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Hausdorff WP, Anderson JD, Bagamian KH, Bourgeois AL, Mills M, Sawe F, Scheele S, Talaat K, Giersing BK. Vaccine value profile for Shigella. Vaccine 2023; 41 Suppl 2:S76-S94. [PMID: 37827969 DOI: 10.1016/j.vaccine.2022.12.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/14/2022] [Accepted: 12/16/2022] [Indexed: 10/14/2023]
Abstract
Shigella is the leading bacterial cause of diarrhoea and the second leading cause of diarrhoeal mortality among all ages. It also exhibits increasing levels of antibiotic resistance. The greatest burden is among children under five in low- and middle-income countries (LMICs). As such, a priority strategic goal of the World Health Organization (WHO) is the development of a safe, effective and affordable vaccine to reduce morbidity and mortality from Shigella-attributable dysentery and diarrhea, including long term outcomes associated with chronic inflammation and growth faltering, in children under 5 years of age in LMICs. In addition, a safe and effective Shigella vaccine is of potential interest to travellers and military both to prevent acute disease and rarer, long-term sequelae. An effective Shigella vaccine is also anticipated to reduce antibiotic use and thereby help diminish further emergence of enteric pathogens resistant to antimicrobials. The most advanced vaccine candidates are multivalent, parenteral formulations in Phase 2 and Phase 3 clinical studies. They rely on O-antigen-polysaccharide protein conjugate technologies or, alternatively, outer membrane vesicles expressing penta-acylated lipopolysaccharide that has been detoxified. Other parenteral and oral formulations, many delivering a broader array of Shigella antigens, are at earlier stages of clinical development. These formulations are being assessed in alignment with the WHO Preferred Product Characteristics, which call for a 1 to 2 dose primary immunization series given during the first 12 months of life, ideally starting at 6 months of age. This 'Vaccine Value Profile' (VVP) for Shigella is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, government agencies and multi-lateral organizations. All contributors have extensive expertise on various elements of the Shigella VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.
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Affiliation(s)
- William P Hausdorff
- Center for Vaccine Innovation and Access, PATH, 455 Massachusetts Ave NW, Washington, DC 20001, USA; Faculty of Medicine, Université de Bruxelles, Brussels 1070, Belgium.
| | - John D Anderson
- Office of Health Affairs, West Virginia University, Morgantown, WV 26505, USA; Bagamian Scientific Consulting, LLC, Gainesville, FL 32601, USA
| | - Karoun H Bagamian
- Bagamian Scientific Consulting, LLC, Gainesville, FL 32601, USA; Department of Environmental and Global Health, University of Florida, Gainesville, FL 32603, USA
| | - A Louis Bourgeois
- Center for Vaccine Innovation and Access, PATH, 455 Massachusetts Ave NW, Washington, DC 20001, USA
| | - Melody Mills
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Frederick Sawe
- Kenya Medical Research Institute/U.S. Army Medical Research Directorate-Africa/Kenya-Henry Jackson Foundation MRI, Kericho, Kenya
| | - Suzanne Scheele
- Center for Vaccine Innovation and Access, PATH, 455 Massachusetts Ave NW, Washington, DC 20001, USA
| | - Kawsar Talaat
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Birgitte K Giersing
- Department of Immunization, Vaccines and Biologicals (IVB), World Health Organization (WHO), Geneva, Switzerland
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Sztein MB, Booth JS. Controlled human infectious models, a path forward in uncovering immunological correlates of protection: Lessons from enteric fevers studies. Front Microbiol 2022; 13:983403. [PMID: 36204615 PMCID: PMC9530043 DOI: 10.3389/fmicb.2022.983403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Enteric infectious diseases account for more than a billion disease episodes yearly worldwide resulting in approximately 2 million deaths, with children under 5 years old and the elderly being disproportionally affected. Enteric pathogens comprise viruses, parasites, and bacteria; the latter including pathogens such as Salmonella [typhoidal (TS) and non-typhoidal (nTS)], cholera, Shigella and multiple pathotypes of Escherichia coli (E. coli). In addition, multi-drug resistant and extensively drug-resistant (XDR) strains (e.g., S. Typhi H58 strain) of enteric bacteria are emerging; thus, renewed efforts to tackle enteric diseases are required. Many of these entero-pathogens could be controlled by oral or parenteral vaccines; however, development of new, effective vaccines has been hampered by lack of known immunological correlates of protection (CoP) and limited knowledge of the factors contributing to protective responses. To fully comprehend the human response to enteric infections, an invaluable tool that has recently re-emerged is the use of controlled human infection models (CHIMs) in which participants are challenged with virulent wild-type (wt) organisms. CHIMs have the potential to uncover immune mechanisms and identify CoP to enteric pathogens, as well as to evaluate the efficacy of therapeutics and vaccines in humans. CHIMs have been used to provide invaluable insights in the pathogenesis, host-pathogen interaction and evaluation of vaccines. Recently, several Oxford typhoid CHIM studies have been performed to assess the role of multiple cell types (B cells, CD8+ T, Tregs, MAIT, Monocytes and DC) during S. Typhi infection. One of the key messages that emerged from these studies is that baseline antigen-specific responses are important in that they can correlate with clinical outcomes. Additionally, volunteers who develop typhoid disease (TD) exhibit higher levels and more activated cell types (e.g., DC and monocytes) which are nevertheless defective in discrete signaling pathways. Future critical aspects of this research will involve the study of immune responses to enteric infections at the site of entry, i.e., the intestinal mucosa. This review will describe our current knowledge of immunity to enteric fevers caused byS. Typhi and S. Paratyphi A, with emphasis on the contributions of CHIMs to uncover the complex immunological responses to these organisms and provide insights into the determinants of protective immunity.
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Affiliation(s)
- Marcelo B. Sztein
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Marcelo B. Sztein,
| | - Jayaum S. Booth
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
- Jayaum S. Booth,
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MacLennan CA, Grow S, Ma LF, Steele AD. The Shigella Vaccines Pipeline. Vaccines (Basel) 2022; 10:vaccines10091376. [PMID: 36146457 PMCID: PMC9504713 DOI: 10.3390/vaccines10091376] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/06/2022] [Accepted: 08/10/2022] [Indexed: 11/22/2022] Open
Abstract
Shigella is the leading cause of global diarrheal deaths that currently lacks a licensed vaccine. Shigellosis drives antimicrobial resistance and leads to economic impact through linear growth faltering. Today, there is a robust pipeline of vaccines in clinical development which are broadly divided into parenteral glycoconjugate vaccines, consisting of O-antigen conjugated to carrier proteins, and oral live attenuated vaccines, which incorporate targeted genetic mutations seeking to optimize the balance between reactogenicity, immunogenicity and ultimately protection. Proof of efficacy has previously been shown with both approaches but for various reasons no vaccine has been licensed to date. In this report, we outline the requirements for a Shigella vaccine and describe the current pipeline in the context of the many candidates that have previously failed or been abandoned. The report refers to papers from individual vaccine developers in this special supplement of Vaccines which is focused on Shigella vaccines. Once readouts of safety and immunogenicity from current trials of lead candidate vaccines among the target population of young children in low- and middle-income countries are available, the likely time to licensure of a first Shigella vaccine will become clearer.
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Oxford JS, Catchpole A, Mann A, Bell A, Noulin N, Gill D, Oxford JR, Gilbert A, Balasingam S. A Brief History of Human Challenge Studies (1900-2021) Emphasising the Virology, Regulatory and Ethical Requirements, Raison D'etre, Ethnography, Selection of Volunteers and Unit Design. Curr Top Microbiol Immunol 2022. [PMID: 35704095 DOI: 10.1007/82_2022_253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Venetian quarantine 400 years ago was an important public health measure. Since 1900 this has been refined to include "challenge" or deliberate infection with pathogens be they viruses, bacteria, or parasites. Our focus is virology and ranges from the early experiments in Cuba with Yellow Fever Virus to the most widespread pathogen of our current times, COVID-19. The latter has so far caused over four million deaths worldwide and 190 million cases of the disease. Quarantine and challenge were also used to investigate the Spanish Influenza of 1918 which caused over 100 million deaths. We consider here the merits of the approach, that is the speeding up of knowledge in a practical sense leading to the more rapid licensing of vaccines and antimicrobials. At the core of quarantine and challenge initiatives is the design of the unit to allow safe confinement of the pathogen and protection of the staff. Most important though is the safety of volunteers. We can see now, as in 1900, that members of our society are prepared and willing to engage in these experiments for the public good. Our ethnology study, where the investigator observed the experiment from within the quarantine, gave us the first indication of changing attitudes amongst volunteers whilst in quarantine. These quarantine experiments, referred to as challenge studies, human infection studies, or "controlled human infection models" involve thousands of clinical samples taken over two to three weeks and can provide a wealth of immunological and molecular data on the infection itself and could allow the discovery of new targets for vaccines and therapeutics. The Yellow Fever studies from 121 years ago gave the impetus for development of a successful vaccine still used today whilst also uncovering the nature of the Yellow Fever agent, namely that it was a virus. We outline how carefully these experiments are approached and the necessity to have high quality units with self-contained air-flow along with extensive personal protective equipment for nursing and medical staff. Most important is the employment of highly trained scientific, medical and nursing staff. We face a future of emerging pathogens driven by the increasing global population, deforestation, climate change, antibiotic resistance and increased global travel. These emerging pathogens may be pathogens we currently are not aware of or have not caused outbreaks historically but could also be mutated forms of known pathogens including viruses such as influenza (H7N9, H5N1 etc.) and coronaviruses. This calls for challenge studies to be part of future pandemic preparedness as an additional tool to assist with the rapid development of broad-spectrum antimicrobials, immunomodulators and new vaccines.
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Affiliation(s)
- J S Oxford
- Blizzard Institute of Cell and Molecular Science, Queen Mary University of London, London, E1 2AT, UK
| | | | | | | | | | - D Gill
- Blizzard Institute of Cell and Molecular Science, Queen Mary University of London, London, E1 2AT, UK
| | - J R Oxford
- Inveresk Medical Practice, Edinburgh, E21 7BP, UK
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Clarkson KA, Porter CK, Talaat KR, Kapulu MC, Chen WH, Frenck RW, Bourgeois AL, Kaminski RW, Martin LB. Shigella-Controlled Human Infection Models: Current and Future Perspectives. Curr Top Microbiol Immunol 2022. [PMID: 35616717 DOI: 10.1007/82_2021_248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Shigella-controlled human infection models (CHIMs) are an invaluable tool utilized by the vaccine community to combat one of the leading global causes of infectious diarrhea, which affects infants, children and adults regardless of socioeconomic status. The impact of shigellosis disproportionately affects children in low- and middle-income countries (LMICs) resulting in cognitive and physical stunting, perpetuating a cycle that must be halted. Shigella-CHIMs not only facilitate the early evaluation of enteric countermeasures and up-selection of the most promising products but also provide insight into mechanisms of infection and immunity that are not possible utilizing animal models or in vitro systems. The greater understanding of shigellosis obtained in CHIMs builds and empowers the development of new generation solutions to global health issues which are unattainable in the conventional laboratory and clinical settings. Therefore, refining, mining and expansion of safe and reproducible infection models hold the potential to create effective means to end diarrheal disease and associated co-morbidities associated with Shigella infection.
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Affiliation(s)
- Kristen A Clarkson
- Department of Diarrheal Disease Research, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Chad K Porter
- Enteric Disease Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Kawsar R Talaat
- Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, 624 North Broadway Street Hampton House, Baltimore, MD, 21205, USA
| | - Melissa C Kapulu
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi County Hospital, Off Bofa Road, Kilifi, 80108, Kenya
| | - Wilbur H Chen
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD, 21201, USA
| | - Robert W Frenck
- Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - A Louis Bourgeois
- PATH Center for Vaccine Innovation and Access, 455 Massachusetts Avenue NW, Washington, DC, 20001, USA
| | - Robert W Kaminski
- Department of Diarrheal Disease Research, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Laura B Martin
- GSK Vaccines Institute for Global Health, Via Fiorentina 1, 53100, Siena, Italy.
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Immunization of Rabbits with a Quadrivalent Shigella Bioconjugate Vaccine Induces Functional Antibodies Reactive with Shigella Isolates from Kenya. mSphere 2022; 7:e0102021. [PMID: 35611657 PMCID: PMC9241535 DOI: 10.1128/msphere.01020-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diarrheal diseases are a leading cause of global morbidity and mortality, disproportionately affecting children in resource-limited settings. Although improvements in hygiene and access to clean water are helpful, vaccines are considered essential due to the low infectious dose of Shigella species and increasing antibiotic resistance. Building on achievements with conjugate vaccines, a safe and immunogenic novel bioconjugate vaccine linking Shigella O-antigen to Pseudomonas aeruginosa exoprotein A has been developed to induce immunity against Shigella flexneri 2a, 3a, and 6 and S. sonnei. This study evaluated the breadth of reactivity and functionality of pooled serum from rabbits immunized with monovalent and quadrivalent Shigella bioconjugates formulated with or without an adjuvant against Shigella serotypes isolated in Kenya. Rabbit sera were assayed by colony blot for reactivity with 67 isolates of Shigella serotypes targeted by the vaccine, S. flexneri (2a, 3a, and 6) and S. sonnei, and 42 isolates of Shigella serotypes not targeted by the vaccine, S. flexneri (1b, 2b, 4a, and 4b), S. boydii, and S. dysenteriae. Shigella isolates testing positive in the colony blot assay were then used to assess functional activity using a bactericidal assay. Of the 41 Shigella isolates targeted by the vaccine, 22 were reactive with the adjuvanted quadrivalent and the respective monovalent rabbit sera. The S. flexneri 2a and 3a monovalent rabbit serum cross-reacted with S. flexneri 3a, 2b, and 2a, respectively. Immunization with the adjuvanted quadrivalent vaccine also induced cross-reactivity with isolates of S. flexneri 2b, 4a, and 4b. Collectively, these results suggest that the Shigella quadrivalent vaccine may be more broadly protective than designed, offering a promising solution to Shigella infections. IMPORTANCE Diarrheal diseases are the third leading cause of death globally, disproportionally affecting low- to middle-income countries like Kenya, with Shigella species being the leading cause of bacterial diarrhea, especially in children. The low infectious dose and high antibiotic resistance levels complicate treatment, leading to long-term sequelae that necessitate control measures such as vaccines to reduce morbidity and mortality rates, especially among children under 5 years of age. A quadrivalent bioconjugate Shigella vaccine was recently developed to safely and effectively induce immunity against four important Shigella spp. This study demonstrates the breadth of reactivity and functionality of the parenterally administered bioconjugate vaccine by evaluating the ability of rabbit sera to bind and kill Shigella isolates recently collected in Kenya. These results suggest that the Shigella quadrivalent vaccine may be more broadly protective than designed and may offer a promising solution to the morbidity and mortality associated with Shigella infections.
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7
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van
der Put RMF, Smitsman C, de Haan A, Hamzink M, Timmermans H, Uittenbogaard J, Westdijk J, Stork M, Ophorst O, Thouron F, Guerreiro C, Sansonetti PJ, Phalipon A, Mulard LA. The First-in-Human Synthetic Glycan-Based Conjugate Vaccine Candidate against Shigella. ACS CENTRAL SCIENCE 2022; 8:449-460. [PMID: 35559427 PMCID: PMC9088300 DOI: 10.1021/acscentsci.1c01479] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Indexed: 05/12/2023]
Abstract
Shigella, the causative agent of shigellosis, is among the main causes of diarrheal diseases with still a high morbidity in low-income countries. Relying on chemical synthesis, we implemented a multidisciplinary strategy to design SF2a-TT15, an original glycoconjugate vaccine candidate targeting Shigella flexneri 2a (SF2a). Whereas the SF2a O-antigen features nonstoichiometric O-acetylation, SF2a-TT15 is made of a synthetic 15mer oligosaccharide, corresponding to three non-O-acetylated repeats, linked at its reducing end to tetanus toxoid by means of a thiol-maleimide spacer. We report on the scale-up feasibility under GMP conditions of a high yielding bioconjugation process established to ensure a reproducible and controllable glycan/protein ratio. Preclinical and clinical batches complying with specifications from ICH guidelines, WHO recommendations for polysaccharide conjugate vaccines, and (non)compendial tests were produced. The obtained SF2a-TT15 vaccine candidate passed all toxicity-related criteria, was immunogenic in rabbits, and elicited bactericidal antibodies in mice. Remarkably, the induced IgG antibodies recognized a large panel of SF2a circulating strains. These preclinical data have paved the way forward to the first-in-human study for SF2a-TT15, demonstrating safety and immunogenicity. This contribution discloses the yet unreported feasibility of the GMP synthesis of conjugate vaccines featuring a unique homogeneous synthetic glycan hapten fine-tuned to protect against an infectious disease.
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Affiliation(s)
| | | | - Alex de Haan
- Intravacc, P.O. Box 450, 3720 AL Bilthoven, The Netherlands
| | - Martin Hamzink
- Intravacc, P.O. Box 450, 3720 AL Bilthoven, The Netherlands
| | | | | | - Janny Westdijk
- Intravacc, P.O. Box 450, 3720 AL Bilthoven, The Netherlands
| | - Michiel Stork
- Intravacc, P.O. Box 450, 3720 AL Bilthoven, The Netherlands
| | - Olga Ophorst
- Intravacc, P.O. Box 450, 3720 AL Bilthoven, The Netherlands
| | - Françoise Thouron
- Institut
Pasteur, U1202 Inserm, Unité
de Pathogénie Microbienne Moléculaire, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Catherine Guerreiro
- Institut
Pasteur, Université Paris Cité, CNRS UMR3523, Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Philippe J. Sansonetti
- Institut
Pasteur, U1202 Inserm, Unité
de Pathogénie Microbienne Moléculaire, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
- Chaire
de Microbiologie et Maladies Infectieuses, Collège de France, 11, place Marcelin Berthelot, 75005 Paris, France
| | - Armelle Phalipon
- Institut
Pasteur, U1202 Inserm, Unité
de Pathogénie Microbienne Moléculaire, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Laurence A. Mulard
- Institut
Pasteur, Université Paris Cité, CNRS UMR3523, Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
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Pavlinac PB, Rogawski McQuade ET, Platts-Mills JA, Kotloff KL, Deal C, Giersing BK, Isbrucker RA, Kang G, Ma LF, MacLennan CA, Patriarca P, Steele D, Vannice KS. Pivotal Shigella Vaccine Efficacy Trials-Study Design Considerations from a Shigella Vaccine Trial Design Working Group. Vaccines (Basel) 2022; 10:489. [PMID: 35455238 PMCID: PMC9032541 DOI: 10.3390/vaccines10040489] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 01/27/2023] Open
Abstract
Vaccine candidates for Shigella are approaching phase 3 clinical trials in the target population of young children living in low- and middle-income countries. Key study design decisions will need to be made to maximize the success of such trials and minimize the time to licensure and implementation. We convened an ad hoc working group to identify the key aspects of trial design that would meet the regulatory requirements to achieve the desired indication of prevention of moderate or severe shigellosis due to strains included in the vaccine. The proposed primary endpoint of pivotal Shigella vaccine trials is the efficacy of the vaccine against the first episode of acute moderate or severe diarrhea caused by the Shigella strains contained within the vaccine. Moderate or severe shigellosis could be defined by a modified Vesikari score with dysentery and molecular detection of vaccine-preventable Shigella strains. This report summarizes the rationale and current data behind these considerations, which will evolve as new data become available and after further review and consultation by global regulators and policymakers.
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Affiliation(s)
- Patricia B. Pavlinac
- Departments of Global Health and Epidemiology, University of Washington, Seattle, WA 98105, USA
| | | | - James A. Platts-Mills
- Department of Medicine, Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA;
| | - Karen L. Kotloff
- Department of Pediatrics, Medicine, Epidemiology, and Public Health, University of Maryland, Baltimore, MD 21201, USA;
| | - Carolyn Deal
- Enteric and Sexually Transmitted Infections Branch, National Institutes of Health, Rockvile, MD 20892, USA;
| | - Birgitte K. Giersing
- Immunization, Vaccines, and Biologicals Department, World Health Organization, 1211 Geneva, Switzerland; (B.K.G.); (R.A.I.)
| | - Richard A. Isbrucker
- Immunization, Vaccines, and Biologicals Department, World Health Organization, 1211 Geneva, Switzerland; (B.K.G.); (R.A.I.)
| | - Gagandeep Kang
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore 632004, Tamil Nadu, India;
| | - Lyou-Fu Ma
- Enteric and Diarrheal Diseases Program Strategy Team, Bill & Melinda Gates Foundation, Seattle, WA 98102, USA; (L.-F.M.); (C.A.M.); (D.S.); (K.S.V.)
| | - Calman A. MacLennan
- Enteric and Diarrheal Diseases Program Strategy Team, Bill & Melinda Gates Foundation, Seattle, WA 98102, USA; (L.-F.M.); (C.A.M.); (D.S.); (K.S.V.)
| | - Peter Patriarca
- Bill & Melinda Gates Medical Research Institute, Cambridge, MA 02139, USA;
| | - Duncan Steele
- Enteric and Diarrheal Diseases Program Strategy Team, Bill & Melinda Gates Foundation, Seattle, WA 98102, USA; (L.-F.M.); (C.A.M.); (D.S.); (K.S.V.)
| | - Kirsten S. Vannice
- Enteric and Diarrheal Diseases Program Strategy Team, Bill & Melinda Gates Foundation, Seattle, WA 98102, USA; (L.-F.M.); (C.A.M.); (D.S.); (K.S.V.)
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9
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Sensitive recognition of Shiga toxin using biosensor technology: An efficient platform towards bioanalysis of pathogenic bacterial. Microchem J 2022. [DOI: 10.1016/j.microc.2021.106900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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10
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MacLennan CA. The Background, Role and Approach for Development of a Controlled Human Infection Model for Nontyphoidal Salmonella. Curr Top Microbiol Immunol 2021. [PMID: 34958419 DOI: 10.1007/82_2021_246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nontyphoidal Salmonella (NTS) is responsible for a major global burden of disease and economic loss, particularly in low- and middle-income countries. It is designated a priority pathogen by the WHO for vaccine development and, with new impetus from vaccine developers, the establishment of an NTS controlled human infection model (CHIM) is timely and valuable. The broadly dichotomous clinical presentations of diarrhoea and invasive disease, commonly bacteraemia, present significant challenges to the development of an NTS CHIM. Nevertheless, if successful, such a CHIM will be invaluable for understanding the pathogenesis of NTS disease, identifying correlates of protection and advancing candidate vaccines towards licensure. This article describes the background case for a CHIM for NTS, the role of such a CHIM and outlines a potential approach to its development.
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Affiliation(s)
- Calman A MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK.
- Bill & Melinda Gates Foundation, 62 Buckingham Gate, London, SW16AJ, UK.
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11
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Porter CK, Talaat KR, Isidean SD, Kardinaal A, Chakraborty S, Gutiérrez RL, Sack DA, Bourgeois AL. The Controlled Human Infection Model for Enterotoxigenic Escherichia coli. Curr Top Microbiol Immunol 2021. [PMID: 34669040 DOI: 10.1007/82_2021_242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The controlled human infection model (CHIM) for enterotoxigenic Escherichia coli (ETEC) has been instrumental in defining ETEC as a causative agent of acute watery diarrhea, providing insights into disease pathogenesis and resistance to illness, and enabling preliminary efficacy evaluations for numerous products including vaccines, immunoprophylactics, and drugs. Over a dozen strains have been evaluated to date, with a spectrum of clinical signs and symptoms that appear to replicate the clinical illness seen with naturally occurring ETEC. Recent advancements in the ETEC CHIM have enhanced the characterization of clinical, immunological, and microbiological outcomes. It is anticipated that omics-based technologies applied to ETEC CHIMs will continue to broaden our understanding of host-pathogen interactions and facilitate the development of primary and secondary prevention strategies.
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Affiliation(s)
- Chad K Porter
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, 20910, USA.
| | - Kawsar R Talaat
- Center for Immunization Research, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Sandra D Isidean
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, 20910, USA
- Henry M. Jackson Foundation, Bethesda, MD, 20817, USA
| | - Alwine Kardinaal
- NIZO Food Research, Ede, P.O. Box 20, 6710 BA EDE, Kernhemseweg 2, 6718 ZB EDE, The Netherlands
| | - Subhra Chakraborty
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - Ramiro L Gutiérrez
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD, 20910, USA
| | - David A Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA
| | - A Louis Bourgeois
- PATH|Center for Vaccine Innovation and Access, 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001, USA
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12
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Eyvazi S, Baradaran B, Mokhtarzadeh A, Guardia MDL. Recent advances on development of portable biosensors for monitoring of biological contaminants in foods. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.06.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Shigella-Specific Immune Profiles Induced after Parenteral Immunization or Oral Challenge with Either Shigella flexneri 2a or Shigella sonnei. mSphere 2021; 6:e0012221. [PMID: 34259559 PMCID: PMC8386581 DOI: 10.1128/msphere.00122-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigella spp. are a leading cause of diarrhea-associated global morbidity and mortality. Development and widespread implementation of an efficacious vaccine remain the best option to reduce Shigella-specific morbidity. Unfortunately, the lack of a well-defined correlate of protection for shigellosis continues to hinder vaccine development efforts. Shigella controlled human infection models (CHIM) are often used in the early stages of vaccine development to provide preliminary estimates of vaccine efficacy; however, CHIMs also provide the opportunity to conduct in-depth immune response characterizations pre- and postvaccination or pre- and postinfection. In the current study, principal-component analyses were used to examine immune response data from two recent Shigella CHIMs in order to characterize immune response profiles associated with parenteral immunization, oral challenge with Shigella flexneri 2a, or oral challenge with Shigella sonnei. Although parenteral immunization induced an immune profile characterized by robust systemic antibody responses, it also included mucosal responses. Interestingly, oral challenge with S. flexneri 2a induced a distinctively different profile compared to S. sonnei, characterized by a relatively balanced systemic and mucosal response. In contrast, S. sonnei induced robust increases in mucosal antibodies with no differences in systemic responses across shigellosis outcomes postchallenge. Furthermore, S. flexneri 2a challenge induced significantly higher levels of intestinal inflammation compared to S. sonnei, suggesting that both serotypes may also differ in how they trigger induction and activation of innate immunity. These findings could have important implications for Shigella vaccine development as protective immune mechanisms may differ across Shigella serotypes. IMPORTANCE Although immune correlates of protection have yet to be defined for shigellosis, prior studies have demonstrated that Shigella infection provides protection against reinfection in a serotype-specific manner. Therefore, it is likely that subjects with moderate to severe disease post-oral challenge would be protected from a homologous rechallenge, and investigating immune responses in these subjects may help identify immune markers associated with the development of protective immunity. This is the first study to describe distinct innate and adaptive immune profiles post-oral challenge with two different Shigella serotypes. Analyses conducted here provide essential insights into the potential of different immune mechanisms required to elicit protective immunity, depending on the Shigella serotype. Such differences could have significant impacts on vaccine design and development within the Shigella field and should be further investigated across multiple Shigella serotypes.
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Alegun O, Pandeya A, Cui J, Ojo I, Wei Y. Donnan Potential across the Outer Membrane of Gram-Negative Bacteria and Its Effect on the Permeability of Antibiotics. Antibiotics (Basel) 2021; 10:antibiotics10060701. [PMID: 34208097 PMCID: PMC8230823 DOI: 10.3390/antibiotics10060701] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/16/2022] Open
Abstract
The cell envelope structure of Gram-negative bacteria is unique, composed of two lipid bilayer membranes and an aqueous periplasmic space sandwiched in between. The outer membrane constitutes an extra barrier to limit the exchange of molecules between the cells and the exterior environment. Donnan potential is a membrane potential across the outer membrane, resulted from the selective permeability of the membrane, which plays a pivotal role in the permeability of many antibiotics. In this review, we discussed factors that affect the intensity of the Donnan potential, including the osmotic strength and pH of the external media, the osmoregulated periplasmic glucans trapped in the periplasmic space, and the displacement of cell surface charges. The focus of our discussion is the impact of Donnan potential on the cellular permeability of selected antibiotics including fluoroquinolones, tetracyclines, β-lactams, and trimethoprim.
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Affiliation(s)
| | | | | | | | - Yinan Wei
- Correspondence: ; Tel.: +1-8592577085
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Arnold SLM. Target Product Profile and Development Path for Shigellosis Treatment with Antibacterials. ACS Infect Dis 2021; 7:948-958. [PMID: 33689318 DOI: 10.1021/acsinfecdis.0c00889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Enteric infection with Shigella spp. can lead to symptoms ranging from acute watery diarrhea to sudden, severe dysentery. Approximately 212 000 diarrheal deaths annually are attributed to Shigella with a disproportionate impact in low-resource countries. The impact in under-resourced countries was illustrated by a reanalysis of the Global Enteric Multicenter Study which found that Shigella was the leading pathogen associated with moderate-to severe diarrhea in children under 5 years old. While recent studies have highlighted the burden of the disease, there has been a concurrent reduction in therapeutic options for the treatment of shigellosis as drug resistant strains increase in prevalence. In addition, increasing reports of drug resistant shigellosis cases in the men who have sex with men community confirm that the impact is not limited to low-resource countries. Despite the urgent need for new treatments, a target product profile (TPP) has not been established, and there is no clear development path for antibacterial treatments. To address this troubling concern, this manuscript describes a TPP for antishigellosis small molecule therapeutics and a development path that integrates currently available preclinical and clinical models of Shigella infection.
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Affiliation(s)
- Samuel L. M. Arnold
- Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases, University of Washington School of Medicine, Seattle, Washington 98109, United States
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Raqib R, Venkatesan M. Shigella conjugate vaccine efficacy trial in controlled human model and potential immune correlates of protection. EBioMedicine 2021; 66:103343. [PMID: 33873142 PMCID: PMC8082079 DOI: 10.1016/j.ebiom.2021.103343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Rubhana Raqib
- Infectious Diseases Division, icddr,b, Dhaka, Bangladesh
| | - Malabi Venkatesan
- Department of Enteric Infections, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Maryland, USA (recently retired)
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Talaat KR, Alaimo C, Martin P, Bourgeois AL, Dreyer AM, Kaminski RW, Porter CK, Chakraborty S, Clarkson KA, Brubaker J, Elwood D, Frölich R, DeNearing B, Weerts H, Feijoo BL, Halpern J, Sack D, Riddle MS, Fonck VG. Human challenge study with a Shigella bioconjugate vaccine: Analyses of clinical efficacy and correlate of protection. EBioMedicine 2021; 66:103310. [PMID: 33862589 PMCID: PMC8054157 DOI: 10.1016/j.ebiom.2021.103310] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/15/2021] [Accepted: 03/12/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Shigellosis is a major cause of moderate to severe diarrhoea and dysentery in children under 5 years of age in low and middle-income countries. The Flexyn2a vaccine conjugates the O-polysaccharide of Shigella flexneri 2a to Pseudomonas aeruginosa exotoxin A. We describe a Phase 2b proof-of-concept challenge study that evaluated safety, immunogenicity, and efficacy of the Flexyn2a vaccine to protect against shigellosis. METHODS In this randomized, double blind, placebo-controlled trial, healthy adults were randomized 1:1 to receive Flexyn2a (10 µg) or placebo intramuscularly, twice, 4 weeks apart, followed by challenge 4 weeks later with 1500 colony forming units (CFUs) of S. flexneri 2a strain 2457T. The primary outcome was vaccine-induced protection. S. flexneri 2a lipopolysaccharide (LPS)-specific immune responses were assessed. FINDINGS Sixty-seven subjects were enrolled, 34 received vaccine and 33 placebo. The vaccine was well tolerated; the majority of adverse events were mild in nature. Thirty vaccinees and 29 placebo recipients received the S. flexneri 2a challenge. Vaccination resulted in a 30.2% reduction in shigellosis compared with placebo (13/30 vs. 18/29; p = 0.11; 95% CI -15 to 62.6). Vaccine efficacy was more robust against severe disease, reaching 51.7% (p = 0.015, 95% CI 5.3 to 77.9) against moderate/severe diarrhoea or dysentery concurrent with fever or severe enteric symptoms and 72.4% (p = 0.07) against more severe diarrhoea (≥10 lose stools or ≥1000 g loose stools/24 h). Vaccinated subjects were less likely to need early antibiotic intervention following challenge (protective efficacy 51.7%, p = 0.01; 95% CI 9 to 76.8). In those who developed shigellosis, vaccinated subjects had a lower disease severity score (p = 0.002) than placebo-recipients. Additionally, LPS-specific serum IgG responses in Flexyn2a recipients were associated with protection against disease (p = 0.0016) and with a decreased shigellosis disease score (p = 0.002). INTERPRETATION The Flexyn2a bioconjugate vaccine was immunogenic, well tolerated and protected against severe illness after Shigella challenge and is a promising Shigella vaccine construct. We identified a strong association between anti-S. flexneri 2a serum IgG and a reduction in disease outcomes. (Clinicaltrials.gov, NCT02646371.) FUNDING: Funding for this study was through a grant from the Wellcome Trust.
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Affiliation(s)
- Kawsar R Talaat
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.
| | | | | | - A Louis Bourgeois
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States; Now at PATH Center for Vaccine Innovation and Access, Washington, DC, United States
| | | | - Robert W Kaminski
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Chad K Porter
- Naval Medical Research Center, Silver Spring, MD, United States
| | - Subhra Chakraborty
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Kristen A Clarkson
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Jessica Brubaker
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Daniel Elwood
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | | | - Barbara DeNearing
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Hailey Weerts
- Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Brittany L Feijoo
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Jane Halpern
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - David Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Mark S Riddle
- Naval Medical Research Center, Silver Spring, MD, United States
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Clarkson KA, Talaat KR, Alaimo C, Martin P, Bourgeois AL, Dreyer A, Porter CK, Chakraborty S, Brubaker J, Elwood D, Frölich R, DeNearing B, Weerts HP, Feijoo B, Halpern J, Sack D, Riddle MS, Fonck VG, Kaminski RW. Immune response characterization in a human challenge study with a Shigella flexneri 2a bioconjugate vaccine. EBioMedicine 2021; 66:103308. [PMID: 33813141 PMCID: PMC8047506 DOI: 10.1016/j.ebiom.2021.103308] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 02/13/2021] [Accepted: 03/12/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Diarrheal diseases are a leading cause of global morbidity and mortality affecting all ages, but especially children under the age of five in resource-limited settings. Shigella is a leading contributor to diarrheal diseases caused by bacterial pathogens and is considered a significant antimicrobial resistance threat. While improvements in hygiene, and access to clean water help as control measures, vaccination remains one of the most viable options for significantly reducing morbidity and mortality. METHODS Flexyn2a is a bioconjugate vaccine manufactured using novel conjugation methodologies enzymatically linking the O-polysaccharide of S. flexneri 2a to exotoxin A of Pseudomonas aeruginosa. The protective capacity of Flexyn2a was assessed in a controlled human infection model after two intramuscular immunizations. Immune responses pre- and post-immunization and/or infection were investigated and are described here. FINDINGS Flexyn2a induced lipopolysaccharide (LPS)-specific serum IgG responses post-immunization which were associated with protection against shigellosis. Additionally, several other immune parameters, including memory B cell responses, bactericidal antibodies and serum IgA, were also elevated in vaccinees protected against shigellosis. Immunization with Flexyn2a also induced gut-homing, LPS-specific IgG and IgA secreting B cells, indicating the vaccine induced immune effectors functioning at the site of intestinal infection. INTERPRETATION Collectively, the results of these immunological investigations provide insights into protective immune mechanisms post-immunization with Flexyn2a which can be used to further guide vaccine development and may have applicability to the larger Shigella vaccine field. FUNDING Funding for this study was provided through a Wellcome Trust grant.
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Affiliation(s)
- Kristen A Clarkson
- Department of Enteric Infections, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Kawsar R Talaat
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | | | | | | | | | - Chad K Porter
- Naval Medical Research Center, Silver Spring, MD, United States
| | - Subhra Chakraborty
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Jessica Brubaker
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Daniel Elwood
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | | | - Barbara DeNearing
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Hailey P Weerts
- Department of Enteric Infections, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Brittany Feijoo
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Jane Halpern
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - David Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
| | - Mark S Riddle
- Naval Medical Research Center, Silver Spring, MD, United States
| | | | - Robert W Kaminski
- Department of Enteric Infections, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States.
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Peng Y, Yin S, Wang M. Extracellular vesicles of bacteria as potential targets for immune interventions. Hum Vaccin Immunother 2021; 17:897-903. [PMID: 32873124 DOI: 10.1080/21645515.2020.1799667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacterial infection is one of the most common and serious diseases. Extracellular vesicles (EVs) expressed by bacterial cells during infection and their biological functions have been a growing field in recent years. The study of the immune interaction mechanism between EVs and bacteria has become more significant. EVs are released into the extracellular microenvironment during bacterial infection. EVs carry various lipids, proteins, nucleic acids, and other substances of host bacteria and participate in various physiological and pathological processes. EV-based vaccines against bacterial infection are also being evaluated. This review focuses on the biological characteristics of EVs, the interaction between EVs and the host immune system, and the potential of EVs as new vaccines. A deeper understanding of the interaction between EVs and the immune system informs on the biological function and heterogeneity of EVs. This knowledge also can facilitate the development and application of EVs and their potential as vaccines.
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Affiliation(s)
- Yizhi Peng
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Sheng Yin
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Min Wang
- Department of Laboratory Medicine, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
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Abstract
Shigella is a major cause of moderate to severe diarrhea largely affecting children (<5 years old) living in low- and middle-income countries. Several vaccine candidates are in development, and controlled human infection models (CHIMs) can be useful tools to provide an early assessment of vaccine efficacy and potentially support licensure. A lyophilized strain of S. sonnei 53G was manufactured and evaluated to establish a dose that safely and reproducibly induced a ≥60% attack rate. Samples were collected pre- and postchallenge to assess intestinal inflammatory responses, antigen-specific serum and mucosal antibody responses, functional antibody responses, and memory B cell responses. Infection with S. sonnei 53G induced a robust intestinal inflammatory response as well as antigen-specific antibodies in serum and mucosal secretions and antigen-specific IgA- and IgG-secreting B cells positive for the α4β7 gut-homing marker. There was no association between clinical disease outcomes and systemic or functional antibody responses postchallenge; however, higher lipopolysaccharide (LPS)-specific serum IgA- and IgA-secreting memory B cell responses were associated with a reduced risk of disease postchallenge. This study provides unique insights into the immune responses pre- and postinfection with S. sonnei 53G in a CHIM, which could help guide the rational design of future vaccines to induce protective immune responses more analogous to those triggered by infection.IMPORTANCE Correlate(s) of immunity have yet to be defined for shigellosis. As previous disease protects against subsequent infection in a serotype-specific manner, investigating immune response profiles pre- and postinfection provides an opportunity to identify immune markers potentially associated with the development of protective immunity and/or with a reduced risk of developing shigellosis postchallenge. This study is the first to report such an extensive characterization of the immune response after challenge with S. sonnei 53G. Results demonstrate an association of progression to shigellosis with robust intestinal inflammatory and mucosal gut-homing responses. An important finding in this study was the association of elevated Shigella LPS-specific serum IgA and memory B cell IgA responses at baseline with reduced risk of disease. The increased baseline IgA responses may contribute to the lack of dose response observed in the study and suggests that IgA responses should be further investigated as potential correlates of immunity.
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21
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Establishment of a Controlled Human Infection Model with a Lyophilized Strain of Shigella sonnei 53G. mSphere 2020; 5:5/5/e00416-20. [PMID: 32968005 PMCID: PMC7568646 DOI: 10.1128/msphere.00416-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Controlled human infection models (CHIMs) are invaluable tools utilized to understand the human response to infection, potentially leading to protective immune mechanisms and allowing efficacy testing of enteric countermeasures, including vaccines, antibiotics, and other products. The development of an improved Shigella CHIM for both Shigella sonnei and Shigella flexneri is consistent with international efforts, supported by international donors and the World Health Organization, focused on standardizing Shigella CHIMs and using them to accelerate Shigella vaccine development. The use of lyophilized Shigella challenge strains rather than plate-grown inoculum preparations is considered an important step forward in the standardization process. Furthermore, the results of studies such as this justify the development of lyophilized preparations for additional epidemiologically important S. flexneri serotypes, including S. flexneri 3a and S. flexneri 6. Controlled human infection models (CHIMs) are useful for vaccine development. To improve on existing models, we developed a CHIM using a lyophilized preparation of Shigella sonnei strain 53G produced using current good manufacturing practice (cGMP). Healthy adults were enrolled in an open-label dose-ranging study. Following administration of a dose of rehydrated S. sonnei strain 53G, subjects were monitored for development of disease. The first cohort received 500 CFU of 53G, and dosing of subsequent cohorts was based on results from the previous cohort. Subjects were administered ciprofloxacin on day 5 and discharged home on day 8. Subjects returned as outpatients for clinical checks and sample collection. Attack rates increased as the dose of S. sonnei was increased. Among those receiving the highest dose (1,760 CFU), 70% developed moderate to severe diarrhea, 50% had dysentery, and 40% had fever. Antilipopolysaccharide responses were observed across all cohorts. An S. sonnei CHIM using a lyophilized lot of strain 53G was established. A dose in the range of 1,500 to 2,000 CFU of 53G was selected as the dose for future challenge studies using this product. This model will enable direct comparison of study results between institutions and ensure better consistency over time in the challenge inoculum. IMPORTANCE Controlled human infection models (CHIMs) are invaluable tools utilized to understand the human response to infection, potentially leading to protective immune mechanisms and allowing efficacy testing of enteric countermeasures, including vaccines, antibiotics, and other products. The development of an improved Shigella CHIM for both Shigella sonnei and Shigella flexneri is consistent with international efforts, supported by international donors and the World Health Organization, focused on standardizing Shigella CHIMs and using them to accelerate Shigella vaccine development. The use of lyophilized Shigella challenge strains rather than plate-grown inoculum preparations is considered an important step forward in the standardization process. Furthermore, the results of studies such as this justify the development of lyophilized preparations for additional epidemiologically important S. flexneri serotypes, including S. flexneri 3a and S. flexneri 6.
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Bekeredjian-Ding I, Van Molle W, Baay M, Neels P. Human challenge trial workshop: Focus on quality requirements for challenge agents, Langen, Germany, October 22, 2019. Biologicals 2020; 66:53-61. [PMID: 32389512 DOI: 10.1016/j.biologicals.2020.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 01/01/2023] Open
Abstract
Controlled human infection models can be helpful to study pathogenesis and immune responses as a basis for the development of vaccines. In controlled human infection models, human challenge agents are used to infect healthy volunteers, therefore, ethical considerations include that the exposure studies need to be safe and results should be meaningful, e.g. contribute to a better cure. Both in the US and in Europe, the level of Good Manufacturing Practice required is related to the phase of the study ('sliding scale Good Manufacturing Practice'), and, hence, is much more open to speedy drug development than anticipated. Recommendations included: the development of guidelines for human challenge agents; a focus on strain selection, in particular with regard to strain infectivity, stability and purity; the use of whole genome sequencing; a reference repository of challenge agents, the need for early exchange with regulators to ensure acceptability of strain selection and manufacturing for later drug development; sharing of models and challenge agents.
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Affiliation(s)
- Isabelle Bekeredjian-Ding
- Paul-Ehrlich-Institut (PEI), Langen, Germany; Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.
| | | | - Marc Baay
- P95 Epidemiology & Pharmacovigilance, Leuven, Belgium.
| | - Pieter Neels
- International Alliance for Biological Standardization (IABS), Belgium.
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