design, University of California, San Diego, La Jolla, CA USA
- Center for Nano-Immuno Engineering, University of California, San Diego, La Jolla, CA USA
| | - Nicole F. Steinmetz
- Department of Bioengineering, University of California, San Diego, La Jolla, CA USA
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA USA
- Department of Radiology, University of California, San Diego Health, La Jolla, CA USA
- Institute for Materials Discovery and Design, University of California, San Diego, La Jolla, CA USA
- Center for Nano-Immuno Engineering, University of California, San Diego, La Jolla, CA USA
- Moores Cancer Center, University of California, San Diego, La Jolla, CA USA
| |
Collapse
|
27
|
Jugler C, Sun H, Chen Q. SARS-CoV-2 Spike Protein-Induced Interleukin 6 Signaling Is Blocked by a Plant-Produced Anti-Interleukin 6 Receptor Monoclonal Antibody. Vaccines (Basel) 2021; 9:vaccines9111365. [PMID: 34835296 PMCID: PMC8623585 DOI: 10.3390/vaccines9111365] [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: 10/07/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 12/15/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the current COVID-19 pandemic, has caused more than 4.5 million deaths worldwide. Severe and fatal cases of COVID-19 are often associated with increased proinflammatory cytokine levels including interleukin 6 (IL-6) and acute respiratory distress syndrome. In this study, we explored the feasibility of using plants to produce an anti-IL-6 receptor (IL-6R) monoclonal antibody (mAb) and examined its utility in reducing IL-6 signaling in an in vitro model, which simulates IL-6 induction during SARS-CoV-2 infection. The anti-IL6R mAb (IL6RmAb) was quickly expressed and correctly assembled in Nicotiana benthamiana leaves. Plant-produced IL6RmAb (pIL6RmAb) could be enriched to homogeneity by a simple purification scheme. Furthermore, pIL6RmAb was shown to effectively inhibit IL-6 signaling in a cell-based model system. Notably, pIL6RmAb also suppressed IL-6 signaling that was induced by the exposure of human peripheral blood mononuclear cells to the spike protein of SARS-CoV-2. This is the first report of a plant-made anti-IL-6R mAb and its activity against SARS-CoV-2-related cytokine signaling. This study demonstrates the capacity of plants for producing functionally active mAbs that block cytokine signaling and implies their potential efficacy to curb cytokine storm in COVID-19 patients.
Collapse
Affiliation(s)
- Collin Jugler
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (C.J.); (H.S.)
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Haiyan Sun
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (C.J.); (H.S.)
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Qiang Chen
- The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (C.J.); (H.S.)
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
- Correspondence: ; Tel.: +1-480-965-8110; Fax: +1-480-727-7615
| |
Collapse
|
28
|
Singh AA, Pillay P, Tsekoa TL. Engineering Approaches in Plant Molecular Farming for Global Health. Vaccines (Basel) 2021; 9:vaccines9111270. [PMID: 34835201 PMCID: PMC8623924 DOI: 10.3390/vaccines9111270] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 12/16/2022] Open
Abstract
Since the demonstration of the first plant-produced proteins of medical interest, there has been significant growth and interest in the field of plant molecular farming, with plants now being considered a viable production platform for vaccines. Despite this interest and development by a few biopharmaceutical companies, plant molecular farming is yet to be embraced by ‘big pharma’. The plant system offers a faster alternative, which is a potentially more cost-effective and scalable platform for the mass production of highly complex protein vaccines, owing to the high degree of similarity between the plant and mammalian secretory pathway. Here, we identify and address bottlenecks in the use of plants for vaccine manufacturing and discuss engineering approaches that demonstrate both the utility and versatility of the plant production system as a viable biomanufacturing platform for global health. Strategies for improving the yields and quality of plant-produced vaccines, as well as the incorporation of authentic posttranslational modifications that are essential to the functionality of these highly complex protein vaccines, will also be discussed. Case-by-case examples are considered for improving the production of functional protein-based vaccines. The combination of all these strategies provides a basis for the use of cutting-edge genome editing technology to create a general plant chassis with reduced host cell proteins, which is optimised for high-level protein production of vaccines with the correct posttranslational modifications.
Collapse
|
29
|
Lobato Gómez M, Huang X, Alvarez D, He W, Baysal C, Zhu C, Armario‐Najera V, Blanco Perera A, Cerda Bennasser P, Saba‐Mayoral A, Sobrino‐Mengual G, Vargheese A, Abranches R, Abreu IA, Balamurugan S, Bock R, Buyel J, da Cunha NB, Daniell H, Faller R, Folgado A, Gowtham I, Häkkinen ST, Kumar S, Ramalingam SK, Lacorte C, Lomonossoff GP, Luís IM, Ma JK, McDonald KA, Murad A, Nandi S, O’Keefe B, Oksman‐Caldentey K, Parthiban S, Paul MJ, Ponndorf D, Rech E, Rodrigues JCM, Ruf S, Schillberg S, Schwestka J, Shah PS, Singh R, Stoger E, Twyman RM, Varghese IP, Vianna GR, Webster G, Wilbers RHP, Capell T, Christou P. Contributions of the international plant science community to the fight against human infectious diseases - part 1: epidemic and pandemic diseases. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1901-1920. [PMID: 34182608 PMCID: PMC8486245 DOI: 10.1111/pbi.13657] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 05/03/2023]
Abstract
Infectious diseases, also known as transmissible or communicable diseases, are caused by pathogens or parasites that spread in communities by direct contact with infected individuals or contaminated materials, through droplets and aerosols, or via vectors such as insects. Such diseases cause ˜17% of all human deaths and their management and control places an immense burden on healthcare systems worldwide. Traditional approaches for the prevention and control of infectious diseases include vaccination programmes, hygiene measures and drugs that suppress the pathogen, treat the disease symptoms or attenuate aggressive reactions of the host immune system. The provision of vaccines and biologic drugs such as antibodies is hampered by the high cost and limited scalability of traditional manufacturing platforms based on microbial and animal cells, particularly in developing countries where infectious diseases are prevalent and poorly controlled. Molecular farming, which uses plants for protein expression, is a promising strategy to address the drawbacks of current manufacturing platforms. In this review article, we consider the potential of molecular farming to address healthcare demands for the most prevalent and important epidemic and pandemic diseases, focussing on recent outbreaks of high-mortality coronavirus infections and diseases that disproportionately affect the developing world.
Collapse
Affiliation(s)
- Maria Lobato Gómez
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Xin Huang
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Derry Alvarez
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Wenshu He
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Can Baysal
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Changfu Zhu
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Victoria Armario‐Najera
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Amaya Blanco Perera
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Pedro Cerda Bennasser
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Andera Saba‐Mayoral
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | | | - Ashwin Vargheese
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Rita Abranches
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Isabel Alexandra Abreu
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Shanmugaraj Balamurugan
- Plant Genetic Engineering LaboratoryDepartment of BiotechnologyBharathiar UniversityCoimbatoreIndia
| | - Ralph Bock
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Johannes.F. Buyel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachenGermany
- Institute for Molecular BiotechnologyRWTH Aachen UniversityAachenGermany
| | - Nicolau B. da Cunha
- Centro de Análise Proteômicas e Bioquímicas de BrasíliaUniversidade Católica de BrasíliaBrasíliaBrazil
| | - Henry Daniell
- School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Roland Faller
- Department of Chemical EngineeringUniversity of California, DavisDavisCAUSA
| | - André Folgado
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Iyappan Gowtham
- Plant Genetic Engineering LaboratoryDepartment of BiotechnologyBharathiar UniversityCoimbatoreIndia
| | - Suvi T. Häkkinen
- Industrial Biotechnology and Food SolutionsVTT Technical Research Centre of Finland LtdEspooFinland
| | - Shashi Kumar
- International Centre for Genetic Engineering and BiotechnologyNew DelhiIndia
| | - Sathish Kumar Ramalingam
- Plant Genetic Engineering LaboratoryDepartment of BiotechnologyBharathiar UniversityCoimbatoreIndia
| | - Cristiano Lacorte
- Brazilian Agriculture Research CorporationEmbrapa Genetic Resources and Biotechnology and National Institute of Science and Technology Synthetic in BiologyParque Estação BiológicaBrasiliaBrazil
| | | | - Ines M. Luís
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Julian K.‐C. Ma
- Institute for Infection and ImmunitySt. George’s University of LondonLondonUK
| | - Karen. A. McDonald
- Department of Chemical EngineeringUniversity of California, DavisDavisCAUSA
- Global HealthShare InitiativeUniversity of California, DavisDavisCAUSA
| | - Andre Murad
- Brazilian Agriculture Research CorporationEmbrapa Genetic Resources and Biotechnology and National Institute of Science and Technology Synthetic in BiologyParque Estação BiológicaBrasiliaBrazil
| | - Somen Nandi
- Department of Chemical EngineeringUniversity of California, DavisDavisCAUSA
- Global HealthShare InitiativeUniversity of California, DavisDavisCAUSA
| | - Barry O’Keefe
- Molecular Targets ProgramCenter for Cancer Research, National Cancer Institute, and Natural Products BranchDevelopmental Therapeutics ProgramDivision of Cancer Treatment and DiagnosisNational Cancer Institute, NIHFrederickMDUSA
| | | | - Subramanian Parthiban
- Plant Genetic Engineering LaboratoryDepartment of BiotechnologyBharathiar UniversityCoimbatoreIndia
| | - Mathew J. Paul
- Institute for Infection and ImmunitySt. George’s University of LondonLondonUK
| | - Daniel Ponndorf
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | - Elibio Rech
- Brazilian Agriculture Research CorporationEmbrapa Genetic Resources and Biotechnology and National Institute of Science and Technology Synthetic in BiologyParque Estação BiológicaBrasiliaBrazil
| | - Julio C. M. Rodrigues
- Brazilian Agriculture Research CorporationEmbrapa Genetic Resources and Biotechnology and National Institute of Science and Technology Synthetic in BiologyParque Estação BiológicaBrasiliaBrazil
| | - Stephanie Ruf
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMEAachenGermany
- Institute for PhytopathologyJustus‐Liebig‐University GiessenGiessenGermany
| | - Jennifer Schwestka
- Institute of Plant Biotechnology and Cell BiologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Priya S. Shah
- Department of Chemical EngineeringUniversity of California, DavisDavisCAUSA
- Department of Microbiology and Molecular GeneticsUniversity of California, DavisDavisCAUSA
| | - Rahul Singh
- School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Eva Stoger
- Institute of Plant Biotechnology and Cell BiologyUniversity of Natural Resources and Life SciencesViennaAustria
| | | | - Inchakalody P. Varghese
- Plant Genetic Engineering LaboratoryDepartment of BiotechnologyBharathiar UniversityCoimbatoreIndia
| | - Giovanni R. Vianna
- Brazilian Agriculture Research CorporationEmbrapa Genetic Resources and Biotechnology and National Institute of Science and Technology Synthetic in BiologyParque Estação BiológicaBrasiliaBrazil
| | - Gina Webster
- Institute for Infection and ImmunitySt. George’s University of LondonLondonUK
| | - Ruud H. P. Wilbers
- Laboratory of NematologyPlant Sciences GroupWageningen University and ResearchWageningenThe Netherlands
| | - Teresa Capell
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
| | - Paul Christou
- Department of Crop and Forest SciencesUniversity of Lleida‐Agrotecnio CERCA CenterLleidaSpain
- ICREACatalan Institute for Research and Advanced StudiesBarcelonaSpain
| |
Collapse
|
30
|
Stander J, Chabeda A, Rybicki EP, Meyers AE. A Plant-Produced Virus-Like Particle Displaying Envelope Protein Domain III Elicits an Immune Response Against West Nile Virus in Mice. FRONTIERS IN PLANT SCIENCE 2021; 12:738619. [PMID: 34589108 PMCID: PMC8475786 DOI: 10.3389/fpls.2021.738619] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/13/2021] [Indexed: 05/27/2023]
Abstract
West Nile virus (WNV) is a globally disseminated Flavivirus that is associated with encephalitis outbreaks in humans and horses. The continuous global outbreaks of West Nile disease in the bird, human, and horse populations, with no preventative measures for humans, pose a major public health threat. The development of a vaccine that contributes to the "One Health" Initiative could be the answer to prevent the spread of the virus and control human and animal disease. The current commercially available veterinary vaccines are generally costly and most require high levels of biosafety for their manufacture. Consequently, we explored making a particulate vaccine candidate made transiently in plants as a more cost-effective and safer means of production. A WNV virus-like particle-display-based vaccine candidate was generated by the use of the SpyTag/SpyCatcher (ST/SC) conjugation system. The WNV envelope protein domain III (EDIII), which contains WNV-specific epitopes, was fused to and displayed on AP205 phage virus-like particles (VLPs) following the production of both separately in Nicotiana benthamiana. Co-purification of AP205 and EDIII genetically fused to ST and SC, respectively, resulted in the conjugated VLPs displaying EDIII with an average coupling efficiency of 51%. Subcutaneous immunisation of mice with 5 μg of purified AP205: EDIII VLPs elicited a potent IgG response to WNV EDIII. This study presents the potential plants being used as biofactories for making significant pharmaceutical products for the "One Health" Initiative and could be used to address the need for their local production in low- and middle-income countries (LMICs).
Collapse
Affiliation(s)
- Jennifer Stander
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Aleyo Chabeda
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Edward P. Rybicki
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Science, University of Cape Town, Cape Town, South Africa
| | - Ann E. Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
31
|
Sariyatun R, Florence, Kajiura H, Ohashi T, Misaki R, Fujiyama K. Production of Human Acid-Alpha Glucosidase With a Paucimannose Structure by Glycoengineered Arabidopsis Cell Culture. FRONTIERS IN PLANT SCIENCE 2021; 12:703020. [PMID: 34335667 PMCID: PMC8318038 DOI: 10.3389/fpls.2021.703020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/15/2021] [Indexed: 08/25/2023]
Abstract
Plant cell cultures have emerged as a promising platform for the production of biopharmaceutics due to their cost-effectiveness, safety, ability to control the cultivation, and secrete products into culture medium. However, the use of this platform is hindered by the generation of plant-specific N-glycans, the inability to produce essential N-glycans for cellular delivery of biopharmaceutics, and low productivity. In this study, an alternative acid-alpha glucosidase (GAA) for enzyme replacement therapy of Pompe disease was produced in a glycoengineered Arabidopsis alg3 cell culture. The N-glycan composition of the GAA consisted of a predominantly paucimannosidic structure, Man3GlcNAc2 (M3), without the plant-specific N-glycans. Supplementing the culture medium with NaCl to a final concentration of 50 mM successfully increased GAA production by 3.8-fold. GAA from an NaCl-supplemented culture showed a similar N-glycan profile, indicating that the NaCl supplementation did not affect N-glycosylation. The results of this study highlight the feasibility of using a glycoengineered plant cell culture to produce recombinant proteins for which M3 or mannose receptor-mediated delivery is desired.
Collapse
Affiliation(s)
- Ratna Sariyatun
- Laboratory of Applied Microbiology, International Center for Biotechnology, Osaka University, Suita, Japan
| | - Florence
- Laboratory of Applied Microbiology, International Center for Biotechnology, Osaka University, Suita, Japan
| | - Hiroyuki Kajiura
- Laboratory of Applied Microbiology, International Center for Biotechnology, Osaka University, Suita, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
| | - Takao Ohashi
- Laboratory of Applied Microbiology, International Center for Biotechnology, Osaka University, Suita, Japan
| | - Ryo Misaki
- Laboratory of Applied Microbiology, International Center for Biotechnology, Osaka University, Suita, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
| | - Kazuhito Fujiyama
- Laboratory of Applied Microbiology, International Center for Biotechnology, Osaka University, Suita, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
- Cooperative Research Station in Southeast Asia (OU:CRS), Faculty of Science, Mahidol University, Bangkok, Thailand
| |
Collapse
|
32
|
Producing Vaccines against Enveloped Viruses in Plants: Making the Impossible, Difficult. Vaccines (Basel) 2021; 9:vaccines9070780. [PMID: 34358196 PMCID: PMC8310165 DOI: 10.3390/vaccines9070780] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 12/13/2022] Open
Abstract
The past 30 years have seen the growth of plant molecular farming as an approach to the production of recombinant proteins for pharmaceutical and biotechnological uses. Much of this effort has focused on producing vaccine candidates against viral diseases, including those caused by enveloped viruses. These represent a particular challenge given the difficulties associated with expressing and purifying membrane-bound proteins and achieving correct assembly. Despite this, there have been notable successes both from a biochemical and a clinical perspective, with a number of clinical trials showing great promise. This review will explore the history and current status of plant-produced vaccine candidates against enveloped viruses to date, with a particular focus on virus-like particles (VLPs), which mimic authentic virus structures but do not contain infectious genetic material.
Collapse
|
33
|
Shin YJ, König-Beihammer J, Vavra U, Schwestka J, Kienzl NF, Klausberger M, Laurent E, Grünwald-Gruber C, Vierlinger K, Hofner M, Margolin E, Weinhäusel A, Stöger E, Mach L, Strasser R. N-Glycosylation of the SARS-CoV-2 Receptor Binding Domain Is Important for Functional Expression in Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:689104. [PMID: 34211491 PMCID: PMC8239413 DOI: 10.3389/fpls.2021.689104] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/20/2021] [Indexed: 05/17/2023]
Abstract
Nicotiana benthamiana is used worldwide as production host for recombinant proteins. Many recombinant proteins such as monoclonal antibodies, growth factors or viral antigens require posttranslational modifications like glycosylation for their function. Here, we transiently expressed different variants of the glycosylated receptor binding domain (RBD) from the SARS-CoV-2 spike protein in N. benthamiana. We characterized the impact of variations in RBD-length and posttranslational modifications on protein expression, yield and functionality. We found that a truncated RBD variant (RBD-215) consisting of amino acids Arg319-Leu533 can be efficiently expressed as a secreted soluble protein. Purified RBD-215 was mainly present as a monomer and showed binding to the conformation-dependent antibody CR3022, the cellular receptor angiotensin converting enzyme 2 (ACE2) and to antibodies present in convalescent sera. Expression of RBD-215 in glycoengineered ΔXT/FT plants resulted in the generation of complex N-glycans on both N-glycosylation sites. While site-directed mutagenesis showed that the N-glycans are important for proper RBD folding, differences in N-glycan processing had no effect on protein expression and function.
Collapse
Affiliation(s)
- Yun-Ji Shin
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Julia König-Beihammer
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Ulrike Vavra
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Jennifer Schwestka
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Nikolaus F. Kienzl
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Miriam Klausberger
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Elisabeth Laurent
- Department of Biotechnology, Core Facility Biomolecular and Cellular Analysis, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Clemens Grünwald-Gruber
- Department of Chemistry, Core Facility Mass Spectrometry, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Klemens Vierlinger
- Competence Unit Molecular Diagnostics, Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Vienna, Austria
| | - Manuela Hofner
- Competence Unit Molecular Diagnostics, Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Vienna, Austria
| | - Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Andreas Weinhäusel
- Competence Unit Molecular Diagnostics, Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Vienna, Austria
| | - Eva Stöger
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Lukas Mach
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| |
Collapse
|
34
|
Kanduła Z, Lewandowski K. Calreticulin – a multifaced protein. POSTEP HIG MED DOSW 2021. [DOI: 10.5604/01.3001.0014.8892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Calreticulin (CALR) is a highly conserved multi-function protein that primarily localizes within
the lumen of the endoplasmic reticulum (ER). It participates in various processes in the cells,
including glycoprotein chaperoning, regulation of Ca2+ homeostasis, antigen processing and
presentation for adaptive immune response, cell adhesion/migration, cell proliferation, immunogenic
cell death, gene expression and RNA stability. The role of CALR in the assembly,
retrieval and cell surface expression of MHC class I molecules is well known. A fraction of
the total cellular CALR is localized in the cytosol, following its retro-translocation from the
ER. In the cell stress conditions, CALR is also expressed on the cell surface via an interaction
with phosphatidylserine localized on the inner leaflet of the plasma membrane. The abovementioned
mechanism is relevant for the recognition of the cells, as well as immunogenicity
and phagocytic uptake of proapoptotic and apoptotic cells.
Lastly, the presence of CALR exon 9 gene mutations was confirmed in patients with myeloproliferative
neoplasms. Their presence results in an abnormal CALR structure due to the
loss of its ER-retention sequence, CALR extra-ER localisation, the formation of a complex
with thrombopoietin receptor, and oncogenic transformation of hematopoietic stem cells. It
is also known that CALR exon 9 mutants are highly immunogenic and induce T cell response.
Despite this fact, CALR mutant positive hematopoietic cells emerge. The last phenomenon is
probably the result of the inhibition of phagocytosis of the cancer cells exposing CALR mutant
protein by dendritic cells.
Collapse
Affiliation(s)
- Zuzanna Kanduła
- Department of Hematology and Bone Marrow Transplantation, Poznań University of Medical Sciences, Poland
| | - Krzysztof Lewandowski
- Department of Hematology and Bone Marrow Transplantation, Poznań University of Medical Sciences, Poland
| |
Collapse
|
35
|
Infection of Chinese Rhesus Monkeys with a Subtype C SHIV Resulted in Attenuated In Vivo Viral Replication Despite Successful Animal-to-Animal Serial Passages. Viruses 2021; 13:v13030397. [PMID: 33801437 PMCID: PMC7998229 DOI: 10.3390/v13030397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 01/23/2023] Open
Abstract
Rhesus macaques can be readily infected with chimeric simian-human immunodeficiency viruses (SHIV) as a suitable virus challenge system for testing the efficacy of HIV vaccines. Three Chinese-origin rhesus macaques (ChRM) were inoculated intravenously (IV) with SHIVC109P4 in a rapid serial in vivo passage. SHIV recovered from the peripheral blood of the final ChRM was used to generate a ChRM-adapted virus challenge stock. This stock was titrated for the intrarectal route (IR) in 8 ChRMs using undiluted, 1:10 or 1:100 dilutions, to determine a suitable dose for use in future vaccine efficacy testing via repeated low-dose IR challenges. All 11 ChRMs were successfully infected, reaching similar median peak viraemias at 1–2 weeks post inoculation but undetectable levels by 8 weeks post inoculation. T-cell responses were detected in all animals and Tier 1 neutralizing antibodies (Nab) developed in 10 of 11 infected ChRMs. All ChRMs remained healthy and maintained normal CD4+ T cell counts. Sequence analyses showed >98% amino acid identity between the original inoculum and virus recovered at peak viraemia indicating only minimal changes in the env gene. Thus, while replication is limited over time, our adapted SHIV can be used to test for protection of virus acquisition in ChRMs.
Collapse
|
36
|
Buyel JF, Stöger E, Bortesi L. Targeted genome editing of plants and plant cells for biomanufacturing. Transgenic Res 2021; 30:401-426. [PMID: 33646510 PMCID: PMC8316201 DOI: 10.1007/s11248-021-00236-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/03/2021] [Indexed: 02/07/2023]
Abstract
Plants have provided humans with useful products since antiquity, but in the last 30 years they have also been developed as production platforms for small molecules and recombinant proteins. This initially niche area has blossomed with the growth of the global bioeconomy, and now includes chemical building blocks, polymers and renewable energy. All these applications can be described as “plant molecular farming” (PMF). Despite its potential to increase the sustainability of biologics manufacturing, PMF has yet to be embraced broadly by industry. This reflects a combination of regulatory uncertainty, limited information on process cost structures, and the absence of trained staff and suitable manufacturing capacity. However, the limited adaptation of plants and plant cells to the requirements of industry-scale manufacturing is an equally important hurdle. For example, the targeted genetic manipulation of yeast has been common practice since the 1980s, whereas reliable site-directed mutagenesis in most plants has only become available with the advent of CRISPR/Cas9 and similar genome editing technologies since around 2010. Here we summarize the applications of new genetic engineering technologies to improve plants as biomanufacturing platforms. We start by identifying current bottlenecks in manufacturing, then illustrate the progress that has already been made and discuss the potential for improvement at the molecular, cellular and organism levels. We discuss the effects of metabolic optimization, adaptation of the endomembrane system, modified glycosylation profiles, programmable growth and senescence, protease inactivation, and the expression of enzymes that promote biodegradation. We outline strategies to achieve these modifications by targeted gene modification, considering case-by-case examples of individual improvements and the combined modifications needed to generate a new general-purpose “chassis” for PMF.
Collapse
Affiliation(s)
- J F Buyel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstrasse 6, 52074, Aachen, Germany. .,Institute for Molecular Biotechnology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany.
| | - E Stöger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - L Bortesi
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD, Geleen, The Netherlands
| |
Collapse
|
37
|
Geem KR, Song Y, Hwang I, Bae HJ, Lee DW. Production of Gloeophyllum trabeum Endoglucanase Cel12A in Nicotiana benthamiana for Cellulose Degradation. FRONTIERS IN PLANT SCIENCE 2021; 12:696199. [PMID: 34262588 PMCID: PMC8273430 DOI: 10.3389/fpls.2021.696199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/02/2021] [Indexed: 05/06/2023]
Abstract
Lignocellulosic biomass from plants has been used as a biofuel source and the potent acidic endoglucanase GtCel12A has been isolated from Gloeophyllum trabeum, a filamentous fungus. In this study, we established a plant-based platform for the production of active GtCel12A fused to family 3 cellulose-binding module (CBM3). We used the signal sequence of binding immunoglobulin protein (BiP) and the endoplasmic reticulum (ER) retention signal for the accumulation of the produced GtCel12A in the ER. To achieve enhanced enzyme expression, we incorporated the M-domain of the human receptor-type tyrosine-protein phosphatase C into the construct. In addition, to enable the removal of N-terminal domains that are not necessary after protein expression, we further incorporated the cleavage site of Brachypodium distachyon small ubiquitin-like modifier. The GtCel12A-CBM3 fusion protein produced in the leaves of Nicotiana benthamiana exhibited not only high solubility but also efficient endoglucanase activity on the carboxymethyl cellulose substrate as determined by 3,5-dinitrosalicylic acid assay. The endoglucanase activity of GtCel12A-CBM3 was maintained even when immobilized on microcrystalline cellulose beads. Taken together, these results indicate that GtCel12A endoglucanase produced in plants might be used to provide monomeric sugars from lignocellulosic biomass for bioethanol production.
Collapse
Affiliation(s)
- Kyoung Rok Geem
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, South Korea
| | - Younho Song
- Bio-Energy Research Center, Chonnam National University, Gwangju, South Korea
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, South Korea
| | - Hyeun-Jong Bae
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, South Korea
- Bio-Energy Research Center, Chonnam National University, Gwangju, South Korea
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, South Korea
| | - Dong Wook Lee
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, South Korea
- Bio-Energy Research Center, Chonnam National University, Gwangju, South Korea
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, South Korea
- *Correspondence: Dong Wook Lee
| |
Collapse
|
38
|
Margolin E, Allen JD, Verbeek M, van Diepen M, Ximba P, Chapman R, Meyers A, Williamson AL, Crispin M, Rybicki E. Site-Specific Glycosylation of Recombinant Viral Glycoproteins Produced in Nicotiana benthamiana. FRONTIERS IN PLANT SCIENCE 2021; 12:709344. [PMID: 34367227 PMCID: PMC8341435 DOI: 10.3389/fpls.2021.709344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/24/2021] [Indexed: 05/03/2023]
Abstract
There is an urgent need to establish large scale biopharmaceutical manufacturing capacity in Africa where the infrastructure for biologics production is severely limited. Molecular farming, whereby pharmaceuticals are produced in plants, offers a cheaper alternative to mainstream expression platforms, and is amenable to rapid large-scale production. However, there are several differences along the plant protein secretory pathway compared to mammalian systems, which constrain the production of complex pharmaceuticals. Viral envelope glycoproteins are important targets for immunization, yet in some cases they accumulate poorly in plants and may not be properly processed. Whilst the co-expression of human chaperones and furin proteases has shown promise, it is presently unclear how plant-specific differences in glycosylation impact the production of these proteins. In many cases it may be necessary to reproduce features of their native glycosylation to produce immunologically relevant vaccines, given that glycosylation is central to the folding and immunogenicity of these antigens. Building on previous work, we transiently expressed model glycoproteins from HIV and Marburg virus in Nicotiana benthamiana and mammalian cells. The proteins were purified and their site-specific glycosylation was determined by mass-spectrometry. Both glycoproteins yielded increased amounts of protein aggregates when produced in plants compared to the equivalent mammalian cell-derived proteins. The glycosylation profiles of the plant-produced glycoproteins were distinct from the mammalian cell produced proteins: they displayed lower levels of glycan occupancy, reduced complex glycans and large amounts of paucimannosidic structures. The elucidation of the site-specific glycosylation of viral glycoproteins produced in N. benthamiana is an important step toward producing heterologous viral glycoproteins in plants with authentic human-like glycosylation.
Collapse
Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
- *Correspondence: Emmanuel Margolin,
| | - Joel D. Allen
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Matthew Verbeek
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Michiel van Diepen
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Phindile Ximba
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Rosamund Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Ann Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
- Max Crispin,
| | - Edward Rybicki
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
39
|
Mamedov T, Gurbuzaslan I, Yuksel D, Ilgin M, Mammadova G, Ozkul A, Hasanova G. Soluble Human Angiotensin- Converting Enzyme 2 as a Potential Therapeutic Tool for COVID-19 is Produced at High Levels In Nicotiana benthamiana Plant With Potent Anti-SARS-CoV-2 Activity. FRONTIERS IN PLANT SCIENCE 2021; 12:742875. [PMID: 34938305 PMCID: PMC8685454 DOI: 10.3389/fpls.2021.742875] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/08/2021] [Indexed: 05/05/2023]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread to more than 222 countries and has put global public health at high risk. The world urgently needs a safe, cost-effective SARS-CoV-2 vaccine as well as therapeutic and antiviral drugs to combat COVID-19. Angiotensin-converting enzyme 2 (ACE2), as a key receptor for SARS-CoV-2 infections, has been proposed as a potential therapeutic tool in patients with COVID-19. In this study, we report a high-level production (about ∼0.75 g/kg leaf biomass) of human soluble (truncated) ACE2 in the Nicotiana benthamiana plant. After the Ni-NTA single-step, the purification yields of recombinant plant produced ACE2 protein in glycosylated and deglycosylated forms calculated as ∼0.4 and 0.5 g/kg leaf biomass, respectively. The plant produced recombinant human soluble ACE2s successfully bind to the SARS-CoV-2 spike protein. Importantly, both deglycosylated and glycosylated forms of ACE2 are stable at increased temperatures for extended periods of time and demonstrated strong anti-SARS-CoV-2 activities in vitro. The half maximal inhibitory concentration (IC50) values of glycosylated ACE2 (gACE2) and deglycosylated ACE2 (dACE2) were ∼1.0 and 8.48 μg/ml, respectively, for the pre-entry infection, when incubated with 100TCID50 of SARS-CoV-2. Therefore, plant produced soluble ACE2s are promising cost-effective and safe candidates as a potential therapeutic tool in the treatment of patients with COVID-19.
Collapse
Affiliation(s)
- Tarlan Mamedov
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
- Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
- *Correspondence: Tarlan Mamedov,
| | - Irem Gurbuzaslan
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Damla Yuksel
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Merve Ilgin
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Gunay Mammadova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Aykut Ozkul
- Department of Virology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
- Biotechnology Institute, Ankara University, Ankara, Turkey
| | - Gulnara Hasanova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| |
Collapse
|
40
|
Margolin E, Crispin M, Meyers A, Chapman R, Rybicki EP. A Roadmap for the Molecular Farming of Viral Glycoprotein Vaccines: Engineering Glycosylation and Glycosylation-Directed Folding. FRONTIERS IN PLANT SCIENCE 2020; 11:609207. [PMID: 33343609 PMCID: PMC7744475 DOI: 10.3389/fpls.2020.609207] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/09/2020] [Indexed: 05/03/2023]
Abstract
Immunization with recombinant glycoprotein-based vaccines is a promising approach to induce protective immunity against viruses. However, the complex biosynthetic maturation requirements of these glycoproteins typically necessitate their production in mammalian cells to support their folding and post-translational modification. Despite these clear advantages, the incumbent costs and infrastructure requirements with this approach can be prohibitive in developing countries, and the production scales and timelines may prove limiting when applying these production systems to the control of pandemic viral outbreaks. Plant molecular farming of viral glycoproteins has been suggested as a cheap and rapidly scalable alternative production system, with the potential to perform post-translational modifications that are comparable to mammalian cells. Consequently, plant-produced glycoprotein vaccines for seasonal and pandemic influenza have shown promise in clinical trials, and vaccine candidates against the newly emergent severe acute respiratory syndrome coronavirus-2 have entered into late stage preclinical and clinical testing. However, many other viral glycoproteins accumulate poorly in plants, and are not appropriately processed along the secretory pathway due to differences in the host cellular machinery. Furthermore, plant-derived glycoproteins often contain glycoforms that are antigenically distinct from those present on the native virus, and may also be under-glycosylated in some instances. Recent advances in the field have increased the complexity and yields of biologics that can be produced in plants, and have now enabled the expression of many viral glycoproteins which could not previously be produced in plant systems. In contrast to the empirical optimization that predominated during the early years of molecular farming, the next generation of plant-made products are being produced by developing rational, tailor-made approaches to support their production. This has involved the elimination of plant-specific glycoforms and the introduction into plants of elements of the biosynthetic machinery from different expression hosts. These approaches have resulted in the production of mammalian N-linked glycans and the formation of O-glycan moieties in planta. More recently, plant molecular engineering approaches have also been applied to improve the glycan occupancy of proteins which are not appropriately glycosylated, and to support the folding and processing of viral glycoproteins where the cellular machinery differs from the usual expression host of the protein. Here we highlight recent achievements and remaining challenges in glycoengineering and the engineering of glycosylation-directed folding pathways in plants, and discuss how these can be applied to produce recombinant viral glycoproteins vaccines.
Collapse
Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Ann Meyers
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Edward P. Rybicki
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
41
|
Abstract
The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a global pandemic, prompting unprecedented efforts to contain the virus. Many developed countries have implemented widespread testing and have rapidly mobilized research programmes to develop vaccines and therapeutics. However, these approaches may be impractical in Africa, where the infrastructure for testing is poorly developed and owing to the limited manufacturing capacity to produce pharmaceuticals. Furthermore, a large burden of HIV-1 and tuberculosis in Africa could exacerbate the severity of infection and may affect vaccine immunogenicity. This Review discusses global efforts to develop diagnostics, therapeutics and vaccines, with these considerations in mind. We also highlight vaccine and diagnostic production platforms that are being developed in Africa and that could be translated into clinical development through appropriate partnerships for manufacture. The COVID-19 pandemic has prompted unparalleled progress in the development of vaccines and therapeutics in many countries, but it has also highlighted the vulnerability of resource-limited countries in Africa. Margolin and colleagues review global efforts to develop SARS-CoV-2 diagnostics, therapeutics and vaccines, with a focus on the opportunities and challenges in Africa.
Collapse
|
42
|
Margolin EA, Strasser R, Chapman R, Williamson AL, Rybicki EP, Meyers AE. Engineering the Plant Secretory Pathway for the Production of Next-Generation Pharmaceuticals. Trends Biotechnol 2020; 38:1034-1044. [PMID: 32818443 DOI: 10.1016/j.tibtech.2020.03.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/06/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023]
Abstract
Production of biologics in plants, or plant molecular pharming, is a promising protein expression technology that is receiving increasing attention from the pharmaceutical industry. Previously, low expression yields of recombinant proteins and the realization that certain post-translational modifications (PTMs) may not occur optimally limited the widespread acceptance of the technology. However, molecular engineering of the plant secretory pathway is now enabling the production of increasingly complex biomolecules using tailored protein-specific approaches to ensure their maturation. These involve the elimination of undesired processing events, and the introduction of heterologous biosynthetic machinery to support the production of specific target proteins. Here, we discuss recent advances in the production of pharmaceutical proteins in plants, which leverage the unique advantages of the technology.
Collapse
Affiliation(s)
- Emmanuel A Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa.
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward P Rybicki
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Ann E Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| |
Collapse
|