51
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Evidence for globally shared, cross-reacting polymorphic epitopes in the pregnancy-associated malaria vaccine candidate VAR2CSA. Infect Immun 2008; 76:1791-800. [PMID: 18250177 DOI: 10.1128/iai.01470-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pregnancy-associated malaria (PAM) is characterized by the placental sequestration of Plasmodium falciparum-infected erythrocytes (IEs) with the ability to bind to chondroitin sulfate A (CSA). VAR2CSA is a leading candidate for a pregnancy malaria vaccine, but its large size ( approximately 350 kDa) and extensive polymorphism may pose a challenge to vaccine development. In this study, rabbits were immunized with individual VAR2CSA Duffy binding-like (DBL) domains expressed in Pichia pastoris or var2csa plasmid DNA and sera were screened on different CSA-binding parasite lines. Rabbit antibodies to three recombinant proteins (DBL1, DBL3, and DBL6) and four plasmid DNAs (DBL1, DBL3, DBL5, and DBL6) reacted with homologous FCR3-CSA IEs. By comparison, antibodies to the DBL4 domain were unable to react with native VAR2CSA protein unless it was first partially proteolyzed with trypsin or chymotrypsin. To investigate the antigenic relationship of geographically diverse CSA-binding isolates, rabbit immune sera were screened on four heterologous CSA-binding lines from different continental origins. Antibodies did not target conserved epitopes exposed in all VAR2CSA alleles; however, antisera to several DBL domains cross-reacted on parasite isolates that had polymorphic loops in common with the homologous immunogen. This study demonstrates that VAR2CSA contains common polymorphic epitopes that are shared between geographically diverse CSA-binding lines.
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Luxembourg A, Evans CF, Hannaman D. Electroporation-based DNA immunisation: translation to the clinic. Expert Opin Biol Ther 2007; 7:1647-64. [DOI: 10.1517/14712598.7.11.1647] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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53
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Vilalta A, Jimenez G, Rusalov D, Planchon R, Lalor P, Carner K, Chaplin JA, Komai M, Manthorpe M, Kaslow DC, Rolland A. Vaccination with Polymerase Chain Reaction-Generated Linear Expression Cassettes Protects Mice Against Lethal Influenza A Challenge. Hum Gene Ther 2007; 18:763-71. [PMID: 17705698 DOI: 10.1089/hum.2007.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The feasibility of a linear expression cassette (LEC)-based influenza A DNA vaccine was demonstrated in mice, using a lethal dose (LD90) of a mouse-adapted A/Hong Kong/8/68 (H3N2) influenza strain. LECs expressing hemagglutinin (HA) from either the homotypic H3N2 or the heterotypic H1N1 (A/Puerto Rico/8/34) influenza virus were produced by polymerase chain reaction and either phosphodiester- or phosphorothioate-modified oligonucleotide primers. Survival subsequent to lethal viral challenge was used as a primary end point; weight loss was the secondary end point. Survival and weight loss data showed that protection can be achieved in mice with 50 microg of phosphate-buffered saline-formulated LEC DNA or 2 microg of Vaxfectin-formulated LEC DNA. Survival correlated with neutralizing antibody titers (hemagglutination inhibition, HAI); titers obtained after vaccination with LEC were equivalent to those obtained with HA (H3N2) plasmid DNA control. Vaccination with heterotypic H1 HA-LEC DNA provided no protection against viral challenge.
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54
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Sedegah M, Rogers WO, Belmonte A, Belmonte M, Banania G, Patterson N, Ferrari M, Kaslow DC, Carucci DJ, Richie TL, Doolan DL. Vaxfectin™ enhances immunogenicity and protective efficacy of P. yoelii circumsporozoite DNA vaccines. Vaccine 2006; 24:1921-7. [PMID: 16298024 DOI: 10.1016/j.vaccine.2005.10.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 10/14/2005] [Accepted: 10/21/2005] [Indexed: 10/25/2022]
Abstract
We evaluated the capacity of the cationic lipid based formulation, Vaxfectin, to enhance the immunogenicity and protective efficacy of DNA-based vaccine regimens in the Plasmodium yoelii murine malaria model. We immunized Balb/c mice with varying doses (0.4-50 microg) of plasmid DNA (pDNA) encoding the P. yoelii circumsporozoite protein (PyCSP), either in a homologous DNA/DNA regimen (D-D) or a heterologous prime-boost DNA-poxvirus regimen (D-V). At the lowest pDNA doses, Vaxfectin substantially enhanced IFA titers, ELISPOT frequencies, and protective efficacy. Clinical trials of pDNA vaccines have often used low pDNA doses based on a per kilogram weight basis. Formulation of pDNA vaccines in Vaxfectin may improve their potency in human clinical trials.
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Affiliation(s)
- Martha Sedegah
- Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA.
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55
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Margalith M, Vilalta A. Sustained protective rabies neutralizing antibody titers after administration of cationic lipid-formulated pDNA vaccine. GENETIC VACCINES AND THERAPY 2006; 4:2. [PMID: 16480501 PMCID: PMC1431525 DOI: 10.1186/1479-0556-4-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 02/15/2006] [Indexed: 11/21/2022]
Abstract
Published data indicate that formulation of pDNA with cationic lipids could greatly enhance the response to a pDNA vaccine in larger mammals. The present work tested the influence of several pDNA:cationic lipid formulations on rabies neutralizing titers. Plasmid expressing Rabies G protein (CVS strain) was evaluated in vivo for ability to elicit neutralizing titers. pDNA:DMRIE-DOPE formulated at two DNA:cationic lipid molar ratios was compared in mice to a Vaxfectin™-pDNA formulation. Mouse data indicate that Vaxfectin™ is more effective than DMRIE-DOPE in eliciting neutralizing titers. In addition, the ratio of pDNA to DMRIE-DOPE can also affect neutralizing titers. Our data show that sustained neutralizing titers (120 days) can be obtained after a single administration of DMRIE-DOPE-formulated pDNA in rabbits.
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Affiliation(s)
- Michal Margalith
- Vical Incorporated, 10390 Pacific Center Ct, San Diego, CA 92121, USA
| | - Adrián Vilalta
- Vical Incorporated, 10390 Pacific Center Ct, San Diego, CA 92121, USA
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56
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Rush CM, Mitchell TJ, Burke B, Garside P. Dissecting the components of the humoral immune response elicited by DNA vaccines. Vaccine 2006; 24:776-84. [PMID: 16198029 DOI: 10.1016/j.vaccine.2005.08.080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Accepted: 08/16/2005] [Indexed: 10/25/2022]
Abstract
Although DNA vaccines appear to be efficient at inducing strong cellular immune responses, a number of questions remain regarding their ability to induce humoral immunity. The essential components for generating an antibody response include B and T cell recognition of antigen, subsequent activation, clonal expansion of each lymphocyte type and migration of T cells into B cell follicles to provide help, all leading to germinal centre formation and antibody production. We have employed a double adoptive transfer system based on ovalbumin (OVA)-specific CD4+ DO11.10 T cells and hen egg lysozyme (HEL)-specific MD4 B cells to assess all of these parameters in the context of DNA vaccination in vivo. We find that vaccination with DNA constructs expressing an OVA-HEL gene fusion (encoding contiguous T and B cell epitopes) can induce T cell activation, clonal expansion and migration into B cell follicles accompanied by B cell activation, blastogenesis, expansion and antibody production. These findings show that DNA vaccination can induce all of the components required for humoral immunity and also provide a system for in depth analysis of factors that influence the development of antibody responses. Such strategies may facilitate the rational design of vaccines capable of inducing effective humoral immunity.
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Affiliation(s)
- Catherine M Rush
- Division of Immunology, Infection and Inflammation, Western Infirmary, University of Glasgow, Glasgow G116NT, UK.
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57
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Abstract
DNA vaccination is vaccination at its simplest. Due to renewed interest in vaccination against anthrax and other biothreat agents, a genetic immunisation approach offers attractive possibilities for rapid, responsive vaccine development. DNA vaccination against anthrax is an active area of research showing promising results at present, which in the short-term and in the future could form the basis for new advances in multi-agent vaccine development. The anthrax 'model' constitutes an important experimental system for genetic immunisation technology development.
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Affiliation(s)
- Darrell R Galloway
- Naval Medical Research Center, Biodefense Research Directorate, Silver Spring, MD, USA
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58
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Lee CG, Choi SY, Park SH, Park KS, Ryu SH, Sung YC. The synthetic peptide Trp-Lys-Tyr-Met-Val-D-Met as a novel adjuvant for DNA vaccine. Vaccine 2005; 23:4703-10. [PMID: 15936851 DOI: 10.1016/j.vaccine.2005.03.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Revised: 02/25/2005] [Accepted: 03/03/2005] [Indexed: 11/29/2022]
Abstract
Trp-Lys-Tyr-Met-Val-D-Met (WKYMVm) is a synthetic peptide known to activate human neutrophils, monocytes and dendritic cells, resulting in the enhancement of superoxide generation, bactericidal activity, chemotactic migration and survival. In this study, we demonstrated that WKYMVm enhanced the surface expression of CD80, but not that of CD40, CD86 and MHC class II, on mouse bone marrow-derived dendritic cells which is one of the essential costimulatory signals for the induction of immune responses. Furthermore, when WKYMVm was codelivered with HIV, HBV and Influenza DNA vaccines, WKYMVm selectively enhanced the vaccine-induced CD8(+) T cell responses in a dose-dependent manner, in terms of IFN-gamma secretion and cytolytic activity. Our results indicate that a synthetic peptide, WKYMVm can function as a novel adjuvant for DNA vaccine.
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Affiliation(s)
- Chang Geun Lee
- National Research Laboratory of DNA medicine, Division of Molecular and Life Science, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, Republic of Korea
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59
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Vilalta A, Mahajan RK, Hartikka J, Leamy V, Martin T, Rusalov D, Bozoukova V, Lalor P, Hall K, Kaslow DC, Rolland A. II. Cationic Lipid-Formulated Plasmid DNA-Based Bacillus anthracis Vaccine: Evaluation of Plasmid DNA Persistence and Integration Potential. Hum Gene Ther 2005; 16:1151-6. [PMID: 16218776 DOI: 10.1089/hum.2005.16.1151] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Several formulated plasmid DNA (pDNA)-based vaccines are being evaluated for safety and efficacy in healthy human subjects. A safety concern for any vaccine that contains genetic material, be it whole organism, live-attenuated, or gene-based, is the potential for integration into genomic DNA (gDNA). To address this concern, a preclinical pDNA persistence/integration study was conducted in rabbits to determine the level of pDNA in muscle 2, 28, and 64 days after intramuscular injection of DMRIE:DOPE-formulated pDNAs encoding Bacillus anthracis detoxified LF and PA proteins (VCL-AB01 vaccine). Total DNA was extracted from day 64 muscle tissue and fractionated by column agarose gel electrophoresis (CAGE). Plasmid copy number (PCN) in muscle 64 days after injection (geometric mean, 2808 PCN/microg of total DNA or 150,000 diploid genomes) was determined by quantitative polymerase chain reaction. Analysis of total DNA from five VCLAB01- injected rabbits revealed that two of five samples had no detectable PCN in the high molecular weight fraction after one round of CAGE, two samples had PCN under the lower limit of quantitation, and the remaining sample had 123 PCN/microg. All PCN in the latter sample cleared after an additional round of CAGE. It appears, therefore, that persisting PCN fractionate as low molecular weight material and are most likely not integrated into gDNA. Even if the worst-case assumption is made that the highest PCN found associated with gDNA represented covalently integrated pDNA inserts, the frequency of mutation would still be 500-fold lower than the autosomal spontaneous mutation rate.
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60
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Vilalta A, Mahajan RK, Hartikka J, Leamy V, Martin T, Rusalov D, Bozoukova V, Lalor P, Hall K, Kaslow DC, Rolland A. II. Cationic Lipid-Formulated Plasmid DNA-Based Bacillus anthracis Vaccine: Evaluation of Plasmid DNA Persistence and Integration Potential. Hum Gene Ther 2005. [DOI: 10.1089/hum.2005.16.ft-124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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61
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Vilalta A, Mahajan RK, Hartikka J, Leamy V, Martin T, Rusalov D, Bozoukova V, Lalor P, Hall K, Kaslow DC, Rolland A. II. Cationic Lipid-Formulated Plasmid DNA-Based Bacillus anthracis Vaccine: Evaluation of Plasmid DNA Persistence and Integration Potential. Hum Gene Ther 2005. [DOI: 10.1089/hum.2005.16.ft-117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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62
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Manthorpe M, Hobart P, Hermanson G, Ferrari M, Geall A, Goff B, Rolland A. Plasmid vaccines and therapeutics: from design to applications. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2005; 99:41-92. [PMID: 16568888 DOI: 10.1007/10_003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In the late 1980s, Vical and collaborators discovered that the injection into tissues of unformulated plasmid encoding various proteins resulted in the uptake of the plasmid by cells and expression of the encoded proteins. After this discovery, a period of technological improvements in plasmid delivery and expression and in pharmaceutical and manufacturing development was quickly followed by a plethora of human clinical trials testing the ability of injected plasmid to provide therapeutic benefits. In this chapter, we summarize in detail the technologies used in the most recent company-sponsored clinical trials and discuss the potential for future improvements in plasmid design, manufacturing, delivery, formulation and administration. A generic path for the clinical development of plasmid-based products is outlined and then exemplified using a case study on the development of a plasmid vaccine from concept to clinical trial.
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63
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Hermanson G, Whitlow V, Parker S, Tonsky K, Rusalov D, Ferrari M, Lalor P, Komai M, Mere R, Bell M, Brenneman K, Mateczun A, Evans T, Kaslow D, Galloway D, Hobart P. A cationic lipid-formulated plasmid DNA vaccine confers sustained antibody-mediated protection against aerosolized anthrax spores. Proc Natl Acad Sci U S A 2004; 101:13601-6. [PMID: 15342913 PMCID: PMC518760 DOI: 10.1073/pnas.0405557101] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
DNA vaccines provide an attractive technology platform against bioterrorism agents due to their safety record in humans and ease of construction, testing, and manufacture. We have designed monovalent and bivalent anthrax plasmid DNA (pDNA) vaccines encoding genetically detoxified protective antigen (PA) and lethal factor (LF) proteins and tested their immunogenicity and ability to protect rabbits from an aerosolized inhalation spore challenge. Immune responses after two or three injections of cationic lipid-formulated PA, PA plus LF, or LF pDNAs were at least equivalent to two doses of anthrax vaccine adsorbed (AVA). High titers of anti-PA, anti-LF, and neutralizing antibody to lethal toxin (Letx) were achieved in all rabbits. Eight or nine animals in each group were challenged with 100x LD(50) of aerosolized anthrax spores 5 or 9 weeks after vaccination. An additional 10 animals vaccinated with PA pDNA were challenged >7 months postvaccination. All animals receiving PA or PA plus LF pDNA vaccines were protected. In addition, 5 of 9 animals receiving LF pDNA survived, and the time to death was significantly delayed in the others. Groups receiving three immunizations with PA or PA plus LF pDNA showed no increase in anti-PA, anti-LF, or Letx neutralizing antibody titers postchallenge, suggesting little or no spore germination. In contrast, titer increases were seen in AVA animals, and in surviving animals vaccinated with LF pDNA alone. Preclinical evaluation of this cationic lipid-formulated bivalent PA and LF vaccine is complete, and the vaccine has received U.S. Food and Drug Administration Investigational New Drug allowance.
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64
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Romano M, Denis O, D'Souza S, Wang XM, Ottenhoff THM, Brulet JM, Huygen K. Induction of in vivo functional Db-restricted cytolytic T cell activity against a putative phosphate transport receptor of Mycobacterium tuberculosis. THE JOURNAL OF IMMUNOLOGY 2004; 172:6913-21. [PMID: 15153510 DOI: 10.4049/jimmunol.172.11.6913] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Using plasmid vaccination with DNA encoding the putative phosphate transport receptor PstS-3 from Mycobacterium tuberculosis and 36 overlapping 20-mer peptides spanning the entire PstS-3 sequence, we determined the immunodominant Th1-type CD4(+) T cell epitopes in C57BL/10 mice, as measured by spleen cell IL-2 and IFN-gamma production. Furthermore, a potent IFN-gamma-inducing, D(b)-restricted CD8(+) epitope was identified using MHC class I mutant B6.C-H-2(bm13) mice and intracellular IFN-gamma and whole blood CD8(+) T cell tetramer staining. Using adoptive transfer of CFSE-labeled, peptide-pulsed syngeneic spleen cells from naive animals into DNA vaccinated or M. tuberculosis-infected recipients, we demonstrated a functional in vivo CTL activity against this D(b)-restricted PstS-3 epitope. IFN-gamma ELISPOT responses to this epitope were also detected in tuberculosis-infected mice. The CD4(+) and CD8(+) T cell epitopes defined for PstS-3 were completely specific and not recognized in mice vaccinated with either PstS-1 or PstS-2 DNA. The H-2 haplotype exerted a strong influence on immune reactivity to the PstS-3 Ag, and mice of the H-2(b, p, and f) haplotype produced significant Ab and Th1-type cytokine levels, whereas mice of H-2(d, k, r, s, and q) haplotype were completely unreactive. Low responsiveness against PstS-3 in MHC class II mutant B6.C-H-2(bm12) mice could be overcome by DNA vaccination. IFN-gamma-producing CD8(+) T cells could also be detected against the D(b)-restricted epitope in H-2(p) haplotype mice. These results highlight the potential of DNA vaccination for the induction and characterization of CD4(+) and particularly CD8(+) T cell responses against mycobacterial Ags.
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Affiliation(s)
- Marta Romano
- Laboratory of Mycobacterial Immunology, Pasteur Institute of Brussels, Brussels, Belgium
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65
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Abstract
The objective of this study was to determine whether a DNA prime-protein boost immunization against the Bacillus anthracis protective antigen (PA) and lethal factor (LF) antigens could induce a protective immune response against significant aerosol challenge in the rabbit model. Rabbits were vaccinated with different regimens of DNA vaccines (Table 1) and aerosol challenged with B. anthracis spores, Ames strain, with an average dose of 50 LD(50s) with a range from 18 to 169 LD(50s.) Of the five vaccinated rabbits that survived, two were immunized intramuscularly (i.m.) with DNA followed with a protein boost and three were immunized subcutaneous (s.q.) with recombinant protein. A major factor predicting survival was the ability of the animal to mount a lasting antibody response to PA. Rabbit sera were collected prior to and following aerosol challenge and titrated for PA antibodies by indirect ELISA. The results of this study indicate that DNA-based immunization against PA and LF induces significant protective immunity against aerosol challenge in the rabbit model and compares favorably with protein-based immunization.
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Affiliation(s)
- Darrell Galloway
- Department of Microbiology, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
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66
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Cai H, Tian X, Hu XD, Zhuang YH, Zhu YX. Combined DNA Vaccines Formulated in DDA Enhance Protective Immunity against Tuberculosis. DNA Cell Biol 2004; 23:450-6. [PMID: 15294094 DOI: 10.1089/1044549041474742] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study evaluated the adjuvant Dimethyldioctyldecyl Ammonium Bromide (DDA) effect on the protective immunity induced by a combination of plasmids containing genes encoding antigens Ag85B, MPT-83, and ESAT-6 from Mycobacterium tuberculosis. The combined DNA vaccines in DDA resulted in significant increases in both specific IgG and splenic T-cell-derived Th1-type cytokine gamma interferon (IFN-gamma) production in response to the three purified antigens when compared to that of combined DNA vaccines in saline. Vaccines in DDA increased the protective efficacy of mice challenged with M. tuberculosis H37Rv as measured by reduced relative CFU counts in their lungs. Mice immunized with the combined DNA vaccines were shown to limit the growth of tubercle bacilli both in lungs and in spleens. Histopathological analyses showed that vaccinated mice had substantially improved postinfection lung pathology relative to the controls. We suggest that our combination of antigens together with DDA formulation may provide a new insight into tuberculosis prevention.
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Affiliation(s)
- H Cai
- The National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing People's Republic of China
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67
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Locher CP, Witt SA, Ashlock BM, Polacino P, Hu SL, Shiboski S, Schmidt AM, Agy MB, Anderson DM, Staprans SI, zur Megede J, Levy JA. Human immunodeficiency virus type 2 DNA vaccine provides partial protection from acute baboon infection. Vaccine 2004; 22:2261-72. [PMID: 15149785 DOI: 10.1016/j.vaccine.2003.11.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2003] [Revised: 11/06/2003] [Accepted: 11/12/2003] [Indexed: 10/26/2022]
Abstract
We determined if the genetic adjuvants, granulocyte-macrophage colony stimulating factor (GM-CSF) and B7-2, could improve the immunogenicity and efficacy of an HIV-2 DNA vaccine. The vaccine consisted of the HIV-2 tat, nef, gag, and env genes synthesized using optimized codons and formulated with cationic liposomes. Baboons (Papio cynocephalus hamadryas) were immunized by the intramuscular, intradermal, and intranasal routes with these expression constructs and challenged with HIV-2(UC2) by the intravaginal route. In the first month after HIV-2 vaginal challenge, the baboons receiving the HIV-2 DNA vaccine with or without the genetic adjuvants had significant reductions in the viral loads in the peripheral blood mononuclear cells (PBMC) (P = 0.028) while the reductions in their plasma viremia were suggestive of a protective effect (P = 0.1). These data demonstrate that partial protection against HIV-2 vaginal challenge, as measured by reduced viral load, can be achieved using only a DNA vaccine formulation.
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MESH Headings
- Adjuvants, Immunologic
- Animals
- Antigens, CD/administration & dosage
- Antigens, CD/genetics
- Antigens, CD/immunology
- B7-2 Antigen
- CD8-Positive T-Lymphocytes/immunology
- Cytotoxicity, Immunologic
- Female
- Gene Products, env/genetics
- Gene Products, env/immunology
- Gene Products, gag/genetics
- Gene Products, gag/immunology
- Gene Products, nef/genetics
- Gene Products, nef/immunology
- Gene Products, tat/genetics
- Gene Products, tat/immunology
- Granulocyte-Macrophage Colony-Stimulating Factor/administration & dosage
- Granulocyte-Macrophage Colony-Stimulating Factor/genetics
- Granulocyte-Macrophage Colony-Stimulating Factor/immunology
- HIV Antibodies/blood
- HIV Infections/prevention & control
- HIV-2/genetics
- HIV-2/immunology
- HIV-2/isolation & purification
- HIV-2/physiology
- Leukocytes, Mononuclear/virology
- Liposomes
- Membrane Glycoproteins/administration & dosage
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Papio
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- Vagina/virology
- Viral Load
- nef Gene Products, Human Immunodeficiency Virus
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Christopher P Locher
- Department of Medicine, Division of Hematology and Oncology, University of California, 514 Parnassus Avenue, San Francisco, CA 94143-1270, USA
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68
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Locher CP, Witt SA, Ashlock BM, Levy JA. Evaluation of genetic immunization adjuvants to improve the effectiveness of a human immunodeficiency virus type 2 (HIV-2) envelope DNA vaccine. DNA Cell Biol 2004; 23:107-10. [PMID: 15000750 DOI: 10.1089/104454904322759911] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In an effort to develop a more effective genetic immunization strategy for HIV, we developed an HIV-2 env DNA vaccine and evaluated three adjuvant formulations. The gp140 gene from HIV-2(UC2 )was synthesized using mammalian codons and cloned into a plasmid vector that expresses eukaryotic genes at high levels. We found that after three immunizations in mice, a novel cationic liposome formulation (Vaxfectin) was superior at inducing systemic and mucosal antibody responses compared to a naked DNA, a controlled release device (an Alzet minipump) and polysaccharide microparticles made from chitosan (P = 0.027). Vaxfectin also induced higher levels of systemic antibodies for each isotype and IgG subclass as well as levels of HIV-2-specific mucosal IgA (P = 0.034). When different routes of immunization were used with the Vaxfectin formulation, gp140-specific systemic antibody responses were highest by the intradermal route, mucosal antibody responses were highest by the intramuscular route, while the intranasal route was the least effective. These results suggest that this cationic liposome formulation is an important adjuvant to improve the effectiveness of genetic immunization strategies for AIDS, and that multiple routes of immunization should be employed for optimal efficacy for HIV vaccine candidates.
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Affiliation(s)
- Christopher P Locher
- Department of Medicine, Division of Hematology and Oncology, University of California, San Francisco, San Francisco, California, USA.
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69
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Fischer L, Minke J, Dufay N, Baudu P, Audonnet JC. Rabies DNA vaccine in the horse: strategies to improve serological responses. Vaccine 2003; 21:4593-6. [PMID: 14575772 DOI: 10.1016/s0264-410x(03)00504-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In order for DNA vaccines to become a practical alternative to conventional vaccines their ability to induce antibody responses in large mammals needs to be improved. We used DNA vaccination against rabies in the horse as a model to test the potential of two different strategies to enhance antibody responses in a large mammalian species. The administration of the DNA vaccine in the presence of aluminum phosphate improved both the onset and the intensity of serological responses but was not potent enough to achieve seroconversion in all vaccinated ponies. However, when the DNA vaccine was formulated with the cationic lipid DMRIE-DOPE instead of aluminum phosphate, a very strong impact on both onset and intensity of serological responses was observed. This latter strategy ensured excellent seroconversion in all vaccinated ponies after a primary course of two injections, demonstrating a clear improvement of the homogeneity of the induced responses. These data indicate that rabies DNA vaccination is feasible in horses and further suggests that properly formulated DNA vaccines can generate immune responses in large veterinary species at a level comparable to the responses achieved with conventional vaccines.
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Affiliation(s)
- Laurent Fischer
- Merial SAS, Biological Discovery Research, 254 rue Marcel Mérieux, 69007 Lyon, France.
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70
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Nukuzuma C, Ajiro N, Wheeler CJ, Konishi E. Enhancing effect of vaxfectin on the ability of a Japanese encephalitis DNA vaccine to induce neutralizing antibody in mice. Viral Immunol 2003; 16:183-9. [PMID: 12828869 DOI: 10.1089/088282403322017910] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vaxfectin, a recently developed adjuvant, was evaluated for its enhancing effect on immunogenicity of a Japanese encephalitis (JE) DNA vaccine plasmid encoding the JE virus premembrane (prM) and envelope (E) genes (designated pcJEME), using BALB/c and ICR mice. Formulation of pcJEME with Vaxfectin provided > or =8-fold higher neutralizing antibody titers than those induced by pcJEME alone and reduced the amount of pcJEME to one-tenth to induce comparable levels of neutralizing antibody. Use of Vaxfectin did not alter a Th1 type IgG isotype immune response (IgG1 < IgG2a) induced by pcJEME in mice. These results indicate that Vaxfectin has an ability to enhance immunogenicity of pcJEME and is considered as a useful adjuvant for DNA vaccines in murine experimental models.
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Affiliation(s)
- Chiyoko Nukuzuma
- Department of Health Sciences, Kobe University School of Medicine, Kobe, Japan
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71
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Abstract
DNA vaccines have been widely used in laboratory animals and non-human primates over the last decade to induce antibody and cellular immune responses. This approach has shown some promise, in models of infectious diseases of both bacterial and viral origin as well as in tumour models. Clinical trials have shown that DNA vaccines appear safe and well tolerated, but need to be made much more potent to be candidates for preventive immunisation of humans. This review describes recent work to improve the delivery of plasmid DNA vaccines and also to increase the immunogenicity of antigens expressed from the DNA vaccine plasmids, including various formulations and molecular adjuvants. Because DNA vaccines are relatively new and represent a novel vaccine technology, certain safety issues, such as the potential for induction of autoimmune disease and integration into the host genome, must be examined carefully. If potency can be improved and safety established, plasmid DNA vaccines offer advantages in speed, simplicity, and breadth of immune response that may be useful for the immunisation of humans against infectious diseases and cancers.
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Affiliation(s)
- John Donnelly
- Chiron Corporation, 4560 Horton Street--M/S 4.3, Emeryville, CA 94608, USA
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72
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Fischer L, Tronel JP, Minke J, Barzu S, Baudu P, Audonnet JC. Vaccination of puppies with a lipid-formulated plasmid vaccine protects against a severe canine distemper virus challenge. Vaccine 2003; 21:1099-102. [PMID: 12559786 DOI: 10.1016/s0264-410x(02)00608-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We assessed whether the formulation of a DNA vaccine expressing the canine distemper virus (CDV) hemagglutinin (HA) and fusion (F) immunogens with the cationic lipid DMRIE-DOPE could induce serological responses and protection against a severe CDV challenge in the dog. Although clear protection was observed in dogs vaccinated with formulated plasmids only limited CDV specific antibody titers were observed in protected dogs before challenge, suggesting that protection could be explained by cell-mediated immunity and/or by a strong antibody-based memory response (priming) triggered by the infectious challenge. The high level of protection achieved in this study, demonstrated that formulated DNA CDV vaccines can generate in dogs a level a protection comparable to conventional CDV vaccines.
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Affiliation(s)
- Laurent Fischer
- Merial SAS, Biological Discovery Research, 254 rue Marcel Mérieux, 69007 Lyon, France.
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73
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Audouy SAL, de Leij LFMH, Hoekstra D, Molema G. In vivo characteristics of cationic liposomes as delivery vectors for gene therapy. Pharm Res 2002; 19:1599-605. [PMID: 12458664 DOI: 10.1023/a:1020989709019] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
After a decade of clinical trials, gene therapy seems to have found its place between excessive ambitions and feasible aims, with encouraging results obtained in recent years. Intracellular delivery of genetic material is the key step in gene therapy. Optimization of delivery vectors is of major importance for turning gene therapy into a successful therapeutic method. Nonviral gene delivery relies mainly on the complexes formed from cationic liposomes (or cationic polymers) and DNA, i.e., lipoplexes (or polyplexes). Many lipoplex formulations have been studied, but in vivo activity is generally low compared to that of viral systems. This review gives a concise overview of studies on the application of cationic liposomes in vivo in animal models of diseases and in clinical studies. The transfection efficiency, the pharmacokinetic and pharmacodynamic properties of the lipid-DNA complexes, and potentially relevant applications for cationic liposomes are discussed. Furthermore, the toxicity of, and the induction of an inflammatory response in association with the administration of lipoplexes are described. Increasing understanding of lipoplex behavior and gene transfer capacities in vivo offers new possibilities to enhance their efficiency and paves the path to more extensive clinical applications in the future.
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Affiliation(s)
- Sandrine A L Audouy
- Department of Membrane Cell Biology, Groningen University Institute for Drug Exploration, Groningen, The Netherlands
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74
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Sankar V, Baccaglini L, Sawdey M, Wheeler CJ, Pillemer SR, Baum BJ, Atkinson JC. Salivary gland delivery of pDNA-cationic lipoplexes elicits systemic immune responses. Oral Dis 2002; 8:275-81. [PMID: 12477057 DOI: 10.1034/j.1601-0825.2002.02856.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To test the ability of two cationic lipoplexes, Vaxfectin and GAP-DLRIE/DOPE, to facilitate transfection and elicit immune responses from plasmid DNAs (pDNAs) after retrograde instillation into salivary glands. METHODS Two pDNA expression vectors encoding either the influenza NP protein or human growth hormone (hGH) were complexed with the cationic lipid transfection reagents, GAP-DLRIE/DOPE or Vaxfectin, and delivered to the submandibular glands of rats. Samples from rats receiving the influenza NP protein pDNA and cationic lipoplexes were analyzed for anti-influenza NP-specific IgG1, IgG2a, and IgG2b in serum, and IgA in saliva, by an enzyme- linked immunosorbent assay (ELISA). Cytotoxic T-cell lymphocyte (CTL) assays were also performed. Transgene protein expression (hGH) was determined from extracts of submandibular glands of rats receiving hGH lipoplexes. RESULTS Serum antibodies (IgG) against the NP protein developed and were highest in all rats vaccinated with GAP-DLRIE/DOPE or Vaxfectin. The major serum IgG subclass stimulated by this route of immunization was IgG2b, followed by IgG2a. CTL assay results showed statistically significantly higher percentage killing in the Vaxfectin group than controls (P < 0.05). No rats developed IgA antibodies to NP protein in saliva. Animals receiving plasmid encoding hGH and either lipoplex expressed significantly higher amounts of hGH compared with those receiving the hGH plasmid and water. Although hGH expression was higher in the animals receiving pDNA/Vaxfectin (approximately 30-fold > pDNA/water), the difference with those receiving pDNA/GAP-DLRIE/DOPE (approximately 10-fold > pDNA/water) was not significant. CONCLUSIONS Retrograde instillation of pDNA complexed with Vaxfectin into the salivary glands can stimulate cytotoxic and humoral responses to the influenza NP protein antigen. Optimization of the conditions required to stimulate humoral and secretory antibody formation may facilitate use of this tissue for specific clinical applications of pDNA immunization.
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Affiliation(s)
- V Sankar
- Gene Therapy and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), NIH, Bethesda, MD 20892, USA.
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75
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D'Souza S, Rosseels V, Denis O, Tanghe A, De Smet N, Jurion F, Palfliet K, Castiglioni N, Vanonckelen A, Wheeler C, Huygen K. Improved tuberculosis DNA vaccines by formulation in cationic lipids. Infect Immun 2002; 70:3681-8. [PMID: 12065510 PMCID: PMC128113 DOI: 10.1128/iai.70.7.3681-3688.2002] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mice were vaccinated with plasmid DNA (pDNA) encoding antigen 85A (Ag85A), Ag85B, or PstS-3 from Mycobacterium tuberculosis either in saline or formulated for intramuscular injections in VC1052:DPyPE (aminopropyl-dimethyl-myristoleyloxy-propanaminium bromide-diphytanoylphosphatidyl-ethanolamine) (Vaxfectin; Vical, Inc., San Diego, Calif.) or for intranasal instillations in GAP-DLRIE:DOPE (aminopropyl-dimethyl-bis-dodecyloxy-propanaminium bromide-dioleoylphosphatidyl-ethanolamine). These two novel cationic and neutral colipid formulations were previously reported to be effective adjuvants for pDNA-induced antibody responses. The levels of Ag85-specific total immunoglobulin G (IgG) and IgG isotypes were all increased 3- to 10-fold by formulation of pDNA in Vaxfectin. The level of production of splenic T-cell-derived Th1-type cytokines (interleukin-2 and gamma interferon) in response to purified Ag85 and to synthetic peptides spanning the entire Ag85A protein was also significantly higher in animals vaccinated with pDNA formulated in Vaxfectin. Cytolytic T-lymphocyte responses generated by pDNA encoding phosphate-binding protein PstS-3 in Vaxfectin were better sustained over time than were those generated by PstS-3 DNA in saline. Intranasal immunization with Ag85A DNA in saline was completely ineffective, whereas administration in GAP-DLRIE:DOPE induced a positive Th1-type cytokine response; however, the extent of the latter response was clearly lower than that obtained following intramuscular immunization with the same DNA dose. Combined intramuscular and intranasal administrations in cationic lipids resulted in stronger immune responses in the spleen and, more importantly, in the lungs as well. Finally, formulation in Vaxfectin increased the protective efficacy of the Ag85B DNA vaccine, as measured by reduced relative light unit counts and CFU counts in the spleen and lungs from mice challenged with bioluminescent M. tuberculosis H37Rv. These results may be of importance for future clinical use of DNA vaccines in humans.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/immunology
- Acyltransferases
- Adjuvants, Immunologic
- Administration, Intranasal
- Animals
- Antibodies, Bacterial/biosynthesis
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- BCG Vaccine/immunology
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Cations
- Injections, Intramuscular
- Interferon-gamma/biosynthesis
- Interleukin-2/biosynthesis
- Lipids
- Lung/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Phosphatidylethanolamines/immunology
- Spleen/immunology
- T-Lymphocytes, Cytotoxic/immunology
- Th1 Cells/immunology
- Tuberculosis/prevention & control
- Vaccination
- Vaccines, DNA/immunology
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Affiliation(s)
- S D'Souza
- Mycobacterial Immunology, Pasteur Institute of Brussels, B1180 Brussels, Belgium
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76
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McKenzie BS, Corbett AJ, Brady JL, Dyer CM, Strugnell RA, Kent SJ, Kramer DR, Boyle JS, Lew AM. Nucleic acid vaccines: tasks and tactics. Immunol Res 2002; 24:225-44. [PMID: 11817323 DOI: 10.1385/ir:24:3:225] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
There are no adequate vaccines against some of the new or reemerged infectious scourges such as HIV and TB. They may require strong and enduring cell-mediated immunity to be elicited. This is quite a task, as the only known basis of protection by current commercial vaccines is antibody. As DNA or RNA vaccines may induce both cell-mediated and humoral immunity, great interest has been shown in them. However, doubt remains whether their efficacy will suffice for their clinical realization. We look at the various tactics to increase the potency of nucleic acid vaccines and divided them broadly under those affecting delivery and those affecting immune induction. For delivery, we have considered ways of improving uptake and the use of bacterial, replicon or viral vectors. For immune induction, we considered aspects of immunostimulatory CpG motifs, coinjection of cytokines or costimulators and alterations of the antigen, its cellular localization and its anatomical localization including the use of ligand-targeting to lymphoid tissue. We also thought that mucosal application of DNA deserved a separate section. In this review, we have taken the liberty to discuss these enhancement methods, whenever possible, in the context of the underlying mechanisms that might argue for or against these strategies.
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Affiliation(s)
- B S McKenzie
- The Walter & Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, Australia
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77
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Ferrari ME, Rusalov D, Enas J, Wheeler CJ. Synergy between cationic lipid and co-lipid determines the macroscopic structure and transfection activity of lipoplexes. Nucleic Acids Res 2002; 30:1808-16. [PMID: 11937635 PMCID: PMC113211 DOI: 10.1093/nar/30.8.1808] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The large number of cytofectin and co-lipid combinations currently used for lipoplex-mediated gene delivery reflects the fact that the optimal cytofectin/co-lipid combination varies with the application. The effects of structural changes in both cytofectin and co-lipid were systematically examined to identify structure-activity relationships. Specifically, alkyl chain length, degree of unsaturation and the head group to which the alkyl side chain was attached were examined to determine their effect on lipoplex structure and biological activity. The macroscopic lipoplex structure was assessed using a dye-binding assay and the biological activity was examined using in vitro transfection in three diverse cell lines. Lipoplexes were formulated in three different vehicles currently in use for in vivo delivery of naked plasmid DNA (pDNA) and lipoplex formulations. The changes in dye accessibility were consistent with structural changes in the lipoplex, which correlated with alterations in the formulation. In contrast, transfection activity of different lipoplexes was cell type and vehicle dependent and did not correlate with dye accessibility. Overall, the results show a correlation between transfection and enhanced membrane fluidity in both the lipoplex and cellular membranes.
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Affiliation(s)
- Marilyn E Ferrari
- Department of Chemistry, Vical Incorporated, 9373 Towne Centre Drive, San Diego, CA 92121, USA
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78
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Reyes L, Hartikka J, Bozoukova V, Sukhu L, Nishioka W, Singh G, Ferrari M, Enas J, Wheeler CJ, Manthorpe M, Wloch MK. Vaxfectin enhances antigen specific antibody titers and maintains Th1 type immune responses to plasmid DNA immunization. Vaccine 2001; 19:3778-86. [PMID: 11395213 DOI: 10.1016/s0264-410x(01)00090-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Antigen specific immune responses were characterized after intramuscular immunization of BALB/c mice with 5 antigen encoding plasmid DNAs (pDNAs) complexed with Vaxfectin, a cationic lipid formulation. Vaxfectin increased IgG titers for all of the antigens with no effect on the CTL responses to the 2 antigens for which CTL assays were performed. Both antigen specific IgG1 and IgG2a were increased, although IgG2a remained greater than IgG1. Furthermore, Vaxfectin had no effect on IFN-gamma or IL-4 production by splenocytes re-stimulated with antigen, suggesting that the Th1 type responses typical of intramuscular pDNA immunization were not altered. Studies with IL-6 -/- mice suggest that the antibody enhancement is IL-6 dependent and results in a correlative increase in antigen specific antibody secreting cells.
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Affiliation(s)
- L Reyes
- Department of Cell Biology, Vical Incorporated, 9373 Towne Centre Dr., Suite 100, San Diego, CA 92121, USA
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79
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Tanghe A, D'Souza S, Rosseels V, Denis O, Ottenhoff TH, Dalemans W, Wheeler C, Huygen K. Improved immunogenicity and protective efficacy of a tuberculosis DNA vaccine encoding Ag85 by protein boosting. Infect Immun 2001; 69:3041-7. [PMID: 11292722 PMCID: PMC98258 DOI: 10.1128/iai.69.5.3041-3047.2001] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
C57BL/6 mice were vaccinated with plasmid DNA encoding Ag85 from Mycobacterium tuberculosis, with Ag85 protein in adjuvant, or with a combined DNA prime-protein boost regimen. While DNA immunization, as previously described, induced robust Th1-type cytokine responses, protein-in-adjuvant vaccination elicited very poor cytokine responses, which were 10-fold lower than those observed with DNA immunization alone. Injection of Ag85 DNA-primed mice with 30 to 100 microg of purified Ag85 protein in adjuvant increased the interleukin-2 and gamma interferon (IFN-gamma) response in spleen two- to fourfold. Further, intracellular cytokine analysis by flow cytometry also showed an increase in IFN-gamma-producing CD4(+) T cells in DNA-primed-protein-boosted animals, compared to those that received only the DNA vaccination. Moreover, these responses appeared to be better sustained over time. Antibodies were readily produced by all three methods of immunization but were exclusively of the immunoglobulin G1 (IgG1) isotype following protein immunization in adjuvant and preferentially of the IgG2a isotype following DNA and DNA prime-protein boost vaccination. Finally, protein boosting increased the protective efficacy of the DNA vaccine against an intravenous M. tuberculosis H37Rv challenge infection, as measured by CFU or relative light unit counts in lungs 1 and 2 months after infection. The capacity of exogenously given protein to boost the DNA-primed vaccination effect underlines the dominant role of Th1-type CD4(+) helper T cells in mediating protection.
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Affiliation(s)
- A Tanghe
- Pasteur Institute of Brussels, Mycobacterial Immunology, B1180 Brussels, Belgium
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80
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Ferrari ME, Rusalov D, Enas J, Wheeler CJ. Trends in lipoplex physical properties dependent on cationic lipid structure, vehicle and complexation procedure do not correlate with biological activity. Nucleic Acids Res 2001; 29:1539-48. [PMID: 11266556 PMCID: PMC31288 DOI: 10.1093/nar/29.7.1539] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using a group of structurally related cytofectins, the effects of different vehicle constituents and mixing techniques on the physical properties and biological activity of lipoplexes were systematically examined. Physical properties were examined using a combination of dye accessibility assays, centrifugation, gel electrophoresis and dynamic light scattering. Biological activity was examined using in vitro transfection. Lipoplexes were formulated using two injection vehicles commonly used for in vivo delivery (PBS pH 7.2 and 0.9% saline), and a sodium phosphate vehicle previously shown to enhance the biological activity of naked pDNA and lipoplex formulations. Phosphate was found to be unique in its effect on lipoplexes. Specifically, the accessible pDNA in lipoplexes formulated with cytofectins containing a gamma-amine substitution in the headgroup was dependent on alkyl side chain length and sodium phosphate concentration, but the same effects were not observed when using cytofectins containing a beta-OH headgroup substitution. The physicochemical features of the phosphate anion, which give rise to this effect in gamma-amine cytofectins, were deduced using a series of phosphate analogs. The effects of the formulation vehicle on transfection were found to be cell type-dependent; however, of the formulation variables examined, the liposome/pDNA mixing method had the greatest effect on transgene expression in vitro. Thus, though predictive physical structure relationships involving the vehicle and cytofectin components of the lipoplex were uncovered, they did not extrapolate to trends in biological activity.
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Affiliation(s)
- M E Ferrari
- Department of Chemistry, Vical Incorporated, 9373 Towne Centre Drive, Suite 100, San Diego, CA 92121, USA
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