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Miura K, Flores-Garcia Y, Long CA, Zavala F. Vaccines and monoclonal antibodies: new tools for malaria control. Clin Microbiol Rev 2024; 37:e0007123. [PMID: 38656211 DOI: 10.1128/cmr.00071-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
SUMMARYMalaria remains one of the biggest health problems in the world. While significant reductions in malaria morbidity and mortality had been achieved from 2000 to 2015, the favorable trend has stalled, rather significant increases in malaria cases are seen in multiple areas. In 2022, there were 249 million estimated cases, and 608,000 malaria-related deaths, mostly in infants and children aged under 5 years, globally. Therefore, in addition to the expansion of existing anti-malarial control measures, it is critical to develop new tools, such as vaccines and monoclonal antibodies (mAbs), to fight malaria. In the last 2 years, the first and second malaria vaccines, both targeting Plasmodium falciparum circumsporozoite proteins (PfCSP), have been recommended by the World Health Organization to prevent P. falciparum malaria in children living in moderate to high transmission areas. While the approval of the two malaria vaccines is a considerable milestone in vaccine development, they have much room for improvement in efficacy and durability. In addition to the two approved vaccines, recent clinical trials with mAbs against PfCSP, blood-stage vaccines against P. falciparum or P. vivax, and transmission-blocking vaccine or mAb against P. falciparum have shown promising results. This review summarizes the development of the anti-PfCSP vaccines and mAbs, and recent topics in the blood- and transmission-blocking-stage vaccine candidates and mAbs. We further discuss issues of the current vaccines and the directions for the development of next-generation vaccines.
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Affiliation(s)
- Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Yevel Flores-Garcia
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Malaria Research Institute, Baltimore, Maryland, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Fidel Zavala
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Malaria Research Institute, Baltimore, Maryland, USA
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Yadav M, Dahiya N, Janjoter S, Kataria D, Dixit R, Sehrawat N. A review on RNA interference studies in Anophelines to reveal candidate genes for malaria transmission blocking vaccine. Life Sci 2024; 351:122822. [PMID: 38866221 DOI: 10.1016/j.lfs.2024.122822] [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: 11/16/2023] [Revised: 05/24/2024] [Accepted: 06/07/2024] [Indexed: 06/14/2024]
Abstract
Malaria is a major public health concern. The development of parasite-based vaccine RTS/AS01 has some therapeutic value but its lower efficacy is one of the major limitations. Mosquito-based transmission-blocking vaccines could have a higher potential for parasite inhibition within the mosquitoes. Several genes of mosquito midgut, salivary gland, hemolymph, etc. get activate in response to the Plasmodium-infected blood and helps in parasite invasion directly or indirectly inside the mosquito. The studies of such genes provided a new insight into developing the more efficient vaccines. In the field of malaria genetics research, RNAi has become an innovative strategy used to identify mosquito candidate genes for transmission-blocking vaccines. This review targeted the gene studies that have been conducted in the period 2000-2023 in different malaria vectors against different malarial parasites using the RNAi approach to reveal mosquito novel gene candidates for vaccine development.
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Affiliation(s)
- Mahima Yadav
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Nisha Dahiya
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Sangeeta Janjoter
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Divya Kataria
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | | | - Neelam Sehrawat
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India.
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Meredith S, Majam V, Zheng H, Verma N, Puri A, Akue A, KuKuruga M, Oakley M, Kumar S. Protective efficacy and correlates of immunity of immunodominant recombinant Babesia microti antigens. Infect Immun 2023; 91:e0016223. [PMID: 37728332 PMCID: PMC10580920 DOI: 10.1128/iai.00162-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/13/2023] [Indexed: 09/21/2023] Open
Abstract
Babesia microti, an intraerythrocytic apicomplexan parasite, is the primary causative agent of human babesiosis and an emerging threat to public health in the United States and elsewhere. An effective vaccine against B. microti would reduce disease severity in acute babesiosis patients and shorten the parasitemic period in asymptomatic individuals, thereby minimizing the risk of transfusion-transmitted babesiosis. Here we report on immunogenicity, protective efficacy, and correlates of immunity following immunization with four immunodominant recombinantly produced B. microti antigens-Serine Reactive Antigen 1 (SERA1), Maltese Cross Form Related Protein 1 (MCFRP1), Piroplasm β-Strand Domain 1 (PiβS1), and Babesia microti Alpha Helical Cell Surface Protein 1 (BAHCS1)-delivered subcutaneously in Montanide ISA 51/CpG adjuvant in three doses to BALB/c mice. Following B. microti parasite challenge, BAHCS1 led to the highest reduction in peak parasitemia (67.8%), followed by SERA1 (44.8%) and MCFRP1 (41.9%); PiβS1 (27.6%) had minimal protective effect. All four B. microti antigens induced high ELISA total IgG and each isotype; however, antibody levels did not directly correlate with anti-parasitic activity in mice. Increased prechallenge levels of some cell populations including follicular helper T cells (TFH) and memory B cells, along with a set of six cytokines [IL-1α, IL-2, IL-3, IL-6, IL-12(p40), and G-CSF] that belong to both innate and adaptive immune responses, were generally associated with protective immunity. Our results indicate that mechanisms driving recombinant B. microti antigen-induced immunity are complex and multifactorial. We think that BAHCS1 warrants further evaluation in preclinical studies.
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Affiliation(s)
- Scott Meredith
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Victoria Majam
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Hong Zheng
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Nitin Verma
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Ankit Puri
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Adovi Akue
- Division of Bacterial, Parasitic, and Allergenic Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Mark KuKuruga
- Division of Bacterial, Parasitic, and Allergenic Products, Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Miranda Oakley
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
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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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He Z, Yu C, Pan Z, Li X, Zhang X, Huang Q, Liao X, Hu J, Zeng F, Ru L, Yu W, Xu Q, Song J, Liang J. Erythrocyte membrane with CLIPPKF as biomimetic nanodecoy traps merozoites and attaches to infected red blood cells to prevent Plasmodium infection. J Nanobiotechnology 2023; 21:15. [PMID: 36647056 PMCID: PMC9841648 DOI: 10.1186/s12951-022-01709-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 11/14/2022] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Malaria remains a serious threat to global public health. With poor efficacies of vaccines and the emergence of drug resistance, novel strategies to control malaria are urgently needed. RESULTS We developed erythrocyte membrane-camouflaged nanoparticles loaded with artemether based on the growth characteristics of Plasmodium. The nanoparticles could capture the merozoites to inhibit them from repeatedly infecting normal erythrocytes, owing to the interactions between merozoites and heparin-like molecules on the erythrocyte membrane. Modification with a phosphatidylserine-targeting peptide (CLIPPKF) improved the drug accumulation in infected red blood cells (iRBCs) from the externalized phosphatidylserine induced by Plasmodium infection. In Plasmodium berghei ANKA strain (pbANKA)-infected C57BL/6 mice, the nanoparticles significantly attenuated Plasmodium-induced inflammation, apoptosis, and anemia. We observed reduced weight variation and prolonged survival time in pbANKA-challenged mice, and the nanoparticles showed good biocompatibility and negligible cytotoxicity. CONCLUSION Erythrocyte membrane-camouflaged nanoparticles loaded with artemether were shown to provide safe and effective protection against Plasmodium infection.
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Affiliation(s)
- Zhouqing He
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Chuyi Yu
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Ziyi Pan
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Xiaobo Li
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Xiangxiang Zhang
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Qijing Huang
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Xingcheng Liao
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Jiaoting Hu
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Feng Zeng
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Li Ru
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Wanlin Yu
- grid.413402.00000 0004 6068 0570Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, 510120 China
| | - Qin Xu
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Jianping Song
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China
| | - Jianming Liang
- grid.411866.c0000 0000 8848 7685Artemisinin Research Center, The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510405 China ,grid.8547.e0000 0001 0125 2443Key Laboratory of Smart Drug Delivery, School of Pharmacy, Ministry of Education, Fudan University, Shanghai, 201203 China
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Mansourou A, Joos C, Niass O, Diouf B, Tall A, Perraut R, Niang M, Toure-Balde A. Improvement of the antibody-dependent respiratory burst assay for assessing protective immune responses to malaria. Open Biol 2022; 12:210288. [PMID: 35291880 PMCID: PMC8924748 DOI: 10.1098/rsob.210288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The antibody-dependent respiratory burst (ADRB) assay is a sensitive isoluminol-based chemiluminescence (CL) functional assay designed to assess the capacity of opsonizing antibodies against merozoites to induce neutrophil respiratory burst. ADRB was shown to measure protective immunity against malaria in endemic areas, but the assay needed further improvement to ensure better sensitivity and reproducibility. Here, we adjusted parameters such as the freezing-thawing procedure of merozoites, merozoites's concentration and the buffer solution's pH, and we used the improved assay to measure ADRB activity of 207 sera from 97 and 110 individuals living, respectively, in Dielmo and Ndiop villages with differing malaria endemicity. The improvement led to increased CL intensity and assay sensitivity, and a higher reproducibility. In both areas, ADRB activity correlated with malaria endemicity and individual's age discriminated groups with and without clinical malaria episodes, and significantly correlated with in vivo clinical protection from Plasmodium falciparum malaria. Our results demonstrate that the improved ADRB assay can be valuably used to assess acquired immunity during monitoring by control programmes and/or clinical trials.
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Affiliation(s)
| | - Charlotte Joos
- Unité Immunologie, 36 Avenue Pasteur, 220 Dakar, Sénégal
| | - Oumy Niass
- Unité Immunologie, 36 Avenue Pasteur, 220 Dakar, Sénégal
| | - Babacar Diouf
- Unité Immunologie, 36 Avenue Pasteur, 220 Dakar, Sénégal
| | - Adama Tall
- Unité Epidémiologie, 36 Avenue Pasteur, 220 Dakar, Sénégal
| | - Ronald Perraut
- Unité Immunologie, 36 Avenue Pasteur, 220 Dakar, Sénégal
| | - Makhtar Niang
- Unité Immunologie, 36 Avenue Pasteur, 220 Dakar, Sénégal
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Neutrophils and Influenza: A Thin Line between Helpful and Harmful. Vaccines (Basel) 2021; 9:vaccines9060597. [PMID: 34199803 PMCID: PMC8228962 DOI: 10.3390/vaccines9060597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/28/2021] [Accepted: 05/30/2021] [Indexed: 01/01/2023] Open
Abstract
Influenza viruses are one of the most prevalent respiratory pathogens known to humans and pose a significant threat to global public health each year. Annual influenza epidemics are responsible for 3-5 million infections worldwide and approximately 500,000 deaths. Presently, yearly vaccinations represent the most effective means of combating these viruses. In humans, influenza viruses infect respiratory epithelial cells and typically cause localized infections of mild to moderate severity. Neutrophils are the first innate cells to be recruited to the site of the infection and possess a wide range of effector functions to eliminate viruses. Some well-described effector functions include phagocytosis, degranulation, the production of reactive oxygen species (ROS), and the formation of neutrophil extracellular traps (NETs). However, while these mechanisms can promote infection resolution, they can also contribute to the pathology of severe disease. Thus, the role of neutrophils in influenza viral infection is nuanced, and the threshold at which protective functions give way to immunopathology is not well understood. Moreover, notable differences between human and murine neutrophils underscore the need to exercise caution when applying murine findings to human physiology. This review aims to provide an overview of neutrophil characteristics, their classic effector functions, as well as more recently described antibody-mediated effector functions. Finally, we discuss the controversial role these cells play in the context of influenza virus infections and how our knowledge of this cell type can be leveraged in the design of universal influenza virus vaccines.
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Wockner LF, Hoffmann I, O'Rourke P, McCarthy JS, Marquart L. Comparison of statistical models to estimate parasite growth rate in the induced blood stage malaria model. Malar J 2017; 16:352. [PMID: 28841864 PMCID: PMC5574106 DOI: 10.1186/s12936-017-1999-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 08/20/2017] [Indexed: 11/28/2022] Open
Abstract
Background The efficacy of vaccines aimed at inhibiting the growth of malaria parasites in the blood can be assessed by comparing the growth rate of parasitaemia in the blood of subjects treated with a test vaccine compared to controls. In studies using induced blood stage malaria (IBSM), a type of controlled human malaria infection, parasite growth rate has been measured using models with the intercept on the y-axis fixed to the inoculum size. A set of statistical models was evaluated to determine an optimal methodology to estimate parasite growth rate in IBSM studies. Methods Parasite growth rates were estimated using data from 40 subjects published in three IBSM studies. Data was fitted using 12 statistical models: log-linear, sine-wave with the period either fixed to 48 h or not fixed; these models were fitted with the intercept either fixed to the inoculum size or not fixed. All models were fitted by individual, and overall by study using a mixed effects model with a random effect for the individual. Results Log-linear models and sine-wave models, with the period fixed or not fixed, resulted in similar parasite growth rate estimates (within 0.05 log10 parasites per mL/day). Average parasite growth rate estimates for models fitted by individual with the intercept fixed to the inoculum size were substantially lower by an average of 0.17 log10 parasites per mL/day (range 0.06–0.24) compared with non-fixed intercept models. Variability of parasite growth rate estimates across the three studies analysed was substantially higher (3.5 times) for fixed-intercept models compared with non-fixed intercept models. The same tendency was observed in models fitted overall by study. Modelling data by individual or overall by study had minimal effect on parasite growth estimates. Conclusions The analyses presented in this report confirm that fixing the intercept to the inoculum size influences parasite growth estimates. The most appropriate statistical model to estimate the growth rate of blood-stage parasites in IBSM studies appears to be a log-linear model fitted by individual and with the intercept estimated in the log-linear regression. Future studies should use this model to estimate parasite growth rates. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1999-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leesa F Wockner
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia
| | - Isabell Hoffmann
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia.,Institute of Medical Biostatistics, Epidemiology and Informatics, Medical Center of Johannes Gutenberg University, 55101, Mainz, Germany
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia. .,School of Medicine, University of Queensland, Brisbane, QLD, 4072, Australia. .,Q-Pharm Pty Ltd, Brisbane, QLD, 4006, Australia.
| | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, 4006, Australia
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Theisen M, Adu B, Mordmüller B, Singh S. The GMZ2 malaria vaccine: from concept to efficacy in humans. Expert Rev Vaccines 2017; 16:907-917. [PMID: 28699823 DOI: 10.1080/14760584.2017.1355246] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION GMZ2 is a recombinant protein consisting of conserved domains of GLURP and MSP3, two asexual blood-stage antigens of Plasmodium falciparum, and is designed with the aim of mimicking naturally acquired anti-malarial immunity. The rationale for combining these two antigens is based on a series of immune epidemiological studies from geographically diverse malaria endemic regions; functional in vitro studies; and pre-clinical studies in rodents and New World monkeys. GMZ2 adjuvanted with alhydrogel® (alum) was well tolerated and immunogenic in three phase 1 studies. The recently concluded phase 2 trial of GMZ2/alum, involving 1849 participants 12 to 60 month of age in four countries in West, Central and Eastern Africa, showed that GMZ2 is well tolerated and has some, albeit modest, efficacy in the target population. Areas covered: PubMed ( www.ncbi.nlm.nih.gov/pubmed ) was searched to review the progress and future prospects for clinical development of GMZ2 sub-unit vaccine. We will focus on discovery, naturally acquired immunity, functional activity of specific antibodies, sequence diversity, production, pre-clinical and clinical studies. Expert commentary: GMZ2 is well tolerated and has some, albeit modest, efficacy in the target population. More immunogenic formulations should be developed.
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Affiliation(s)
- Michael Theisen
- a Department for Congenital Disorders , Statens Serum Institut , Copenhagen , Denmark.,b Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology , University of Copenhagen , Copenhagen , Denmark.,c Department of Infectious Diseases , Copenhagen University Hospital , Rigshospitalet , Denmark
| | - Bright Adu
- d Noguchi Memorial Institute for Medical Research , University of Ghana , Legon , Ghana
| | - Benjamin Mordmüller
- e Institute of Tropical Medicine and Center for Infection Research, partner site Tübingen , University of Tübingen , Tübingen , Germany
| | - Subhash Singh
- f Indian Institute of Integrative Medicine , Jammu , India
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10
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Hill DL, Schofield L, Wilson DW. IgG opsonization of merozoites: multiple immune mechanisms for malaria vaccine development. Int J Parasitol 2017; 47:585-595. [PMID: 28668325 DOI: 10.1016/j.ijpara.2017.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/12/2017] [Accepted: 05/12/2017] [Indexed: 02/07/2023]
Abstract
Global eradication of the human-infecting malaria parasite Plasmodium falciparum, the major cause of malaria mortality, is unlikely to be achieved without an effective vaccine. However, our limited understanding of how protective immune responses target malaria parasites in humans, and how to best elicit these immune responses through vaccination, has hampered vaccine development. The red blood cell invading stage of the parasite lifecycle (merozoite) displays antigens that are attractive vaccine candidates as they are accessible to antibodies and raise high antibody titres in naturally immune individuals. The number of merozoite antigens that elicit an immune response, and their structural and functional diversity, has led to a large number of lead antigens being pursued as vaccine candidates. Despite being seemingly spoilt for choice in terms of vaccine candidates, there is still a lack of consensus on exactly how merozoite antibodies reduce parasitemia and malaria disease. In this review we describe the various immune mechanisms that can result from IgG opsonization of merozoites, and highlight recent developments that support a role for these functional antibodies in naturally acquired and vaccine-induced immunity.
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Affiliation(s)
- Danika L Hill
- Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom; The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia.
| | - Louis Schofield
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia; Burnet Institute, 85 Commercial Road, Melbourne 3004, Victoria, Australia.
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11
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A Plasmodium vivax Plasmid DNA- and Adenovirus-Vectored Malaria Vaccine Encoding Blood-Stage Antigens AMA1 and MSP1 42 in a Prime/Boost Heterologous Immunization Regimen Partially Protects Aotus Monkeys against Blood-Stage Challenge. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00539-16. [PMID: 28179404 DOI: 10.1128/cvi.00539-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/06/2017] [Indexed: 01/30/2023]
Abstract
Malaria is caused by parasites of the genus Plasmodium, which are transmitted to humans by the bites of Anopheles mosquitoes. After the elimination of Plasmodium falciparum, it is predicted that Plasmodium vivax will remain an important cause of morbidity and mortality outside Africa, stressing the importance of developing a vaccine against P. vivax malaria. In this study, we assessed the immunogenicity and protective efficacy of two P. vivax antigens, apical membrane antigen 1 (AMA1) and the 42-kDa C-terminal fragment of merozoite surface protein 1 (MSP142) in a plasmid recombinant DNA prime/adenoviral (Ad) vector boost regimen in Aotus monkeys. Groups of 4 to 5 monkeys were immunized with plasmid DNA alone, Ad alone, prime/boost regimens with each antigen, prime/boost regimens with both antigens, and empty vector controls and then subjected to blood-stage challenge. The heterologous immunization regimen with the antigen pair was more protective than either antigen alone or both antigens delivered with a single vaccine platform, on the basis of their ability to induce the longest prepatent period and the longest time to the peak level of parasitemia, the lowest peak and mean levels of parasitemia, the smallest area under the parasitemia curve, and the highest self-cure rate. Overall, prechallenge MSP142 antibody titers strongly correlated with a decreased parasite burden. Nevertheless, a significant proportion of immunized animals developed anemia. In conclusion, the P. vivax plasmid DNA/Ad serotype 5 vaccine encoding blood-stage parasite antigens AMA1 and MSP142 in a heterologous prime/boost immunization regimen provided significant protection against blood-stage challenge in Aotus monkeys, indicating the suitability of these antigens and this regimen for further development.
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Hodgson SH, Llewellyn D, Silk SE, Milne KH, Elias SC, Miura K, Kamuyu G, Juma EA, Magiri C, Muia A, Jin J, Spencer AJ, Longley RJ, Mercier T, Decosterd L, Long CA, Osier FH, Hoffman SL, Ogutu B, Hill AVS, Marsh K, Draper SJ. Changes in Serological Immunology Measures in UK and Kenyan Adults Post-controlled Human Malaria Infection. Front Microbiol 2016; 7:1604. [PMID: 27790201 PMCID: PMC5061779 DOI: 10.3389/fmicb.2016.01604] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/26/2016] [Indexed: 11/15/2022] Open
Abstract
Background: The timing of infection is closely determined in controlled human malaria infection (CHMI) studies, and as such they provide a unique opportunity to dissect changes in immunological responses before and after a single infection. The first Kenyan Challenge Study (KCS) (Pan African Clinical Trial Registry: PACTR20121100033272) was performed in 2013 with the aim of establishing the CHMI model in Kenya. This study used aseptic, cryopreserved, attenuated Plasmodium falciparum sporozoites administered by needle and syringe (PfSPZ Challenge) and was the first to evaluate parasite dynamics post-CHMI in individuals with varying degrees of prior exposure to malaria. Methods: We describe detailed serological and functional immunological responses pre- and post-CHMI for participants in the KCS and compare these with those from malaria-naïve UK volunteers who also underwent CHMI (VAC049) (ClinicalTrials.gov NCT01465048) using PfSPZ Challenge. We assessed antibody responses to three key blood-stage merozoite antigens [merozoite surface protein 1 (MSP1), apical membrane protein 1 (AMA1), and reticulocyte-binding protein homolog 5 (RH5)] and functional activity using two candidate measures of anti-merozoite immunity; the growth inhibition activity (GIA) assay and the antibody-dependent respiratory burst activity (ADRB) assay. Results:Clear serological differences were observed pre- and post-CHMI by ELISA between malaria-naïve UK volunteers in VAC049, and Kenyan volunteers who had prior malaria exposure. Antibodies to AMA1 and schizont extract correlated with parasite multiplication rate (PMR) post-CHMI in KCS. Serum from volunteer 110 in KCS, who demonstrated a dramatically reduced PMR in vivo, had no in vitro GIA prior to CHMI but the highest level of ADRB activity. A significant difference in ADRB activity was seen between KCS volunteers with minimal and definite prior exposure to malaria and significant increases were seen in ADRB activity post-CHMI in Kenyan volunteers. Quinine and atovaquone/proguanil, previously assumed to be removed by IgG purification, were identified as likely giving rise to aberrantly high in vitro GIA results. Conclusions: The ADRB activity assay is a promising functional assay that warrants further investigation as a measure of prior exposure to malaria and predictor of control of parasite growth. The CHMI model can be used to evaluate potential measures of naturally-acquired immunity to malaria.
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Affiliation(s)
| | | | - Sarah E Silk
- The Jenner Institute, University of Oxford Oxford, UK
| | | | - Sean C Elias
- The Jenner Institute, University of Oxford Oxford, UK
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIH-National Institute of Allergy and Infectious Diseases Rockville, MD, USA
| | - Gathoni Kamuyu
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute-Wellcome Trust Kilifi, Kenya
| | - Elizabeth A Juma
- Centre for Clinical Research, Kenya Medical Research InstituteNairobi, Kenya; Centre for Research in Therapeutic Sciences, Strathmore UniversityNairobi, Kenya
| | - Charles Magiri
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya
| | - Alfred Muia
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya
| | - Jing Jin
- The Jenner Institute, University of Oxford Oxford, UK
| | | | | | - Thomas Mercier
- Division of Clinical Pharmacology, Hôpital Beaumont, Université de Lausanne Lausanne, Switzerland
| | - Laurent Decosterd
- Division of Clinical Pharmacology, Hôpital Beaumont, Université de Lausanne Lausanne, Switzerland
| | - Carole A Long
- Laboratory of Malaria and Vector Research, NIH-National Institute of Allergy and Infectious Diseases Rockville, MD, USA
| | - Faith H Osier
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute-Wellcome Trust Kilifi, Kenya
| | | | - Bernhards Ogutu
- Centre for Clinical Research, Kenya Medical Research InstituteNairobi, Kenya; Centre for Research in Therapeutic Sciences, Strathmore UniversityNairobi, Kenya
| | | | - Kevin Marsh
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute-Wellcome TrustKilifi, Kenya; Department of Tropical Medicine, University of OxfordOxford, UK
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Merozoite Antigens of Plasmodium falciparum Elicit Strain-Transcending Opsonizing Immunity. Infect Immun 2016; 84:2175-2184. [PMID: 27185785 DOI: 10.1128/iai.00145-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/11/2016] [Indexed: 02/06/2023] Open
Abstract
It is unclear whether naturally acquired immunity to Plasmodium falciparum results from the acquisition of antibodies to multiple, diverse antigens or to fewer, highly conserved antigens. Moreover, the specific antibody functions required for malaria immunity are unknown, and hence informative immunological assays are urgently needed to address these knowledge gaps and guide vaccine development. In this study, we investigated whether merozoite-opsonizing antibodies are associated with protection from malaria in a strain-specific or strain-transcending manner by using a novel field isolate and an immune plasma-matched cohort from Papua New Guinea with our validated assay of merozoite phagocytosis. Highly correlated opsonization responses were observed across the 15 parasite strains tested, as were strong associations with protection (composite phagocytosis score across all strains in children uninfected at baseline: hazard ratio of 0.15, 95% confidence interval of 0.04 to 0.63). Opsonizing antibodies had a strong strain-transcending component, and the opsonization of transgenic parasites deficient for MSP3, MSP6, MSPDBL1, or P. falciparum MSP1-19 (PfMSP1-19) was similar to that of wild-type parasites. We have provided the first evidence that merozoite opsonization is predominantly strain transcending, and the highly consistent associations with protection against diverse parasite strains strongly supports the use of merozoite opsonization as a correlate of immunity for field studies and vaccine trials. These results demonstrate that conserved domains within merozoite antigens targeted by opsonization generate strain-transcending immune responses and represent promising vaccine candidates.
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Ord RL, Rodriguez M, Lobo CA. Malaria invasion ligand RH5 and its prime candidacy in blood-stage malaria vaccine design. Hum Vaccin Immunother 2016; 11:1465-73. [PMID: 25844685 DOI: 10.1080/21645515.2015.1026496] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
With drug resistance to available therapeutics continuing to develop against Plasmodium falciparum malaria, the development of an effective vaccine candidate remains a major research goal. Successful interruption of invasion of parasites into erythrocytes during the blood stage of infection will prevent the severe clinical symptoms and complications associated with malaria. Previously studied blood stage antigens have highlighted the hurdles that are inherent to this life-cycle stage, namely that highly immunogenic antigens are also globally diverse, resulting in protection only against the vaccine strain, or that naturally acquired immunity to blood stage antigens do not always correlate with actual protection. The blood stage antigen reticulocyte binding homolog RH5 is essential for parasite viability, has globally limited diversity, and is associated with protection from disease. Here we summarize available information on this invasion ligand and recent findings that highlight its candidacy for inclusion in a blood-stage malaria vaccine.
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Affiliation(s)
- Rosalynn L Ord
- a Blood-Borne Parasites; Lindsley Kimball Research Institute; New York Blood Center ; New York , NY , USA
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15
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Payne RO, Milne KH, Elias SC, Edwards NJ, Douglas AD, Brown RE, Silk SE, Biswas S, Miura K, Roberts R, Rampling TW, Venkatraman N, Hodgson SH, Labbé GM, Halstead FD, Poulton ID, Nugent FL, de Graaf H, Sukhtankar P, Williams NC, Ockenhouse CF, Kathcart AK, Qabar AN, Waters NC, Soisson LA, Birkett AJ, Cooke GS, Faust SN, Woods C, Ivinson K, McCarthy JS, Diggs CL, Vekemans J, Long CA, Hill AVS, Lawrie AM, Dutta S, Draper SJ. Demonstration of the Blood-Stage Plasmodium falciparum Controlled Human Malaria Infection Model to Assess Efficacy of the P. falciparum Apical Membrane Antigen 1 Vaccine, FMP2.1/AS01. J Infect Dis 2016; 213:1743-51. [PMID: 26908756 DOI: 10.1093/infdis/jiw039] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/21/2016] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Models of controlled human malaria infection (CHMI) initiated by mosquito bite have been widely used to assess efficacy of preerythrocytic vaccine candidates in small proof-of-concept phase 2a clinical trials. Efficacy testing of blood-stage malaria parasite vaccines, however, has generally relied on larger-scale phase 2b field trials in malaria-endemic populations. We report the use of a blood-stage P. falciparum CHMI model to assess blood-stage vaccine candidates, using their impact on the parasite multiplication rate (PMR) as the primary efficacy end point. METHODS Fifteen healthy United Kingdom adult volunteers were vaccinated with FMP2.1, a protein vaccine that is based on the 3D7 clone sequence of apical membrane antigen 1 (AMA1) and formulated in Adjuvant System 01 (AS01). Twelve vaccinees and 15 infectivity controls subsequently underwent blood-stage CHMI. Parasitemia was monitored by quantitative real-time polymerase chain reaction (PCR) analysis, and PMR was modeled from these data. RESULTS FMP2.1/AS01 elicited anti-AMA1 T-cell and serum antibody responses. Analysis of purified immunoglobulin G showed functional growth inhibitory activity against P. falciparum in vitro. There were no vaccine- or CHMI-related safety concerns. All volunteers developed blood-stage parasitemia, with no impact of the vaccine on PMR. CONCLUSIONS FMP2.1/AS01 demonstrated no efficacy after blood-stage CHMI. However, the model induced highly reproducible infection in all volunteers and will accelerate proof-of-concept testing of future blood-stage vaccine candidates. CLINICAL TRIALS REGISTRATION NCT02044198.
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Affiliation(s)
- Ruth O Payne
- Jenner Institute Laboratories Centre for Clinical Vaccinology and Tropical Medicine
| | | | | | | | | | | | | | | | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda
| | | | - Thomas W Rampling
- Jenner Institute Laboratories Centre for Clinical Vaccinology and Tropical Medicine
| | - Navin Venkatraman
- Jenner Institute Laboratories Centre for Clinical Vaccinology and Tropical Medicine
| | - Susanne H Hodgson
- Jenner Institute Laboratories Centre for Clinical Vaccinology and Tropical Medicine
| | | | | | - Ian D Poulton
- Centre for Clinical Vaccinology and Tropical Medicine
| | | | - Hans de Graaf
- National Institute for Health Research (NIHR) Wellcome Trust Clinical Research Facility, University Hospital Southampton National Health Service (NHS) Foundation Trust Faculty of Medicine, University of Southampton
| | - Priya Sukhtankar
- National Institute for Health Research (NIHR) Wellcome Trust Clinical Research Facility, University Hospital Southampton National Health Service (NHS) Foundation Trust Faculty of Medicine, University of Southampton
| | - Nicola C Williams
- Centre for Statistics in Medicine Botnar Research Centre, University of Oxford
| | - Christian F Ockenhouse
- Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland PATH Malaria Vaccine Initiative
| | - April K Kathcart
- Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Aziz N Qabar
- Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Norman C Waters
- Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | | | | | - Graham S Cooke
- NIHR Wellcome Trust Clinical Research Facility, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Saul N Faust
- National Institute for Health Research (NIHR) Wellcome Trust Clinical Research Facility, University Hospital Southampton National Health Service (NHS) Foundation Trust Faculty of Medicine, University of Southampton
| | | | | | | | | | | | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda
| | | | | | - Sheetij Dutta
- Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
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Abstract
There have been significant decreases in malaria mortality and morbidity in the last 10-15 years, and the most advanced pre-erythrocytic malaria vaccine, RTS,S, received a positive opinion from European regulators in July 2015. However, no blood-stage vaccine has reached a phase III trial. The first part of this review summarizes the pros and cons of various assays and models that have been and will be used to predict the efficacy of blood-stage vaccines. In the second part, blood-stage vaccine candidates that showed some efficacy in human clinical trials or controlled human malaria infection models are discussed. Then, candidates under clinical investigation are described in the third part, and other novel candidates and strategies are reviewed in the last part.
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Affiliation(s)
- Kazutoyo Miura
- a Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases , National Institutes of Health , Rockville , MD , USA
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17
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Draper SJ, Angov E, Horii T, Miller LH, Srinivasan P, Theisen M, Biswas S. Recent advances in recombinant protein-based malaria vaccines. Vaccine 2015; 33:7433-43. [PMID: 26458807 PMCID: PMC4687528 DOI: 10.1016/j.vaccine.2015.09.093] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 09/05/2015] [Accepted: 09/28/2015] [Indexed: 01/03/2023]
Abstract
Protein-based vaccines remain the cornerstone approach for B cell and antibody induction against leading target malaria antigens. Advances in antigen selection, immunogen design and epitope-focusing are advancing the field. New heterologous expression platforms are enabling cGMP production of next-generation protein vaccines. Next-generation antigens, protein-based immunogens and virus-like particle (VLP) delivery platforms are in clinical development. Protein-based vaccines will form part of a highly effective multi-component/multi-stage/multi-antigen subunit formulation against malaria.
Plasmodium parasites are the causative agent of human malaria, and the development of a highly effective vaccine against infection, disease and transmission remains a key priority. It is widely established that multiple stages of the parasite's complex lifecycle within the human host and mosquito vector are susceptible to vaccine-induced antibodies. The mainstay approach to antibody induction by subunit vaccination has been the delivery of protein antigen formulated in adjuvant. Extensive efforts have been made in this endeavor with respect to malaria vaccine development, especially with regard to target antigen discovery, protein expression platforms, adjuvant testing, and development of soluble and virus-like particle (VLP) delivery platforms. The breadth of approaches to protein-based vaccines is continuing to expand as innovative new concepts in next-generation subunit design are explored, with the prospects for the development of a highly effective multi-component/multi-stage/multi-antigen formulation seeming ever more likely. This review will focus on recent progress in protein vaccine design, development and/or clinical testing for a number of leading malaria antigens from the sporozoite-, merozoite- and sexual-stages of the parasite's lifecycle–including PfCelTOS, PfMSP1, PfAMA1, PfRH5, PfSERA5, PfGLURP, PfMSP3, Pfs48/45 and Pfs25. Future prospects and challenges for the development, production, human delivery and assessment of protein-based malaria vaccines are discussed.
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Affiliation(s)
- Simon J Draper
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK.
| | - Evelina Angov
- Walter Reed Army Institute of Research, U. S. Military Malaria Research Program, Malaria Vaccine Branch, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 561-873, Japan
| | - Louis H Miller
- Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Prakash Srinivasan
- Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark; Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology and Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sumi Biswas
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK
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18
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Douglas AD, Baldeviano GC, Lucas CM, Lugo-Roman LA, Crosnier C, Bartholdson SJ, Diouf A, Miura K, Lambert LE, Ventocilla JA, Leiva KP, Milne KH, Illingworth JJ, Spencer AJ, Hjerrild KA, Alanine DGW, Turner AV, Moorhead JT, Edgel KA, Wu Y, Long CA, Wright GJ, Lescano AG, Draper SJ. A PfRH5-based vaccine is efficacious against heterologous strain blood-stage Plasmodium falciparum infection in aotus monkeys. Cell Host Microbe 2015; 17:130-9. [PMID: 25590760 PMCID: PMC4297294 DOI: 10.1016/j.chom.2014.11.017] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 09/11/2014] [Accepted: 11/13/2014] [Indexed: 12/22/2022]
Abstract
Antigenic diversity has posed a critical barrier to vaccine development against the pathogenic blood-stage infection of the human malaria parasite Plasmodium falciparum. To date, only strain-specific protection has been reported by trials of such vaccines in nonhuman primates. We recently showed that P. falciparum reticulocyte binding protein homolog 5 (PfRH5), a merozoite adhesin required for erythrocyte invasion, is highly susceptible to vaccine-inducible strain-transcending parasite-neutralizing antibody. In vivo efficacy of PfRH5-based vaccines has not previously been evaluated. Here, we demonstrate that PfRH5-based vaccines can protect Aotus monkeys against a virulent vaccine-heterologous P. falciparum challenge and show that such protection can be achieved by a human-compatible vaccine formulation. Protection was associated with anti-PfRH5 antibody concentration and in vitro parasite-neutralizing activity, supporting the use of this in vitro assay to predict the in vivo efficacy of future vaccine candidates. These data suggest that PfRH5-based vaccines have potential to achieve strain-transcending efficacy in humans. Vaccines based on the P. falciparum merozoite antigen PfRH5 were tested in Aotus monkeys PfRH5-based vaccines afforded protection against heterologous strains of P. falciparum Protection correlated with anti-PfRH5 IgG concentration and in vivo neutralization
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Affiliation(s)
| | | | - Carmen M Lucas
- US Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | | | | | | | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Lynn E Lambert
- Laboratory of Malaria Immunology and Vaccinology, NIAID/NIH, Rockville, MD 20852, USA
| | | | - Karina P Leiva
- US Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | | | | | | | | | | | | | | | | | - Yimin Wu
- Laboratory of Malaria Immunology and Vaccinology, NIAID/NIH, Rockville, MD 20852, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | | | | | - Simon J Draper
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
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Viebig NK, D'Alessio F, Draper SJ, Sim BKL, Mordmüller B, Bowyer PW, Luty AJF, Jungbluth S, Chitnis CE, Hill AVS, Kremsner P, Craig AG, Kocken CHM, Leroy O. Workshop report: Malaria vaccine development in Europe--preparing for the future. Vaccine 2015; 33:6137-44. [PMID: 26431986 DOI: 10.1016/j.vaccine.2015.09.074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 09/03/2015] [Accepted: 09/22/2015] [Indexed: 10/23/2022]
Abstract
The deployment of a safe and effective malaria vaccine will be an important tool for the control of malaria and the reduction in malaria deaths. With the launch of the 2030 Malaria Vaccine Technology Roadmap, the malaria community has updated the goals and priorities for the development of such a vaccine and is now paving the way for a second phase of malaria vaccine development. During a workshop in Brussels in November 2014, hosted by the European Vaccine Initiative, key players from the European, North American and African malaria vaccine community discussed European strategies for future malaria vaccine development in the global context. The recommendations of the European malaria community should guide researchers, policy makers and funders of global health research and development in fulfilling the ambitious goals set in the updated Malaria Vaccine Technology Roadmap.
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Affiliation(s)
- Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany.
| | - Flavia D'Alessio
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Simon J Draper
- The Jenner Institute, University of Oxford , Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - B Kim Lee Sim
- Sanaria Inc., 9800 Medical Center Drive, Suite A209, Rockville, MD 20850, USA
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany; Centre de Recherches Médicales de Lambaréné, B.P. 118 Lambaréné, Gabon
| | - Paul W Bowyer
- The National Institute for Biological Standards and Control (NIBSC), Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK
| | - Adrian J F Luty
- IRD MERIT UMR 216, 75006 Paris, France; COMUE Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75270 Paris, France
| | - Stefan Jungbluth
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Chetan E Chitnis
- Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - Adrian V S Hill
- The Jenner Institute, University of Oxford , Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Peter Kremsner
- Institut für Tropenmedizin, Universitätsklinikum Tübingen, Wilhelmstraße 27, 72074 Tübingen, Germany; Centre de Recherches Médicales de Lambaréné, B.P. 118 Lambaréné, Gabon
| | - Alister G Craig
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Clemens H M Kocken
- Biomedical Primate Research Centre, Department of Parasitology, Lange Kleiweg 161, 2288 GJ Rijswijk, The Netherlands
| | - Odile Leroy
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
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Lover AA. Considerations for Comprehensive Analyses of Sporozoite-Based Controlled Human Malaria Infection Studies. Am J Trop Med Hyg 2015; 93:1130-1133. [PMID: 26392161 PMCID: PMC4674223 DOI: 10.4269/ajtmh.15-0327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/12/2015] [Indexed: 11/30/2022] Open
Abstract
There has been renewed interest in the use of sporozoite-based approaches for controlled human malaria infections (CHMIs), and several sets of human challenge studies have recently completed. A study undertaken in Tanzania and published in 2014 found dose dependence between 10,000 and 25,000 sporozoite doses, as well as divergent times-to-parasitemia relative to earlier studies in European volunteers, with important implications for planning future studies. Analysis of time-to-event data has had extensive development in recent years, but these methods have had limited exposure outside biostatistics. Expansion of the published analyses to include recent methodological approaches optimized for the types of data used could provide a richer analysis of these studies and may result in alternative findings. Specifically, in a re-analysis of these data using survival analysis techniques, the differences recorded in prepatent periods between the two dosing regimens do not reach statistical significance, and there is no evidence for statistically significant differences in prepatent periods between the Dutch and Tanzanian study sites. Although these findings do not impact the reported safety and tolerability of challange with cryopreserved Plasmodium falciparum sporozoites (PfSPZ), or invalidate the authors' hypotheses regarding naturally acquired immunity and its effect on parasite growth rates and prepatent periods, they highlight important opportunities to more fully use datasets from these trials and related CHMI experiments in the planning of future challenge studies.
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Affiliation(s)
- Andrew A. Lover
- *Address correspondence to Andrew A. Lover, Malaria Elimination Initiative, University of California, 550 16th Street, 3F, San Francisco, CA 94158. E-mails: or
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Wilhelm A, Kendrekar P, Noreljaleel AEM, Abay ET, Bonnet SL, Wiesner L, de Kock C, Swart KJ, van der Westhuizen JH. Syntheses and in Vitro Antiplasmodial Activity of Aminoalkylated Chalcones and Analogues. JOURNAL OF NATURAL PRODUCTS 2015; 78:1848-58. [PMID: 26235033 DOI: 10.1021/acs.jnatprod.5b00114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A series of readily synthesized and inexpensive aminoalkylated chalcones and diarylpropane analogues (1-55) were synthesized and tested against chloroquinone-sensitive (D10 and NF54) and -resistant (Dd2 and K1) strains of Plasmodium falciparum. Hydrogenation of the enone to a diarylpropane moiety increased antiplasmodial bioactivity significantly. The influence of the structure of the amine moiety, A-ring substituents, propyl vs ethyl linker, and chloride salt formation on further enhancing antiplasmodial activity was investigated. Several compounds have IC₅₀ values similar to or better than chloroquine (CQ). The most active compound (26) had an IC₅₀ value of 0.01 μM. No signs of resistance were detected, as can be expected from compounds with structures unrelated to CQ and other currently used antimalarial drugs. Toxicity tests (in vitro CHO cell assay) gave high SI indices.
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Affiliation(s)
| | | | | | - Efrem T Abay
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town , Cape Town, South Africa
| | | | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town , Cape Town, South Africa
| | - Carmen de Kock
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town , Cape Town, South Africa
| | - Kenneth J Swart
- PAREXEL International Clinical Research Organization , Private Bag X09, Brandhof 9324, Bloemfontein 339, South Africa
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Immunization with the MAEBL M2 Domain Protects against Lethal Plasmodium yoelii Infection. Infect Immun 2015; 83:3781-92. [PMID: 26169268 DOI: 10.1128/iai.00262-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 07/03/2015] [Indexed: 01/18/2023] Open
Abstract
Malaria remains a world-threatening disease largely because of the lack of a long-lasting and fully effective vaccine. MAEBL is a type 1 transmembrane molecule with a chimeric cysteine-rich ectodomain homologous to regions of the Duffy binding-like erythrocyte binding protein and apical membrane antigen 1 (AMA1) antigens. Although MAEBL does not appear to be essential for the survival of blood-stage forms, ectodomains M1 and M2, homologous to AMA1, seem to be involved in parasite attachment to erythrocytes, especially M2. MAEBL is necessary for sporozoite infection of mosquito salivary glands and is expressed in liver stages. Here, the Plasmodium yoelii MAEBL-M2 domain was expressed in a prokaryotic vector. C57BL/6J mice were immunized with doses of P. yoelii recombinant protein rPyM2-MAEBL. High levels of antibodies, with balanced IgG1 and IgG2c subclasses, were achieved. rPyM2-MAEBL antisera were capable of recognizing the native antigen. Anti-MAEBL antibodies recognized different MAEBL fragments expressed in CHO cells, showing stronger IgM and IgG responses to the M2 domain and repeat region, respectively. After a challenge with P. yoelii YM (lethal strain)-infected erythrocytes (IE), up to 90% of the immunized animals survived and a reduction of parasitemia was observed. Moreover, splenocytes harvested from immunized animals proliferated in a dose-dependent manner in the presence of rPyM2-MAEBL. Protection was highly dependent on CD4(+), but not CD8(+), T cells toward Th1. rPyM2-MAEBL antisera were also able to significantly inhibit parasite development, as observed in ex vivo P. yoelii erythrocyte invasion assays. Collectively, these findings support the use of MAEBL as a vaccine candidate and open perspectives to understand the mechanisms involved in protection.
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Hodgson SH, Juma E, Salim A, Magiri C, Njenga D, Molyneux S, Njuguna P, Awuondo K, Lowe B, Billingsley PF, Cole AO, Ogwang C, Osier F, Chilengi R, Hoffman SL, Draper SJ, Ogutu B, Marsh K. Lessons learnt from the first controlled human malaria infection study conducted in Nairobi, Kenya. Malar J 2015; 14:182. [PMID: 25927522 PMCID: PMC4416324 DOI: 10.1186/s12936-015-0671-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/15/2015] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Controlled human malaria infection (CHMI) studies, in which healthy volunteers are infected with Plasmodium falciparum to assess the efficacy of novel malaria vaccines and drugs, have become a vital tool to accelerate vaccine and drug development. CHMI studies provide a cost-effective and expeditious way to circumvent the use of large-scale field efficacy studies to deselect intervention candidates. However, to date few modern CHMI studies have been performed in malaria-endemic countries. METHODS An open-label, randomized pilot CHMI study was conducted using aseptic, purified, cryopreserved, infectious P. falciparum sporozoites (SPZ) (Sanaria® PfSPZ Challenge) administered intramuscularly (IM) to healthy Kenyan adults (n = 28) with varying degrees of prior exposure to P. falciparum. The purpose of the study was to establish the PfSPZ Challenge CHMI model in a Kenyan setting with the aim of increasing the international capacity for efficacy testing of malaria vaccines and drugs, and allowing earlier assessment of efficacy in a population for which interventions are being developed. This was part of the EDCTP-funded capacity development of the CHMI platform in Africa. DISCUSSION This paper discusses in detail lessons learnt from conducting the first CHMI study in Kenya. Issues pertinent to the African setting, including community sensitization, consent and recruitment are considered. Detailed reasoning regarding the study design (for example, dose and route of administration of PfSPZ Challenge, criteria for grouping volunteers according to prior exposure to malaria and duration of follow-up post CHMI) are given and changes other centres may want to consider for future studies are suggested. CONCLUSIONS Performing CHMI studies in an African setting presents unique but surmountable challenges and offers great opportunity for acceleration of malaria vaccine and drug development. The reflections in this paper aim to aid other centres and partners intending to use the CHMI model in Africa.
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Affiliation(s)
| | - Elizabeth Juma
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
- Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya.
| | - Amina Salim
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Charles Magiri
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Daniel Njenga
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Sassy Molyneux
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Patricia Njuguna
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Ken Awuondo
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Brett Lowe
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | | | - Andrew O Cole
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
- Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya.
| | - Caroline Ogwang
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Faith Osier
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Roma Chilengi
- Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.
| | | | | | - Bernhards Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
- Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya.
| | - Kevin Marsh
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
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Abstract
The development of a highly effective malaria vaccine remains a key goal to aid in the control and eventual eradication of this devastating parasitic disease. The field has made huge strides in recent years, with the first-generation vaccine RTS,S showing modest efficacy in a Phase III clinical trial. The updated 2030 Malaria Vaccine Technology Roadmap calls for a second generation vaccine to achieve 75% efficacy over two years for both Plasmodium falciparum and Plasmodium vivax, and for a vaccine that can prevent malaria transmission. Whole-parasite immunisation approaches and combinations of pre-erythrocytic subunit vaccines are now reporting high-level efficacy, whilst exciting new approaches to the development of blood-stage and transmission-blocking vaccine subunit components are entering clinical development. The development of a highly effective multi-component multi-stage subunit vaccine now appears to be a realistic ambition. This review will cover these recent developments in malaria vaccinology.
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Hodgson SH, Douglas AD, Edwards NJ, Kimani D, Elias SC, Chang M, Daza G, Seilie AM, Magiri C, Muia A, Juma EA, Cole AO, Rampling TW, Anagnostou NA, Gilbert SC, Hoffman SL, Draper SJ, Bejon P, Ogutu B, Marsh K, Hill AVS, Murphy SC. Increased sample volume and use of quantitative reverse-transcription PCR can improve prediction of liver-to-blood inoculum size in controlled human malaria infection studies. Malar J 2015; 14:33. [PMID: 25627033 PMCID: PMC4318195 DOI: 10.1186/s12936-015-0541-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 01/05/2015] [Indexed: 01/08/2023] Open
Abstract
Background Controlled human malaria infection (CHMI) studies increasingly rely on nucleic acid test (NAT) methods to detect and quantify parasites in the blood of infected participants. The lower limits of detection and quantification vary amongst the assays used throughout the world, which may affect the ability of mathematical models to accurately estimate the liver-to-blood inoculum (LBI) values that are used to judge the efficacy of pre-erythrocytic vaccine and drug candidates. Methods Samples were collected around the time of onset of pre-patent parasitaemia from subjects who enrolled in two different CHMI clinical trials. Blood samples were tested for Plasmodium falciparum 18S rRNA and/or rDNA targets by different NAT methods and results were compared. Methods included an ultrasensitive, large volume modification of an established quantitative reverse transcription PCR (qRT-PCR) assay that achieves detection of as little as one parasite/mL of whole blood. Results Large volume qRT-PCR at the University of Washington was the most sensitive test and generated quantifiable data more often than any other NAT methodology. Standard quantitative PCR (qPCR) performed at the University of Oxford and standard volume qRT-PCR performed at the University of Washington were less sensitive than the large volume qRT-PCR, especially at 6.5 days after CHMI. In these trials, the proportion of participants for whom LBI could be accurately quantified using parasite density value greater than or equal to the lower limit of quantification was increased. A greater improvement would be expected in trials in which numerous subjects receive a lower LBI or low dose challenge. Conclusions Standard qPCR and qRT-PCR methods with analytical sensitivities of ~20 parasites/mL probably suffice for most CHMI purposes, but the newly developed large volume qRT-PCR may be able to answer specific questions when more analytical sensitivity is required.
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Affiliation(s)
| | | | | | - Domtila Kimani
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Sean C Elias
- The Jenner Institute, University of Oxford, Oxford, UK.
| | - Ming Chang
- Department of Laboratory Medicine and Center for Emerging and Re-Emerging Infectious Diseases, University of Washington (UW), 750 Republican St., E633, Seattle, WA, 98109, USA.
| | - Glenda Daza
- Department of Laboratory Medicine and Center for Emerging and Re-Emerging Infectious Diseases, University of Washington (UW), 750 Republican St., E633, Seattle, WA, 98109, USA.
| | - Annette M Seilie
- Department of Laboratory Medicine and Center for Emerging and Re-Emerging Infectious Diseases, University of Washington (UW), 750 Republican St., E633, Seattle, WA, 98109, USA.
| | - Charles Magiri
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Alfred Muia
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Elizabeth A Juma
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya. .,Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya.
| | - Andrew O Cole
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.
| | | | | | | | | | | | - Philip Bejon
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | - Bernhards Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya. .,Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya.
| | - Kevin Marsh
- Kenya Medical Research Institute - Wellcome Trust, Centre for Geographical Medical Research (Coast), Kilifi, Kenya.
| | | | - Sean C Murphy
- Department of Laboratory Medicine and Center for Emerging and Re-Emerging Infectious Diseases, University of Washington (UW), 750 Republican St., E633, Seattle, WA, 98109, USA.
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Abstract
An effective malaria vaccine that reduces morbidity and mortality and contributes to malaria elimination is a much-needed tool, particularly in endemic areas where health-care delivery and vector control efforts are difficult to sustain. RTS,S/AS01 is likely to be the first licensed malaria vaccine and represents an important step toward malaria control and elimination. However, a partially effective vaccine such as RTS,S/AS01 poses challenges for evaluating the efficacy of second-generation malaria vaccines. Whole-sporozoite immunization approaches have shown promising results, inducing sterile immunity in small-scale trials of malaria-naïve adults, but may not achieve durable sterile protection in endemic populations. Vaccines targeting both the pre-erythrocytic and the erythrocyte-invasive form of the parasite (merozoites) may abrogate breakthrough infections by neutralizing merozoites emerging from infected hepatocytes, whereas vaccines targeting the sexual stages seek to break the transmission cycle. Moving forward, a multi-stage vaccine could be the next step toward malaria elimination and eradication.
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Hodgson SH, Juma E, Salim A, Magiri C, Kimani D, Njenga D, Muia A, Cole AO, Ogwang C, Awuondo K, Lowe B, Munene M, Billingsley PF, James ER, Gunasekera A, Sim BKL, Njuguna P, Rampling TW, Richman A, Abebe Y, Kamuyu G, Muthui M, Elias SC, Molyneux S, Gerry S, Macharia A, Williams TN, Bull PC, Hill AVS, Osier FH, Draper SJ, Bejon P, Hoffman SL, Ogutu B, Marsh K. Evaluating controlled human malaria infection in Kenyan adults with varying degrees of prior exposure to Plasmodium falciparum using sporozoites administered by intramuscular injection. Front Microbiol 2014; 5:686. [PMID: 25566206 PMCID: PMC4264479 DOI: 10.3389/fmicb.2014.00686] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/14/2014] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Controlled human malaria infection (CHMI) studies are a vital tool to accelerate vaccine and drug development. As CHMI trials are performed in a controlled environment, they allow unprecedented, detailed evaluation of parasite growth dynamics (PGD) and immunological responses. However, CHMI studies have not been routinely performed in malaria-endemic countries or used to investigate mechanisms of naturally-acquired immunity (NAI) to Plasmodium falciparum. METHODS We conducted an open-label, randomized CHMI pilot-study using aseptic, cryopreserved P. falciparum sporozoites (PfSPZ Challenge) to evaluate safety, infectivity and PGD in Kenyan adults with low to moderate prior exposure to P. falciparum (Pan African Clinical Trial Registry: PACTR20121100033272). RESULTS All participants developed blood-stage infection confirmed by quantitative polymerase chain reaction (qPCR). However one volunteer (110) remained asymptomatic and blood-film negative until day 21 post-injection of PfSPZ Challenge. This volunteer had a reduced parasite multiplication rate (PMR) (1.3) in comparison to the other 27 volunteers (median 11.1). A significant correlation was seen between PMR and screening anti-schizont Enzyme Linked Immunosorbent Assays (ELISA) OD (p = 0.044, R = -0.384) but not when volunteer 110 was excluded from the analysis (p = 0.112, R = -0.313). CONCLUSIONS PfSPZ Challenge is safe and infectious in malaria-endemic populations and could be used to assess the efficacy of malaria vaccines and drugs in African populations. Whilst our findings are limited by sample size, our pilot study has demonstrated for the first time that NAI may impact on PMR post-CHMI in a detectable fashion, an important finding that should be evaluated in further CHMI studies.
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Affiliation(s)
| | - Elizabeth Juma
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya ; Centre for Research in Therapeutic Sciences, Strathmore University Nairobi, Kenya
| | - Amina Salim
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Charles Magiri
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya
| | - Domtila Kimani
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Daniel Njenga
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya
| | - Alfred Muia
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya
| | - Andrew O Cole
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya ; Centre for Research in Therapeutic Sciences, Strathmore University Nairobi, Kenya
| | - Caroline Ogwang
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Ken Awuondo
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Brett Lowe
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Marianne Munene
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | | | | | | | | | - Patricia Njuguna
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | | | | | | | - Gathoni Kamuyu
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Michelle Muthui
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Sean C Elias
- The Jenner Institute, University of Oxford Oxford, UK
| | - Sassy Molyneux
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Stephen Gerry
- Centre for Statistics in Medicine, University of Oxford Oxford, UK
| | - Alex Macharia
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | - Thomas N Williams
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya ; Department of Medicine, Imperial College London London, UK
| | - Peter C Bull
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | | | - Faith H Osier
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | | | - Philip Bejon
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
| | | | - Bernhards Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute Nairobi, Kenya ; Centre for Research in Therapeutic Sciences, Strathmore University Nairobi, Kenya
| | - Kevin Marsh
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute - Wellcome Trust Kilifi, Kenya
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Terkawi MA, Kuroda Y, Fukumoto S, Tanaka S, Kojima N, Nishikawa Y. Plasmodium berghei circumsporozoite protein encapsulated in oligomannose-coated liposomes confers protection against sporozoite infection in mice. Malar J 2014; 13:426. [PMID: 25373617 PMCID: PMC4232614 DOI: 10.1186/1475-2875-13-426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 10/26/2014] [Indexed: 12/12/2022] Open
Abstract
Background The design and development of an effective malaria vaccine against the pre-erythrocytic and erythrocytic-stages of infection present a great challenge. Methods In the present study, protective efficacy of oligomannose-coated liposome (OML)-entrapped merozoite and sporozoite antigens against Plasmodium berghei challenge infection in BALB/c mice was evaluated. Results Subcutaneous immunization with truncated merozoite surface protein 1 entrapped with OML (OML-PbMSP1) prolonged survival, but failed to protect the mice from erythrocytic-stage infection, despite the antigen-specific antibody responses induced by the immunization regimen. In contrast, immunization with circumsporozoite protein entrapped with OML (OML-PbCSP) elicited antigen-specific humoral and cellular responses, which correlated with substantial protection against sporozoite challenge infections. Conclusions The current results represent the use of an oligomannose-coated liposome-based vaccine against pre-erythrocytic and erythrocytic stages malaria infection. This approach may offer a new vaccination strategy against malaria infection.
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Affiliation(s)
| | | | | | | | | | - Yoshifumi Nishikawa
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
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29
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Hodgson SH, Choudhary P, Elias SC, Milne KH, Rampling TW, Biswas S, Poulton ID, Miura K, Douglas AD, Alanine DG, Illingworth JJ, de Cassan SC, Zhu D, Nicosia A, Long CA, Moyle S, Berrie E, Lawrie AM, Wu Y, Ellis RD, Hill AVS, Draper SJ. Combining viral vectored and protein-in-adjuvant vaccines against the blood-stage malaria antigen AMA1: report on a phase 1a clinical trial. Mol Ther 2014; 22:2142-2154. [PMID: 25156127 PMCID: PMC4250079 DOI: 10.1038/mt.2014.157] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/05/2014] [Indexed: 12/21/2022] Open
Abstract
The development of effective vaccines against difficult disease targets will require the identification of new subunit vaccination strategies that can induce and maintain effective immune responses in humans. Here we report on a phase 1a clinical trial using the AMA1 antigen from the blood-stage Plasmodium falciparum malaria parasite delivered either as recombinant protein formulated with Alhydrogel adjuvant with and without CPG 7909, or using recombinant vectored vaccines—chimpanzee adenovirus ChAd63 and the orthopoxvirus MVA. A variety of promising “mixed-modality” regimens were tested. All volunteers were primed with ChAd63, and then subsequently boosted with MVA and/or protein-in-adjuvant using either an 8- or 16-week prime-boost interval. We report on the safety of these regimens, as well as the T cell, B cell, and serum antibody responses. Notably, IgG antibody responses primed by ChAd63 were comparably boosted by AMA1 protein vaccine, irrespective of whether CPG 7909 was included in the Alhydrogel adjuvant. The ability to improve the potency of a relatively weak aluminium-based adjuvant in humans, by previously priming with an adenoviral vaccine vector encoding the same antigen, thus offers a novel vaccination strategy for difficult or neglected disease targets when access to more potent adjuvants is not possible.
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Affiliation(s)
- Susanne H Hodgson
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK; Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford, Churchill Hospital, Oxford, UK.
| | | | - Sean C Elias
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Kathryn H Milne
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Thomas W Rampling
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK; Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford, Churchill Hospital, Oxford, UK
| | - Sumi Biswas
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Ian D Poulton
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford, Churchill Hospital, Oxford, UK
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | | | | | | | | | - Daming Zhu
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Alfredo Nicosia
- Okairòs, Rome, Italy; CEINGE, Naples, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Carole A Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Sarah Moyle
- Clinical Biomanufacturing Facility, University of Oxford, Churchill Hospital, Oxford, UK
| | - Eleanor Berrie
- Clinical Biomanufacturing Facility, University of Oxford, Churchill Hospital, Oxford, UK
| | - Alison M Lawrie
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford, Churchill Hospital, Oxford, UK
| | - Yimin Wu
- Laboratory of Malaria Immunology and Vaccinology, NIAID/NIH, Rockville, Maryland, USA
| | - Ruth D Ellis
- Laboratory of Malaria Immunology and Vaccinology, NIAID/NIH, Rockville, Maryland, USA
| | - Adrian V S Hill
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
| | - Simon J Draper
- The Jenner Institute Laboratories, University of Oxford, Oxford, UK
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30
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Kapelski S, Klockenbring T, Fischer R, Barth S, Fendel R. Assessment of the neutrophilic antibody-dependent respiratory burst (ADRB) response to Plasmodium falciparum. J Leukoc Biol 2014; 96:1131-42. [PMID: 25118179 DOI: 10.1189/jlb.4a0614-283rr] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Semi-immunity against Pf malaria is based on a combination of cellular and humoral immune responses. PMNs and IgGs are considered important components of this process, but the underlying mechanisms are unclear. We investigated the neutrophilic ADRB by analyzing the production of ROS in response to Pf antigen-specific IgGs bound to solid-phase immobilized antigens (sADRB) or whole merozoites (mADRB). We found that the PMN stimulations in each assay were based on different underlying mechanisms, demonstrating the importance of the assay set-up for the evaluation of antibody-triggered PMN responses. In the sADRB assay, ROS were produced externally, and by specific blocking of CD32(a)/FcγRII(a), the immediate neutrophilic response was abolished, whereas the removal of CD16(b)/FcγRIII(b) had no substantial effect. The key role of CD32(a) was confirmed using CD16(b)-deficient PMNs, in which similar changes of neutrophilic ADRB profiles were recorded after treatment. In the mADRB assay, ROS were produced almost exclusively within the cell, suggesting that the underlying mechanism was phagocytosis. This was confirmed using an additional phagocytosis assay, in which PMNs specifically ingested merozoites opsonized with Ghanaian plasma IgGs, seven times more often than merozoites opsonized with European plasma IgGs (P<0.001). Our data show that assay set-ups used to evaluate the responses of PMNs and perhaps other effector cells must be chosen carefully to evaluate the appropriate cellular responses. Our robust, stable, and well-characterized methods could therefore be useful in malaria vaccine studies to analyze the antimalarial effector function of antibodies.
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Affiliation(s)
- Stephanie Kapelski
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and
| | - Torsten Klockenbring
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and
| | - Stefan Barth
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Institute for Applied Medical Engineering at Rheinisch-Westfälische Technische Hochschule Aachen University and Hospital, Department of Experimental Medicine and Immunotherapy, Aachen, Germany
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Department of Pharmaceutical Product Development, Aachen, Germany; Rheinisch-Westfälische Technische Hochschule Aachen University, Institute for Molecular Biotechnology, Aachen, Germany; and
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31
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A next-generation genetically attenuated Plasmodium falciparum parasite created by triple gene deletion. Mol Ther 2014; 22:1707-15. [PMID: 24827907 DOI: 10.1038/mt.2014.85] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/29/2014] [Indexed: 12/14/2022] Open
Abstract
Immunization with live-attenuated Plasmodium sporozoites completely protects against malaria infection. Genetic engineering offers a versatile platform to create live-attenuated sporozoite vaccine candidates. We previously generated a genetically attenuated parasite (GAP) by deleting the P52 and P36 genes in the NF54 wild-type (WT) strain of Plasmodium falciparum (Pf p52(-)/p36(-) GAP). Preclinical assessment of p52(-)/p36(-) GAP in a humanized mouse model indicated an early and severe liver stage growth defect. However, human exposure to >200 Pf p52(-)/p36(-) GAP-infected mosquito bites in a safety trial resulted in peripheral parasitemia in one of six volunteers, revealing that this GAP was incompletely attenuated. We have now created a triple gene deleted GAP by additionally removing the SAP1 gene (Pf p52(-)/p36(-)/sap1(-) GAP) and employed flippase (FLP)/flippase recognition target (FRT) recombination for drug selectable marker cassette removal. This next-generation GAP was indistinguishable from WT parasites in blood stage and mosquito stage development. Using an improved humanized mouse model transplanted with human hepatocytes and human red blood cells, we show that despite a high-dose sporozoite challenge, Pf p52(-)/p36(-)/sap1(-) GAP did not transition to blood stage infection and appeared to be completely attenuated. Thus, clinical testing of Pf p52(-)/p36(-)/sap1(-) GAP assessing safety, immunogenicity, and efficacy against sporozoite challenge is warranted.
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32
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Affiliation(s)
- Gavin J. Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (GJW); (JCR)
| | - Julian C. Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (GJW); (JCR)
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