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Fonseca JA, Cabrera-Mora M, Kashentseva EA, Villegas JP, Fernandez A, Van Pelt A, Dmitriev IP, Curiel DT, Moreno A. A Plasmodium Promiscuous T Cell Epitope Delivered within the Ad5 Hexon Protein Enhances the Protective Efficacy of a Protein Based Malaria Vaccine. PLoS One 2016; 11:e0154819. [PMID: 27128437 PMCID: PMC4851317 DOI: 10.1371/journal.pone.0154819] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/19/2016] [Indexed: 12/20/2022] Open
Abstract
A malaria vaccine is a public health priority. In order to produce an effective vaccine, a multistage approach targeting both the blood and the liver stage infection is desirable. The vaccine candidates also need to induce balanced immune responses including antibodies, CD4+ and CD8+ T cells. Protein-based subunit vaccines like RTS,S are able to induce strong antibody response but poor cellular reactivity. Adenoviral vectors have been effective inducing protective CD8+ T cell responses in several models including malaria; nonetheless this vaccine platform exhibits a limited induction of humoral immune responses. Two approaches have been used to improve the humoral immunogenicity of recombinant adenovirus vectors, the use of heterologous prime-boost regimens with recombinant proteins or the genetic modification of the hypervariable regions (HVR) of the capsid protein hexon to express B cell epitopes of interest. In this study, we describe the development of capsid modified Ad5 vectors that express a promiscuous Plasmodium yoelii T helper epitope denominated PyT53 within the hexon HVR2 region. Several regimens were tested in mice to determine the relevance of the hexon modification in enhancing protective immune responses induced by the previously described protein-based multi-stage experimental vaccine PyCMP. A heterologous prime-boost immunization regime that combines a hexon modified vector with transgenic expression of PyCMP followed by protein immunizations resulted in the induction of robust antibody and cellular immune responses in comparison to a similar regimen that includes a vector with unmodified hexon. These differences in immunogenicity translated into a better protective efficacy against both the hepatic and red blood cell stages of P. yoelii. To our knowledge, this is the first time that a hexon modification is used to deliver a promiscuous T cell epitope. Our data support the use of such modification to enhance the immunogenicity and protective efficacy of adenoviral based malaria vaccines.
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Affiliation(s)
- Jairo Andres Fonseca
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Monica Cabrera-Mora
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Elena A. Kashentseva
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - John Paul Villegas
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Alejandra Fernandez
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Amelia Van Pelt
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Igor P. Dmitriev
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - David T. Curiel
- Cancer Biology Division, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
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Prospects for oral replicating adenovirus-vectored vaccines. Vaccine 2013; 31:3236-43. [PMID: 23707160 DOI: 10.1016/j.vaccine.2013.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 12/22/2022]
Abstract
Orally delivered replicating adenovirus (Ad) vaccines have been used for decades to prevent adenovirus serotype 4 and 7 respiratory illness in military recruits, demonstrating exemplary safety and high efficacy. That experience suggests that oral administration of live recombinant Ads (rAds) holds promise for immunization against other infectious diseases, including those that have been refractory to traditional vaccination methods. Live rAds can express intact antigens from free-standing transgenes during replication in infected cells. Alternatively, antigenic epitopes can be displayed on the rAd capsid itself, allowing presentation of the epitope to the immune system both prior to and during replication of the virus. Such capsid-display rAds offer a novel vaccine approach that could be used either independently of or in combination with transgene expression strategies to provide a new tool in the search for protection from infectious disease.
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Flatt JW, Kim R, Smith JG, Nemerow GR, Stewart PL. An intrinsically disordered region of the adenovirus capsid is implicated in neutralization by human alpha defensin 5. PLoS One 2013; 8:e61571. [PMID: 23620768 PMCID: PMC3631211 DOI: 10.1371/journal.pone.0061571] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Human α-defensins are proteins of the innate immune system that suppress viral and bacterial infections by multiple mechanisms including membrane disruption. For viruses that lack envelopes, such as human adenovirus (HAdV), other, less well defined, mechanisms must be involved. A previous structural study on the interaction of an α-defensin, human α-defensin 5 (HD5), with HAdV led to a proposed mechanism in which HD5 stabilizes the vertex region of the capsid and blocks uncoating steps required for infectivity. Studies with virus chimeras comprised of capsid proteins from sensitive and resistant serotypes supported this model. To further characterize the critical binding site, we determined subnanometer resolution cryo-electron microscopy (cryoEM) structures of HD5 complexed with both neutralization-sensitive and -resistant HAdV chimeras. Models were built for the vertex regions of these chimeras with monomeric and dimeric forms of HD5 in various initial orientations. CryoEM guided molecular dynamics flexible fitting (MDFF) was used to restrain the majority of the vertex model in well-defined cryoEM density. The RGD-containing penton base loops of both the sensitive and resistant virus chimeras are predicted to be intrinsically disordered, and little cryoEM density is observed for them. In simulations these loops from the sensitive virus chimera, interact with HD5, bridge the penton base and fiber proteins, and provides significant stabilization with a three-fold increase in the intermolecular nonbonded interactions of the vertex complex. In the case of the resistant virus chimera, simulations revealed fewer bridging interactions and reduced stabilization by HD5. This study implicates a key dynamic region in mediating a stabilizing interaction between a viral capsid and a protein of the innate immune system with potent anti-viral activity.
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Affiliation(s)
- Justin W. Flatt
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Robert Kim
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jason G. Smith
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Glen R. Nemerow
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Phoebe L. Stewart
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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