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Slyke GV, Ehrbar DJ, Doering J, Yates JL, Vitetta ES, Donini O, Mantis NJ. Endpoint and epitope-specific antibody responses as correlates of vaccine-mediated protection of mice against ricin toxin. Vaccine 2020; 38:6721-6729. [PMID: 32891474 DOI: 10.1016/j.vaccine.2020.08.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/17/2022]
Abstract
The successful licensure of vaccines for biodefense is contingent upon the availability of well-established correlates of protection (CoP) in at least two animal species that can be applied to humans, without the need to assess efficacy in the clinic. In this report we describe a multivariate model that combines pre-challenge serum antibody endpoint titers (EPT) and values derived from an epitope profiling immune-competition capture (EPICC) assay as a predictor in mice of vaccine-mediated immunity against ricin toxin (RT), a Category B biothreat. EPICC is a modified competition ELISA in which serum samples from vaccinated mice were assessed for their ability to inhibit the capture of soluble, biotinylated (b)-RT by a panel of immobilized monoclonal antibodies (mAbs) directed against four immunodominant toxin-neutralizing regions on the enzymatic A chain (RTA) of RT. In a test cohort of mice (n = 40) vaccinated with suboptimal doses of the RTA subunit vaccine, RiVax®, we identified two mAbs, PB10 and SyH7, which had EPICC inhibition values in pre-challenge serum samples that correlated with survival following a challenge with 5 × LD50 of RT administered by intraperitoneal (IP) injection. Analysis of a larger cohort of mice (n = 645) revealed that a multivariate model combining endpoint titers and EPICC values for PB10 and SyH7 as predictive variables had significantly higher statistical power than any one of the independent variables alone. Establishing the correlates of vaccine-mediated protection in mice represents an important steppingstone in the development of RiVax® as a medical countermeasure under the United States Food and Drug Administration's "Animal Rule."
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Affiliation(s)
- Greta Van Slyke
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Dylan J Ehrbar
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Jennifer Doering
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Jennifer L Yates
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Ellen S Vitetta
- Department of Immunology and Microbiology, University of Texas Southwestern Medical School, Dallas, TX, United States
| | | | - Nicholas J Mantis
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States.
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Williamson ED, Westlake GE. Vaccines for emerging pathogens: prospects for licensure. Clin Exp Immunol 2019; 198:170-183. [PMID: 30972733 PMCID: PMC6797873 DOI: 10.1111/cei.13284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2019] [Indexed: 12/28/2022] Open
Abstract
Globally, there are a number of emerging pathogens. For most, there are no licensed vaccines available for human use, although there is ongoing research and development. However, given the extensive and increasing list of emerging pathogens and the investment required to bring vaccines into clinical use, the task is huge. Overlaid on this task is the risk of anti‐microbial resistance (AMR) acquisition by micro‐organisms which can endow a relatively harmless organism with pathogenic potential. Furthermore, climate change also introduces a challenge by causing some of the insect vectors and environmental conditions prevalent in tropical regions to begin to spread out from these traditional areas, thus increasing the risk of migration of zoonotic disease. Vaccination provides a defence against these emerging pathogens. However, vaccines for pathogens which cause severe, but occasional, disease outbreaks in endemic pockets have suffered from a lack of commercial incentive for development to a clinical standard, encompassing Phase III clinical trials for efficacy. An alternative is to develop such vaccines to request US Emergency Use Authorization (EUA), or equivalent status in the United States, Canada and the European Union, making use of a considerable number of regulatory mechanisms that are available prior to licensing. This review covers the status of vaccine development for some of the emerging pathogens, the hurdles that need to be overcome to achieve EUA or an equivalent regional or national status and how these considerations may impact vaccine development for the future, such that a more comprehensive stockpile of promising vaccines can be achieved.
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Affiliation(s)
- E D Williamson
- CBR Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK
| | - G E Westlake
- CBR Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK
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Westfall J, Yates JL, Van Slyke G, Ehrbar D, Measey T, Straube R, Donini O, Mantis NJ. Thermal stability and epitope integrity of a lyophilized ricin toxin subunit vaccine. Vaccine 2018; 36:5967-5976. [PMID: 30172637 PMCID: PMC6320669 DOI: 10.1016/j.vaccine.2018.08.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/18/2018] [Accepted: 08/23/2018] [Indexed: 12/18/2022]
Abstract
Biodefense vaccine are destined to be stockpiled for periods of time and deployed in the event of a public health emergency. In this report, we compared the potency of liquid and lyophilized (thermostabilized) formulations of a candidate ricin toxin subunit vaccine, RiVax, adsorbed to aluminum salts adjuvant, over a 12-month period. The liquid and lyophilized formulations were stored at stressed (40 °C) and unstressed (4 °C) conditions and evaluated at 3, 6 and 12-month time points for potency in a mouse model of lethal dose ricin challenge. At the same time points, the vaccine formulations were interrogated in vitro by competition ELISA for conformational integrity using a panel of three monoclonal antibodies (mAbs), PB10, WECB2, and SyH7, directed against known immunodominant toxin-neutralizing epitopes on RiVax. We found that the liquid vaccine under stress conditions declined precipitously within the first three months, as evidenced by a reduction in in vivo potency and concomitant loss of mAb recognition in vitro. In contrast, the lyophilized RiVax vaccine retained in vivo potency and conformational integrity for up to one year at 4 °C and 40 °C. We discuss the utility of monitoring the integrity of one or more toxin-neutralizing epitopes on RiVax as a possible supplement to animal studies to assess vaccine potency.
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Affiliation(s)
- Jennifer Westfall
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Jennifer L Yates
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Greta Van Slyke
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Dylan Ehrbar
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | | | | | | | - Nicholas J Mantis
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States.
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4
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Sano K, Ainai A, Suzuki T, Hasegawa H. Intranasal inactivated influenza vaccines for the prevention of seasonal influenza epidemics. Expert Rev Vaccines 2018; 17:687-696. [PMID: 30092690 DOI: 10.1080/14760584.2018.1507743] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Intranasal influenza vaccines are expected to confer protection among vaccine recipients by successful induction of mucosal immune response in the upper respiratory tract. Though only live attenuated influenza virus vaccines (LAIVs) are licensed and available for intranasal use in humans today, intranasal inactivated influenza vaccines (IIVs) are currently under reconsideration as a promising intranasal influenza vaccine. AREAS COVERED This review addresses the history of intranasal IIV research and development, along with a summary of the studies done so far to address the mechanism of action of intranasal IIVs. EXPERT COMMENTARY From numerous in vitro and in vivo studies, it has been shown that intranasal IIVs can protect hosts from a broad spectrum of influenza virus strains. In-depth studies of the mucosal antibody response following intranasal IIV administration have also elucidated the detailed functions of secretory IgA (immunoglobulin A) antibodies which are responsible for the mechanism of action of intranasal vaccines. Safe and effective intranasal IIVs are expected to be an important tool to combat seasonal influenza.
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Affiliation(s)
- Kaori Sano
- a Department of Pathology , National Institute of Infectious Diseases , Tokyo , Japan.,b Division of Infectious Diseases Pathology, Department of Global Infectious Diseases , Tohoku Graduate School of Medicine , Miyagi , Japan
| | - Akira Ainai
- a Department of Pathology , National Institute of Infectious Diseases , Tokyo , Japan
| | - Tadaki Suzuki
- a Department of Pathology , National Institute of Infectious Diseases , Tokyo , Japan
| | - Hideki Hasegawa
- a Department of Pathology , National Institute of Infectious Diseases , Tokyo , Japan.,b Division of Infectious Diseases Pathology, Department of Global Infectious Diseases , Tohoku Graduate School of Medicine , Miyagi , Japan
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High-Definition Mapping of Four Spatially Distinct Neutralizing Epitope Clusters on RiVax, a Candidate Ricin Toxin Subunit Vaccine. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00237-17. [PMID: 29046307 DOI: 10.1128/cvi.00237-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/12/2017] [Indexed: 12/20/2022]
Abstract
RiVax is a promising recombinant ricin toxin A subunit (RTA) vaccine antigen that has been shown to be safe and immunogenic in humans and effective at protecting rhesus macaques against lethal-dose aerosolized toxin exposure. We previously used a panel of RTA-specific monoclonal antibodies (MAbs) to demonstrate, by competition enzyme-linked immunosorbent assay (ELISA), that RiVax elicits similar serum antibody profiles in humans and macaques. However, the MAb binding sites on RiVax have yet to be defined. In this study, we employed hydrogen exchange-mass spectrometry (HX-MS) to localize the epitopes on RiVax recognized by nine toxin-neutralizing MAbs and one nonneutralizing MAb. Based on strong protection from hydrogen exchange, the nine MAbs grouped into four spatially distinct epitope clusters (namely, clusters I to IV). Cluster I MAbs protected RiVax's α-helix B (residues 94 to 107), a protruding immunodominant secondary structure element known to be a target of potent toxin-neutralizing antibodies. Cluster II consisted of two subclusters located on the "back side" (relative to the active site pocket) of RiVax. One subcluster involved α-helix A (residues 14 to 24) and α-helices F-G (residues 184 to 207); the other encompassed β-strand d (residues 62 to 69) and parts of α-helices D-E (154 to 164) and the intervening loop. Cluster III involved α-helices C and G on the front side of RiVax, while cluster IV formed a sash from the front to back of RiVax, spanning strands b, c, and d (residues 35 to 59). Having a high-resolution B cell epitope map of RiVax will enable the development and optimization of competitive serum profiling assays to examine vaccine-induced antibody responses across species.
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Cunningham AL, Garçon N, Leo O, Friedland LR, Strugnell R, Laupèze B, Doherty M, Stern P. Vaccine development: From concept to early clinical testing. Vaccine 2016; 34:6655-6664. [DOI: 10.1016/j.vaccine.2016.10.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/21/2016] [Accepted: 10/04/2016] [Indexed: 12/21/2022]
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Oyston PCF, Williamson ED. Modern Advances against Plague. ADVANCES IN APPLIED MICROBIOLOGY 2016; 81:209-41. [PMID: 22958531 DOI: 10.1016/b978-0-12-394382-8.00006-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Plague has been a scourge of humanity, responsible for the deaths of millions. The etiological agent, Yersinia pestis, has evolved relatively recently from an enteropathogen, Yersinia pseudotuberculosis. The evolution of the plague pathogen has involved a complex series of genetic acquisitions, deletions, and rearrangements in its transition from an enteric niche to becoming a systemic, flea-vectored pathogen. With the advent of modern molecular biology techniques, we are starting to understand how the organism adapts to the diverse niches it encounters and how to combat the threat it poses.
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Animal Models for the Pathogenesis, Treatment, and Prevention of Infection by Bacillus anthracis. Microbiol Spectr 2016; 3:TBS-0001-2012. [PMID: 26104551 DOI: 10.1128/microbiolspec.tbs-0001-2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This article reviews the characteristics of the major animal models utilized for studies on Bacillus anthracis and highlights their contributions to understanding the pathogenesis and host responses to anthrax and its treatment and prevention. Advantages and drawbacks associated with each model, to include the major models (murine, guinea pig, rabbit, nonhuman primate, and rat), and other less frequently utilized models, are discussed. Although the three principal forms of anthrax are addressed, the main focus of this review is on models for inhalational anthrax. The selection of an animal model for study is often not straightforward and is dependent on the specific aims of the research or test. No single animal species provides complete equivalence to humans; however, each species, when used appropriately, can contribute to a more complete understanding of anthrax and its etiologic agent.
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9
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Williamson D. Approaches to modelling the human immune response in transition of candidates from research to development. J Immunol Res 2014; 2014:395302. [PMID: 24949489 PMCID: PMC4033477 DOI: 10.1155/2014/395302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 03/11/2014] [Indexed: 11/28/2022] Open
Abstract
This review considers the steps required to evaluate a candidate biodefense vaccine or therapy as it emerges from the research phase, in order to transition it to development. The options for preclinical modelling of efficacy are considered in the context of the FDA's Animal Rule.
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Affiliation(s)
- Diane Williamson
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury, Wilts SP4 0JQ, UK
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Kaur M, Singh S, Bhatnagar R. Anthrax vaccines: present status and future prospects. Expert Rev Vaccines 2014; 12:955-70. [PMID: 23984963 DOI: 10.1586/14760584.2013.814860] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The management of anthrax remains a top priority among the biowarfare/bioterror agents. It was the Bacillus anthracis spore attack through the US mail system after the September 11, 2001, terrorist attacks in the USA that highlighted the potential of B. anthracis as a bioterrorism agent and the threat posed by its deliberate dissemination. These attacks invigorated the efforts toward understanding the anthrax pathogenesis and development of more comprehensive medical intervention strategies for its containment in case of both natural disease and manmade, accidental or deliberate infection of a non-suspecting population. Currently, efforts are directed toward the development of safe and efficacious vaccines as well as intervention tools for controlling the disease in the advanced fulminant stage when toxemia has already developed. This work presents an overview of the current understanding of anthrax pathogenesis and recent advances made, particularly after 2001, for the successful management of anthrax and outlines future perspectives.
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Affiliation(s)
- Manpreet Kaur
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, Delhi, India
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11
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Williamson ED, Oyston PCF. Protecting against plague: towards a next-generation vaccine. Clin Exp Immunol 2013; 172:1-8. [PMID: 23480179 PMCID: PMC3719925 DOI: 10.1111/cei.12044] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2012] [Indexed: 01/22/2023] Open
Abstract
The causative organism of plague is the bacterium Yersinia pestis. Advances in understanding the complex pathogenesis of plague infection have led to the identification of the F1- and V-antigens as key components of a next-generation vaccine for plague, which have the potential to be effective against all forms of the disease. Here we review the roles of F1- and V-antigens in the context of the range of virulence mechanisms deployed by Y. pestis, in order to develop a greater understanding of the protective immune responses required to protect against plague.
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Affiliation(s)
- E D Williamson
- Biomedical Sciences Department, Defence Science and Technology Laboratory, Salisbury, Wilts, UK.
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12
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13
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Correlates of protection following vaccination of mice with gene deletion mutants of Francisella tularensis subspecies tularensis strain, SCHU S4 that elicit varying degrees of immunity to systemic and respiratory challenge with wild-type bacteria. Mol Immunol 2012. [PMID: 23201853 DOI: 10.1016/j.molimm.2012.10.043] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Francisella tularensis subspecies tularensis is an extremely virulent facultative intracellular bacterial pathogen capable of causing significant mortality in humans when inhaled. Consequently, subspecies tularensis was developed as a biological weapon more than 50 years ago. To counter this threat the US Army empirically developed a live vaccine strain, F. tularensis LVS, from the less virulent holarctica subspecies. In human experiments LVS afforded substantial protection against transdermal challenge with clinical subspecies tularensis strain, SCHU S4, but lesser protection against infection initiated by inhalation of the pathogen. Several regulatory and clinical issues remain unresolved for this vaccine, including the absence of a robust correlate of protection. To try to address this, we have developed several defined gene deletion mutants of SCHU S4 that elicit varying degrees of protection in a mouse dermal or respiratory challenge model. In the present study, we have examined whether host immune responses to immunization with such live vaccine candidates can serve as correlates of protection. Antibody responses were unable to distinguish between effective and ineffective vaccine strains. However, several cytokine responses to vaccination showed some promise. Especially, serum levels of TNFα, IFNγ, and MCP-1 between days 4 and 7 after vaccination appear to correlate with protection against respiratory challenge.
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14
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Plague vaccines: current developments and future perspectives. Emerg Microbes Infect 2012; 1:e36. [PMID: 26038406 PMCID: PMC3630923 DOI: 10.1038/emi.2012.34] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 12/21/2022]
Abstract
Despite many decades of intensive studies of Yersinia pestis, the causative agent of plague, there is no safe and efficient vaccine against this devastating disease. A recently developed F1/V subunit vaccine candidate, which relies mainly on humoral immunity, showed promising results in animal studies; however, its efficacy in humans still has to be carefully evaluated. In addition, those developing next-generation plague vaccines need to pay particular attention to the importance of eliciting cell-mediated immunity. In this review, we analyzed the current progress in developing subunit, DNA and live carrier platforms of delivery by bacterial and viral vectors, as well as approaches for controlled attenuation of virulent strains of Y. pestis.
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Twine S, Shen H, Harris G, Chen W, Sjostedt A, Ryden P, Conlan W. BALB/c mice, but not C57BL/6 mice immunized with a ΔclpB mutant of Francisella tularensis subspecies tularensis are protected against respiratory challenge with wild-type bacteria: association of protection with post-vaccination and post-challenge immune responses. Vaccine 2012; 30:3634-45. [PMID: 22484348 DOI: 10.1016/j.vaccine.2012.03.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 02/23/2012] [Accepted: 03/16/2012] [Indexed: 01/08/2023]
Abstract
Francisella tularensis subspecies tularensis is highly virulent for humans especially when it is inhaled. Therefore, it has the potential to be used as a biothreat agent. Vaccines against F. tularensis will need to be approved in accordance with the FDA Animal Rule. This will require identification of robust correlates of protection in experimental animals and the demonstration that similar immune responses are generated in vaccinated humans. Towards this goal, we have developed an experimental live vaccine strain by deleting the gene, clpB, encoding a heat shock protein from virulent subsp. tularensis strain, SCHU S4. SCHU S4ΔclpB administered intradermally protects BALB/c, but not C57BL/6 mice from subsequent respiratory challenge with wildtype SCHU S4. A comparison of post-vaccination and post-challenge immune responses in these two mouse strains shows an association between several antibody and cytokine responses and protection. In particular, elevated IFNγ levels in the skin 2 days after vaccination, sero-conversion to hypothetical membrane protein FTT_1778c, and to 30S ribosomal protein S1 (FTT_0183c) of F. tularensis after 30 days of vaccination, and elevated levels of pulmonary IL-17 on day 7 after respiratory challenge with SCHU S4 were all associated with protection.
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Affiliation(s)
- Susan Twine
- National Research Council Canada, Institute for Biological Sciences, Ottawa, Ontario, K1A 0R6, Canada
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16
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Conlan JW. Tularemia vaccines: recent developments and remaining hurdles. Future Microbiol 2011; 6:391-405. [PMID: 21526941 DOI: 10.2217/fmb.11.22] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Francisella tularensis subsp. tularensis is a facultative intracellular bacterial pathogen of humans and other mammals. Its inhaled infectious dose is very low and can result in very high mortality. Historically, subsp. tularensis was developed as a biological weapon and there are now concerns about its abuse as such by terrorists. A live attenuated vaccine developed pragmatically more than half a century ago from the less virulent holarctica subsp. is the sole prophylactic available, but it remains unlicensed. In recent years several other potential live, killed and subunit vaccine candidates have been developed and tested in mice for their efficacy against respiratory challenge with subsp. tularensis. This article will review these vaccine candidates and the development hurdles they face.
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Affiliation(s)
- J Wayne Conlan
- National Research Council, Institute for Biological Sciences, Ottawa, Ontario, Canada.
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The role of immune correlates and surrogate markers in the development of vaccines and immunotherapies for plague. Adv Prev Med 2011; 2012:365980. [PMID: 21991451 PMCID: PMC3182760 DOI: 10.1155/2012/365980] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 08/08/2011] [Indexed: 01/28/2023] Open
Abstract
One of the difficulties in developing countermeasures to biothreat agents is the challenge inherent in demonstrating their efficacy in man. Since the first publication of the Animal Rule by the FDA, there has been increased discussion of potential correlates of protection in animal models and their use to establish surrogate markers of efficacy in man. The latter need to be relatively easy to measure in assays that are at least qualified, if not validated, in order to derive a quantitative assessment of the clinical benefit conferred. The demonstration of safety and clinical benefit is essential to achieve regulatory approval for countermeasures for which clinical efficacy cannot be tested directly, as is the case for example, for biodefence vaccines. Plague is an ancient, serious infectious disease which is still endemic in regions of the modern world and is a potential biothreat agent. This paper discusses potential immune correlates of protection for plague, from which it may be possible to derive surrogate markers of efficacy, in order to predict the clinical efficacy of candidate prophylaxes and therapies.
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Rocchi MS, Bartley PM, Inglis NF, Collantes-Fernandez E, Entrican G, Katzer F, Innes EA. Selection of Neospora caninum antigens stimulating bovine CD4+ve T cell responses through immuno-potency screening and proteomic approaches. Vet Res 2011; 42:91. [PMID: 21813001 PMCID: PMC3167765 DOI: 10.1186/1297-9716-42-91] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 08/03/2011] [Indexed: 11/23/2022] Open
Abstract
Neospora caninum is recognised worldwide as a major cause of bovine infectious abortion. There is a real need to develop effective strategies to control infection during pregnancy which may lead to either abortion or congenital transmission. Due to the intracellular nature of the parasite, cell-mediated immune (CMI) responses involving CD4+ve, CD8+ve, γ/δ TCR+ve T cells and NK cells, as well as production of IFN-γ, are thought to be important for protective immunity. In this study we applied a combination of proteomic and immunological approaches to identify antigens of N. caninum that are recognized by CD4+ve T cell lines derived from infected cattle. Initially, N. caninum tachyzoite Water Soluble Antigens (NcWSA) were fractionated by size-exclusion HPLC and then screened for immune-potency using CD4+ve T cell lines. LC-ESI-MS/MS (liquid chromatography electrospray ionisation tandem mass spectrometry) was employed to catalogue and identify the proteins comprising three immunologically selected fractions and led to the identification of six N. caninum target proteins as well as sixteen functional orthologues of Toxoplasma gondii. This approach allows the screening of biologically reactive antigenic fractions by the immune cells responsible for protection (such as bovine CD4+ve cells) and the subsequent identification of the stimulating components using tandem mass spectrometry.
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Affiliation(s)
- Mara S Rocchi
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, UK.
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Lin JS, Park S, Adamovicz JJ, Hill J, Bliska JB, Cote CK, Perlin DS, Amemiya K, Smiley ST. TNFα and IFNγ contribute to F1/LcrV-targeted immune defense in mouse models of fully virulent pneumonic plague. Vaccine 2010; 29:357-62. [PMID: 20840834 DOI: 10.1016/j.vaccine.2010.08.099] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 08/25/2010] [Accepted: 08/29/2010] [Indexed: 10/19/2022]
Abstract
Immunization with the Yersinia pestis F1 and LcrV proteins improves survival in mouse and non-human primate models of pneumonic plague. F1- and LcrV-specific antibodies contribute to protection, however, the mechanisms of antibody-mediated defense are incompletely understood and serum antibody titers do not suffice as quantitative correlates of protection. Previously we demonstrated roles for tumor necrosis factor-alpha (TNFα) and gamma-interferon (IFNγ) during defense against conditionally attenuated pigmentation (pgm) locus-negative Y. pestis. Here, using intranasal challenge with fully virulent pgm-positive Y. pestis strain CO92, we demonstrate that neutralizing TNFα and IFNγ interferes with the capacity of therapeutically administered F1- or LcrV-specific antibody to reduce bacterial burden and increase survival. Moreover, using Y. pestis strain CO92 in an aerosol challenge model, we demonstrate that neutralizing TNFα and IFNγ interferes with protection conferred by immunization with recombinant F1-LcrV fusion protein vaccine (p<0.0005). These findings establish that TNFα and IFNγ contribute to protection mediated by pneumonic plague countermeasures targeting F1 and LcrV, and suggest that an individual's capacity to produce these cytokines in response to Y. pestis challenge will be an important co-determinant of antibody-mediated defense against pneumonic plague.
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Affiliation(s)
- Jr-Shiuan Lin
- Trudeau Institute, 154 Algonquin Avenue, Saranac Lake, NY 12983, USA
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