Advances in DNA Vaccines

A special issue of Vaccines (ISSN 2076-393X).

Deadline for manuscript submissions: closed (28 February 2019) | Viewed by 123733

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Special Issue Editors


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Guest Editor
1. Department of Research, Riga Stradins University, LV-1007 Riga, Latvia
2. Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
Interests: human immunodeficiency virus type 1; human hepatitis C virus; DNA vaccines; in vivo imaging; T cell response; B cell response; mouse models; cancer; oxidative stress
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Guest Editor
Director of Preclinical Development, Eurocine Vaccines AB, Fogdevreten 2, Karolinska Institutet Science Park, 171 65 Solna, Sweden
Interests: immunity; immunology of infectious diseases; infection; viral infection; cell culture; innate immunity; PCR; emerging infectious diseases; HIV; cellular immunology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

DNA is a rapidly developing vaccine platform for cancer, infectious and non-infectious diseases. Plasmids use as immunogens to encode proteins to be further synthesized in vaccine recipients. DNA is mainly synthetic, ensuring enhanced expression. Their introduction into the host induces antibody and cellular responses. The latter are often more pronounced, and mimic the events occurring in infection, especially viral. There are a few distinct ways in which the vaccine antigen can be processed and presented, which determine the resulting immune response and which can be manipulated. Routenly, the antigen synthesized within the host cell is processed by proteasome, loaded onto, and presented in a complex with MHC I molecules. Processing can be re-routed to the lysosome, or immunogen can be secreted for further presentation in a complex with MHC II. Apart from the expression, the vaccination efficacy depends on DNA delivery. DNA immunogens are generally administered by intramuscular or intradermal injections, usually followed by electroporation, which enhances delivery 1000-fold. Other techniques are also used, such as noninvasive introduction by biojectors, skin applications with plasters and microneedles/chips, sonication, magnetofection, and even tattooing. An intense debate regarding the pros and cons of different routes of delivery is ongoing. A number of studies have compared the effect of delivery methods on the level of immunogen expression, and the magnitude and specificity of the resulting immune response. According to some, the delivery route determines the immunogenic performance, according to others, it can modulate the level of response, but not its specificity or polarity. The progress of research aiming at the optimization of DNA vaccine design, delivery, and immunogenic performance have led to a marked increase in their efficacy in large species and man. New DNA vaccines for use in the treatment of infectious diseases, cancer, allergies and autoimmunity are forthcoming. This Special Issue will deal with all aspects of DNA vaccine development.

Dr. Maria G. Isaguliants
Dr. Karl Ljungberg
Guest Editors

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Keywords

  • DNA vaccine
  • plasmid
  • delivery
  • adjuvants
  • viral vaccines
  • bacterial vaccines
  • cancer vaccines
  • animal model
  • preclinical trial
  • safety
  • assessment of immunogenicity
  • in vivo imaging

Published Papers (12 papers)

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Editorial

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5 pages, 180 KiB  
Editorial
DNA Vaccine Development at Pre- and Post-Operation Warp Speed
by Karl Ljungberg and Maria Isaguliants
Vaccines 2020, 8(4), 737; https://doi.org/10.3390/vaccines8040737 - 04 Dec 2020
Cited by 3 | Viewed by 2330
Abstract
DNA is a rapidly developing vaccine platform for combatting cancer, infectious and noninfectious diseases [...] Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)

Research

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21 pages, 2377 KiB  
Article
Genetically Modified Mouse Mesenchymal Stem Cells Expressing Non-Structural Proteins of Hepatitis C Virus Induce Effective Immune Response
by Olga V. Masalova, Ekaterina I. Lesnova, Regina R. Klimova, Ekaterina D. Momotyuk, Vyacheslav V. Kozlov, Alla M. Ivanova, Olga V. Payushina, Nina N. Butorina, Natalia F. Zakirova, Alexander N. Narovlyansky, Alexander V. Pronin, Alexander V. Ivanov and Alla A. Kushch
Vaccines 2020, 8(1), 62; https://doi.org/10.3390/vaccines8010062 - 02 Feb 2020
Cited by 13 | Viewed by 3590
Abstract
Hepatitis C virus (HCV) is one of the major causes of chronic liver disease and leads to cirrhosis and hepatocarcinoma. Despite extensive research, there is still no vaccine against HCV. In order to induce an immune response in DBA/2J mice against HCV, we [...] Read more.
Hepatitis C virus (HCV) is one of the major causes of chronic liver disease and leads to cirrhosis and hepatocarcinoma. Despite extensive research, there is still no vaccine against HCV. In order to induce an immune response in DBA/2J mice against HCV, we obtained modified mouse mesenchymal stem cells (mMSCs) simultaneously expressing five nonstructural HCV proteins (NS3-NS5B). The innate immune response to mMSCs was higher than to DNA immunization, with plasmid encoding the same proteins, and to naïve unmodified MSCs. mMSCs triggered strong phagocytic activity, enhanced lymphocyte proliferation, and production of type I and II interferons. The adaptive immune response to mMSCs was also more pronounced than in the case of DNA immunization, as exemplified by a fourfold stronger stimulation of lymphocyte proliferation in response to HCV, a 2.6-fold higher rate of biosynthesis, and a 30-fold higher rate of secretion of IFN-γ, as well as by a 40-fold stronger production of IgG2a antibodies to viral proteins. The immunostimulatory effect of mMSCs was associated with pronounced IL-6 secretion and reduction in the population of myeloid derived suppressor cells (MDSCs). Thus, this is the first example that suggests the feasibility of using mMSCs for the development of an effective anti-HCV vaccine. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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13 pages, 1151 KiB  
Article
The Increase of the Magnitude of Spontaneous Viral Blips in Some Participants of Phase II Clinical Trial of Therapeutic Optimized HIV DNA Vaccine Candidate
by Ekaterina Akulova, Boris Murashev, Sergey Verevochkin, Alexey Masharsky, Ruslan Al-Shekhadat, Valeriy Poddubnyy, Olga Zozulya, Natalia Vostokova and Andrei P. Kozlov
Vaccines 2019, 7(3), 92; https://doi.org/10.3390/vaccines7030092 - 20 Aug 2019
Cited by 3 | Viewed by 3757
Abstract
We developed a candidate DNA vaccine called “DNA-4”consisting of 4 plasmid DNAs encoding Nef, Gag, Pol(rt), and gp140 HIV-1 proteins. The vaccine was found to be safe and immunogenic in a phase I clinical trial. Here we present the results of a phase [...] Read more.
We developed a candidate DNA vaccine called “DNA-4”consisting of 4 plasmid DNAs encoding Nef, Gag, Pol(rt), and gp140 HIV-1 proteins. The vaccine was found to be safe and immunogenic in a phase I clinical trial. Here we present the results of a phase II clinical trial of “DNA-4”. This was a multicenter, double-blind, placebo-controlled clinical trial of safety, and dose selection of “DNA-4” in HIV-1 infected people receiving antiretroviral therapy (ART). Fifty-four patients were randomized into 3 groups (17 patients—group DNA-4 0.25 mg, 17 patients—group DNA-4 0.5 mg, 20 patients—the placebo group). All patients were immunized 4 times on days 0, 7, 11, and 15 followed by a 24-week follow-up period. “DNA-4” was found to be safe and well-tolerated at doses of 0.25 mg and 0.5 mg. We found that the amplitudes of the spontaneous viral load increases in three patients immunized with the candidate DNA vaccine were much higher than that in placebo group—2800, 180,000 and 709 copies/mL, suggesting a possible influence of therapeutic DNA vaccination on viral reservoirs in some patients on ART. We hypothesize that this influence was associated with the reactivation of proviral genomes. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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19 pages, 3756 KiB  
Article
Recombinant BCG Expressing HTI Prime and Recombinant ChAdOx1 Boost Is Safe and Elicits HIV-1-Specific T-Cell Responses in BALB/c Mice
by Athina Kilpeläinen, Narcís Saubi, Núria Guitart, Alex Olvera, Tomáš Hanke, Christian Brander and Joan Joseph
Vaccines 2019, 7(3), 78; https://doi.org/10.3390/vaccines7030078 - 02 Aug 2019
Cited by 16 | Viewed by 4889
Abstract
Despite the availability of anti-retroviral therapy, HIV-1 infection remains a massive burden on healthcare systems. Bacillus Calmette-Guérin (BCG), the only licensed vaccine against tuberculosis, confers protection against meningitis and miliary tuberculosis in infants. Recombinant BCG has been used as a vaccine vehicle to [...] Read more.
Despite the availability of anti-retroviral therapy, HIV-1 infection remains a massive burden on healthcare systems. Bacillus Calmette-Guérin (BCG), the only licensed vaccine against tuberculosis, confers protection against meningitis and miliary tuberculosis in infants. Recombinant BCG has been used as a vaccine vehicle to express both HIV-1 and Simian Immunodeficiemcy Virus (SIV) immunogens. In this study, we constructed an integrative E. coli-mycobacterial shuttle plasmid, p2auxo.HTI.int, expressing the HIVACAT T-cell immunogen (HTI). The plasmid was transformed into a lysine auxotrophic Mycobacterium bovis BCG strain (BCGΔLys) to generate the vaccine BCG.HTI2auxo.int. The DNA sequence coding for the HTI immunogen and HTI protein expression were confirmed, and working vaccine stocks were genetically and phenotypically characterized. We demonstrated that the vaccine was stable in vitro for 35 bacterial generations, and that when delivered in combination with chimpanzee adenovirus (ChAd)Ox1.HTI in adult BALB/c mice, it was well tolerated and induced HIV-1-specific T-cell responses. Specifically, priming with BCG.HTI2auxo.int doubled the magnitude of the T-cell response in comparison with ChAdOx1.HTI alone while maintaining its breadth. The use of integrative expression vectors and novel HIV-1 immunogens can aid in improving mycobacterial vaccine stability as well as specific immunogenicity. This vaccine candidate may be a useful tool in the development of an effective vaccine platform for priming protective responses against HIV-1/TB and other prevalent pediatric pathogens. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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27 pages, 9221 KiB  
Article
Long-Lasting Mucosal and Systemic Immunity against Influenza A Virus Is Significantly Prolonged and Protective by Nasal Whole Influenza Immunization with Mucosal Adjuvant N3 and DNA-Plasmid Expressing Flagellin in Aging In- and Outbred Mice
by Jorma Hinkula, Sanna Nyström, Claudia Devito, Andreas Bråve and Steven E. Applequist
Vaccines 2019, 7(3), 64; https://doi.org/10.3390/vaccines7030064 - 16 Jul 2019
Cited by 9 | Viewed by 3688
Abstract
Background: Vaccination is commonly used to prevent and control influenza infection in humans. However, improvements in the ease of delivery and strength of immunogenicity could markedly improve herd immunity. The aim of this pre-clinical study is to test the potential improvements to [...] Read more.
Background: Vaccination is commonly used to prevent and control influenza infection in humans. However, improvements in the ease of delivery and strength of immunogenicity could markedly improve herd immunity. The aim of this pre-clinical study is to test the potential improvements to existing intranasal delivery of formalin-inactivated whole Influenza A vaccines (WIV) by formulation with a cationic lipid-based adjuvant (N3). Additionally, we combined WIV and N3 with a DNA-encoded TLR5 agonist secreted flagellin (pFliC(-gly)) as an adjuvant, as this adjuvant has previously been shown to improve the effectiveness of plasmid-encoded DNA antigens. Methods: Outbred and inbred mouse strains were intranasally immunized with unadjuvanted WIV A/H1N1/SI 2006 or WIV that was formulated with N3 alone. Additional groups were immunized with WIV and N3 adjuvant combined with pFliC(-gly). Homo and heterotypic humoral anti-WIV immune responses were assayed from serum and lung by ELISA and hemagglutination inhibition assay. Homo and heterotypic cellular immune responses to WIV and Influenza A NP were also determined. Results: WIV combined with N3 lipid adjuvant the pFliC(-gly) significantly increased homotypic influenza specific serum antibody responses (>200-fold), increased the IgG2 responses, indicating a mixed Th1/Th2-type immunity, and increased the HAI-titer (>100-fold). Enhanced cell-mediated IFNγ secreting influenza directed CD4+ and CD8+ T cell responses (>40-fold) to homotypic and heterosubtypic influenza A virus and peptides. Long-term and protective immunity was obtained. Conclusions: These results indicate that inactivated influenza virus that was formulated with N3 cationic adjuvant significantly enhanced broad systemic and mucosal influenza specific immune responses. These responses were broadened and further increased by incorporating DNA plasmids encoding FliC from S. typhimurum as an adjuvant providing long lasting protection against heterologous Influenza A/H1N1/CA09pdm virus challenge. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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16 pages, 2311 KiB  
Article
Novel Synthetic DNA Immunogens Targeting Latent Expressed Antigens of Epstein–Barr Virus Elicit Potent Cellular Responses and Inhibit Tumor Growth
by Krzysztof Wojtak, Alfredo Perales-Puchalt and David B. Weiner
Vaccines 2019, 7(2), 44; https://doi.org/10.3390/vaccines7020044 - 24 May 2019
Cited by 12 | Viewed by 4376
Abstract
Infectious diseases are linked to 15%–20% of cancers worldwide. Among them, Epstein–Barr virus (EBV) is an oncogenic herpesvirus that chronically infects over 90% of the adult population, with over 200,000 cases of cancer and 150,000 cancer-related deaths attributed to it yearly. Acute EBV [...] Read more.
Infectious diseases are linked to 15%–20% of cancers worldwide. Among them, Epstein–Barr virus (EBV) is an oncogenic herpesvirus that chronically infects over 90% of the adult population, with over 200,000 cases of cancer and 150,000 cancer-related deaths attributed to it yearly. Acute EBV infection can present as infectious mononucleosis, and lead to the future onset of multiple cancers, including Burkitt lymphoma, Hodgkin lymphoma, nasopharyngeal carcinoma, and gastric carcinoma. Many of these cancers express latent viral genes, including Epstein–Barr virus nuclear antigen 1 (EBNA1) and latent membrane proteins 1 and 2 (LMP1 and LMP2). Previous attempts to create potent immunogens against EBV have been reported but generated mixed success. We designed novel Synthetic Consensus (SynCon) DNA vaccines against EBNA1, LMP1 and LMP2 to improve on the immune potency targeting important antigens expressed in latently infected cells. These EBV tumor antigens are hypothesized to be useful targets for potential immunotherapy of EBV-driven cancers. We optimized the genetic sequences for these three antigens, studied them for expression, and examined their immune profiles in vivo. We observed that these immunogens generated unique profiles based on which antigen was delivered as the vaccine target. EBNA1vax and LMP2Avax generated the most robust T cell immunity. Interestingly, LMP1vax was a very weak immunogen, generating very low levels of CD8 T cell immunity both as a standalone vaccine and as part of a trivalent vaccine cocktail. LMP2Avax was able to drive immunity that impacted EBV-antigen-positive tumor growth. These studies suggest that engineered EBV latent protein vaccines deserve additional study as potential agents for immunotherapy of EBV-driven cancers. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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22 pages, 2767 KiB  
Article
Designed DNA-Encoded IL-36 Gamma Acts as a Potent Molecular Adjuvant Enhancing Zika Synthetic DNA Vaccine-Induced Immunity and Protection in a Lethal Challenge Model
by Lumena Louis, Megan C. Wise, Hyeree Choi, Daniel O. Villarreal, Kar Muthumani and David B. Weiner
Vaccines 2019, 7(2), 42; https://doi.org/10.3390/vaccines7020042 - 22 May 2019
Cited by 10 | Viewed by 4427
Abstract
Identification of novel molecular adjuvants which can boost and enhance vaccine-mediated immunity and provide dose-sparing potential against complex infectious diseases and for immunotherapy in cancer is likely to play a critical role in the next generation of vaccines. Given the number of challenging [...] Read more.
Identification of novel molecular adjuvants which can boost and enhance vaccine-mediated immunity and provide dose-sparing potential against complex infectious diseases and for immunotherapy in cancer is likely to play a critical role in the next generation of vaccines. Given the number of challenging targets for which no or only partial vaccine options exist, adjuvants that can address some of these concerns are in high demand. Here, we report that a designed truncated Interleukin-36 gamma (IL-36 gamma) encoded plasmid can act as a potent adjuvant for several DNA-encoded vaccine targets including human immunodeficiency virus (HIV), influenza, and Zika in immunization models. We further show that the truncated IL-36 gamma (opt-36γt) plasmid provides improved dose sparing as it boosts immunity to a suboptimal dose of a Zika DNA vaccine, resulting in potent protection against a lethal Zika challenge. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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15 pages, 1663 KiB  
Article
In silico Designed Ebola Virus T-Cell Multi-Epitope DNA Vaccine Constructions Are Immunogenic in Mice
by Sergei I. Bazhan, Denis V. Antonets, Larisa I. Karpenko, Svetlana F. Oreshkova, Olga N. Kaplina, Ekaterina V. Starostina, Sergei G. Dudko, Sofia A. Fedotova and Alexander A. Ilyichev
Vaccines 2019, 7(2), 34; https://doi.org/10.3390/vaccines7020034 - 29 Mar 2019
Cited by 47 | Viewed by 6349
Abstract
Background: The lack of effective vaccines against Ebola virus initiates a search for new approaches to overcoming this problem. The aim of the study was to design artificial polyepitope T-cell immunogens—candidate DNA vaccines against Ebola virus and to evaluate their capacity to [...] Read more.
Background: The lack of effective vaccines against Ebola virus initiates a search for new approaches to overcoming this problem. The aim of the study was to design artificial polyepitope T-cell immunogens—candidate DNA vaccines against Ebola virus and to evaluate their capacity to induce a specific immune response in a laboratory animal model. Method: Design of two artificial polyepitope T-cell immunogens, one of which (EV.CTL) includes cytotoxic and the other (EV.Th)—T-helper epitopes of Ebola virus proteins was carried out using original TEpredict/PolyCTLDesigner software. Synthesized genes were cloned in pcDNA3.1 plasmid vector. Target gene expression was estimated by synthesis of specific mRNAs and proteins in cells transfected with recombinant plasmids. Immunogenicity of obtained DNA vaccine constructs was evaluated according to their capacity to induce T-cell response in BALB/c mice using IFN ELISpot and ICS. Results: We show that recombinant plasmids pEV.CTL and pEV.Th encoding artificial antigens provide synthesis of corresponding mRNAs and proteins in transfected cells, as well as induce specific responses both to CD4+ and CD8+ T-lymphocytes in immunized animals. Conclusions: The obtained recombinant plasmids can be regarded as promising DNA vaccine candidates in future studies of their capacity to induce cytotoxic and protective responses against Ebola virus. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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Review

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12 pages, 1812 KiB  
Review
Use of a Novel Enhanced DNA Vaccine Vector for Preclinical Virus Vaccine Investigation
by Rosamund Chapman and Edward P. Rybicki
Vaccines 2019, 7(2), 50; https://doi.org/10.3390/vaccines7020050 - 13 Jun 2019
Cited by 12 | Viewed by 4412
Abstract
DNA vaccines are stable, safe, and cost effective to produce and relatively quick and easy to manufacture. However, to date, DNA vaccines have shown relatively poor immunogenicity in humans despite promising preclinical results. Consequently, a number of different approaches have been investigated to [...] Read more.
DNA vaccines are stable, safe, and cost effective to produce and relatively quick and easy to manufacture. However, to date, DNA vaccines have shown relatively poor immunogenicity in humans despite promising preclinical results. Consequently, a number of different approaches have been investigated to improve the immunogenicity of DNA vaccines. These include the use of improved delivery methods, adjuvants, stronger promoters and enhancer elements to increase antigen expression, and codon optimization of the gene of interest. This review describes the creation and use of a DNA vaccine vector containing a porcine circovirus (PCV-1) enhancer element that significantly increases recombinant antigen expression and immunogenicity and allows for dose sparing. A 172 bp region containing the PCV-1 capsid protein promoter (Pcap) and a smaller element (PC; 70 bp) within this were found to be equally effective. DNA vaccines containing the Pcap region expressing various HIV-1 antigens were found to be highly immunogenic in mice, rabbits, and macaques at 4–10-fold lower doses than normally used and to be highly effective in heterologous prime-boost regimens. By lowering the amount of DNA used for immunization, safety concerns over injecting large amounts of DNA into humans can be overcome. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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14 pages, 1679 KiB  
Review
Cytolytic Perforin as an Adjuvant to Enhance the Immunogenicity of DNA Vaccines
by Ashish C. Shrestha, Danushka K. Wijesundara, Makutiro G. Masavuli, Zelalem A. Mekonnen, Eric J. Gowans and Branka Grubor-Bauk
Vaccines 2019, 7(2), 38; https://doi.org/10.3390/vaccines7020038 - 30 Apr 2019
Cited by 11 | Viewed by 4730
Abstract
DNA vaccines present one of the most cost-effective platforms to develop global vaccines, which have been tested for nearly three decades in preclinical and clinical settings with some success in the clinic. However, one of the major challenges for the development of DNA [...] Read more.
DNA vaccines present one of the most cost-effective platforms to develop global vaccines, which have been tested for nearly three decades in preclinical and clinical settings with some success in the clinic. However, one of the major challenges for the development of DNA vaccines is their poor immunogenicity in humans, which has led to refinements in DNA delivery, dosage in prime/boost regimens and the inclusion of adjuvants to enhance their immunogenicity. In this review, we focus on adjuvants that can enhance the immunogenicity of DNA encoded antigens and highlight the development of a novel cytolytic DNA platform encoding a truncated mouse perforin. The application of this innovative DNA technology has considerable potential in the development of effective vaccines. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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20 pages, 318 KiB  
Review
A Comparison of Plasmid DNA and mRNA as Vaccine Technologies
by Margaret A. Liu
Vaccines 2019, 7(2), 37; https://doi.org/10.3390/vaccines7020037 - 24 Apr 2019
Cited by 275 | Viewed by 75105
Abstract
This review provides a comparison of the theoretical issues and experimental findings for plasmid DNA and mRNA vaccine technologies. While both have been under development since the 1990s, in recent years, significant excitement has turned to mRNA despite the licensure of several veterinary [...] Read more.
This review provides a comparison of the theoretical issues and experimental findings for plasmid DNA and mRNA vaccine technologies. While both have been under development since the 1990s, in recent years, significant excitement has turned to mRNA despite the licensure of several veterinary DNA vaccines. Both have required efforts to increase their potency either via manipulating the plasmid DNA and the mRNA directly or through the addition of adjuvants or immunomodulators as well as delivery systems and formulations. The greater inherent inflammatory nature of the mRNA vaccines is discussed for both its potential immunological utility for vaccines and for the potential toxicity. The status of the clinical trials of mRNA vaccines is described along with a comparison to DNA vaccines, specifically the immunogenicity of both licensed veterinary DNA vaccines and select DNA vaccine candidates in human clinical trials. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
10 pages, 248 KiB  
Review
Plasmid DNA-Based Alphavirus Vaccines
by Kenneth Lundstrom
Vaccines 2019, 7(1), 29; https://doi.org/10.3390/vaccines7010029 - 08 Mar 2019
Cited by 17 | Viewed by 4342
Abstract
Alphaviruses have been engineered as vectors for high-level transgene expression. Originally, alphavirus-based vectors were applied as recombinant replication-deficient particles, subjected to expression studies in mammalian and non-mammalian cell lines, primary cell cultures, and in vivo. However, vector engineering has expanded the application range [...] Read more.
Alphaviruses have been engineered as vectors for high-level transgene expression. Originally, alphavirus-based vectors were applied as recombinant replication-deficient particles, subjected to expression studies in mammalian and non-mammalian cell lines, primary cell cultures, and in vivo. However, vector engineering has expanded the application range to plasmid DNA-based delivery and expression. Immunization studies with DNA-based alphavirus vectors have demonstrated tumor regression and protection against challenges with infectious agents and tumor cells in animal tumor models. The presence of the RNA replicon genes responsible for extensive RNA replication in the RNA/DNA layered alphavirus vectors provides superior transgene expression in comparison to conventional plasmid DNA-based expression. Immunization with alphavirus DNA vectors revealed that 1000-fold less DNA was required to elicit similar immune responses compared to conventional plasmid DNA. In addition to DNA-based delivery, immunization with recombinant alphavirus particles and RNA replicons has demonstrated efficacy in providing protection against lethal challenges by infectious agents and tumor cells. Full article
(This article belongs to the Special Issue Advances in DNA Vaccines)
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