1
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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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2
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Dayananda P, Chiu C, Openshaw P. Controlled Human Infection Challenge Studies with RSV. Curr Top Microbiol Immunol 2022. [PMID: 35704096 DOI: 10.1007/82_2022_257] [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
Despite considerable momentum in the development of RSV vaccines and therapeutics, there remain substantial barriers to the development and licensing of effective agents, particularly in high-risk populations. The unique immunobiology of RSV and lack of clear protective immunological correlates has held back RSV vaccine development, which, therefore, depends on large and costly clinical trials to demonstrate efficacy. Studies involving the deliberate infection of human volunteers offer an intermediate step between pre-clinical and large-scale studies of natural infection. Human challenge has been used to demonstrate the potential efficacy of vaccines and antivirals while improving our understanding of the protective immunity against RSV infection. Early RSV human infection challenge studies determined the role of routes of administration and size of inoculum on the disease. However, inherent limitations, the use of highly attenuated/laboratory-adapted RSV strains and the continued evolutionary adaptation of RSV limits extrapolation of results to present-day vaccine testing. With advances in technology, it is now possible to perform more detailed investigations of human mucosal immunity against RSV in experimentally infected adults and, more recently, older adults to optimise the design of vaccines and novel therapies. These studies identified defects in RSV-induced humoral and CD8+ T cell immunity that may partly explain susceptibility to recurrent RSV infection. We discuss the insights from human infection challenge models, ethical and logistical considerations, potential benefits, and role in streamlining and accelerating novel antivirals and vaccines against RSV. Finally, we consider how human challenges might be extended to include relevant at-risk populations.
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Affiliation(s)
- Pete Dayananda
- Department of Infectious Disease, Imperial College London, London, UK
| | - Christopher Chiu
- Department of Infectious Disease, Imperial College London, London, UK.
| | - Peter Openshaw
- National Heart and Lung Institute, Imperial College London, London, UK
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3
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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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4
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Santiago HC, Pereira-Neto TA, Gonçalves-Pereira MH, Terzian ACB, Durbin AP. Peculiarities of Zika Immunity and Vaccine Development: Lessons from Dengue and the Contribution from Controlled Human Infection Model. Pathogens 2022; 11:pathogens11030294. [PMID: 35335618 PMCID: PMC8951202 DOI: 10.3390/pathogens11030294] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/10/2022] [Accepted: 02/15/2022] [Indexed: 01/27/2023] Open
Abstract
The Zika virus (ZIKV) was first isolated from a rhesus macaque in the Zika forest of Uganda in 1947. Isolated cases were reported until 2007, when the first major outbreaks of Zika infection were reported from the Island of Yap in Micronesia and from French Polynesia in 2013. In 2015, ZIKV started to circulate in Latin America, and in 2016, ZIKV was considered by WHO to be a Public Health Emergency of International Concern due to cases of Congenital Zika Syndrome (CZS), a ZIKV-associated complication never observed before. After a peak of cases in 2016, the infection incidence dropped dramatically but still causes concern because of the associated microcephaly cases, especially in regions where the dengue virus (DENV) is endemic and co-circulates with ZIKV. A vaccine could be an important tool to mitigate CZS in endemic countries. However, the immunological relationship between ZIKV and other flaviviruses, especially DENV, and the low numbers of ZIKV infections are potential challenges for developing and testing a vaccine against ZIKV. Here, we discuss ZIKV vaccine development with the perspective of the immunological concerns implicated by DENV-ZIKV cross-reactivity and the use of a controlled human infection model (CHIM) as a tool to accelerate vaccine development.
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Affiliation(s)
- Helton C. Santiago
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 30270-901, MG, Brazil; (T.A.P.-N.); (M.H.G.-P.)
- Correspondence: ; Tel.: +55-31-3409-2664
| | - Tertuliano A. Pereira-Neto
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 30270-901, MG, Brazil; (T.A.P.-N.); (M.H.G.-P.)
| | - Marcela H. Gonçalves-Pereira
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 30270-901, MG, Brazil; (T.A.P.-N.); (M.H.G.-P.)
| | - Ana C. B. Terzian
- Laboratory of Cellular Immunology, Rene Rachou Institute, Fiocruz, Belo Horizonte 30190-002, MG, Brazil;
| | - Anna P. Durbin
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA;
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Erdem R, Ambler G, Al-Ibrahim M, Fraczek K, Dong SD, Gast C, Mercer LD, Raine M, Tennant SM, Chen WH, de Hostos EL, Choy RKM. A Phase 2a randomized, single-center, double-blind, placebo-controlled study to evaluate the safety and preliminary efficacy of oral iOWH032 against cholera diarrhea in a controlled human infection model. PLoS Negl Trop Dis 2021; 15:e0009969. [PMID: 34793441 PMCID: PMC8639072 DOI: 10.1371/journal.pntd.0009969] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 12/02/2021] [Accepted: 11/03/2021] [Indexed: 11/23/2022] Open
Abstract
Cholera remains a major cause of infectious diarrhea globally. Despite the increased availability of cholera vaccines, there is still an urgent need for other effective interventions to reduce morbidity and mortality. Furthermore, increased prevalence of antibiotic-resistant Vibrio cholerae threatens the use of many drugs commonly used to treat cholera. We developed iOWH032, a synthetic small molecule inhibitor of the cystic fibrosis transmembrane conductance regulator chloride channel, as an antisecretory, host-directed therapeutic for cholera. In the study reported here, we tested iOWH032 in a Phase 2a cholera controlled human infection model. Forty-seven subjects were experimentally infected with V. cholerae El Tor Inaba strain N16961 in an inpatient setting and randomized to receive 500 mg iOWH032 or placebo by mouth every 8 hours for 3 days to determine the safety and efficacy of the compound as a potential treatment for cholera. We found that iOWH032 was generally safe and achieved a mean (± standard deviation) plasma level of 4,270 ng/mL (±2,170) after 3 days of oral dosing. However, the median (95% confidence interval) diarrheal stool output rate for the iOWH032 group was 25.4 mL/hour (8.9, 58.3), compared to 32.6 mL/hour (15.8, 48.2) for the placebo group, a reduction of 23%, which was not statistically significant. There was also no significant decrease in diarrhea severity and number or frequency of stools associated with iOWH032 treatment. We conclude that iOWH032 does not merit future development for treatment of cholera and offer lessons learned for others developing antisecretory therapeutic candidates that seek to demonstrate proof of principle in a cholera controlled human infection model study. Trial registration: This study is registered with ClinicalTrials.gov as NCT04150250. Cholera, a disease caused by infection with the bacterium Vibrio cholerae, remains a major cause of diarrheal illness and death, particularly in settings with poor sanitation and hygiene. We developed a synthetic chemical, named “iOWH032,” as a potential treatment for cholera, which is administered as oral tablets. The chemical acts by blocking secretions from cells in the intestine, and thereby was expected to prevent fluid loss and dehydration caused by cholera illness. We tested iOWH032 in a clinical study using a cholera human challenge model. Study volunteers were intentionally infected with V. cholerae in an inpatient clinic setting to better study the effects of iOWH032 on infected individuals. This challenge model had been used previously to test cholera vaccine candidates, but this study represents the first test of a potential cholera treatment using the model. We found that treatment of individuals with iOWH032 was safe, but did not result in a significant reduction of cholera illness, based on several different measurements of diarrheal symptoms and severity. This study demonstrates how human challenge models incorporating a relatively small number of subjects can help support decision-making about potential new therapeutics and other interventions for infectious diseases.
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Affiliation(s)
- Rahsan Erdem
- PATH, Seattle, Washington, United States of America
| | - Gwen Ambler
- PATH, Seattle, Washington, United States of America
| | | | | | | | | | | | | | - Sharon M. Tennant
- Center for Vaccine Development and Global Health, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Wilbur H. Chen
- Center for Vaccine Development and Global Health, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
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Kunda-Ng'andu EM, Simuyandi M, Kapulu M, Chirwa-Chobe M, Mwanyungwi-Chinganya H, Mwale S, Chilengi R, Sharma A. Engagement of ethics and regulatory authorities on human infection studies: Proceedings of an engagement workshop in Zambia. Wellcome Open Res 2021; 6:31. [PMID: 33824912 PMCID: PMC7993625 DOI: 10.12688/wellcomeopenres.16432.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2021] [Indexed: 11/23/2022] Open
Abstract
Human infection studies (HIS) have generally been used as a tool in the pathway for vaccine development in high income settings. Over the last decade, this model has been implemented in LMICs with the aim of accelerating development of next generation vaccines that would perform better in these settings. However, in most LMICs, the ethics and regulatory framework for the conduct of these studies are not in place. In Zambia, these studies are yet to be conducted and thus we conducted a stakeholder engagement workshop in October 2019. We engaged with bioethicists, regulatory authority officials, and scientists from within Zambia and other African countries to anticipate and address foreseeable ethical and regulatory issues when conducting HIS in Zambia for the first time. The workshop largely focused on sensitizing the stakeholders on the benefits of these studies with the following main points for consideration on the implementation of these studies in Zambia: need for in-country legal framework and guidelines; need for adequate informed consent based on comprehensive understanding of the concept of HIS and study requirements; and requirements for heightened vigilance to assure participant safety including good ethical and clinical practice with regulatory, ethical, data safety, and community oversight. Additionally, the workshop emphasized the need for rigorous health screening prior to enrolment; suitable infrastructure for containment; and personnel to provide appropriate treatment including emergency resuscitation and evacuation if indicated. Specific recommendations included compensation for burden of participation; access to care and provision for study related injury (e.g. no-fault insurance); and withdrawal and exit procedures to preserve individual and community safety. Finally, the meeting concluded that researchers should actively engage key gate keepers including civic leaders such as parliamentarians, universities, researchers, potential participants and laypersons to avoid circulation of misinformation.
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Affiliation(s)
| | - Michelo Simuyandi
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Melissa Kapulu
- Biosciences, KEMRI-Wellcome trust research Programme, Kilifi, Kenya.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Masuzyo Chirwa-Chobe
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Hope Mwanyungwi-Chinganya
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Stanley Mwale
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Roma Chilengi
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Anjali Sharma
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
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7
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Dissecting serotype-specific contributions to live oral cholera vaccine efficacy. Proc Natl Acad Sci U S A 2021; 118:2018032118. [PMID: 33558237 DOI: 10.1073/pnas.2018032118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The O1 serogroup of Vibrio cholerae causes pandemic cholera and is divided into the Ogawa and Inaba serotypes. The O-antigen is V. cholerae's immunodominant antigen, and the two serotypes, which differ by the presence or absence of a terminally methylated O-antigen, likely influence development of immunity to cholera and oral cholera vaccines (OCVs). However, there is no consensus regarding the relative immunological potency of each serotype, in part because previous studies relied on genetically heterogeneous strains. Here, we engineered matched serotype variants of a live OCV candidate, HaitiV, and used a germfree mouse model to evaluate the immunogenicity and protective efficacy of each vaccine serotype. By combining vibriocidal antibody quantification with single- and mixed-strain infection assays, we found that all three HaitiV variants-InabaV, OgawaV, and HikoV (bivalent Inaba/Ogawa)-were immunogenic and protective. None of the vaccine serotypes were superior across both of these vaccine metrics, suggesting that the impact of O1-serotype variation in OCV design, although detectable, is subtle. However, all three live vaccines significantly outperformed formalin-killed HikoV, supporting the idea that live OCV usage will bolster current cholera control practices. The potency of OCVs was found to be challenge strain-dependent, emphasizing the importance of appropriate strain selection for cholera challenge studies. Our findings and experimental approaches will be valuable for guiding the development of live OCVs and oral vaccines for additional pathogens.
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8
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Kunda-Ng'andu EM, Simuyandi M, Kapulu M, Chirwa-Chobe M, Mwanyungwi-Chinganya H, Mwale S, Chilengi R, Sharma A. Engagement of ethics and regulatory authorities on human infection studies: Proceedings of an engagement workshop in Zambia. Wellcome Open Res 2021; 6:31. [PMID: 33824912 DOI: 10.12688/wellcomeopenres.16432.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2021] [Indexed: 11/20/2022] Open
Abstract
Human infection studies (HIS) have generally been used as a tool in the pathway for vaccine development in high income settings. Over the last decade, this model has been implemented in LMICs with the aim of accelerating development of next generation vaccines that would perform better in these settings. However, in most LMICs, the ethics and regulatory framework for the conduct of these studies are not in place. In Zambia, these studies are yet to be conducted and thus we conducted a stakeholder engagement workshop in October 2019. We engaged with bioethicists, regulatory authority, and scientists from within Zambia and other African countries to anticipate and address foreseeable ethical and regulatory issues when conducting HIS in Zambia for the first time. The workshop largely focused on sensitizing the stakeholders on the benefits of these studies with the following main points for consideration on the implementation of these studies in Zambia: need for in-country legal framework and guidelines; need for adequate informed consent based on comprehensive understanding of the concept of HIS and study requirements; and requirements for heightened vigilance to assure participant safety including good ethical and clinical practice with regulatory, ethical, data safety, and community oversight. Additionally, the workshop emphasized the need for rigorous health screening prior to enrolment; suitable infrastructure for containment; and personnel to provide appropriate treatment including emergency resuscitation and evacuation if indicated. Specific recommendations included compensation for burden of participation; access to care and provision for study related injury (e.g. no-fault insurance); and withdrawal and exit procedures to preserve individual and community safety. Finally, the meeting concluded that researchers should actively engage key gate keepers including civic leaders such as parliamentarians, universities, researchers, potential participants and laypersons to avoid circulation of misinformation.
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Affiliation(s)
| | - Michelo Simuyandi
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Melissa Kapulu
- Biosciences, KEMRI-Wellcome trust research Programme, Kilifi, Kenya.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Masuzyo Chirwa-Chobe
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Hope Mwanyungwi-Chinganya
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Stanley Mwale
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Roma Chilengi
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
| | - Anjali Sharma
- Research Department, The centre for Infectious Disease Research in Zambia, Lusaka, Zambia, 10101, Zambia
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Kirchhelle C, Vanderslott S. Editorial: The Need for Harmonised International Guidelines ahead of COVID-19 Human Infection Studies. Public Health Rev 2021; 42:1603962. [PMID: 33796341 PMCID: PMC7904247 DOI: 10.3389/phrs.2021.1603962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Claas Kirchhelle
- University College Dublin, Dublin, United Kingdom
- Oxford Martin School, University of Oxford, Oxford, United Kingdom
| | - Samantha Vanderslott
- Oxford Vaccine Group and Oxford Martin School, University of Oxford, Oxford, United Kingdom
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Berry DA, Berry S, Hale P, Isakov L, Lo AW, Siah KW, Wong CH. A cost/benefit analysis of clinical trial designs for COVID-19 vaccine candidates. PLoS One 2020; 15:e0244418. [PMID: 33362278 PMCID: PMC7757868 DOI: 10.1371/journal.pone.0244418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 12/09/2020] [Indexed: 01/08/2023] Open
Abstract
We compare and contrast the expected duration and number of infections and deaths averted among several designs for clinical trials of COVID-19 vaccine candidates, including traditional and adaptive randomized clinical trials and human challenge trials. Using epidemiological models calibrated to the current pandemic, we simulate the time course of each clinical trial design for 756 unique combinations of parameters, allowing us to determine which trial design is most effective for a given scenario. A human challenge trial provides maximal net benefits-averting an additional 1.1M infections and 8,000 deaths in the U.S. compared to the next best clinical trial design-if its set-up time is short or the pandemic spreads slowly. In most of the other cases, an adaptive trial provides greater net benefits.
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Affiliation(s)
- Donald A. Berry
- Department of Biostatistics, University of Texas, Houston, Texas, United States of America
- Berry Consultants, Austin, Texas, United States of America
| | - Scott Berry
- Berry Consultants, Austin, Texas, United States of America
| | - Peter Hale
- The Foundation for Vaccine Research, Washington, D.C., United States of America
| | - Leah Isakov
- Seqirus, Cambridge, Massachusetts, United States of America
| | - Andrew W. Lo
- MIT Sloan School of Management, Cambridge, Massachusetts, United States of America
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Kien Wei Siah
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Chi Heem Wong
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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Xu H, Alzhrani RF, Warnken ZN, Thakkar SG, Zeng M, Smyth HDC, Williams RO, Cui Z. Immunogenicity of Antigen Adjuvanted with AS04 and Its Deposition in the Upper Respiratory Tract after Intranasal Administration. Mol Pharm 2020; 17:3259-3269. [PMID: 32787271 DOI: 10.1021/acs.molpharmaceut.0c00372] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Adjuvant system 04 (AS04) is in injectable human vaccines. AS04 contains two known adjuvants, 3-O-desacyl-4'-monophosphoryl lipid A (MPL) and insoluble aluminum salts. Data from previous studies showed that both MPL and insoluble aluminum salts have nasal mucosal vaccine adjuvant activity. The present study was designed to test the feasibility of using AS04 as an adjuvant to help nasally administered antigens to induce specific mucosal and systemic immunity as well as to evaluate the deposition of antigens in the upper respiratory tract when adjuvanted with AS04. Alhydrogel, an aluminum (oxy)hydroxide suspension, was mixed with MPL to form AS04, which was then mixed with ovalbumin (OVA) or 3× M2e-HA2, a synthetic influenza virus hemagglutinin fusion protein, as an antigen to prepare OVA/AS04 and 3× M2e-HA2/AS04 vaccines, respectively. In mice, AS04 enabled antigens, when given intranasally, to induce specific IgA response in nasal and lung mucosal secretions as well as specific IgG response in the serum samples of the immunized mice, whereas subcutaneous injection of the same vaccine induced specific antibody responses only in the serum samples but not in the mucosal secretions. Splenocytes isolated from mice intranasally immunized with the OVA/AS04 also proliferated and released cytokines (i.e., IL-4 and IFN-γ) after in vitro stimulation with the antigen. In the immunogenicity test, intranasal OVA/AS04 was not more effective than intranasal OVA/MPL at the dosing regimens tested. However, when compared to OVA/MPL, OVA/AS04 showed a different atomized droplet size distribution and more importantly a more favorable OVA deposition profile when atomized into a nasal cast that was 3-D printed based on the computer tomography scan of the nose of a child. It is concluded that AS04 has mucosal adjuvant activity when given intranasally. In addition, there is a reason to be optimistic about using AS04 as an adjuvant to target an antigen of interest to the right region of the nasal cavity in humans for immune response induction.
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Affiliation(s)
- Haiyue Xu
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Riyad F Alzhrani
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zachary N Warnken
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Sachin G Thakkar
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Mingtao Zeng
- Department of Molecular and Translational Medicine, Center of Emphasis in Infectious Diseases, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, United States
| | - Hugh D C Smyth
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Robert O Williams
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zhengrong Cui
- College of Pharmacy, Division of Molecular Pharmaceutics and Drug Delivery, The University of Texas at Austin, Austin, Texas 78712, United States
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12
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Bekeredjian-Ding I. Challenges for Clinical Development of Vaccines for Prevention of Hospital-Acquired Bacterial Infections. Front Immunol 2020; 11:1755. [PMID: 32849627 PMCID: PMC7419648 DOI: 10.3389/fimmu.2020.01755] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 06/30/2020] [Indexed: 12/19/2022] Open
Abstract
Increasing antibiotic resistance in bacteria causing endogenous infections has entailed a need for innovative approaches to therapy and prophylaxis of these infections and raised a new interest in vaccines for prevention of colonization and infection by typically antibiotic resistant pathogens. Nevertheless, there has been a long history of failures in late stage clinical development of this type of vaccines, which remains not fully understood. This article provides an overview on present and past vaccine developments targeting nosocomial bacterial pathogens; it further highlights the specific challenges associated with demonstrating clinical efficacy of these vaccines and the facts to be considered in future study designs. Notably, these vaccines are mainly applied to subjects with preexistent immunity to the target pathogen, transient or chronic immunosuppression and ill-defined microbiome status. Unpredictable attack rates and changing epidemiology as well as highly variable genetic and immunological strain characteristics complicate the development. In views of the clinical need, re-thinking of the study designs and expectations seems warranted: first of all, vaccine development needs to be footed on a clear rationale for choosing the immunological mechanism of action and the optimal time point for vaccination, e.g., (1) prevention (or reduction) of colonization vs. prevention of infection and (2) boosting of a preexistent immune response vs. altering the quality of the immune response. Furthermore, there are different, probably redundant, immunological and microbiological defense mechanisms that provide protection from infection. Their interplay is not well-understood but as a consequence their effect might superimpose vaccine-mediated resolution of infection and lead to failure to demonstrate efficacy. This implies that improved characterization of patient subpopulations within the trial population should be obtained by pro- and retrospective analyses of trial data on subject level. Statistical and systems biology approaches could help to define immune and microbiological biomarkers that discern populations that benefit from vaccination from those where vaccines might not be effective.
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Affiliation(s)
- Isabelle Bekeredjian-Ding
- Division of Microbiology, Langen, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
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13
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Gbesemete D, Barker M, Lawrence WT, Watson D, de Graaf H, Read RC. Exploring the acceptability of controlled human infection with SARSCoV2-a public consultation. BMC Med 2020; 18:209. [PMID: 32635912 PMCID: PMC7339437 DOI: 10.1186/s12916-020-01670-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/19/2020] [Indexed: 12/20/2022] Open
Abstract
Rapid development of an effective vaccine for SARSCoV2 is a global priority. A controlled human infection model (CHIM) would accelerate the efficacy assessment of candidate vaccines. This strategy would require deliberate exposure of volunteers to SARSCoV2 with no currently available treatment and a small but definite risk of serious illness or death. This raises complex questions about the social and ethical acceptability of risk to individuals, given the potential benefit to the wider population, and as such, a study cannot be done without public involvement. We conducted a structured public consultation with 57 individuals aged 20-40 years to understand public attitudes to a CHIM, and pre-requisites for enrolment. The overall response to this strategy was positive, and many would volunteer altruistically. Carefully controlled infection is viewed as safer than natural exposure to wild virus. The prolonged social isolation required for the proposed CHIM is considered an obstacle but not insurmountable, with reasonable compensation and supportive care. Given the significant level of public interest, a CHIM should be done as open science with regular, controlled dissemination of information into the public domain. Importantly, there was a strong view that the final decision whether to conduct a CHIM should be in the hands of qualified and experienced clinician-scientists and the authorities.
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Affiliation(s)
- D Gbesemete
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, School of Clinical and Experimental Sciences, NIHR Clinical Research Facility and NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust Mailpoint 218, University Hospital Southampton NHS Foundation Trust Tremona Road, Southampton, SO16 6YD, UK
| | - M Barker
- MRC Lifecourse Epidemiology Unit, University of Southampton, D08 Institute of Developmental Science and NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospitals Southampton NHS Foundation Trust, Southampton, UK
| | - W T Lawrence
- MRC Lifecourse Epidemiology Unit, University of Southampton, D08 Institute of Developmental Science and NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospitals Southampton NHS Foundation Trust, Southampton, UK
| | - D Watson
- School of Human Development and Health, Faculty of Medicine, University of Southampton, D08 Institute of Developmental Science, University Hospitals Southampton NHS Foundation Trust, Southampton, UK
| | - H de Graaf
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, School of Clinical and Experimental Sciences, NIHR Clinical Research Facility and NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust Mailpoint 218, University Hospital Southampton NHS Foundation Trust Tremona Road, Southampton, SO16 6YD, UK
| | - R C Read
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, School of Clinical and Experimental Sciences, NIHR Clinical Research Facility and NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, University of Southampton, Southampton General Hospital, South Academic Block, Mailpoint 814, Tremona Road, Southampton, SO16 6YD, UK.
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14
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Tanner R, Satti I, Harris SA, O'Shea MK, Cizmeci D, O'Connor D, Chomka A, Matsumiya M, Wittenberg R, Minassian AM, Meyer J, Fletcher HA, McShane H. Tools for Assessing the Protective Efficacy of TB Vaccines in Humans: in vitro Mycobacterial Growth Inhibition Predicts Outcome of in vivo Mycobacterial Infection. Front Immunol 2020; 10:2983. [PMID: 31998295 PMCID: PMC6968127 DOI: 10.3389/fimmu.2019.02983] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/05/2019] [Indexed: 12/16/2022] Open
Abstract
Tuberculosis (TB) remains a leading global cause of morbidity and mortality and an effective new vaccine is urgently needed. A major barrier to the rational development of novel TB vaccines is the lack of a validated immune correlate or biomarker of protection. Mycobacterial Growth Inhibition Assays (MGIAs) provide an unbiased measure of ability to control mycobacterial growth in vitro, and may represent a functional correlate of protection. However, the biological relevance of any potential correlate can only be assessed by determining the association with in vivo protection from either a controlled mycobacterial infection or natural development of TB disease. Our data demonstrate that the direct MGIA using peripheral blood mononuclear cells (PBMC) is measuring a biologically relevant response that correlates with protection from in vivo human BCG infection across two independent cohorts. This is the first report of an MGIA correlating with in vivo protection in the species-of-interest, humans, and furthermore on a per-individual as well as per-group basis. Control of mycobacterial growth in the MGIA is associated with a range of immune parameters measured post-BCG infection in vivo including the IFN-γ ELISpot response, frequency of PPD-specific IFN-γ or TNF-α producing CD4+ T cells and frequency of specific sub-populations of polyfunctional CD4+ T cells. Distinct transcriptomic profiles are associated with good vs. poor mycobacterial control in the MGIA, with good controllers showing enrichment for gene sets associated with antigen processing/presentation and the IL-23 pathway, and poor controllers showing enrichment for hypoxia-related pathways. This study represents an important step toward biologically validating the direct PBMC MGIA for use in TB vaccine development and furthermore demonstrates the utility of this assay in determining relevant immune mechanisms and pathways of protection.
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Affiliation(s)
- Rachel Tanner
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Iman Satti
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Stephanie A. Harris
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Matthew K. O'Shea
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, United Kingdom
| | - Deniz Cizmeci
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Daniel O'Connor
- Department of Paediatrics, University of Oxford, Oxford, United Kingdom
| | - Agnieszka Chomka
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Magali Matsumiya
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Rachel Wittenberg
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Angela M. Minassian
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Joel Meyer
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Helen A. Fletcher
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Helen McShane
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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15
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Hoggarth A, Weaver A, Pu Q, Huang T, Schettler J, Chen F, Yuan X, Wu M. Mechanistic research holds promise for bacterial vaccines and phage therapies for Pseudomonas aeruginosa. DRUG DESIGN DEVELOPMENT AND THERAPY 2019; 13:909-924. [PMID: 30936684 PMCID: PMC6431001 DOI: 10.2147/dddt.s189847] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vaccines for Pseudomonas aeruginosa have been of longstanding interest to immunologists, bacteriologists, and clinicians, due to the widespread prevalence of hospital-acquired infection. As P. aeruginosa becomes increasingly antibiotic resistant, there is a dire need for novel treatments and preventive vaccines. Despite intense efforts, there currently remains no vaccine on the market to combat this dangerous pathogen. This article summarizes current and past vaccines under development that target various constituents of P. aeruginosa. Targeting lipopolysaccharides and O-antigens have shown some promise in preventing infection. Recombinant flagella and pili that target TLR5 have been utilized to combat P. aeruginosa by blocking its motility and adhesion. The type 3 secretion system components, such as needle-like structure PcrV or exotoxin PopB, are also potential vaccine targets. Outer membrane proteins including OprF and OprI are newer representatives of vaccine candidates. Live attenuated vaccines are a focal point in this review, and are also considered for novel vaccines. In addition, phage therapy is revived as an effective option for treating refractory infections after failure with antibiotic treatment. Many of the aforementioned vaccines act on a single target, thus lacking a broad range of protection. Recent studies have shown that mixtures of vaccines and combination approaches may significantly augment immunogenicity, thereby increasing their preventive and therapeutic potential.
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Affiliation(s)
- Austin Hoggarth
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Andrew Weaver
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Qinqin Pu
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Ting Huang
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA, .,Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, China
| | - Jacob Schettler
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
| | - Feng Chen
- Pulmonary and Allergy Institute, Affiliated Hospital of Southwestern Medical University, Luzhou, China
| | - Xiefang Yuan
- Pulmonary and Allergy Institute, Affiliated Hospital of Southwestern Medical University, Luzhou, China
| | - Min Wu
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA,
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16
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Davis MM, Tato CM. Will Systems Biology Deliver Its Promise and Contribute to the Development of New or Improved Vaccines? Seeing the Forest Rather than a Few Trees. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a028886. [PMID: 29038119 DOI: 10.1101/cshperspect.a028886] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Preventing morbidity and mortality from infectious disease through the development and use of effective vaccines is one of medicine's greatest achievements and greatest frustrations. We are struggling with improving vaccine efficacy for some of the most globally widespread diseases, such as malaria and tuberculosis. In an effort to gain an edge, systems biology approaches have begun to be employed to more broadly investigate the pathways leading to protective vaccine responses. As such, we are now at a critical juncture, needing to evaluate how fruitful these approaches have been. Herein we discuss the level of success achieved as compared to the original promise of systems methodologies, and conclude that while we have indeed begun to make clear inroads into understanding the immune response to vaccines, we still have much to learn and gain from the more comprehensive approach of systems-level analysis.
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Affiliation(s)
- Mark M Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94304.,Institute of Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, California 94304.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94304
| | - Cristina M Tato
- Institute of Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, California 94304
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17
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Eneslätt K, Golovliov I, Rydén P, Sjöstedt A. Vaccine-Mediated Mechanisms Controlling Replication of Francisella tularensis in Human Peripheral Blood Mononuclear Cells Using a Co-culture System. Front Cell Infect Microbiol 2018; 8:27. [PMID: 29468144 PMCID: PMC5808333 DOI: 10.3389/fcimb.2018.00027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/23/2018] [Indexed: 11/17/2022] Open
Abstract
Cell-mediated immunity (CMI) is normally required for efficient protection against intracellular infections, however, identification of correlates is challenging and they are generally lacking. Francisella tularensis is a highly virulent, facultative intracellular bacterium and CMI is critically required for protection against the pathogen, but how this is effectuated in humans is poorly understood. To understand the protective mechanisms, we established an in vitro co-culture assay to identify how control of infection of F. tularensis is accomplished by human cells and hypothesized that the model will mimic in vivo immune mechanisms. Non-adherent peripheral blood mononuclear cells (PBMCs) were expanded with antigen and added to cultures with adherent PBMC infected with the human vaccine strain, LVS, or the highly virulent SCHU S4 strain. Intracellular numbers of F. tularensis was followed for 72 h and secreted and intracellular cytokines were analyzed. Addition of PBMC expanded from naïve individuals, i.e., those with no record of immunization to F. tularensis, generally resulted in little or no control of intracellular bacterial growth, whereas addition of PBMC from a majority of F. tularensis-immune individuals executed static and sometimes cidal effects on intracellular bacteria. Regardless of infecting strain, statistical differences between the two groups were significant, P < 0.05. Secretion of 11 cytokines was analyzed after 72 h of infection and significant differences with regard to secretion of IFN-γ, TNF, and MIP-1β was observed between immune and naïve individuals for LVS-infected cultures. Also, in LVS-infected cultures, CD4 T cells from vaccinees, but not CD8 T cells, showed significantly higher expression of IFN-γ, MIP-1β, TNF, and CD107a than cells from naïve individuals. The co-culture system appears to identify correlates of immunity that are relevant for the understanding of mechanisms of the protective host immunity to F. tularensis.
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Affiliation(s)
- Kjell Eneslätt
- Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Igor Golovliov
- Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Patrik Rydén
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, Sweden
| | - Anders Sjöstedt
- Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
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18
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Gordon SB, Rylance J, Luck A, Jambo K, Ferreira DM, Manda-Taylor L, Bejon P, Ngwira B, Littler K, Seager Z, Gibani M, Gmeiner M, Roestenberg M, Mlombe Y. A framework for Controlled Human Infection Model (CHIM) studies in Malawi: Report of a Wellcome Trust workshop on CHIM in Low Income Countries held in Blantyre, Malawi. Wellcome Open Res 2017; 2:70. [PMID: 29018841 PMCID: PMC5627502 DOI: 10.12688/wellcomeopenres.12256.1] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2017] [Indexed: 11/29/2022] Open
Abstract
Controlled human infection model (CHIM) studies have pivotal importance in vaccine development, being useful for proof of concept, pathogenesis, down-selection and immunogenicity studies. To date, however, they have seldom been carried out in low and middle income countries (LMIC), which is where the greatest burden of vaccine preventable illness is found. This workshop discussed the benefits and barriers to CHIM studies in Malawi. Benefits include improved vaccine effectiveness and host country capacity development in clinical, laboratory and governance domains. Barriers include acceptability, safety and regulatory issues. The report suggests a framework by which ethical, laboratory, scientific and governance issues may be addressed by investigators considering or planning CHIM in LMIC.
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Affiliation(s)
- Stephen B Gordon
- The Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Jamie Rylance
- The Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Amy Luck
- Vaccines, Wellcome Trust, London, NW1 2BE, UK
| | - Kondwani Jambo
- The Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | | | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Zoe Seager
- Vaccines, Wellcome Trust, London, NW1 2BE, UK
| | - Malick Gibani
- Oxford Vaccines Group, Department of Paediatrics, Children's Hospital, Oxford, OX3 9DU, UK
| | - Markus Gmeiner
- The Malawi Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Yohannie Mlombe
- College of Medicine Research Ethics Committee, John Chiphangwi Learning Resource Centre, Blantyre, Malawi
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19
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Porter CK, Riddle MS, Alcala AN, Sack DA, Harro C, Chakraborty S, Gutierrez RL, Savarino SJ, Darsley M, McKenzie R, DeNearing B, Steinsland H, Tribble DR, Bourgeois AL. An Evidenced-Based Scale of Disease Severity following Human Challenge with Enteroxigenic Escherichia coli. PLoS One 2016; 11:e0149358. [PMID: 26938983 PMCID: PMC4777366 DOI: 10.1371/journal.pone.0149358] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/29/2016] [Indexed: 11/30/2022] Open
Abstract
Background Experimental human challenge models have played a major role in enhancing our understanding of infectious diseases. Primary outcomes have typically utilized overly simplistic outcomes that fail to entirely account for complex illness syndromes. We sought to characterize clinical outcomes associated with experimental infection with enterotoxigenic Escherichia coli (ETEC) and to develop a disease score. Methods Data were obtained from prior controlled human ETEC infection studies. Correlation and univariate regression across sign and symptom severity was performed. A multiple correspondence analysis was conducted. A 3-parameter disease score with construct validity was developed in an iterative fashion, compared to standard outcome definitions and applied to prior vaccine challenge trials. Results Data on 264 subjects receiving seven ETEC strains at doses from 1x105 to 1x1010 cfu were used to construct a standardized dataset. The strongest observed correlation was between vomiting and nausea (r = 0.65); however, stool output was poorly correlated with subjective activity-impacting outcomes. Multiple correspondence analyses showed covariability in multiple signs and symptoms, with severity being the strongest factor corresponding across outcomes. The developed disease score performed well compared to standard outcome definitions and differentiated disease in vaccinated and unvaccinated subjects. Conclusion Frequency and volumetric definitions of diarrhea severity poorly characterize ETEC disease. These data support a disease severity score accounting for stool output and other clinical signs and symptoms. Such a score could serve as the basis for better field trial outcomes and gives an additional outcome measure to help select future vaccines that warrant expanded testing in pivotal pre-licensure trials.
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Affiliation(s)
- Chad K. Porter
- Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, MD, United States of America
- * E-mail:
| | - Mark S. Riddle
- Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, MD, United States of America
| | - Ashley N. Alcala
- Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, MD, United States of America
| | - David A. Sack
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
| | - Clayton Harro
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
| | - Subhra Chakraborty
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
| | - Ramiro L. Gutierrez
- Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, MD, United States of America
| | - Stephen J. Savarino
- Enteric Disease Department, Infectious Disease Directorate, Naval Medical Research Center, Silver Spring, MD, United States of America
| | | | - Robin McKenzie
- School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Barbara DeNearing
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
| | - Hans Steinsland
- Centre for Intervention Science in Maternal and Child Health (CISMAC), Centre for International Health, and Department of Biomedicine, University of Bergen, Bergen, Norway
| | - David R. Tribble
- Infectious Disease Clinical Research Program, Bethesda, MD, United States of America
| | - A. Louis Bourgeois
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States of America
- PATH, Washington, DC, United States of America
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Abstract
While much progress has been made in the fight against the scourge of tuberculosis (TB), we are still some way from reaching the ambitious targets of eliminating it as a global public health problem by the mid twenty-first century. A new and effective vaccine that protects against pulmonary TB disease will be an essential element of any control strategy. Over a dozen vaccines are currently in development, but recent efficacy trial data from one of the most advanced candidates have been disappointing. Limitations of current preclinical animal models exist, together with a lack of a complete understanding of host immunity to TB or robust correlates of disease risk and protection. Therefore, in the context of such obstacles, we discuss the lessons identified from recent efficacy trials, current concepts of biomarkers and correlates of protection, the potential of innovative clinical models such as human challenge and conducting trials in high-incidence settings to evaluate TB vaccines in humans, and the use of systems vaccinology and novel technologies including transcriptomics and metabolomics, that may facilitate their utility.
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Affiliation(s)
| | - Helen McShane
- a The Jenner Institute, University of Oxford , Oxford , UK
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