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Domazet-Lošo T. mRNA Vaccines: Why Is the Biology of Retroposition Ignored? Genes (Basel) 2022; 13:719. [PMID: 35627104 PMCID: PMC9141755 DOI: 10.3390/genes13050719] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 02/07/2023] Open
Abstract
The major advantage of mRNA vaccines over more conventional approaches is their potential for rapid development and large-scale deployment in pandemic situations. In the current COVID-19 crisis, two mRNA COVID-19 vaccines have been conditionally approved and broadly applied, while others are still in clinical trials. However, there is no previous experience with the use of mRNA vaccines on a large scale in the general population. This warrants a careful evaluation of mRNA vaccine safety properties by considering all available knowledge about mRNA molecular biology and evolution. Here, I discuss the pervasive claim that mRNA-based vaccines cannot alter genomes. Surprisingly, this notion is widely stated in the mRNA vaccine literature but never supported by referencing any primary scientific papers that would specifically address this question. This discrepancy becomes even more puzzling if one considers previous work on the molecular and evolutionary aspects of retroposition in murine and human populations that clearly documents the frequent integration of mRNA molecules into genomes, including clinical contexts. By performing basic comparisons, I show that the sequence features of mRNA vaccines meet all known requirements for retroposition using L1 elements-the most abundant autonomously active retrotransposons in the human genome. In fact, many factors associated with mRNA vaccines increase the possibility of their L1-mediated retroposition. I conclude that is unfounded to a priori assume that mRNA-based therapeutics do not impact genomes and that the route to genome integration of vaccine mRNAs via endogenous L1 retroelements is easily conceivable. This implies that we urgently need experimental studies that would rigorously test for the potential retroposition of vaccine mRNAs. At present, the insertional mutagenesis safety of mRNA-based vaccines should be considered unresolved.
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Affiliation(s)
- Tomislav Domazet-Lošo
- Laboratory of Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička Cesta 54, HR-10000 Zagreb, Croatia;
- School of Medicine, Catholic University of Croatia, Ilica 242, HR-10000 Zagreb, Croatia
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2
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Optimization of Synthesis of Modified mRNA. Methods Mol Biol 2022; 2573:77-87. [PMID: 36040588 DOI: 10.1007/978-1-0716-2707-5_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Modified mRNA (modRNA) is a safe and effective vector for gene-based therapies. Notably, the safety of modRNA has been validated through COVID-19 vaccines which incorporate modRNA technology to translate spike proteins. Alternative gene delivery methods using plasmids, lentiviruses, adenoviruses, and adeno-associated viruses have suffered from key challenges such as genome integration, delayed and uncontrolled expression, and immunogenic responses. However, modRNA poses no risk of genome integration, has transient and rapid expression, and lacks an immunogenic response. Our lab utilizes modRNA-based therapies to promote cardiac regeneration following myocardial infarction and heart failure. We have also developed and refined an optimized and economical method for synthesis of modRNA. Here, we provide an updated methodology with improved translational efficiency for in vitro and in vivo application.
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Mehmood I, Ijaz M, Ahmad S, Ahmed T, Bari A, Abro A, Allemailem KS, Almatroudi A, Tahir ul Qamar M. SARS-CoV-2: An Update on Genomics, Risk Assessment, Potential Therapeutics and Vaccine Development. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041626. [PMID: 33567746 PMCID: PMC7915969 DOI: 10.3390/ijerph18041626] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 02/06/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a great threat to public health, being a causative pathogen of a deadly coronavirus disease (COVID-19). It has spread to more than 200 countries and infected millions of individuals globally. Although SARS-CoV-2 has structural/genomic similarities with the previously reported SARS-CoV and MERS-CoV, the specific mutations in its genome make it a novel virus. Available therapeutic strategies failed to control this virus. Despite strict standard operating procedures (SOPs), SARS-CoV-2 has spread globally and it is mutating gradually as well. Diligent efforts, special care, and awareness are needed to reduce transmission among susceptible masses particularly elder people, children, and health care workers. In this review, we highlighted the basic genome organization and structure of SARS-CoV-2. Its transmission dynamics, symptoms, and associated risk factors are discussed. This review also presents the latest mutations identified in its genome, the potential therapeutic options being used, and a brief explanation of vaccine development efforts against COVID-19. The effort will not only help readers to understand the deadly SARS-CoV-2 virus but also provide updated information to researchers for their research work.
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Affiliation(s)
- Iqra Mehmood
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad 38000, Pakistan; (I.M.); (M.I.)
| | - Munazza Ijaz
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad 38000, Pakistan; (I.M.); (M.I.)
| | - Sajjad Ahmad
- Department of Microbiology and Pharmacy, Abasyn University, Peshawar 25000, Pakistan;
| | - Temoor Ahmed
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China;
| | - Amna Bari
- College of Informatics, Huazhong Agricultural University, Wuhan 430070, China;
| | - Asma Abro
- Department of Biotechnology, Faculty of Life Sciences and Informatics, Balochistan University of Information Technology Engineering and Management Sciences, Quetta 87100, Pakistan;
| | - Khaled S. Allemailem
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia;
| | - Ahmad Almatroudi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia;
- Correspondence: (A.A.); (M.T.u.Q.)
| | - Muhammad Tahir ul Qamar
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
- Correspondence: (A.A.); (M.T.u.Q.)
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4
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Trepotec Z, Geiger J, Plank C, Aneja MK, Rudolph C. Segmented poly(A) tails significantly reduce recombination of plasmid DNA without affecting mRNA translation efficiency or half-life. RNA (NEW YORK, N.Y.) 2019; 25:507-518. [PMID: 30647100 PMCID: PMC6426288 DOI: 10.1261/rna.069286.118] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/22/2018] [Indexed: 05/27/2023]
Abstract
Extensive research in the past decade has brought mRNA closer to the clinical realization of its therapeutic potential. One common structural feature for all cellular messenger RNAs is a poly(A) tail, which can either be brought in cotranscriptionally via the DNA template (plasmid- or PCR-based) or added to the mRNA in a post-transcriptional enzymatic process. Plasmids containing poly(A) regions recombine in E. coli, resulting in extensive shortening of the poly(A) tail. Using a segmented poly(A) approach, we could significantly reduce recombination of plasmids in E. coli without any negative effect on mRNA half-life and protein expression. This effect was independent of the coding sequence. A segmented poly(A) tail is characterized in that it consists of at least two A-containing elements, each defined as a nucleotide sequence consisting of 40-60 adenosines, separated by a spacer element of different length. Furthermore, reducing the spacer length between the poly(A) segments resulted in higher translation efficiencies compared to homogeneous poly(A) tail and reduced recombination (depending upon the choice of spacer nucleotide). Our results demonstrate the superior potential of segmented poly(A) tails compared to the conventionally used homogeneous poly(A) tails with respect to recombination of the plasmids and the resulting mRNA performance (half-life and translational efficiency).
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Affiliation(s)
- Zeljka Trepotec
- Department of Pediatrics, Ludwig-Maximilian-University of Munich, 80337 Munich, Germany
| | | | - Christian Plank
- Ethris GmbH, Planegg, 82152 Planegg, Germany
- Institute of Molecular Immunology and Experimental Oncology, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | | | - Carsten Rudolph
- Department of Pediatrics, Ludwig-Maximilian-University of Munich, 80337 Munich, Germany
- Ethris GmbH, Planegg, 82152 Planegg, Germany
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5
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Delivery of mRNA Therapeutics for the Treatment of Hepatic Diseases. Mol Ther 2018; 27:794-802. [PMID: 30655211 DOI: 10.1016/j.ymthe.2018.12.012] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 12/13/2022] Open
Abstract
Promising improvements in the field of transcript therapeutics have clearly enhanced the potential of mRNA as a new pillar for protein replacement therapies. Synthetic mRNAs are engineered to replace mutated mRNAs and to be immunologically inconspicuous and highly stable while maximizing protein expression. Approaches to deliver mRNA into the cellular cytoplasm safely and efficiently have been further developed so that two mRNA-based approaches replacing vascular endothelial growth factor (VEGF) and cystic fibrosis transmembrane conductance regulator (CFTR) have now made it into clinical trials. These studies bring mRNA therapeutics for protein replacement therapy closer to clinical realization. Herein, we provide an overview of preclinical and clinical developments of mRNA therapeutics for liver diseases.
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Abstract
mRNA is the central molecule of all forms of life. It is generally accepted that current life on Earth descended from an RNA world. mRNA, after its first therapeutic description in 1992, has recently come into increased focus as a method to deliver genetic information. The recent solution to the two main difficulties in using mRNA as a therapeutic, immune stimulation and potency, has provided the basis for a wide range of applications. While mRNA-based cancer immunotherapies have been in clinical trials for a few years, novel approaches; including, in vivo delivery of mRNA to replace or supplement proteins, mRNA-based generation of pluripotent stem cells, or genome engineering using mRNA-encoded meganucleases are beginning to be realized. This review presents the current state of mRNA drug technologies and potential applications, as well as discussing the challenges and prospects in mRNA development and drug discovery.
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Affiliation(s)
- Drew Weissman
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Xu J, Luft JC, Yi X, Tian S, Owens G, Wang J, Johnson A, Berglund P, Smith J, Napier ME, DeSimone JM. RNA replicon delivery via lipid-complexed PRINT protein particles. Mol Pharm 2013; 10:3366-74. [PMID: 23924216 PMCID: PMC3948333 DOI: 10.1021/mp400190z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Herein we report the development of a nonviral lipid-complexed PRINT (particle replication in nonwetting templates) protein particle system (LPP particle) for RNA replicon delivery with a view toward RNA replicon-based vaccination. Cylindrical bovine serum albumin (BSA) particles (diameter (d) 1 μm, height (h) 1 μm) loaded with RNA replicon and stabilized with a fully reversible disulfide cross-linker were fabricated using PRINT technology. Highly efficient delivery of the particles to Vero cells was achieved by complexing particles with a mixture of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) lipids. Our data suggest that (1) this lipid-complexed protein particle is a promising system for delivery of RNA replicon-based vaccines and (2) it is necessary to use a degradable cross-linker for successful delivery of RNA replicon via protein-based particles.
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Affiliation(s)
- Jing Xu
- Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina, Chapel Hill, NC 27599
| | - J. Christopher Luft
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
- UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599
- Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina, Chapel Hill, NC 27599
- Institute for Advanced Materials, University of North Carolina, Chapel Hill, NC 27599
- Institute for Nanomedicine, University of North Carolina, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
| | - Xianwen Yi
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
| | - Shaomin Tian
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
- Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina, Chapel Hill, NC 27599
- Institute for Advanced Materials, University of North Carolina, Chapel Hill, NC 27599
- Institute for Nanomedicine, University of North Carolina, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
| | | | - Jin Wang
- Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina, Chapel Hill, NC 27599
| | - Ashley Johnson
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
| | | | | | - Mary E. Napier
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
- Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina, Chapel Hill, NC 27599
- Institute for Advanced Materials, University of North Carolina, Chapel Hill, NC 27599
- Institute for Nanomedicine, University of North Carolina, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Joseph M. DeSimone
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
- Carolina Center of Cancer Nanotechnology Excellence, University of North Carolina, Chapel Hill, NC 27599
- Institute for Advanced Materials, University of North Carolina, Chapel Hill, NC 27599
- Institute for Nanomedicine, University of North Carolina, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
- Sloan-Kettering Institute for Cancer Research, Memorial Sloan-Kettering Cancer Center, New York, NY 10021
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, and North Carolina State University, Raleigh, NC 27695
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Abstract
Nucleofection permits efficient transfection even with difficult cell types such as primary and non-dividing cells, and is used to deliver various nucleic acids including DNA, mRNA, and siRNA. Unlike DNA and siRNA, mRNA is subject to rapid degradation, which necessitates instant early translation following mRNA delivery. We examined factors important in translation following nucleofection and observed rapid phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α) following nucleofection, which occurred in the absence of delivered nucleic acid. We studied the involvement of 3 ubiquitous kinases capable of phosphorylating eIF2α in mammalian cells and identified that nucleofection-mediated phosphorylation of eIF2α was dependent on general control non-derepressible 2 (GCN2) and protein kinase RNA-activated (PKR)-like ER kinase (PERK) but not PKR. A reduction in translation due to eIF2α phosphorylation was observed post nucleofection demonstrating functional significance. Understanding the impact of nucleofection on translational machinery has important implications for therapeutics currently under development based on the delivery of mRNA, DNA, and siRNA. Strategies to circumvent eIF2α phosphorylation and other downstream effects of activating GCN2 and PERK will facilitate further advancement of nucleic acid-based therapies.
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Affiliation(s)
- R Scott McIvor
- Center for Genome Engineering, Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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Widman DG, Frolov I, Mason PW. Third-generation flavivirus vaccines based on single-cycle, encapsidation-defective viruses. Adv Virus Res 2009; 72:77-126. [PMID: 19081489 DOI: 10.1016/s0065-3527(08)00402-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Flaviviruses are arthropod-borne pathogens that cause significant disease on all continents of the world except Antarctica. Flavivirus diseases are particularly important in tropical regions where arthropod vectors are abundant. Live-attenuated virus vaccines (LAVs) and inactivated virus vaccines (INVs) exist for some of these diseases. LAVs are economical to produce and potent, but are not suitable for use in the immunocompromised. INVs are safer, but are more expensive to produce and less potent. Despite the success of both classes of these first-generation flavivirus vaccines, problems associated with their use indicate a need for improved products. Furthermore, there are no suitable vaccines available for important emerging flavivirus diseases, notably dengue and West Nile encephalitis (WNE). To address these needs, new products, including LAVs, INVs, viral-vectored, genetically engineered LAVs, naked DNA, and subunit vaccines are in various stages of development. Here we describe the current state of these first- and second-generation vaccine candidates, and compare these products to our recently described single-cycle, encapsidation defective flavivirus vaccine: RepliVAX. RepliVAX can be propagated in C-expressing cells (or as a unique two-component virus) using methods similar to those used to produce today's economical and potent LAVs. However, due to deletion of most of the gene for the C protein, RepliVAX cannot spread between normal cells, and is unable to cause disease in vaccinated animals. Nevertheless, RepliVAX is potent and efficacious in animal models for WNE and Japanese encephalitis, demonstrating its utility as a third-generation flavivirus vaccine that should be potent, economical to produce, and safe in the immunocompromised.
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Affiliation(s)
- Douglas G Widman
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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Abstract
HIV poses a serious health threat in the world. Mucosal transmission of HIV through the genitourinary tract may be the most important route of transmission. Intranasal immunisations induce vaginal and systemic immune responses. Various protein-, DNA- and RNA-based immunopotentiating adjuvants/delivery systems and live bacterial and viral vectors are available for intranasal immunisations, and these systems may differ in their ability to induce a specific type of immune response (e.g., a cytotoxic T cell versus an antibody response). As the protection against HIV may require both cytotoxic T cell and antibodies, a combination of adjuvants/delivery systems for combinations of mucosal and parenteral immunisations may be required in order to develop a protective anti-HIV vaccine.
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Affiliation(s)
- Michael Vajdy
- Chiron Vaccines, 4560 Horton Street, Emeryville, CA 94608, USA.
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Pan CH, Valsamakis A, Colella T, Nair N, Adams RJ, Polack FP, Greer CE, Perri S, Polo JM, Griffin DE. Modulation of disease, T cell responses, and measles virus clearance in monkeys vaccinated with H-encoding alphavirus replicon particles. Proc Natl Acad Sci U S A 2005; 102:11581-8. [PMID: 16037211 PMCID: PMC1187989 DOI: 10.1073/pnas.0504592102] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Measles remains a major worldwide problem partly because of difficulties with vaccination of young infants. New vaccine strategies need to be safe and to provide sustained protective immunity. We have developed Sindbis virus replicon particles that express the measles virus (MV) hemagglutinin (SIN-H) or fusion (SIN-F) proteins. In mice, SIN-H induced high-titered, dose-dependent, MV-neutralizing antibody after a single vaccination. SIN-F, or SIN-H and SIN-F combined, induced somewhat lower responses. To assess protective efficacy, juvenile macaques were vaccinated with a single dose of 10(6) or 10(8) SIN-H particles and infant macaques with two doses of 10(8) particles. A dose of 10(8) particles induced sustained levels of high-titered, MV-neutralizing antibody and IFN-gamma-producing memory T cells, and most monkeys were protected from rash when challenged with wild-type MV 18 months later. After challenge, there was a biphasic appearance of H- and F-specific IFN-gamma-secreting CD4+ and CD8+ T cells in vaccinated monkeys, with peaks approximately 1 and 3-4 months after challenge. Viremia was cleared within 14 days, but MV RNA was detectable for 4-5 months. These studies suggest that complete clearance of MV after infection is a prolonged, phased, and complex process influenced by prior vaccination.
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Affiliation(s)
- Chien-Hsiung Pan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Vajdy M, Srivastava I, Polo J, Donnelly J, O'Hagan D, Singh M. Mucosal adjuvants and delivery systems for protein-, DNA- and RNA-based vaccines. Immunol Cell Biol 2005; 82:617-27. [PMID: 15550120 DOI: 10.1111/j.1440-1711.2004.01288.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Almost all vaccinations today are delivered through parenteral routes. Mucosal vaccination offers several benefits over parenteral routes of vaccination, including ease of administration, the possibility of self-administration, elimination of the chance of injection with infected needles, and induction of mucosal as well as systemic immunity. However, mucosal vaccines have to overcome several formidable barriers in the form of significant dilution and dispersion; competition with a myriad of various live replicating bacteria, viruses, inert food and dust particles; enzymatic degradation; and low pH before reaching the target immune cells. It has long been known that vaccination through mucosal membranes requires potent adjuvants to enhance immunogenicity, as well as delivery systems to decrease the rate of dilution and degradation and to target the vaccine to the site of immune function. This review is a summary of current approaches to mucosal vaccination, and it primarily focuses on adjuvants as immunopotentiators and vaccine delivery systems for mucosal vaccines based on protein, DNA or RNA. In this context, we define adjuvants as protein or oligonucleotides with immunopotentiating properties co-administered with pathogen-derived antigens, and vaccine delivery systems as chemical formulations that are more inert and have less immunomodulatory effects than adjuvants, and that protect and deliver the vaccine through the site of administration. Although vaccines can be quite diverse in their composition, including inactivated virus, virus-like particles and inactivated bacteria (which are inert), protein-like vaccines, and non-replicating viral vectors such as poxvirus and adenovirus (which can serve as DNA delivery systems), this review will focus primarily on recombinant protein antigens, plasmid DNA, and alphavirus-based replicon RNA vaccines and delivery systems. This review is not an exhaustive list of all available protein, DNA and RNA vaccines, with related adjuvants and delivery systems, but rather is an attempt to highlight many of the currently available approaches in immunopotentiation of mucosal vaccines.
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Zhou FJ, Hu ZL, Dai JX, Chen RW, Shi K, Lin Y, Sun SH. Protection of tree shrews by pVAX-PS DNA vaccine against HBV infection. DNA Cell Biol 2003; 22:475-8. [PMID: 12932306 DOI: 10.1089/104454903322247352] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The immunological protection of pVAX-PS, a DNA vaccine, was assessed in the tree shrews model. pVAX-PS was constructed by inserting the gene encoding the middle (pre-S2 plus S) envelope protein of HBV into a plasmid vector pVAX1. Tree shrews (Tupaia belangeri chinenesis) were experimentally infected with human HBV by inoculation with human serum positive for HBV markers. DNA vaccination-induced seroconversion and antibody to HBV surface antigen (anti-HBs) were analyzed by ELISA, and protective effects elicited by pVAX-PS vaccination against subsequent HBV challenge were evaluated by detection of HBV seromarkers and observation of hepatic lesions in HBV-infected tree shrews. The results shown that anti-HBs were detectable in serum at week 2 after pVAX-PS vaccination and peaked at week 4, and immunization with pVAX-PS decreased the positive conversion rate of HBV seromarkers and relieved hepatic lesions in tree shrews challenged with HBV. These results indicated that pVAX-PS immunization could induce remarkable humoral immune response and prevent the experimental tree shrews from infection of HBV.
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Affiliation(s)
- Feng-Juan Zhou
- Department of Medical Genetics, The Second Military Medical University, Shanghai, China
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