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Mertens JE, Rigby CA, Bardelli M, Quinkert D, Hou MM, Diouf A, Silk SE, Chitnis CE, Minassian AM, Moon RW, Long CA, Draper SJ, Miura K. Evaluation of the precision of the Plasmodium knowlesi growth inhibition assay for Plasmodium vivax Duffy-binding protein-based malaria vaccine development. Vaccine 2024; 42:3621-3629. [PMID: 38704253 PMCID: PMC11128340 DOI: 10.1016/j.vaccine.2024.04.073] [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: 03/01/2024] [Revised: 04/17/2024] [Accepted: 04/23/2024] [Indexed: 05/06/2024]
Abstract
Recent data indicate increasing disease burden and importance of Plasmodium vivax (Pv) malaria. A robust assay will be essential for blood-stage Pv vaccine development. Results of the in vitro growth inhibition assay (GIA) with transgenic P. knowlesi (Pk) parasites expressing the Pv Duffy-binding protein region II (PvDBPII) correlate with in vivo protection in the first PvDBPII controlled human malaria infection (CHMI) trials, making the PkGIA an ideal selection tool once the precision of the assay is defined. To determine the precision in percentage of inhibition in GIA (%GIA) and in GIA50 (antibody concentration that gave 50 %GIA), ten GIAs with transgenic Pk parasites were conducted with four different anti-PvDBPII human monoclonal antibodies (mAbs) at concentrations of 0.016 to 2 mg/mL, and three GIAs with eighty anti-PvDBPII human polyclonal antibodies (pAbs) at 10 mg/mL. A significant assay-to-assay variation was observed, and the analysis revealed a standard deviation (SD) of 13.1 in the mAb and 5.94 in the pAb dataset for %GIA, with a LogGIA50 SD of 0.299 (for mAbs). Moreover, the ninety-five percent confidence interval (95 %CI) for %GIA or GIA50 in repeat assays was calculated in this investigation. The error range determined in this study will help researchers to compare PkGIA results from different assays and studies appropriately, thus supporting the development of future blood-stage malaria vaccine candidates, specifically second-generation PvDBPII-based formulations.
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Affiliation(s)
- Jonas E Mertens
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Institute for Infection Research and Vaccine Development (IIRVD), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Cassandra A Rigby
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom
| | - Martino Bardelli
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom
| | - Doris Quinkert
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom
| | - Mimi M Hou
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville 20852, MD, United States
| | - Sarah E Silk
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom
| | - Chetan E Chitnis
- Unité de Biologie de Plasmodium et Vaccins, Institut Pasteur, Université Paris Cité, 25-28 Rue du Dr Roux, 75015 Paris, France
| | - Angela M Minassian
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Robert W Moon
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville 20852, MD, United States
| | - Simon J Draper
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, United Kingdom; NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville 20852, MD, United States.
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Hart MN, Mohring F, DonVito SM, Thomas JA, Muller-Sienerth N, Wright GJ, Knuepfer E, Saibil HR, Moon RW. Sequential roles for red blood cell binding proteins enable phased commitment to invasion for malaria parasites. Nat Commun 2023; 14:4619. [PMID: 37528099 PMCID: PMC10393984 DOI: 10.1038/s41467-023-40357-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 07/20/2023] [Indexed: 08/03/2023] Open
Abstract
Invasion of red blood cells (RBCs) by Plasmodium merozoites is critical to their continued survival within the host. Two major protein families, the Duffy binding-like proteins (DBPs/EBAs) and the reticulocyte binding like proteins (RBLs/RHs) have been studied extensively in P. falciparum and are hypothesized to have overlapping, but critical roles just prior to host cell entry. The zoonotic malaria parasite, P. knowlesi, has larger invasive merozoites and contains a smaller, less redundant, DBP and RBL repertoire than P. falciparum. One DBP (DBPα) and one RBL, normocyte binding protein Xa (NBPXa) are essential for invasion of human RBCs. Taking advantage of the unique biological features of P. knowlesi and iterative CRISPR-Cas9 genome editing, we determine the precise order of key invasion milestones and demonstrate distinct roles for each family. These distinct roles support a mechanism for phased commitment to invasion and can be targeted synergistically with invasion inhibitory antibodies.
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Affiliation(s)
- Melissa N Hart
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
| | - Franziska Mohring
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Sophia M DonVito
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - James A Thomas
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | | | - Gavin J Wright
- Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Biology, Hull York Medical School, York Biomedical Research Institute, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Ellen Knuepfer
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
- Malaria Parasitology Laboratory, Francis Crick Institute, London, NW1 1AT, UK
| | - Helen R Saibil
- ISMB, Biological Sciences, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
| | - Robert W Moon
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
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Lee WC, Cheong FW, Amir A, Lai MY, Tan JH, Phang WK, Shahari S, Lau YL. Plasmodium knowlesi: the game changer for malaria eradication. Malar J 2022; 21:140. [PMID: 35505339 PMCID: PMC9066973 DOI: 10.1186/s12936-022-04131-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/18/2022] [Indexed: 11/12/2022] Open
Abstract
Plasmodium knowlesi is a zoonotic malaria parasite that has gained increasing medical interest over the past two decades. This zoonotic parasitic infection is prevalent in Southeast Asia and causes many cases with fulminant pathology. Despite several biogeographical restrictions that limit its distribution, knowlesi malaria cases have been reported in different parts of the world due to travelling and tourism activities. Here, breakthroughs and key information generated from recent (over the past five years, but not limited to) studies conducted on P. knowlesi were reviewed, and the knowledge gap in various research aspects that need to be filled was discussed. Besides, challenges and strategies required to control and eradicate human malaria with this emerging and potentially fatal zoonosis were described.
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Affiliation(s)
- Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amirah Amir
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Meng Yee Lai
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jia Hui Tan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Shahhaziq Shahari
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
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Ong JJY, Russell B, Han JH. Plasmodium cynomolgi Berok Growth Inhibition Assay by Thiol-reactive Probe Based Flow Cytometric Measurement. Bio Protoc 2021; 11:e4147. [PMID: 34604452 DOI: 10.21769/bioprotoc.4147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 01/18/2023] Open
Abstract
The relapsing malaria species, Plasmodium vivax, is the most widely distributed and difficult-to-treat cause of human malaria. The merozoites of P. vivax preferentially invade ephemeral human CD71+ reticulocytes (nascent reticulocytes), thereby limiting the development of a robust continuous culture in vitro. Fortunately, P. vivax's sister species, P. cynomolgi Berok, can be cultured continuously, providing the ability to screen novel therapeutics drug and vaccine candidates in a reliable and high-throughput manner. Based on well-established growth inhibition activity (GIA) assays against P. falciparum and P. knowlesi, this protocol adopts the current flow cytometry assay methodology and investigates P. vivax inhibitory antibodies using the P. cynomolgi Berok invasion model based on the thiol-reactivity and DNA abundance of viable parasites in macaque erythrocytes. Established GIA assays screen antibodies at either a single concentration or high/low dose concentrations to provide quick insights for prioritizing potential antibodies capable of specifically interrupting parasite ligand and host receptor binding with minimal concentrations. Hence, this protocol expands on the existing GIA assay by using serially diluted antibodies and generating a dose-response curve to better quantify the inhibitory efficacy amongst selected vaccine candidates.
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Affiliation(s)
- Jessica Jie Ying Ong
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Jin-Hee Han
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
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