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Macamo ED, Mkhize-Kwitshana ZL, Mthombeni J, Naidoo P. The Impact of HIV and Parasite Single Infection and Coinfection on Telomere Length: A Systematic Review. Curr Issues Mol Biol 2024; 46:7258-7290. [PMID: 39057072 PMCID: PMC11275449 DOI: 10.3390/cimb46070431] [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] [Received: 05/27/2024] [Revised: 07/03/2024] [Accepted: 07/04/2024] [Indexed: 07/28/2024] Open
Abstract
HIV and parasite infections accelerate biological aging, resulting in immune senescence, apoptosis and cellular damage. Telomere length is considered to be one of the most effective biomarkers of biological aging. HIV and parasite infection have been reported to shorten telomere length in the host. This systematic review aimed to highlight work that explored the influence of HIV and parasite single infections and coinfection on telomere length. Using specific keywords related to the topic of interest, an electronic search of several online databases (Google Scholar, Web of Science, Scopus, Science Direct and PubMed) was conducted to extract eligible articles. The association between HIV infection or parasite infection and telomere length and the association between HIV and parasite coinfection and telomere length were assessed independently. The studies reported were mostly conducted in the European countries. Of the 42 eligible research articles reviewed, HIV and parasite single infections were independently associated with telomere length shortening. Some studies found no association between antiretroviral therapy (ART) and telomere length shortening, while others found an association between ART and telomere length shortening. No studies reported on the association between HIV and parasite coinfection and telomere length. HIV and parasite infections independently accelerate telomere length shortening and biological aging. It is possible that coinfection with HIV and parasites may further accelerate telomere length shortening; however, this is a neglected field of research with no reported studies to date.
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Affiliation(s)
- Engelinah D. Macamo
- Department of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R. Mandela Medical School Campus, University of KwaZulu-Natal, Durban 4001, South Africa
- Division of Research Capacity Development (RCD), South African Medical Research Council (SAMRC), Tygerberg, Cape Town 7505, South Africa
| | - Zilungile L. Mkhize-Kwitshana
- Department of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R. Mandela Medical School Campus, University of KwaZulu-Natal, Durban 4001, South Africa
- Division of Research Capacity Development (RCD), South African Medical Research Council (SAMRC), Tygerberg, Cape Town 7505, South Africa
- Department of Biomedical Sciences, Doorfontein Campus, University of Johannesburg, Johannesburg 1710, South Africa
- Biomedical Sciences Department of Life and Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Florida Campus, Johannesburg 1710, South Africa
| | - Julian Mthombeni
- Department of Biomedical Sciences, Doorfontein Campus, University of Johannesburg, Johannesburg 1710, South Africa
| | - Pragalathan Naidoo
- Department of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R. Mandela Medical School Campus, University of KwaZulu-Natal, Durban 4001, South Africa
- Division of Research Capacity Development (RCD), South African Medical Research Council (SAMRC), Tygerberg, Cape Town 7505, South Africa
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2
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Ribeiro LB, Gazzinelli A, Santiago HDC, Fiuza JA, Lobato L, Correa de Oliveira R, Gazzinelli Bethony MF. Public engagement for the conduct of a controlled human infection study testing vaccines against Necator americanus (hookworm) in areas of active hookworm transmission in Brazil. PLoS One 2024; 19:e0299022. [PMID: 38829836 PMCID: PMC11146735 DOI: 10.1371/journal.pone.0299022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/03/2024] [Indexed: 06/05/2024] Open
Abstract
Controlled Human Infection Models (CHIS) involve administering human pathogens to healthy participants in controlled medical settings, which can elicit complex bioethical issues. Understanding how the community perceives such studies can significantly increase the participant's sense of cooperation and increases the researcher's and the participant's transparency. The current study describes the development of an educational intervention to achieve these ends as it aims to (1) analyze perceptions of the Controlled Human Infection Studies (CHIS), and (2) evaluate the participants' comprehension of the CHIS. METHODS This is a qualitative action research that includes the development of an educational intervention with residents of a rural area in Minas Gerais, Brazil, where there is continuous natural transmission of the human pathogen Necator americanus ("hookworm"). In this area, it is intended to carry out a proposed phase 3 vaccine clinical trial in the future to test the efficacy of hookworm vaccines using controlled human infection. Two data collection strategies were used: an educational intervention and a focus group. RESULTS The participants' perceptions showed distinct perspectives on CHIS. On one side, they recognized that the investigation is essential for the community, but on the other side, they thought that there would be resistance to its conduct by fear of infection. The idea that the study would generate a benefit for the greater good, contributing to the prevention of hookworm infection, was clearly stated. The participants perceived that the study offered concrete risks that could be reduced by constant monitoring by the researchers. They also mentioned the importance of access to information and the positive influence those who express interest in participating in the study can exert in the community. In relation to comprehension the participants memorized the information, mobilized it to explain everyday situations and created strategies to disseminate the study and engage the community in its development. By repeating and making sense of the information, the participant not only assimilates the knowledge transmitted, but also creates new knowledge. CONCLUSION We concluded that an educational process of discussion and dialogue around participants' perceptions about the CHIS, promotes understanding and allows ways to disseminate information about the research to be collectively created.
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Affiliation(s)
- Luciene Barra Ribeiro
- School of Nursing, From the Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Andréa Gazzinelli
- School of Nursing, From the Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Helton da Costa Santiago
- Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Jacqueline Araújo Fiuza
- Group of Cellular and Molecular Immunology- Instituto René Rachou/ Fiocruz Minas, Belo Horizonte, MG, Brazil
| | - Lucas Lobato
- Clinical Hospital /UFMG-EBSERH, Belo Horizonte, MG, Brazil
| | - Rodrigo Correa de Oliveira
- Group of Cellular and Molecular Immunology- Instituto René Rachou/ Fiocruz Minas, Belo Horizonte, MG, Brazil
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3
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Chugh S, Bahal RK, Dhiman R, Singh R. Antigen identification strategies and preclinical evaluation models for advancing tuberculosis vaccine development. NPJ Vaccines 2024; 9:57. [PMID: 38461350 PMCID: PMC10924964 DOI: 10.1038/s41541-024-00834-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 02/05/2024] [Indexed: 03/11/2024] Open
Abstract
In its myriad devastating forms, Tuberculosis (TB) has existed for centuries, and humanity is still affected by it. Mycobacterium tuberculosis (M. tuberculosis), the causative agent of TB, was the foremost killer among infectious agents until the COVID-19 pandemic. One of the key healthcare strategies available to reduce the risk of TB is immunization with bacilli Calmette-Guerin (BCG). Although BCG has been widely used to protect against TB, reports show that BCG confers highly variable efficacy (0-80%) against adult pulmonary TB. Unwavering efforts have been made over the past 20 years to develop and evaluate new TB vaccine candidates. The failure of conventional preclinical animal models to fully recapitulate human response to TB, as also seen for the failure of MVA85A in clinical trials, signifies the need to develop better preclinical models for TB vaccine evaluation. In the present review article, we outline various approaches used to identify protective mycobacterial antigens and recent advancements in preclinical models for assessing the efficacy of candidate TB vaccines.
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Affiliation(s)
- Saurabh Chugh
- Centre for Tuberculosis Research, Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, Faridabad, 121001, Haryana, India
| | - Ritika Kar Bahal
- Marshall Centre, School of Biomedical Sciences, University of Western Australia, Perth, Australia
| | - Rohan Dhiman
- Laboratory of Mycobacterial Immunology, Department of Life Science, National Institute of Technology, Rourkela, 769008, Odisha, India
| | - Ramandeep Singh
- Centre for Tuberculosis Research, Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, Faridabad, 121001, Haryana, India.
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4
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Dabira ED, Fehr A, Beloum N, Van Geertruyden JP, Achan J, Erhart A, Martinez-Alvarez M, D'Alessandro U. Perceptions and acceptability of the controlled human malaria infection (CHMI) model in The Gambia: a qualitative study. Sci Rep 2023; 13:8708. [PMID: 37248260 DOI: 10.1038/s41598-023-35752-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 05/23/2023] [Indexed: 05/31/2023] Open
Abstract
Controlled human malaria infection (CHMI) studies, i.e. the deliberate infection of healthy volunteers with malaria parasites to study immune response and/or test drug or vaccine efficacy, are increasingly being conducted in malaria endemic countries, including in sub-Saharan Africa. However, there have been few studies on the perceptions and acceptability of CHMI by the local communities. This qualitative study assessed the perception and acceptability of such studies in The Gambia following the first CHMI study conducted in the country in March-May 2018. Data were collected through non-participant observation, in-depth interviews and focus group discussions and analyzed using NVivo 12 software with an inductive-deductive approach. Sixty-seven participants were involved, including volunteers enrolled in the CHMI, community stakeholders and members of the Gambian Ethics Committee. Respondents expressed a positive view about CHMI. Key motivating factors for participation were the financial compensation, comprehensive health checks, and willingness to support malaria research. Risks associated with participation were considered low. Concerns raised included the frequency of bleeding and the blood volume collected.
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Affiliation(s)
- Edgard Diniba Dabira
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Fajara, The Gambia.
- Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium.
| | - Alexandra Fehr
- London School of Hygiene and Tropical Medicine, London, UK
| | - Nathalie Beloum
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Fajara, The Gambia
| | | | | | - Annette Erhart
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Fajara, The Gambia
| | - Melisa Martinez-Alvarez
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Fajara, The Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine (MRCG at LSHTM), Fajara, The Gambia
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5
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Roobsoong W, Yadava A, Draper SJ, Minassian AM, Sattabongkot J. The challenges of Plasmodium vivax human malaria infection models for vaccine development. Front Immunol 2023; 13:1006954. [PMID: 36685545 PMCID: PMC9849360 DOI: 10.3389/fimmu.2022.1006954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/09/2022] [Indexed: 01/07/2023] Open
Abstract
Controlled Human Malaria Infection models (CHMI) have been critical to advancing new vaccines for malaria. Stringent and safe preparation of a challenge agent is key to the success of any CHMI. Difficulty producing the Plasmodium vivax parasite in vitro has limited production of qualified parasites for CHMI as well as the functional assays required to screen and down-select candidate vaccines for this globally distributed parasite. This and other challenges to P. vivax CHMI (PvCHMI), including scientific, logistical, and ethical obstacles, are common to P. vivax research conducted in both non-endemic and endemic countries, with additional hurdles unique to each. The challenges of using CHMI for P. vivax vaccine development and evaluation, lessons learned from previous and ongoing clinical trials, and the way forward to effectively perform PvCHMI to support vaccine development, are discussed.
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Affiliation(s)
- Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Anjali Yadava
- Biologics Research & Development, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Simon J. Draper
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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6
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Kumar A, Kabra A, Igarashi I, Krause PJ. Animal models of the immunology and pathogenesis of human babesiosis. Trends Parasitol 2023; 39:38-52. [PMID: 36470781 DOI: 10.1016/j.pt.2022.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/03/2022] [Accepted: 11/03/2022] [Indexed: 12/04/2022]
Abstract
Animal models of human babesiosis have provided a basic understanding of the immunological mechanisms that clear, or occasionally exacerbate, Babesia infection and those pathological processes that cause disease complications. Human Babesia infection can cause asymptomatic infection, mild to moderate disease, or severe disease resulting in organ dysfunction and death. More than 100 Babesia species infect a wide array of wild and domestic animals, and many of the immunologic and pathologic responses to Babesia infection are similar in animals and humans. In this review, we summarize the knowledge gained from animal studies, their limitations, and how animal models or alternative approaches can be further leveraged to improve our understanding of human babesiosis.
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Affiliation(s)
- Abhinav Kumar
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Aditya Kabra
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Ikuo Igarashi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Peter J Krause
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA; Department of Infectious Diseases, Yale School of Medicine, New Haven, CT 06510, USA.
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Abstract
Since the identification of sickle cell trait as a heritable form of resistance to malaria, candidate gene studies, linkage analysis paired with sequencing, and genome-wide association (GWA) studies have revealed many examples of genetic resistance and susceptibility to infectious diseases. GWA studies enabled the identification of many common variants associated with small shifts in susceptibility to infectious diseases. This is exemplified by multiple loci associated with leprosy, malaria, HIV, tuberculosis, and coronavirus disease 2019 (COVID-19), which illuminate genetic architecture and implicate pathways underlying pathophysiology. Despite these successes, most of the heritability of infectious diseases remains to be explained. As the field advances, current limitations may be overcome by applying methodological innovations such as cellular GWA studies and phenome-wide association (PheWA) studies as well as by improving methodological rigor with more precise case definitions, deeper phenotyping, increased cohort diversity, and functional validation of candidate loci in the laboratory or human challenge studies.
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Affiliation(s)
- Kyle D Gibbs
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, North Carolina, USA;
| | - Benjamin H Schott
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, North Carolina, USA; .,Duke University Program in Genetics and Genomics, Duke University, Durham, North Carolina, USA
| | - Dennis C Ko
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, North Carolina, USA; .,Duke University Program in Genetics and Genomics, Duke University, Durham, North Carolina, USA.,Division of Infectious Diseases, Department of Medicine, School of Medicine, Duke University, Durham, North Carolina, USA
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8
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Marsh AA, Magalhaes M, Peeler M, Rose SM, Darton TC, Eyal N, Morrison J, Shah SK, Schmit V. Characterizing altruistic motivation in potential volunteers for SARS-CoV-2 challenge trials. PLoS One 2022; 17:e0275823. [PMID: 36322529 PMCID: PMC9629635 DOI: 10.1371/journal.pone.0275823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/23/2022] [Indexed: 11/05/2022] Open
Abstract
In human challenge trials (HCTs), volunteers are deliberately infected with an infectious agent. Such trials can be used to accelerate vaccine development and answer important scientific questions. Starting early in the COVID-19 pandemic, ethical concerns were raised about using HCTs to accelerate development and approval of a vaccine. Some of those concerns pertained to potential exploitation of and/or lack of truly informed consent from volunteers. Specific areas of concern arose around individuals who may be unusually risk-seeking or too economically vulnerable to refuse the payments these trials provide, as opposed to being motivated primarily by altruistic goals. This pre-registered study is the first large-scale survey to characterize people who, early in the pandemic, expressed interest and intention to volunteer to participate in COVID-19 HCTs. We found that individuals expressing interest in SARS-CoV-2 HCTs exhibit consistently altruistic motivations without any special indication of poor risk perception or economic vulnerability. In finding that, early in the pandemic, COVID-19 HCTs were able to attract volunteers whose values align with the nature of these trials, and who are not unusually vulnerable to exploitation, this study may allay some ethical concerns about the volunteers interested in participating in such trials.
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Affiliation(s)
- Abigail A. Marsh
- Department of Psychology, Georgetown University, Washington, DC, United States of America
- * E-mail:
| | - Monica Magalhaes
- Center for Population-Level Bioethics, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Matthew Peeler
- Department of Mathematics, Rowan-Cabarrus Community College, Salisbury, North Carolina, United States of America
| | - Sophie M. Rose
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Thomas C. Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Nir Eyal
- Center for Population-Level Bioethics, Rutgers University, New Brunswick, New Jersey, United States of America
- Department of Health Behavior, Society and Policy, Rutgers School of Public Health, Piscataway, New Jersey, United States of America
- Department of Philosophy, Rutgers University, New Brunswick, New Jersey, United States of America
| | - Josh Morrison
- 1Day Sooner, Claymont, Delaware, United States of America
| | - Seema K. Shah
- Smith Child Health Outcomes, Research and Evaluation Center, Lurie Children’s Hospital, Chicago, Illinois, United States of America
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
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9
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Britto C, Alter G. The next frontier in vaccine design: blending immune correlates of protection into rational vaccine design. Curr Opin Immunol 2022; 78:102234. [PMID: 35973352 PMCID: PMC9612370 DOI: 10.1016/j.coi.2022.102234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/27/2022] [Accepted: 07/13/2022] [Indexed: 02/02/2023]
Abstract
Despite the extraordinary speed and success in SARS-Cov-2 vaccine development, the emergence of variants of concern perplexed the vaccine development community. Neutralizing antibodies waned antibodies waned and were evaded by viral variants, despite the preservation of protection against severe disease and death across vaccinated populations. Similar to other vaccine design efforts, the lack of mechanistic correlates of immunity against Coronavirus Disease 2019, raised questions related to the need for vaccine redesign and boosting. Hence, our limited understanding of mechanistic correlates of immunity - across pathogens - remains a major obstacle in vaccine development. The identification and incorporation of mechanistic correlates of immunity are key to the accelerated design of highly impactful globally relevant vaccines. Systems-biology tools can be applied strategically to define a complete understanding of mechanistic correlates of immunity. Embedding immunological dissection and target immune profile identification, beyond canonical antibody binding and neutralization, may accelerate the design and success of durable protective vaccines.
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Affiliation(s)
- Carl Britto
- Department of Pediatrics, Boston Children's Hospital, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA.
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10
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Nunes-Cabaço H, Moita D, Prudêncio M. Five decades of clinical assessment of whole-sporozoite malaria vaccines. Front Immunol 2022; 13:977472. [PMID: 36159849 PMCID: PMC9493004 DOI: 10.3389/fimmu.2022.977472] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
In 1967, pioneering work by Ruth Nussenzweig demonstrated for the first time that irradiated sporozoites of the rodent malaria parasite Plasmodium berghei protected mice against a challenge with infectious parasites of the same species. This remarkable finding opened up entirely new prospects of effective vaccination against malaria using attenuated sporozoites as immunization agents. The potential for whole-sporozoite-based immunization in humans was established in a clinical study in 1973, when a volunteer exposed to X-irradiated P. falciparum sporozoites was found to be protected against malaria following challenge with a homologous strain of this parasite. Nearly five decades later, much has been achieved in the field of whole-sporozoite malaria vaccination, and multiple reports on the clinical evaluation of such candidates have emerged. However, this process has known different paces before and after the turn of the century. While only a few clinical studies were published in the 1970’s, 1980’s and 1990’s, remarkable progress was made in the 2000’s and beyond. This article reviews the history of the clinical assessment of whole-sporozoite malaria vaccines over the last forty-nine years, highlighting the impressive achievements made over the last few years, and discussing some of the challenges ahead.
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11
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Egesa M, Ssali A, Tumwesige E, Kizza M, Driciru E, Luboga F, Roestenberg M, Seeley J, Elliott AM. Ethical and practical considerations arising from community consultation on implementing controlled human infection studies using Schistosoma mansoni in Uganda. Glob Bioeth 2022; 33:78-102. [PMID: 35814190 PMCID: PMC9258062 DOI: 10.1080/11287462.2022.2091503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 11/28/2021] [Indexed: 11/21/2022] Open
Abstract
Issues related to controlled human infection studies using Schistosoma mansoni (CHI-S) were explored to ensure the ethical and voluntary participation of potential CHI-S volunteers in an endemic setting in Uganda. We invited volunteers from a fishing community and a tertiary education community to guide the development of informed consent procedures. Consultative group discussions were held to modify educational materials on schistosomiasis, vaccines and the CHI-S model and similar discussions were held with a test group. With both groups, a mock consent process was conducted. Fourteen in-depth key informant interviews and three group discussions were held to explore perceptions towards participating in a CHI-S. Most of the participants had not heard of the CHI-S. Willingness to take part depended on understanding the study procedures and the consenting process. Close social networks were key in deciding to take part. The worry of adverse effects was cited as a possible hindrance to taking part. Volunteer time compensation was unclear for a CHI-S. Potential volunteers in these communities are willing to take part in a CHI-S. Community engagement is needed to build trust and time must be taken to share study procedures and ensure understanding of key messages.
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Affiliation(s)
- Moses Egesa
- Immunomodulation and Vaccines Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- Uganda Virus Research Institute, Entebbe, Uganda
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Agnes Ssali
- Social Aspects of Health Across the Life-Course Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Edward Tumwesige
- Social Aspects of Health Across the Life-Course Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Moses Kizza
- Immunomodulation and Vaccines Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Emmanuella Driciru
- Immunomodulation and Vaccines Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Fiona Luboga
- Uganda Virus Research Institute, Entebbe, Uganda
| | - Meta Roestenberg
- Social Aspects of Health Across the Life-Course Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Janet Seeley
- Social Aspects of Health Across the Life-Course Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | - Alison M. Elliott
- Immunomodulation and Vaccines Programme, MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
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12
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Kibwana E, Kapulu M, Bejon P. Controlled Human Malaria Infection Studies in Africa-Past, Present, and Future. Curr Top Microbiol Immunol 2022. [PMID: 35704094 DOI: 10.1007/82_2022_256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Controlled human infection studies have contributed significantly to the understanding of pathogeneses and treatment of infectious diseases. In malaria, deliberately infecting humans with malaria parasites was used as a treatment for neurosyphilis in the early 1920s. More recently, controlled human malaria infection (CHMI) has become a valuable, cost-effective tool to fast-track the development and evaluation of new anti-malarial drugs and/or vaccines. CHMI studies have also been used to define host/parasite interactions and immunological correlates of protection. CHMI involves infecting a small number of healthy volunteers with malaria parasites, monitoring their parasitemia and providing anti-malarial treatment when a set threshold is reached. In this review we discuss the introduction, development, and challenges of modern-day Plasmodium falciparum CHMI studies conducted in Africa, and the impact of naturally acquired immunity on infectivity and vaccine efficacy. CHMIs have shown to be an invaluable tool particularly in accelerating malaria vaccine research. Although there are limitations of CHMI studies for estimating public health impacts and for regulatory purposes, their strength lies in proof-of-concept efficacy data at an early stage of development, providing a faster way to select vaccines for further development and providing valuable insights in understanding the mechanisms of immunity to malarial infection.
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Affiliation(s)
- Elizabeth Kibwana
- Bioscience Department, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
| | - Melissa Kapulu
- Bioscience Department, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya.
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13
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Lai JW, Maah MJ, Sarip R, Lim YAL, Tim KL, Ng CH. Potency of copper(II) complexes towards drug-sensitive and -resistant Plasmodium falciparum: structure-activity relationship, ROS-generation and proteasome inhibition. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Daubenberger C. Assessment of experimental malaria vaccine induced protection in pre-exposed populations. THE LANCET. INFECTIOUS DISEASES 2022; 22:305-307. [PMID: 34801111 DOI: 10.1016/s1473-3099(21)00359-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Affiliation(s)
- Claudia Daubenberger
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, Basel, Switzerland.
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15
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Simwela NV, Waters AP. Current status of experimental models for the study of malaria. Parasitology 2022; 149:1-22. [PMID: 35357277 PMCID: PMC9378029 DOI: 10.1017/s0031182021002134] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 01/09/2023]
Abstract
Infection by malaria parasites (Plasmodium spp.) remains one of the leading causes of morbidity and mortality, especially in tropical regions of the world. Despite the availability of malaria control tools such as integrated vector management and effective therapeutics, these measures have been continuously undermined by the emergence of vector resistance to insecticides or parasite resistance to frontline antimalarial drugs. Whilst the recent pilot implementation of the RTS,S malaria vaccine is indeed a remarkable feat, highly effective vaccines against malaria remain elusive. The barriers to effective vaccines result from the complexity of both the malaria parasite lifecycle and the parasite as an organism itself with consequent major gaps in our understanding of their biology. Historically and due to the practical and ethical difficulties of working with human malaria infections, research into malaria parasite biology has been extensively facilitated by animal models. Animals have been used to study disease pathogenesis, host immune responses and their (dys)regulation and further disease processes such as transmission. Moreover, animal models remain at the forefront of pre-clinical evaluations of antimalarial drugs (drug efficacy, mode of action, mode of resistance) and vaccines. In this review, we discuss commonly used animal models of malaria, the parasite species used and their advantages and limitations which hinder their extrapolation to actual human disease. We also place into this context the most recent developments such as organoid technologies and humanized mice.
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Affiliation(s)
- Nelson V. Simwela
- Institute of Infection, Immunity & Inflammation, Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Andrew P. Waters
- Institute of Infection, Immunity & Inflammation, Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
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16
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Potential Application of Exosomes in Vaccine Development and Delivery. Pharm Res 2022; 39:2635-2671. [PMID: 35028802 PMCID: PMC8757927 DOI: 10.1007/s11095-021-03143-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/15/2021] [Indexed: 02/06/2023]
Abstract
Exosomes are cell-derived components composed of proteins, lipid, genetic information, cytokines, and growth factors. They play a vital role in immune modulation, cell-cell communication, and response to inflammation. Immune modulation has downstream effects on the regeneration of damaged tissue, promoting survival and repair of damaged resident cells, and promoting the tumor microenvironment via growth factors, antigens, and signaling molecules. On top of carrying biological messengers like mRNAs, miRNAs, fragmented DNA, disease antigens, and proteins, exosomes modulate internal cell environments that promote downstream cell signaling pathways to facilitate different disease progression and induce anti-tumoral effects. In this review, we have summarized how vaccines modulate our immune response in the context of cancer and infectious diseases and the potential of exosomes as vaccine delivery vehicles. Both pre-clinical and clinical studies show that exosomes play a decisive role in processes like angiogenesis, prognosis, tumor growth metastasis, stromal cell activation, intercellular communication, maintaining cellular and systematic homeostasis, and antigen-specific T- and B cell responses. This critical review summarizes the advancement of exosome based vaccine development and delivery, and this comprehensive review can be used as a valuable reference for the broader delivery science community.
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17
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Shibeshi W, Bagchus W, Yalkinoglu Ö, Tappert A, Engidawork E, Oeuvray C. Reproducibility of malaria sporozoite challenge model in humans for evaluating efficacy of vaccines and drugs: a systematic review. BMC Infect Dis 2021; 21:1274. [PMID: 34930178 PMCID: PMC8686662 DOI: 10.1186/s12879-021-06953-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/06/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The development of novel malaria vaccines and antimalarial drugs is limited partly by emerging challenges to conduct field trials in malaria endemic areas, including unknown effects of existing immunity and a reported fall in malaria incidence. As a result, Controlled Human Malaria Infection (CHMI) has become an important approach for accelerated development of malarial vaccines and drugs. We conducted a systematic review of the literature to establish aggregate evidence on the reproducibility of a malaria sporozoite challenge model. METHODS A systematic review of research articles published between 1990 and 2018 on efficacy testing of malaria vaccines and drugs using sporozoite challenge and sporozoite infectivity studies was conducted using Pubmed, Scopus, Embase and Cochrane Library, ClinicalTrials.gov and Trialtrove. The inclusion criteria were randomized and non-randomized, controlled or open-label trials using P. falciparum or P. vivax sporozoite challenges. The data were extracted from articles using standardized data extraction forms and descriptive analysis was performed for evidence synthesis. The endpoints considered were infectivity, prepatent period, parasitemia and safety of sporozoite challenge. RESULTS Seventy CHMI trials conducted with a total of 2329 adult healthy volunteers were used for analysis. CHMI was induced by bites of mosquitoes infected with P. falciparum or P. vivax in 52 trials and by direct venous inoculation of P. falciparum sporozoites (PfSPZ challenge) in 18 trials. Inoculation with P. falciparum-infected mosquitoes produced 100% infectivity in 40 studies and the mean/median prepatent period assessed by thick blood smear (TBS) microscopy was ≤ 12 days in 24 studies. On the other hand, out of 12 infectivity studies conducted using PfSPZ challenge, 100% infection rate was reproduced in 9 studies with a mean or median prepatent period of 11 to 15.3 days as assessed by TBS and 6.8 to 12.6 days by PCR. The safety profile of P. falciparum and P.vivax CHMI was characterized by consistent features of malaria infection. CONCLUSION There is ample evidence on consistency of P. falciparum CHMI models in terms of infectivity and safety endpoints, which supports applicability of CHMI in vaccine and drug development. PfSPZ challenge appears more feasible for African trials based on current evidence of safety and efficacy.
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Affiliation(s)
- Workineh Shibeshi
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
- Global Health Institute of Merck, Ares Trading S.A., A subsidiary of Merck KGaA, Darmstadt, Germany.
| | - Wilhelmina Bagchus
- Translational Medicine, Merck Serono S.A., An Affiliate of Merck KGaA, Darmstadt, Germany
| | - Özkan Yalkinoglu
- Translational Medicine, Merck Healthcare KGaA, Darmstadt, Germany
| | - Aliona Tappert
- Global Patient Safety, Merck Healthcare KGaA, Darmstadt, Germany
| | - Ephrem Engidawork
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Claude Oeuvray
- Global Health Institute of Merck, Ares Trading S.A., A subsidiary of Merck KGaA, Darmstadt, Germany
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18
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Gupta A, Styczynski MP, Galinski MR, Voit EO, Fonseca LL. Dramatic transcriptomic differences in Macaca mulatta and Macaca fascicularis with Plasmodium knowlesi infections. Sci Rep 2021; 11:19519. [PMID: 34593836 PMCID: PMC8484567 DOI: 10.1038/s41598-021-98024-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 08/30/2021] [Indexed: 12/02/2022] Open
Abstract
Plasmodium knowlesi, a model malaria parasite, is responsible for a significant portion of zoonotic malaria cases in Southeast Asia and must be controlled to avoid disease severity and fatalities. However, little is known about the host-parasite interactions and molecular mechanisms in play during the course of P. knowlesi malaria infections, which also may be relevant across Plasmodium species. Here we contrast P. knowlesi sporozoite-initiated infections in Macaca mulatta and Macaca fascicularis using whole blood RNA-sequencing and transcriptomic analysis. These macaque hosts are evolutionarily close, yet malaria-naïve M. mulatta will succumb to blood-stage infection without treatment, whereas malaria-naïve M. fascicularis controls parasitemia without treatment. This comparative analysis reveals transcriptomic differences as early as the liver phase of infection, in the form of signaling pathways that are activated in M. fascicularis, but not M. mulatta. Additionally, while most immune responses are initially similar during the acute stage of the blood infection, significant differences arise subsequently. The observed differences point to prolonged inflammation and anti-inflammatory effects of IL10 in M. mulatta, while M. fascicularis undergoes a transcriptional makeover towards cell proliferation, consistent with its recovery. Together, these findings suggest that timely detection of P. knowlesi in M. fascicularis, coupled with control of inflammation while initiating the replenishment of key cell populations, helps contain the infection. Overall, this study points to specific genes and pathways that could be investigated as a basis for new drug targets that support recovery from acute malaria.
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Affiliation(s)
- Anuj Gupta
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Mark P Styczynski
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Mary R Galinski
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Eberhard O Voit
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
| | - Luis L Fonseca
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Laboratory for Systems Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA
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19
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Bonam SR, Rénia L, Tadepalli G, Bayry J, Kumar HMS. Plasmodium falciparum Malaria Vaccines and Vaccine Adjuvants. Vaccines (Basel) 2021; 9:1072. [PMID: 34696180 PMCID: PMC8541031 DOI: 10.3390/vaccines9101072] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/10/2021] [Accepted: 09/22/2021] [Indexed: 12/02/2022] Open
Abstract
Malaria-a parasite vector-borne disease-is a global health problem, and Plasmodium falciparum has proven to be the deadliest among Plasmodium spp., which causes malaria in humans. Symptoms of the disease range from mild fever and shivering to hemolytic anemia and neurological dysfunctions. The spread of drug resistance and the absence of effective vaccines has made malaria disease an ever-emerging problem. Although progress has been made in understanding the host response to the parasite, various aspects of its biology in its mammalian host are still unclear. In this context, there is a pressing demand for the development of effective preventive and therapeutic strategies, including new drugs and novel adjuvanted vaccines that elicit protective immunity. The present article provides an overview of the current knowledge of anti-malarial immunity against P. falciparum and different options of vaccine candidates in development. A special emphasis has been made on the mechanism of action of clinically used vaccine adjuvants.
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Affiliation(s)
- Srinivasa Reddy Bonam
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Equipe-Immunopathologie et Immunointervention Thérapeutique, Sorbonne Université, Université de Paris, F-75006 Paris, France;
| | - Laurent Rénia
- A*STAR Infectious Diseases Labs, 8A Biomedical Grove, Singapore 138648, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore 308232, Singapore
| | - Ganesh Tadepalli
- Vaccine Immunology Laboratory, Organic Synthesis and Process Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India;
| | - Jagadeesh Bayry
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, Equipe-Immunopathologie et Immunointervention Thérapeutique, Sorbonne Université, Université de Paris, F-75006 Paris, France;
- Biological Sciences & Engineering, Indian Institute of Technology Palakkad, Palakkad 678623, India
| | - Halmuthur Mahabalarao Sampath Kumar
- Vaccine Immunology Laboratory, Organic Synthesis and Process Chemistry Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India;
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20
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Swan DA, Goyal A, Bracis C, Moore M, Krantz E, Brown E, Cardozo-Ojeda F, Reeves DB, Gao F, Gilbert PB, Corey L, Cohen MS, Janes H, Dimitrov D, Schiffer JT. Mathematical Modeling of Vaccines That Prevent SARS-CoV-2 Transmission. Viruses 2021; 13:1921. [PMID: 34696352 PMCID: PMC8539635 DOI: 10.3390/v13101921] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 09/01/2021] [Accepted: 09/16/2021] [Indexed: 12/22/2022] Open
Abstract
SARS-CoV-2 vaccine clinical trials assess efficacy against disease (VEDIS), the ability to block symptomatic COVID-19. They only partially discriminate whether VEDIS is mediated by preventing infection completely, which is defined as detection of virus in the airways (VESUSC), or by preventing symptoms despite infection (VESYMP). Vaccine efficacy against transmissibility given infection (VEINF), the decrease in secondary transmissions from infected vaccine recipients, is also not measured. Using mathematical modeling of data from King County Washington, we demonstrate that if the Moderna (mRNA-1273QS) and Pfizer-BioNTech (BNT162b2) vaccines, which demonstrated VEDIS > 90% in clinical trials, mediate VEDIS by VESUSC, then a limited fourth epidemic wave of infections with the highly infectious B.1.1.7 variant would have been predicted in spring 2021 assuming rapid vaccine roll out. If high VEDIS is explained by VESYMP, then high VEINF would have also been necessary to limit the extent of this fourth wave. Vaccines which completely protect against infection or secondary transmission also substantially lower the number of people who must be vaccinated before the herd immunity threshold is reached. The limited extent of the fourth wave suggests that the vaccines have either high VESUSC or both high VESYMP and high VEINF against B.1.1.7. Finally, using a separate intra-host mathematical model of viral kinetics, we demonstrate that a 0.6 log vaccine-mediated reduction in average peak viral load might be sufficient to achieve 50% VEINF, which suggests that human challenge studies with a relatively low number of infected participants could be employed to estimate all three vaccine efficacy metrics.
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Affiliation(s)
- David A. Swan
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
| | - Ashish Goyal
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
| | - Chloe Bracis
- TIMC-IMAG/BCM, Université Grenoble Alpes, 38000 Grenoble, France;
| | - Mia Moore
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
| | - Elizabeth Krantz
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
| | - Elizabeth Brown
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Fabian Cardozo-Ojeda
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
| | - Daniel B. Reeves
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
| | - Fei Gao
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Peter B. Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Lawrence Corey
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Myron S. Cohen
- Institute of Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Holly Janes
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Dobromir Dimitrov
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Department of Applied Mathematics, University of Washington, Seattle, WA 98195, USA
| | - Joshua T. Schiffer
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; (D.A.S.); (A.G.); (M.M.); (E.K.); (E.B.); (F.C.-O.); (D.B.R.); (F.G.); (P.B.G.); (L.C.); (H.J.); (D.D.)
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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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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22
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Biomarkers of cellular aging during a controlled human malaria infection. Sci Rep 2021; 11:18733. [PMID: 34548530 PMCID: PMC8455531 DOI: 10.1038/s41598-021-97985-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 08/23/2021] [Indexed: 11/08/2022] Open
Abstract
Cellular aging is difficult to study in individuals with natural infection, given the diversity of symptom duration and clinical presentation, and the high interference of aging-related processes with host and environmental factors. To address this challenge, we took advantage of the controlled human malaria infection (CHMI) model. This approach allowed us to characterize the relationship among cellular aging markers prior, during and post malaria pathophysiology in humans, controlling for infection dose, individual heterogeneity, previous exposure and co-infections. We demonstrate that already low levels of Plasmodium falciparum impact cellular aging by inducing high levels of inflammation and redox-imbalance; and that cellular senescence reversed after treatment and parasite clearance. This study provides insights into the complex relationship of telomere length, cellular senescence, telomerase expression and aging-related processes during a single malaria infection.
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23
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Expression Patterns of Plasmodium falciparum Clonally Variant Genes at the Onset of a Blood Infection in Malaria-Naive Humans. mBio 2021; 12:e0163621. [PMID: 34340541 PMCID: PMC8406225 DOI: 10.1128/mbio.01636-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clonally variant genes (CVGs) play fundamental roles in the adaptation of Plasmodium falciparum to fluctuating conditions of the human host. However, their expression patterns under the natural conditions of the blood circulation have been characterized in detail for only a few specific gene families. Here, we provide a detailed characterization of the complete P. falciparum transcriptome across the full intraerythrocytic development cycle (IDC) at the onset of a blood infection in malaria-naive human volunteers. We found that the vast majority of transcriptional differences between parasites obtained from the volunteers and the parental parasite line maintained in culture occurred in CVGs. In particular, we observed a major increase in the transcript levels of most genes of the pfmc-2tm and gbp families and of specific genes of other families, such as phist, hyp10, rif, or stevor, in addition to previously reported changes in var and clag3 gene expression. Increased transcript levels of individual pfmc-2tm, rif, and stevor genes involved activation in small subsets of parasites. Large transcriptional differences correlated with changes in the distribution of heterochromatin, confirming their epigenetic nature. Furthermore, the similar expression of several CVGs between parasites collected at different time points along the blood infection suggests that the epigenetic memory for multiple CVG families is lost during transmission stages, resulting in a reset of their transcriptional state. Finally, the CVG expression patterns observed in a volunteer likely infected by a single sporozoite suggest that new epigenetic patterns are established during liver stages.
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24
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Memvanga PB, Nkanga CI. Liposomes for malaria management: the evolution from 1980 to 2020. Malar J 2021; 20:327. [PMID: 34315484 PMCID: PMC8313885 DOI: 10.1186/s12936-021-03858-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/16/2021] [Indexed: 12/31/2022] Open
Abstract
Malaria is one of the most prevalent parasitic diseases and the foremost cause of morbidity in the tropical regions of the world. Strategies for the efficient management of this parasitic infection include adequate treatment with anti-malarial therapeutics and vaccination. However, the emergence and spread of resistant strains of malaria parasites to the majority of presently used anti-malarial medications, on the other hand, complicates malaria treatment. Other shortcomings of anti-malarial drugs include poor aqueous solubility, low permeability, poor bioavailability, and non-specific targeting of intracellular parasites, resulting in high dose requirements and toxic side effects. To address these limitations, liposome-based nanotechnology has been extensively explored as a new solution in malaria management. Liposome technology improves anti-malarial drug encapsulation, bioavailability, target delivery, and controlled release, resulting in increased effectiveness, reduced resistance progression, and fewer adverse effects. Furthermore, liposomes are exploited as immunological adjuvants and antigen carriers to boost the preventive effectiveness of malaria vaccine candidates. The present review discusses the findings from studies conducted over the last 40 years (1980-2020) using in vitro and in vivo settings to assess the prophylactic and curative anti-malarial potential of liposomes containing anti-malarial agents or antigens. This paper and the discussion herein provide a useful resource for further complementary investigations and may pave the way for the research and development of several available and affordable anti-malarial-based liposomes and liposomal malaria vaccines by allowing a thorough evaluation of liposomes developed to date for the management of malaria.
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Affiliation(s)
- Patrick B Memvanga
- Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, University of Kinshasa, B.P. 212, Kinshasa XI, Democratic Republic of the Congo.
| | - Christian I Nkanga
- Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, University of Kinshasa, B.P. 212, Kinshasa XI, Democratic Republic of the Congo
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25
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Reuling IJ, Mendes AM, de Jong GM, Fabra-García A, Nunes-Cabaço H, van Gemert GJ, Graumans W, Coffeng LE, de Vlas SJ, Yang ASP, Lee C, Wu Y, Birkett AJ, Ockenhouse CF, Koelewijn R, van Hellemond JJ, van Genderen PJJ, Sauerwein RW, Prudêncio M. An open-label phase 1/2a trial of a genetically modified rodent malaria parasite for immunization against Plasmodium falciparum malaria. Sci Transl Med 2021; 12:12/544/eaay2578. [PMID: 32434846 DOI: 10.1126/scitranslmed.aay2578] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 04/22/2020] [Indexed: 12/14/2022]
Abstract
For some diseases, successful vaccines have been developed using a nonpathogenic counterpart of the causative microorganism of choice. The nonpathogenicity of the rodent Plasmodium berghei (Pb) parasite in humans prompted us to evaluate its potential as a platform for vaccination against human infection by Plasmodium falciparum (Pf), a causative agent of malaria. We hypothesized that the genetic insertion of a leading protein target for clinical development of a malaria vaccine, Pf circumsporozoite protein (CSP), in its natural pre-erythrocytic environment, would enhance Pb's capacity to induce protective immunity against Pf infection. Hence, we recently generated a transgenic Pb sporozoite immunization platform expressing PfCSP (PbVac), and we now report the clinical evaluation of its biological activity against controlled human malaria infection (CHMI). This first-in-human trial shows that PbVac is safe and well tolerated, when administered by a total of ~300 PbVac-infected mosquitoes per volunteer. Although protective efficacy evaluated by CHMI showed no sterile protection at the tested dose, significant delays in patency (2.2 days, P = 0.03) and decreased parasite density were observed after immunization, corresponding to an estimated 95% reduction in Pf liver parasite burden (confidence interval, 56 to 99%; P = 0.010). PbVac elicits dose-dependent cross-species cellular immune responses and functional PfCSP-dependent antibody responses that efficiently block Pf sporozoite invasion of liver cells in vitro. This study demonstrates that PbVac immunization elicits a marked biological effect, inhibiting a subsequent infection by the human Pf parasite, and establishes the clinical validation of a new paradigm in malaria vaccination.
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Affiliation(s)
- Isaie J Reuling
- Radboud Center for Infectious Diseases, Department of Medical Microbiology, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - António M Mendes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Gerdie M de Jong
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015 GD Rotterdam, Netherlands
| | - Amanda Fabra-García
- Radboud Center for Infectious Diseases, Department of Medical Microbiology, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - Helena Nunes-Cabaço
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Geert-Jan van Gemert
- Radboud Center for Infectious Diseases, Department of Medical Microbiology, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - Wouter Graumans
- Radboud Center for Infectious Diseases, Department of Medical Microbiology, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, Netherlands
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, 3015 GD Rotterdam, Netherlands
| | - Annie S P Yang
- Radboud Center for Infectious Diseases, Department of Medical Microbiology, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands
| | - Cynthia Lee
- PATH's Malaria Vaccine Initiative, Washington, DC 20001, USA
| | - Yimin Wu
- PATH's Malaria Vaccine Initiative, Washington, DC 20001, USA
| | | | | | - Rob Koelewijn
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015 GD Rotterdam, Netherlands
| | - Jaap J van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015 GD Rotterdam, Netherlands
| | - Perry J J van Genderen
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015 GD Rotterdam, Netherlands. .,Corporate Travel Clinic Erasmus MC, 3015 CP Rotterdam, Netherlands
| | - Robert W Sauerwein
- Radboud Center for Infectious Diseases, Department of Medical Microbiology, Radboud University Medical Center, 6525 GA Nijmegen, Netherlands.
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal.
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26
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Levine MM, Abdullah S, Arabi YM, Darko DM, Durbin AP, Estrada V, Jamrozik E, Kremsner PG, Lagos R, Pitisuttithum P, Plotkin SA, Sauerwein R, Shi SL, Sommerfelt H, Subbarao K, Treanor JJ, Vrati S, King D, Balasingam S, Weller C, Aguilar AO, Cassetti MC, Krause PR, Restrepo AMH. Viewpoint of a WHO Advisory Group Tasked to Consider Establishing a Closely-monitored Challenge Model of Coronavirus Disease 2019 (COVID-19) in Healthy Volunteers. Clin Infect Dis 2021; 72:2035-2041. [PMID: 32857836 PMCID: PMC7499532 DOI: 10.1093/cid/ciaa1290] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Indexed: 12/16/2022] Open
Abstract
WHO convened an Advisory Group (AG) to consider the feasibility, potential value, and limitations of establishing a closely-monitored challenge model of experimental severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) in healthy adult volunteers. The AG included experts in design, establishment, and performance of challenges. This report summarizes issues that render a COVID-19 model daunting to establish (the potential of SARS-CoV-2 to cause severe/fatal illness, its high transmissibility, and lack of a "rescue treatment" to prevent progression from mild/moderate to severe clinical illness) and it proffers prudent strategies for stepwise model development, challenge virus selection, guidelines for manufacturing challenge doses, and ways to contain SARS-CoV-2 and prevent transmission to household/community contacts. A COVID-19 model could demonstrate protection against virus shedding and/or illness induced by prior SARS-CoV-2 challenge or vaccination. A limitation of the model is that vaccine efficacy in experimentally challenged healthy young adults cannot per se be extrapolated to predict efficacy in elderly/high-risk adults.
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Affiliation(s)
- Myron M Levine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Yaseen M Arabi
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Riyadh, Kingdom of Saudi Arabia
| | | | - Anna P Durbin
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Vicente Estrada
- Medical School, Complutense University, Hospital Clínico San Carlos, Madrid, Spain
| | | | - Peter G Kremsner
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | - Rosanna Lagos
- Centro para Vacunas en Desarrollo (CVD-Chile), Santiago, Chile
| | - Punnee Pitisuttithum
- Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stanley A Plotkin
- Department of Pediatrics, University of Pennsylvania, Doylestown, Pennsylvania, USA
| | - Robert Sauerwein
- Medical Parasitology Department, Radboud University, Nijmegen, The Netherlands
| | - Sheng-Li Shi
- Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Wuhan, China
| | - Halvor Sommerfelt
- Centre for Intervention Science in Maternal and Child Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, and Norwegian Institute of Public Health, Oslo, Norway
| | - Kanta Subbarao
- WHO Collaborating Centre for Reference and Research on Influenza and Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute, Melbourne, Australia
| | - John J Treanor
- Infectious Diseases Division, University of Rochester Medical Center, Rochester, New York, USA
| | - Sudhanshu Vrati
- Regional Centre for Biotechnology, Haryana (NCR Delhi), India
| | - Deborah King
- Vaccines Priority Area, Wellcome Trust, London, United Kingdom
| | | | - Charlie Weller
- Vaccines Programme, Wellcome Trust, London, United Kingdom
| | - Anastazia Older Aguilar
- Global Health Discovery & Translational Sciences, Bill & Melinda Gates Foundation, Seattle, Washington, USA
| | - M Cristina Cassetti
- Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Philip R Krause
- Office of Vaccines Research and Review, CEBR, FDA, Silver Spring, Maryland, USA.,Chair, WHO R&D Blueprint COVID-19 Vaccines Working Group
| | - Ana Maria Henao Restrepo
- Office of the Executive Director (WHE), WHO Health Emergencies Programme, World Health Organization, Geneva, Switzerland
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27
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Wang CYT, Ballard EL, Pava Z, Marquart L, Gaydon J, Murphy SC, Whiley D, O'Rourke P, McCarthy JS. Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults. Malar J 2021; 20:181. [PMID: 33838672 PMCID: PMC8035755 DOI: 10.1186/s12936-021-03717-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 03/29/2021] [Indexed: 11/10/2022] Open
Abstract
Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03717-y.
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Affiliation(s)
- Claire Y T Wang
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia. .,Child Health Research Centre, The University of Queensland, Brisbane, Australia.
| | - Emma L Ballard
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Zuleima Pava
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jane Gaydon
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,Child Health Research Centre, The University of Queensland, Brisbane, Australia
| | - Sean C Murphy
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, WA, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - David Whiley
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, The University of Queensland, Brisbane, Australia
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28
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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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29
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De SL, Ntumngia FB, Nicholas J, Adams JH. Progress towards the development of a P. vivax vaccine. Expert Rev Vaccines 2021; 20:97-112. [PMID: 33481638 PMCID: PMC7994195 DOI: 10.1080/14760584.2021.1880898] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Plasmodium vivax causes significant public health problems in endemic regions. A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the development of hypnozoites in the liver with potential for relapse. A minimally effective vaccine should prevent disease and transmission while an ideal vaccine provides sterile immunity. AREAS COVERED Despite decades of research, the complex life cycle, technical challenges and a lack of funding have hampered progress of P. vivax vaccine development. Here, we review the progress of potential P. vivax vaccine candidates from different stages of the parasite life cycle. We also highlight the challenges and important strategies for rational vaccine design. These factors can significantly increase immune effector mechanisms and improve the protective efficacy of these candidates in clinical trials to generate sustained protection over longer periods of time. EXPERT OPINION A vaccine that presents functionally-conserved epitopes from multiple antigens from various stages of the parasite life cycle is key to induce broadly neutralizing strain-transcending protective immunity to effectively disrupt parasite development and transmission.
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Affiliation(s)
- Sai Lata De
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Justin Nicholas
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
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30
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Safety and feasibility of apheresis to harvest and concentrate parasites from subjects with induced blood stage Plasmodium vivax infection. Malar J 2021; 20:43. [PMID: 33446191 PMCID: PMC7807416 DOI: 10.1186/s12936-021-03581-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 01/04/2021] [Indexed: 11/27/2022] Open
Abstract
Background In the absence of a method to culture Plasmodium vivax, the only way to source parasites is ex vivo. This hampers many aspects of P. vivax research. This study aimed to assess the safety of apheresis, a method for selective removal of specific components of blood as a means of extracting and concentrating P. vivax parasites. Methods An iterative approach was employed across four non-immune healthy human subjects in single subject cohorts. All four subjects were inoculated with ~ 564 blood stage P. vivax (HMP013-Pv) and subjected to apheresis 10 to 11 days later. Blood samples collected during apheresis (haematocrit layers 0.5% to 11%) were tested for the presence and concentration of P. vivax by microscopy, flow cytometry, 18S rDNA qPCR for total parasites, and pvs25 qRT-PCR for female gametocyte transcripts. Safety was determined by monitoring adverse events. Malaria transmission to mosquitoes was assessed by membrane feeding assays. Results There were no serious adverse events and no significant safety concerns. Apheresis concentrated asexual parasites by up to 4.9-fold (range: 0.9–4.9-fold) and gametocytes by up to 1.45-fold (range: 0.38–1.45-fold) compared to pre-apheresis densities. No single haematocrit layer contained > 40% of all the recovered P. vivax asexual parasites. Ex vivo concentration of parasites by Percoll gradient centrifugation of whole blood achieved greater concentration of gametocytes than apheresis. Mosquito transmission was enhanced by up to fivefold in a single apheresis sample compared to pre-apheresis. Conclusion The modest level of parasite concentration suggests that the use of apheresis may not be an ideal method for harvesting P. vivax. Trial Registration Australia New Zealand Clinical Trials Registry (ANZCTR) Trial ID: ACTRN12617001502325 registered on 19th October 2017. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373812.
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31
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Miyazaki Y, Marin-Mogollon C, Imai T, Mendes AM, van der Laak R, Sturm A, Geurten FJA, Miyazaki S, Chevalley-Maurel S, Ramesar J, Kolli SK, Kroeze H, van Schuijlenburg R, Salman AM, Wilder BK, Reyes-Sandoval A, Dechering KJ, Prudêncio M, Janse CJ, Khan SM, Franke-Fayard B. Generation of a Genetically Modified Chimeric Plasmodium falciparum Parasite Expressing Plasmodium vivax Circumsporozoite Protein for Malaria Vaccine Development. Front Cell Infect Microbiol 2020; 10:591046. [PMID: 33392104 PMCID: PMC7773900 DOI: 10.3389/fcimb.2020.591046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/11/2020] [Indexed: 12/28/2022] Open
Abstract
Chimeric rodent malaria parasites with the endogenous circumsporozoite protein (csp) gene replaced with csp from the human parasites Plasmodium falciparum (Pf) and P. vivax (Pv) are used in preclinical evaluation of CSP vaccines. Chimeric rodent parasites expressing PfCSP have also been assessed as whole sporozoite (WSP) vaccines. Comparable chimeric P. falciparum parasites expressing CSP of P. vivax could be used both for clinical evaluation of vaccines targeting PvCSP in controlled human P. falciparum infections and in WSP vaccines targeting P. vivax and P. falciparum. We generated chimeric P. falciparum parasites expressing both PfCSP and PvCSP. These Pf-PvCSP parasites produced sporozoite comparable to wild type P. falciparum parasites and expressed PfCSP and PvCSP on the sporozoite surface. Pf-PvCSP sporozoites infected human hepatocytes and induced antibodies to the repeats of both PfCSP and PvCSP after immunization of mice. These results support the use of Pf-PvCSP sporozoites in studies optimizing vaccines targeting PvCSP.
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Affiliation(s)
- Yukiko Miyazaki
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Takashi Imai
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands.,Department of Infectious Diseases and Host Defense, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - António M Mendes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | | | | | - Fiona J A Geurten
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Shinya Miyazaki
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Jai Ramesar
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Surendra K Kolli
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Hans Kroeze
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Ahmed M Salman
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Brandon K Wilder
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Arturo Reyes-Sandoval
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Shahid M Khan
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
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32
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Walk J, Keramati F, de Bree LCJ, Arts RJW, Blok B, Netea MG, Stunnenberg HG, Sauerwein RW. Controlled Human Malaria Infection Induces Long-Term Functional Changes in Monocytes. Front Mol Biosci 2020; 7:604553. [PMID: 33324683 PMCID: PMC7726436 DOI: 10.3389/fmolb.2020.604553] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/02/2020] [Indexed: 12/21/2022] Open
Abstract
Innate immune memory responses (also termed "trained immunity") have been described in monocytes after BCG vaccination and after stimulation in vitro with microbial and endogenous ligands such as LPS, β-glucan, oxidized LDL, and monosodium urate crystals. However, whether clinical infections are also capable of inducing a trained immunity phenotype remained uncertain. We evaluated whether Plasmodium falciparum infection can induce innate immune memory by measuring monocyte-derived cytokine production from five volunteers undergoing Controlled Human Malaria Infection. Monocyte responses followed a biphasic pattern: during acute infection, monocytes produced lower amounts of inflammatory cytokines upon secondary stimulation, but 36 days after malaria infection they produced significantly more IL-6 and TNF-α in response to various stimuli. Furthermore, transcriptomic and epigenomic data analysis revealed a clear reprogramming of monocytes at both timepoints, with long-term changes of H3K4me3 at the promoter regions of inflammatory genes that remain present for several weeks after parasite clearance. These findings demonstrate an epigenetic basis of trained immunity induced by human malaria in vivo.
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Affiliation(s)
- Jona Walk
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Farid Keramati
- Department of Molecular Biology, Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - L Charlotte J de Bree
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands.,Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark.,Odense Patient Data Explorative Network, University of Southern Denmark/Odense University Hospital, Odense, Denmark
| | - Rob J W Arts
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Bas Blok
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands.,Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark.,Odense Patient Data Explorative Network, University of Southern Denmark/Odense University Hospital, Odense, Denmark
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands.,Department for Immunology and Metabolism, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Hendrik G Stunnenberg
- Department of Molecular Biology, Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
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33
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Woodford J, Collins KA, Odedra A, Wang C, Jang IK, Domingo GJ, Watts R, Marquart L, Berriman M, Otto TD, McCarthy JS. An Experimental Human Blood-Stage Model for Studying Plasmodium malariae Infection. J Infect Dis 2020; 221:948-955. [PMID: 30852586 DOI: 10.1093/infdis/jiz102] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/06/2019] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Plasmodium malariae is considered a minor malaria parasite, although its global disease burden is underappreciated. The aim of this study was to develop an induced blood-stage malaria (IBSM) model of P. malariae to study parasite biology, diagnostic assays, and treatment. METHODS This clinical trial involved 2 healthy subjects who were intravenously inoculated with cryopreserved P. malariae-infected erythrocytes. Subjects were treated with artemether-lumefantrine after development of clinical symptoms. Prior to antimalarial therapy, mosquito-feeding assays were performed to investigate transmission, and blood samples were collected for rapid diagnostic testing and parasite transcription profiling. Serial blood samples were collected for biomarker analysis. RESULTS Both subjects experienced symptoms and signs typical of early malaria. Parasitemia was detected 7 days after inoculation, and parasite concentrations increased until antimalarial treatment was initiated 25 and 21 days after inoculation for subjects 1 and 2 respectively (peak parasitemia levels, 174 182 and 50 291 parasites/mL, respectively). The parasite clearance half-life following artemether-lumefantrine treatment was 6.7 hours. Mosquito transmission was observed for 1 subject, while in vivo parasite transcription and biomarkers were successfully profiled. CONCLUSIONS An IBSM model of P. malariae has been successfully developed and may be used to study the biology of, diagnostic testing for, and treatment of this neglected malaria species. CLINICAL TRIALS REGISTRATION ACTRN12617000048381.
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Affiliation(s)
- John Woodford
- QIMR Berghofer Medical Research Institute
- The University of Queensland
| | | | | | - Claire Wang
- Queensland Paediatric Infectious Diseases Laboratory, Brisbane, Australia
| | | | | | | | | | | | - Thomas D Otto
- Wellcome Sanger Institute, Hinxton
- Centre of Immunobiology, Institute of Infection, Immunity, and Inflammation, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute
- The University of Queensland
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Eagon S, Hammill JT, Sigal M, Ahn KJ, Tryhorn JE, Koch G, Belanger B, Chaplan CA, Loop L, Kashtanova AS, Yniguez K, Lazaro H, Wilkinson SP, Rice AL, Falade MO, Takahashi R, Kim K, Cheung A, DiBernardo C, Kimball JJ, Winzeler EA, Eribez K, Mittal N, Gamo FJ, Crespo B, Churchyard A, García-Barbazán I, Baum J, Anderson MO, Laleu B, Guy RK. Synthesis and Structure-Activity Relationship of Dual-Stage Antimalarial Pyrazolo[3,4- b]pyridines. J Med Chem 2020; 63:11902-11919. [PMID: 32945666 DOI: 10.1021/acs.jmedchem.0c01152] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Malaria remains one of the most deadly infectious diseases, causing hundreds of thousands of deaths each year, primarily in young children and pregnant mothers. Here, we report the discovery and derivatization of a series of pyrazolo[3,4-b]pyridines targeting Plasmodium falciparum, the deadliest species of the malaria parasite. Hit compounds in this series display sub-micromolar in vitro activity against the intraerythrocytic stage of the parasite as well as little to no toxicity against the human fibroblast BJ and liver HepG2 cell lines. In addition, our hit compounds show good activity against the liver stage of the parasite but little activity against the gametocyte stage. Parasitological profiles, including rate of killing, docking, and molecular dynamics studies, suggest that our compounds may target the Qo binding site of cytochrome bc1.
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Affiliation(s)
- Scott Eagon
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Jared T Hammill
- Department of Pharmaceutical Sciences, University of Kentucky , Lexington, Kentucky 40508, United States
| | - Martina Sigal
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, Tennessee 38105, United States
| | - Kevin J Ahn
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Julia E Tryhorn
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Grant Koch
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Briana Belanger
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Cory A Chaplan
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Lauren Loop
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Anna S Kashtanova
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Kenya Yniguez
- SRI International, 333 Ravenswood Avenue, Menlo Park, California 94025, United States
| | - Horacio Lazaro
- Promega Biosciences, 277 Granada Drive, San Luis Obispo, California 93401, United States
| | - Steven P Wilkinson
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Amy L Rice
- Department of Pharmaceutical Sciences, University of Kentucky , Lexington, Kentucky 40508, United States
| | - Mofolusho O Falade
- Department of Pharmaceutical Sciences, University of Kentucky , Lexington, Kentucky 40508, United States
| | - Rei Takahashi
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Katie Kim
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Ashley Cheung
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Celine DiBernardo
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Joshua J Kimball
- Promega Biosciences, 277 Granada Drive, San Luis Obispo, California 93401, United States
| | - Elizabeth A Winzeler
- School of Medicine, University of California San Diego, La Jolla, California 92093, United States
| | - Korina Eribez
- School of Medicine, University of California San Diego, La Jolla, California 92093, United States
| | - Nimisha Mittal
- School of Medicine, University of California San Diego, La Jolla, California 92093, United States
| | | | - Benigno Crespo
- GlaxoSmithKline, Global Health, DDW, Tres Cantos, Madrid 28760, Spain
| | - Alisje Churchyard
- Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Irene García-Barbazán
- Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Jake Baum
- Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California 94132, United States
| | - Benoît Laleu
- Medicines for Malaria Venture (MMV), P.O. Box 1826, 20, Route de Pré-Bois, Geneva 1215, Switzerland
| | - R Kiplin Guy
- Department of Pharmaceutical Sciences, University of Kentucky , Lexington, Kentucky 40508, United States
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Jamrozik E, Selgelid MJ. Human infection challenge studies in endemic settings and/or low-income and middle-income countries: key points of ethical consensus and controversy. JOURNAL OF MEDICAL ETHICS 2020; 46:601-609. [PMID: 32381683 PMCID: PMC7476299 DOI: 10.1136/medethics-2019-106001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/26/2020] [Accepted: 03/11/2020] [Indexed: 05/04/2023]
Abstract
Human infection challenge studies (HCS) involve intentionally infecting research participants with pathogens (or other micro-organisms). There have been recent calls for more HCS to be conducted in low-income and middle-income countries (LMICs), where many relevant diseases are endemic. HCS in general, and HCS in LMICs in particular, raise numerous ethical issues. This paper summarises the findings of a project that explored ethical and regulatory issues related to LMIC HCS via (i) a review of relevant literature and (ii) 45 qualitative interviews with scientists and ethicists. Among other areas of consensus, we found that there was widespread agreement that LMIC HCS can be ethically acceptable, provided that they have a sound scientific rationale, are accepted by local communities and meet usual research ethics requirements. Unresolved issues include those related to (i) acceptable approaches to trade-offs between the scientific aim to produce generalisable results and the protection of participants, (iii) the sharing of benefits with LMIC populations, (iii) the acceptable limits to risks and burdens for participants, (iv) the potential for third-party risk and whether the degree of acceptable third-party risk is different in endemic settings, (v) the conditions under which (if any) it would be appropriate to recruit children for disease-causing HCS, (v) appropriate levels of payment to participants and (vi) appropriate governance of (LMIC) HCS. This paper provides preliminary analyses of these ethical considerations in order to (i) inform scientists and policymakers involved in the planning, conduct and/or governance of LMIC HCS and (ii) highlight areas warranting future research. Insofar as this article focuses on HCS in (endemic) settings where diseases are present and/or widespread, much of the analysis provided is relevant to HCS (in HICs or LMICs) involving pandemic diseases including COVID19.
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Affiliation(s)
- Euzebiusz Jamrozik
- Monash Bioethics Centre, Monash University, Melbourne, Victoria, Australia
- Department of General Medicine, Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Michael J Selgelid
- Monash Bioethics Centre, Monash University, Melbourne, Victoria, Australia
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Abstract
The increasing recent interest in human challenge studies or controlled human infection model studies for accelerating vaccine development has been driven by the recognition of the unique ability of these studies to contribute to the understanding of response to infection and the performance of vaccines. With streamlining of ethical processes, conduct and supervision and the availability of new investigative tools from immunophenotyping to glycobiology, the potential to derive valuable data to inform vaccine testing and development has never been greater. However, issues of availability and standardization of challenge strains, conduct of studies in disease endemic locations and the iteration between clinical and laboratory studies still need to be addressed to gain maximal value for vaccine development.
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Affiliation(s)
- Amrita Sekhar
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Gagandeep Kang
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India.
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Troye-Blomberg M, Arama C, Quin J, Bujila I, Östlund Farrants AK. What will studies of Fulani individuals naturally exposed to malaria teach us about protective immunity to malaria? Scand J Immunol 2020; 92:e12932. [PMID: 32652609 PMCID: PMC7583377 DOI: 10.1111/sji.12932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/18/2020] [Accepted: 07/06/2020] [Indexed: 12/27/2022]
Abstract
There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub‐Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide‐treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.
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Affiliation(s)
- Marita Troye-Blomberg
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Charles Arama
- Department of Epidemiology of Parasitic Diseases, International Center of Excellence in Research, Malaria Research and Training Centre, University of Sciences, Technique and Technology of Bamako, Bamako, Mali
| | - Jaclyn Quin
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.,CEITEC Masaryk University, Brno, Czech Republic
| | - Ioana Bujila
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.,Department of Microbiology, Public Health Agency of Sweden, Solna, Sweden
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Kublin JG, Murphy SC, Maenza J, Seilie AM, Jain JP, Berger D, Spera D, Zhao R, Soon RL, Czartoski JL, Potochnic MA, Duke E, Chang M, Vaughan A, Kappe SHI, Leong FJ, Pertel P, Prince WT. Safety, pharmacokinetics and causal prophylactic efficacy of KAF156 in a Plasmodium falciparum human infection study. Clin Infect Dis 2020; 73:e2407-e2414. [PMID: 32644127 DOI: 10.1093/cid/ciaa952] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/07/2020] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND KAF156 is a novel antimalarial drug that is active against both liver- and blood- stage Plasmodium parasites, including drug-resistant strains. Here, we investigated the causal prophylactic efficacy of KAF156 in a controlled human malaria infection (CHMI) model. METHODS In Part 1, healthy, malaria-naïve participants received 800 mg KAF156 or placebo three hr before CHMI with Pf-infected mosquitoes. In Part 2, KAF156 was administered as single doses of 800, 300, 100, 50, or 20 mg 21 hr post-CHMI. All participants received atovaquone/proguanil treatment if blood-stage infection was detected or on day 29. For each cohort, 7-14 subjects were enrolled to KAF156 treatment and up to four subjects to placebo. RESULTS KAF156 at all dose levels was safe and well tolerated. Two serious adverse events were reported - both resolved without sequelae and neither was considered related to KAF156. In Part 1, all participants treated with KAF156 and none of those randomized to placebo were protected against malaria infection. In Part 2, all participants treated with placebo or 20 mg KAF156 developed malaria infection. In contrast, 50 mg KAF156 protected 3/14 participants from infection, and doses of 800, 300, and 100 mg KAF156 protected all subjects against infection. An exposure-response analysis suggested that a 24-hr post-dose concentration of KAF156 of 21·5 ng/mL (90% CI 17.66 to 25.32 ng/mL) would ensure a 95% chance of protection from malaria parasite infection. CONCLUSIONS KAF156 was safe and well tolerated and demonstrated high levels of pre- and post-CHMI protective efficacy.
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Affiliation(s)
- James G Kublin
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,Departments of Laboratory Medicine and Microbiology and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sean C Murphy
- Departments of Laboratory Medicine and Microbiology and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Janine Maenza
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Annette M Seilie
- Departments of Laboratory Medicine and Microbiology and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Jay Prakash Jain
- Novartis Institutes for BioMedical Research, Emeryville, California, USA.,Novartis Healthcare Pvt Ltd, Salarpuria-Sattva Knowledge City Raidurg, Rangareddy District Madhapur/ Hyderabad, Rangareddy, India
| | - David Berger
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Danielle Spera
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Rong Zhao
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Rachel L Soon
- Novartis Pharmaceuticals, Health Plaza, East Hanover, NJ
| | - Julie L Czartoski
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | | | - Elizabeth Duke
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Ming Chang
- Departments of Laboratory Medicine and Microbiology and the Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Ashley Vaughan
- Seattle Children's Research Institute, Seattle, Washington, USA
| | | | - F Joel Leong
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - Peter Pertel
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
| | - William T Prince
- Novartis Institutes for BioMedical Research, Emeryville, California, USA
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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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Graumans W, Jacobs E, Bousema T, Sinnis P. When Is a Plasmodium-Infected Mosquito an Infectious Mosquito? Trends Parasitol 2020; 36:705-716. [PMID: 32620501 DOI: 10.1016/j.pt.2020.05.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/19/2022]
Abstract
Plasmodium parasites experience significant bottlenecks as they transit through the mosquito and are transmitted to their mammalian host. Oocyst prevalence on mosquito midguts and sporozoite prevalence in salivary glands are nevertheless commonly used to confirm successful malaria transmission, assuming that these are reliable indicators of the mosquito's capacity to give rise to secondary infections. Here we discuss recent insights in sporogonic development and transmission bottlenecks for Plasmodium. We highlight critical gaps in our knowledge and frame their importance in understanding the human and mosquito reservoirs of infection. A better understanding of the events that lead to successful inoculation of infectious sporozoites by mosquitoes is critical to designing effective interventions to shrink the malaria map.
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Affiliation(s)
- Wouter Graumans
- Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Ella Jacobs
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Teun Bousema
- Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Medical Microbiology, Nijmegen, The Netherlands; Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
| | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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41
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Achan J, Reuling IJ, Yap XZ, Dabira E, Ahmad A, Cox M, Nwakanma D, Tetteh K, Wu L, Bastiaens GJH, Abebe Y, Manoj A, Kaur H, Miura K, Long C, Billingsley PF, Sim BKL, Hoffman SL, Drakeley C, Bousema T, D’Alessandro U. Serologic Markers of Previous Malaria Exposure and Functional Antibodies Inhibiting Parasite Growth Are Associated With Parasite Kinetics Following a Plasmodium falciparum Controlled Human Infection. Clin Infect Dis 2020; 70:2544-2552. [PMID: 31402382 PMCID: PMC7286377 DOI: 10.1093/cid/ciz740] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/01/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND We assessed the impact of exposure to Plasmodium falciparum on parasite kinetics, clinical symptoms, and functional immunity after controlled human malaria infection (CHMI) in 2 cohorts with different levels of previous malarial exposure. METHODS Nine adult males with high (sero-high) and 10 with low (sero-low) previous exposure received 3200 P. falciparum sporozoites (PfSPZ) of PfSPZ Challenge by direct venous inoculation and were followed for 35 days for parasitemia by thick blood smear (TBS) and quantitative polymerase chain reaction. Endpoints were time to parasitemia, adverse events, and immune responses. RESULTS Ten of 10 (100%) volunteers in the sero-low and 7 of 9 (77.8%) in the sero-high group developed parasitemia detected by TBS in the first 28 days (P = .125). The median time to parasitemia was significantly shorter in the sero-low group than the sero-high group (9 days [interquartile range {IQR} 7.5-11.0] vs 11.0 days [IQR 7.5-18.0], respectively; log-rank test, P = .005). Antibody recognition of sporozoites was significantly higher in the sero-high (median, 17.93 [IQR 12.95-24] arbitrary units [AU]) than the sero-low volunteers (median, 10.54 [IQR, 8.36-12.12] AU) (P = .006). Growth inhibitory activity was significantly higher in the sero-high (median, 21.8% [IQR, 8.15%-29.65%]) than in the sero-low group (median, 8.3% [IQR, 5.6%-10.23%]) (P = .025). CONCLUSIONS CHMI was safe and well tolerated in this population. Individuals with serological evidence of higher malaria exposure were able to better control infection and had higher parasite growth inhibitory activity. CLINICAL TRIALS REGISTRATION NCT03496454.
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Affiliation(s)
- Jane Achan
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Isaie J Reuling
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Xi Zen Yap
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Edgard Dabira
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Abdullahi Ahmad
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Momodou Cox
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Davis Nwakanma
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Kevin Tetteh
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Lindsey Wu
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Guido J H Bastiaens
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Harparkash Kaur
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Carole Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | | | | | | | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Umberto D’Alessandro
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
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Pollard AJ, Sauerwein R, Baay M, Neels P. Third human challenge trial conference, Oxford, United Kingdom, February 6-7, 2020, a meeting report. Biologicals 2020; 66:41-52. [PMID: 32505512 DOI: 10.1016/j.biologicals.2020.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 02/06/2023] Open
Abstract
The third Human Challenge Trial Meeting brought together a broad range of international stakeholders, including academia, regulators, funders and industry, with a considerable delegation from Low- and Middle-Income Countries. Controlled human infection models (CHIMs) can be helpful to study pathogenesis and for the development of vaccines. As challenge agents are used to infect healthy volunteers, ethical considerations include that the challenge studies need to be safe and results should be meaningful. The meeting provided a state-of-the-art overview on a wide range of CHIMs, including viral, bacterial and parasitic challenge agents. Recommendations included globally aligned guidance documents for CHIM studies; further definition of a CHIM, based on the challenge agent used; standardization of methodology and study endpoints; capacity building in Low- and Middle-Income Countries, in performance as well as regulation of CHIM studies; guidance on compensation for participation in CHIM studies; and preparation of CHIM studies, with strong engagement with stakeholders.
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Affiliation(s)
- Andrew J Pollard
- Department of Paediatrics, University of Oxford, United Kingdom.
| | | | - Marc Baay
- P95 Epidemiology & Pharmacovigilance, Leuven, Belgium.
| | - Pieter Neels
- International Alliance for Biological Standardization, Belgium.
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43
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Langenberg MCC, Dekkers OM, Roestenberg M. Are placebo controls necessary in controlled human infection trials for vaccines? THE LANCET. INFECTIOUS DISEASES 2020; 20:e69-e74. [PMID: 32142640 DOI: 10.1016/s1473-3099(20)30020-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 01/02/2020] [Accepted: 01/12/2020] [Indexed: 12/18/2022]
Abstract
Controlled human infection trials, whereby a small group of healthy participants is deliberately exposed to a pathogen under controlled circumstances, can provide preliminary data for vaccine efficacy and for the selection of the most promising candidate vaccines for field trials. Because of the potential harm to participants through the deliberate exposure to a pathogen, the use of smaller groups minimises the cumulative risk. As such, a control group that receives a placebo vaccine followed by controlled exposure to a pathogen should be scientifically well justified. As these types of trials are designed to generate consistent infection rates and thus comparable outcomes across populations and trial sites, data from past studies (historical data) could be used as a valid alternative to placebo groups. In this Personal View, we review this option and highlight the considerations for choosing historical data as a suitable control. For the widespread application of this method, responsibility for the centralisation and sharing of data from controlled human infection trials lies with the scientific community.
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Affiliation(s)
| | - Olaf M Dekkers
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, Netherlands
| | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands.
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44
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Human unconventional T cells in Plasmodium falciparum infection. Semin Immunopathol 2020; 42:265-277. [PMID: 32076813 PMCID: PMC7223888 DOI: 10.1007/s00281-020-00791-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 02/07/2020] [Indexed: 12/22/2022]
Abstract
Malaria is an old scourge of humankind and has a large negative impact on the economic development of affected communities. Recent success in malaria control and reduction of mortality seems to have stalled emphasizing that our current intervention tools need to be complemented by malaria vaccines. Different populations of unconventional T cells such as mucosal-associated invariant T (MAIT) cells, invariant natural killer T (iNKT) cells and γδ T cells are gaining attention in the field of malaria immunology. Significant advances in our basic understanding of unconventional T cell biology in rodent malaria models have been made, however, their roles in humans during malaria are less clear. Unconventional T cells are abundant in skin, gut and liver tissues, and long-lasting expansions and functional alterations were observed upon malaria infection in malaria naïve and malaria pre-exposed volunteers. Here, we review the current understanding of involvement of unconventional T cells in anti-Plasmodium falciparum immunity and highlight potential future research avenues.
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45
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de Jong RM, Tebeje SK, Meerstein‐Kessel L, Tadesse FG, Jore MM, Stone W, Bousema T. Immunity against sexual stage Plasmodium falciparum and Plasmodium vivax parasites. Immunol Rev 2020; 293:190-215. [PMID: 31840844 PMCID: PMC6973022 DOI: 10.1111/imr.12828] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 12/25/2022]
Abstract
The efficient spread of malaria from infected humans to mosquitoes is a major challenge for malaria elimination initiatives. Gametocytes are the only Plasmodium life stage infectious to mosquitoes. Here, we summarize evidence for naturally acquired anti-gametocyte immunity and the current state of transmission blocking vaccines (TBV). Although gametocytes are intra-erythrocytic when present in infected humans, developing Plasmodium falciparum gametocytes may express proteins on the surface of red blood cells that elicit immune responses in naturally exposed individuals. This immune response may reduce the burden of circulating gametocytes. For both P. falciparum and Plasmodium vivax, there is a solid evidence that antibodies against antigens present on the gametocyte surface, when co-ingested with gametocytes, can influence transmission to mosquitoes. Transmission reducing immunity, reducing the burden of infection in mosquitoes, is a well-acknowledged but poorly quantified phenomenon that forms the basis for the development of TBV. Transmission enhancing immunity, increasing the likelihood or intensity of transmission to mosquitoes, is more speculative in nature but is convincingly demonstrated for P. vivax. With the increased interest in malaria elimination, TBV and monoclonal antibodies have moved to the center stage of malaria vaccine development. Methodologies to prioritize and evaluate products are urgently needed.
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MESH Headings
- Antibodies, Blocking/immunology
- Antibodies, Protozoan/immunology
- Host-Parasite Interactions/immunology
- Humans
- Immunity
- Immunomodulation
- Life Cycle Stages
- Malaria Vaccines/immunology
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Malaria, Falciparum/prevention & control
- Malaria, Falciparum/transmission
- Malaria, Vivax/immunology
- Malaria, Vivax/parasitology
- Malaria, Vivax/prevention & control
- Malaria, Vivax/transmission
- Plasmodium falciparum/growth & development
- Plasmodium falciparum/immunology
- Plasmodium vivax/growth & development
- Plasmodium vivax/immunology
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Affiliation(s)
- Roos M. de Jong
- Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | | | - Lisette Meerstein‐Kessel
- Radboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Centre for Molecular and Biomolecular InformaticsRadboud Institute for Molecular Life SciencesNijmegenThe Netherlands
| | - Fitsum G. Tadesse
- Armauer Hansen Research InstituteAddis AbabaEthiopia
- Radboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Matthijs M. Jore
- Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Will Stone
- Department of Immunology and InfectionLondon School of Hygiene and Tropical MedicineLondonUK
| | - Teun Bousema
- Radboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Department of Immunology and InfectionLondon School of Hygiene and Tropical MedicineLondonUK
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46
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Yap XZ, McCall MBB, Sauerwein RW. Fast and fierce versus slow and smooth: Heterogeneity in immune responses to Plasmodium in the controlled human malaria infection model. Immunol Rev 2020; 293:253-269. [PMID: 31605396 PMCID: PMC6973142 DOI: 10.1111/imr.12811] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 12/19/2022]
Abstract
Controlled human malaria infection (CHMI) is an established model in clinical malaria research. Upon exposure to Plasmodium falciparum parasites, malaria-naive volunteers differ in dynamics and composition of their immune profiles and subsequent capacity to generate protective immunity. CHMI volunteers are either inflammatory responders who have prominent cellular IFN-γ production primarily driven by adaptive T cells, or tempered responders who skew toward antibody-mediated humoral immunity. When exposed to consecutive CHMIs under antimalarial chemoprophylaxis, individuals who can control parasitemia after a single immunization (fast responders) are more likely to be protected against a subsequent challenge infection. Fast responders tend to be inflammatory responders who can rapidly induce long-lived IFN-γ+ T cell responses. Slow responders or even non-responders can also be protected, but via a more diverse range of responses that take a longer time to reach full protective efficacy, in part due to their tempered phenotype. The latter group can be identified at baseline before CHMI by higher expression of inhibitory ligands CTLA-4 and TIM-3 on CD4+ T cells. Delineating heterogeneity in human immune responses to P. falciparum will facilitate rational design and strategy towards effective malaria vaccines.
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Affiliation(s)
- Xi Zen Yap
- Department of Medical MicrobiologyRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Center for Infectious DiseasesRadboud University Medical CenterNijmegenThe Netherlands
| | - Matthew B. B. McCall
- Department of Medical MicrobiologyRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Center for Infectious DiseasesRadboud University Medical CenterNijmegenThe Netherlands
| | - Robert W. Sauerwein
- Department of Medical MicrobiologyRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Center for Infectious DiseasesRadboud University Medical CenterNijmegenThe Netherlands
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47
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Tran TM, Crompton PD. Decoding the complexities of human malaria through systems immunology. Immunol Rev 2019; 293:144-162. [PMID: 31680289 DOI: 10.1111/imr.12817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022]
Abstract
The complexity of the Plasmodium parasite and its life cycle poses a challenge to our understanding of the host immune response against malaria. Studying human immune responses during natural and experimental Plasmodium infections can enhance our understanding of malaria-protective immunity and inform the design of disease-modifying adjunctive therapies and next-generation malaria vaccines. Systems immunology can complement conventional approaches to facilitate our understanding of the complex immune response to the highly dynamic malaria parasite. In this review, recent studies that used systems-based approaches to evaluate human immune responses during natural and experimental Plasmodium falciparum and Plasmodium vivax infections as well as during immunization with candidate malaria vaccines are summarized and related to each other. The potential for next-generation technologies to address the current limitations of systems-based studies of human malaria are discussed.
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Affiliation(s)
- Tuan M Tran
- Division of Infectious Diseases, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.,Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Peter D Crompton
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
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48
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Loiseau C, Cooper MM, Doolan DL. Deciphering host immunity to malaria using systems immunology. Immunol Rev 2019; 293:115-143. [PMID: 31608461 DOI: 10.1111/imr.12814] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 12/11/2022]
Abstract
A century of conceptual and technological advances in infectious disease research has changed the face of medicine. However, there remains a lack of effective interventions and a poor understanding of host immunity to the most significant and complex pathogens, including malaria. The development of successful interventions against such intractable diseases requires a comprehensive understanding of host-pathogen immune responses. A major advance of the past decade has been a paradigm switch in thinking from the contemporary reductionist (gene-by-gene or protein-by-protein) view to a more holistic (whole organism) view. Also, a recognition that host-pathogen immunity is composed of complex, dynamic interactions of cellular and molecular components and networks that cannot be represented by any individual component in isolation. Systems immunology integrates the field of immunology with omics technologies and computational sciences to comprehensively interrogate the immune response at a systems level. Herein, we describe the system immunology toolkit and report recent studies deploying systems-level approaches in the context of natural exposure to malaria or controlled human malaria infection. We contribute our perspective on the potential of systems immunity for the rational design and development of effective interventions to improve global public health.
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Affiliation(s)
- Claire Loiseau
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
| | - Martha M Cooper
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
| | - Denise L Doolan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
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Krähenbühl S, Studer F, Guirou E, Deal A, Mächler P, Hosch S, Mpina M, Mswata S, Daubenberger C, Schindler T. ELIMU-MDx: a web-based, open-source platform for storage, management and analysis of diagnostic qPCR data. Biotechniques 2019; 68:22-27. [PMID: 31588775 DOI: 10.2144/btn-2019-0064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The Electronic Laboratory Information and Management Utensil for Molecular Diagnostics (ELIMU-MDx) is a user-friendly platform designed and built to accelerate the turnaround time of diagnostic qPCR assays. ELIMU-MDx is compliant with Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines and has extensive data-import capabilities for all major qPCR instruments by using the RDML data standard. This platform was designed as an open-source software tool and can be accessed through the web browser on all major operating systems.
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Affiliation(s)
- Silvan Krähenbühl
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Fabian Studer
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Etienne Guirou
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Anna Deal
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Equatorial Guinea Malaria Vaccine Initiative, Malabo, Republic of Equatorial Guinea
| | - Philipp Mächler
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Salome Hosch
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Maximilian Mpina
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Equatorial Guinea Malaria Vaccine Initiative, Malabo, Republic of Equatorial Guinea.,Bagamoyo Research & Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania
| | - Sarah Mswata
- Bagamoyo Research & Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania
| | - Claudia Daubenberger
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Tobias Schindler
- Department of Medical Parasitology & Infection Biology, Swiss Tropical & Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
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50
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Manning JE, Morens DM, Kamhawi S, Valenzuela JG, Memoli M. Mosquito Saliva: The Hope for a Universal Arbovirus Vaccine? J Infect Dis 2019; 218:7-15. [PMID: 29617849 DOI: 10.1093/infdis/jiy179] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 03/28/2018] [Indexed: 02/06/2023] Open
Abstract
Arthropod-borne viruses (arboviruses) are taxonomically diverse causes of significant morbidity and mortality. In recent decades, important mosquito-borne viruses such as West Nile, chikungunya, dengue, and Zika have re-emerged and spread widely, in some cases pandemically, to cause serious public health emergencies. There are no licensed vaccines against most of these viruses, and vaccine development and use has been complicated by the number of different viruses to protect against, by subtype and strain variation, and by the inability to predict when and where outbreaks will occur. A new approach to preventing arboviral diseases is suggested by the observation that arthropod saliva facilitates transmission of pathogens, including leishmania parasites, Borrelia burgdorferi, and some arboviruses. Viruses carried within mosquito saliva may more easily initiate host infection by taking advantage of the host's innate and adaptive immune responses to saliva. This provides a rationale for creating vaccines against mosquito salivary proteins, rather than against only the virus proteins contained within the saliva. As proof of principle, immunization with sand fly salivary antigens to prevent leishmania infection has shown promising results in animal models. A similar approach using salivary proteins of important vector mosquitoes, such as Aedes aegypti, might protect against multiple mosquito-borne viral infections.
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Affiliation(s)
- Jessica E Manning
- Laboratory of Malaria and Vector Research, National Institutes of Health, Bethesda, Maryland.,Laboratory of Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - David M Morens
- Office of the Director, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Shaden Kamhawi
- Laboratory of Malaria and Vector Research, National Institutes of Health, Bethesda, Maryland
| | - Jesus G Valenzuela
- Laboratory of Malaria and Vector Research, National Institutes of Health, Bethesda, Maryland
| | - Matthew Memoli
- Laboratory of Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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