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Blanken SL, Barry A, Lanke K, Guelbeogo M, Ouedraogo A, Soulama I, Coulibaly SA, Teelen K, Graumans W, Dumont E, Stone W, Ramjith J, Marti M, Andrade CM, Drakeley C, Collins K, Tiono A, Bousema T. Plasmodium falciparum gametocyte production correlates with genetic markers of parasite replication but is not influenced by experimental exposure to mosquito biting. EBioMedicine 2024; 105:105190. [PMID: 38901148 PMCID: PMC11239461 DOI: 10.1016/j.ebiom.2024.105190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND Plasmodium blood-stage parasites balance asexual multiplication with gametocyte development. Few studies link these dynamics with parasite genetic markers in vivo; even fewer in longitudinally monitored infections. Environmental influences on gametocyte formation, such as mosquito exposure, may influence the parasite's investment in gametocyte production. METHODS We investigated gametocyte production and asexual multiplication in two Plasmodium falciparum infected populations; a controlled human malaria infection (CHMI) study and a 28-day observational study in naturally infected individuals in Burkina Faso with controlled mosquito exposure. We measured gene transcript levels previously related to gametocyte formation (ap2-g, surfin1.2, surfin13.1, gexp-2) or inhibition of asexual multiplication (sir2a) and compared transcript levels to ring-stage parasite and mature gametocyte densities. FINDINGS Three of the five markers (ap2-g, surfin1.2, surfin13.1) predicted peak gametocytaemia in the CHMI study. An increase in all five markers in natural infections was associated with an increase in mature gametocytes 14 days later; the effect of sir2a on future gametocytes was strongest (fold change = 1.65, IQR = 1.22-2.24, P = 0.004). Mosquito exposure was not associated with markers of gametocyte formation (ap2-g P = 0.277; sir2a P = 0.499) or carriage of mature gametocytes (P = 0.379). INTERPRETATION All five parasite genetic markers predicted gametocyte formation over a single cycle of gametocyte formation and maturation in vivo; sir2a and ap2-g were most closely associated with gametocyte growth dynamics. We observed no evidence to support the hypothesis that exposure to Anopheles mosquito bites stimulates gametocyte formation. FUNDING This work was funded by the Bill & Melinda Gates Foundation (INDIE OPP1173572), the European Research Council fellowship (ERC-CoG 864180) and UKRI Medical Research Council (MR/T016272/1) and Wellcome Center (218676/Z/19/Z).
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Affiliation(s)
- Sara Lynn Blanken
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Aissata Barry
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Moussa Guelbeogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Sam Aboubacar Coulibaly
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Karina Teelen
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Wouter Graumans
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Elin Dumont
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Will Stone
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Jordache Ramjith
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Matthias Marti
- Wellcome Centre for Integrative Parasitology, Institute of Infection and Immunity, University of Glasgow, Glasgow, Scotland, UK
| | - Carolina M Andrade
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Chris Drakeley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Katharine Collins
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Alfred Tiono
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands; Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
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Moreno M, Barry A, Gmeiner M, Yaro JB, Sermé SS, Byrne I, Ramjith J, Ouedraogo A, Soulama I, Grignard L, Soremekun S, Koele S, Ter Heine R, Ouedraogo AZ, Sawadogo J, Sanogo E, Ouedraogo IN, Hien D, Sirima SB, Bradley J, Bousema T, Drakeley C, Tiono AB. Understanding and maximising the community impact of seasonal malaria chemoprevention in Burkina Faso (INDIE-SMC): study protocol for a cluster randomised evaluation trial. BMJ Open 2024; 14:e081682. [PMID: 38479748 PMCID: PMC10936478 DOI: 10.1136/bmjopen-2023-081682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/19/2024] [Indexed: 03/26/2024] Open
Abstract
INTRODUCTION Seasonal malaria chemoprevention (SMC) involves repeated administrations of sulfadoxine-pyrimethamine plus amodiaquine to children below the age of 5 years during the peak transmission season in areas of seasonal malaria transmission. While highly impactful in reducing Plasmodium falciparum malaria burden in controlled research settings, the impact of SMC on infection prevalence is moderate in real-life settings. It remains unclear what drives this efficacy decay. Recently, the WHO widened the scope for SMC to target all vulnerable populations. The Ministry of Health (MoH) in Burkina Faso is considering extending SMC to children below 10 years old. We aim to assess the impact of SMC on clinical incidence and parasite prevalence and quantify the human infectious reservoir for malaria in this population. METHODS AND ANALYSIS We will perform a cluster randomised trial in Saponé Health District, Burkina Faso, with three study arms comprising 62 clusters of three compounds: arm 1 (control): SMC in under 5-year-old children, implemented by the MoH without directly observed treatment (DOT) for the full course of SMC; arm 2 (intervention): SMC in under 5-year-old children, with DOT for the full course of SMC; arm 3 (intervention): SMC in under 10-year-old children, with DOT for the full course of SMC. The primary endpoint is parasite prevalence at the end of the malaria transmission season. Secondary endpoints include the impact of SMC on clinical incidence. Factors affecting SMC uptake, treatment adherence, drug concentrations, parasite resistance markers and transmission of parasites will be determined. ETHICS AND DISSEMINATION The London School of Hygiene & Tropical Medicine's Ethics Committee (29193) and the Burkina Faso National Medical Ethics Committee (Deliberation No 2023-05-104) approved this study. The findings will be presented to the community; disease occurrence data and study outcomes will also be shared with the Burkina Faso MoH. Findings will be published irrespective of their results. TRIAL REGISTRATION NUMBER NCT05878366.
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Affiliation(s)
- Marta Moreno
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Aissata Barry
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | - Markus Gmeiner
- Department of Medical Microbiology, Radboud University Nijmegen, Nijmegen, The Netherlands
| | | | - Samuel S Sermé
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | - Isabel Byrne
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Jordache Ramjith
- Department of Medical Microbiology, Radboud University Nijmegen, Nijmegen, The Netherlands
| | | | - Issiaka Soulama
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | - Lynn Grignard
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Seyi Soremekun
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Simon Koele
- Department of Medical Microbiology, Radboud University Nijmegen, Nijmegen, The Netherlands
| | | | | | - Jean Sawadogo
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | - Edith Sanogo
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | | | - Denise Hien
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
| | | | - John Bradley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Alfred B Tiono
- Groupe de Recherche Action en Santé, Ouagadougou, Burkina Faso
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3
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Greyling N, van der Watt M, Gwarinda H, van Heerden A, Greenhouse B, Leroy D, Niemand J, Birkholtz LM. Genetic complexity alters drug susceptibility of asexual and gametocyte stages of Plasmodium falciparum to antimalarial candidates. Antimicrob Agents Chemother 2024; 68:e0129123. [PMID: 38259087 PMCID: PMC10916389 DOI: 10.1128/aac.01291-23] [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: 10/13/2023] [Accepted: 12/06/2023] [Indexed: 01/24/2024] Open
Abstract
Malaria elimination requires interventions able to target both the asexual blood stage (ABS) parasites and transmissible gametocyte stages of Plasmodium falciparum. Lead antimalarial candidates are evaluated against clinical isolates to address key concerns regarding efficacy and to confirm that the current, circulating parasites from endemic regions lack resistance against these candidates. While this has largely been performed on ABS parasites, limited data are available on the transmission-blocking efficacy of compounds with multistage activity. Here, we evaluated the efficacy of lead antimalarial candidates against both ABS parasites and late-stage gametocytes side-by-side, against clinical P. falciparum isolates from southern Africa. We additionally correlated drug efficacy to the genetic diversity of the clinical isolates as determined with a panel of well-characterized, genome-spanning microsatellite markers. Our data indicate varying sensitivities of the isolates to key antimalarial candidates, both for ABS parasites and gametocyte stages. While ABS parasites were efficiently killed, irrespective of genetic complexity, antimalarial candidates lost some gametocytocidal efficacy when the gametocytes originated from genetically complex, multiple-clone infections. This suggests a fitness benefit to multiclone isolates to sustain transmission and reduce drug susceptibility. In conclusion, this is the first study to investigate the efficacy of antimalarial candidates on both ABS parasites and gametocytes from P. falciparum clinical isolates where the influence of parasite genetic complexity is highlighted, ultimately aiding the malaria elimination agenda.
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Affiliation(s)
- Nicola Greyling
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Mariëtte van der Watt
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Hazel Gwarinda
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Ashleigh van Heerden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Jandeli Niemand
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
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Andolina C, Ramjith J, Rek J, Lanke K, Okoth J, Grignard L, Arinaitwe E, Briggs J, Bailey J, Aydemir O, Kamya MR, Greenhouse B, Dorsey G, Staedke SG, Drakeley C, Jonker M, Bousema T. Plasmodium falciparum gametocyte carriage in longitudinally monitored incident infections is associated with duration of infection and human host factors. Sci Rep 2023; 13:7072. [PMID: 37127688 PMCID: PMC10150352 DOI: 10.1038/s41598-023-33657-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 04/17/2023] [Indexed: 05/03/2023] Open
Abstract
Malaria transmission depends on the presence of Plasmodium gametocytes that are the only parasite life stage that can infect mosquitoes. Gametocyte production varies between infections and over the course of infections. Infection duration is highly important for gametocyte production but poorly quantified. Between 2017 and 2019 an all-age cohort of individuals from Tororo, eastern Uganda was followed by continuous passive and routine assessments. We longitudinally monitored 104 incident infections from 98 individuals who were sampled once every 28 days and on any day of symptoms. Among infections that lasted ≥ 3 months, gametocyte appearance was near-universal with 96% of infections having detectable gametocytes prior to clearance. However, most infections were of much shorter duration; 55.7% of asymptomatic infections were detected only once. When considering all asymptomatic infections, regardless of their duration, only 36.3% had detectable gametocytes on at least one time-point prior to parasite clearance. Infections in individuals with sickle-cell trait (HbAS) were more likely to have gametocytes detected (Hazard Rate (HR) = 2.68, 95% CI 1.12, 6.38; p = 0.0231) and had gametocytes detected at higher densities (Density Ratio (DR) = 9.19, 95% CI 2.79, 30.23; p = 0.0002) compared to infections in wildtype (HbAA) individuals. Our findings suggest that a large proportion of incident infections is too short in duration and of too low density to contribute to onward transmission.
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Affiliation(s)
- Chiara Andolina
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jordache Ramjith
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department for Health Evidence, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joseph Okoth
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Lynn Grignard
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Jessica Briggs
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, USA
| | - Jeffrey Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Ozkan Aydemir
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Bryan Greenhouse
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, USA
| | - Grant Dorsey
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, USA
| | - Sarah G Staedke
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Marianne Jonker
- Department for Health Evidence, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK.
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5
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Siddiqui AJ, Bhardwaj J, Saxena J, Jahan S, Snoussi M, Bardakci F, Badraoui R, Adnan M. A Critical Review on Human Malaria and Schistosomiasis Vaccines: Current State, Recent Advancements, and Developments. Vaccines (Basel) 2023; 11:vaccines11040792. [PMID: 37112704 PMCID: PMC10146311 DOI: 10.3390/vaccines11040792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/31/2023] [Accepted: 04/03/2023] [Indexed: 04/07/2023] Open
Abstract
Malaria and schistosomiasis are two major parasitic diseases that remain leading causes of morbidity and mortality worldwide. Co-infections of these two parasites are common in the tropics, where both diseases are endemic. The clinical consequences of schistosomiasis and malaria are determined by a variety of host, parasitic, and environmental variables. Chronic schistosomiasis causes malnutrition and cognitive impairments in children, while malaria can cause fatal acute infections. There are effective drugs available to treat malaria and schistosomiasis. However, the occurrence of allelic polymorphisms and the rapid selection of parasites with genetic mutations can confer reduced susceptibility and lead to the emergence of drug resistance. Moreover, the successful elimination and complete management of these parasites are difficult due to the lack of effective vaccines against Plasmodium and Schistosoma infections. Therefore, it is important to highlight all current vaccine candidates undergoing clinical trials, such as pre-erythrocytic and erythrocytic stage malaria, as well as a next-generation RTS,S-like vaccine, the R21/Matrix-M vaccine, that conferred 77% protection against clinical malaria in a Phase 2b trial. Moreover, this review also discusses the progress and development of schistosomiasis vaccines. Furthermore, significant information is provided through this review on the effectiveness and progress of schistosomiasis vaccines currently under clinical trials, such as Sh28GST, Sm-14, and Sm-p80. Overall, this review provides insights into recent progress in malarial and schistosomiasis vaccines and their developmental approaches.
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Affiliation(s)
- Arif Jamal Siddiqui
- Department of Biology, College of Science, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia
| | - Jyoti Bhardwaj
- Division of Infectious Diseases, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Juhi Saxena
- Department of Biotechnology, University Institute of Biotechnology, Chandigarh University, Gharuan, NH-95, Ludhiana—Chandigarh State Hwy, Mohali 140413, India
| | - Sadaf Jahan
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Al Majmaah 11952, Saudi Arabia
| | - Mejdi Snoussi
- Department of Biology, College of Science, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia
- Laboratory of Genetics, Biodiversity and Valorization of Bio-Resources (LR11ES41), Higher Institute of Biotechnology of Monastir, University of Monastir, Avenue TaharHaddas BP74, Monastir 5000, Tunisia
| | - Fevzi Bardakci
- Department of Biology, College of Science, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia
| | - Riadh Badraoui
- Department of Biology, College of Science, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia
- Section of Histology-Cytology, Medicine Faculty of Tunis, University of Tunis El Manar, Tunis 1017, Tunisia
| | - Mohd Adnan
- Department of Biology, College of Science, University of Ha’il, Ha’il P.O. Box 2440, Saudi Arabia
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Abdi AI, Achcar F, Sollelis L, Silva-Filho JL, Mwikali K, Muthui M, Mwangi S, Kimingi HW, Orindi B, Andisi Kivisi C, Alkema M, Chandrasekar A, Bull PC, Bejon P, Modrzynska K, Bousema T, Marti M. Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment. eLife 2023; 12:e85140. [PMID: 36916164 PMCID: PMC10059685 DOI: 10.7554/elife.85140] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/01/2023] [Indexed: 03/14/2023] Open
Abstract
The malaria parasite life cycle includes asexual replication in human blood, with a proportion of parasites differentiating to gametocytes required for transmission to mosquitoes. Commitment to differentiate into gametocytes, which is marked by activation of the parasite transcription factor ap2-g, is known to be influenced by host factors but a comprehensive model remains uncertain. Here, we analyze data from 828 children in Kilifi, Kenya with severe, uncomplicated, and asymptomatic malaria infection over 18 years of falling malaria transmission. We examine markers of host immunity and metabolism, and markers of parasite growth and transmission investment. We find that inflammatory responses associated with reduced plasma lysophosphatidylcholine levels are associated with markers of increased investment in parasite sexual reproduction (i.e. transmission investment) and reduced growth (i.e. asexual replication). This association becomes stronger with falling transmission and suggests that parasites can rapidly respond to the within-host environment, which in turn is subject to changing transmission.
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Affiliation(s)
- Abdirahman I Abdi
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Pwani University Biosciences Research Centre, Pwani UniversityKilifiKenya
| | - Fiona Achcar
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | - Lauriane Sollelis
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | - João Luiz Silva-Filho
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | | | | | | | | | | | - Cheryl Andisi Kivisi
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Pwani University Biosciences Research Centre, Pwani UniversityKilifiKenya
| | - Manon Alkema
- Radboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Amrita Chandrasekar
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
| | - Peter C Bull
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | - Katarzyna Modrzynska
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
| | - Teun Bousema
- Radboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Matthias Marti
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
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7
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Choy RKM, Bourgeois AL, Ockenhouse CF, Walker RI, Sheets RL, Flores J. Controlled Human Infection Models To Accelerate Vaccine Development. Clin Microbiol Rev 2022; 35:e0000821. [PMID: 35862754 PMCID: PMC9491212 DOI: 10.1128/cmr.00008-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The timelines for developing vaccines against infectious diseases are lengthy, and often vaccines that reach the stage of large phase 3 field trials fail to provide the desired level of protective efficacy. The application of controlled human challenge models of infection and disease at the appropriate stages of development could accelerate development of candidate vaccines and, in fact, has done so successfully in some limited cases. Human challenge models could potentially be used to gather critical information on pathogenesis, inform strain selection for vaccines, explore cross-protective immunity, identify immune correlates of protection and mechanisms of protection induced by infection or evoked by candidate vaccines, guide decisions on appropriate trial endpoints, and evaluate vaccine efficacy. We prepared this report to motivate fellow scientists to exploit the potential capacity of controlled human challenge experiments to advance vaccine development. In this review, we considered available challenge models for 17 infectious diseases in the context of the public health importance of each disease, the diversity and pathogenesis of the causative organisms, the vaccine candidates under development, and each model's capacity to evaluate them and identify correlates of protective immunity. Our broad assessment indicated that human challenge models have not yet reached their full potential to support the development of vaccines against infectious diseases. On the basis of our review, however, we believe that describing an ideal challenge model is possible, as is further developing existing and future challenge models.
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Affiliation(s)
- Robert K. M. Choy
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | - A. Louis Bourgeois
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | | | - Richard I. Walker
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
| | | | - Jorge Flores
- PATH, Center for Vaccine Innovation and Access, Seattle, Washington, USA
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8
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Portugaliza HP, Natama HM, Guetens P, Rovira-Vallbona E, Somé AM, Millogo A, Ouédraogo DF, Valéa I, Sorgho H, Tinto H, van Hong N, Sitoe A, Varo R, Bassat Q, Cortés A, Rosanas-Urgell A. Plasmodium falciparum sexual conversion rates can be affected by artemisinin-based treatment in naturally infected malaria patients. EBioMedicine 2022; 83:104198. [PMID: 35961203 PMCID: PMC9385555 DOI: 10.1016/j.ebiom.2022.104198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 07/05/2022] [Accepted: 07/18/2022] [Indexed: 10/25/2022] Open
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9
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de Jong RM, Alkema M, Oulton T, Dumont E, Teelen K, Nakajima R, de Assis RR, Press KWD, Ngotho P, Tetteh KK, Felgner P, Marti M, Collins KA, Drakeley C, Bousema T, Stone WJ. The acquisition of humoral immune responses targeting Plasmodium falciparum sexual stages in controlled human malaria infections. Front Immunol 2022; 13:930956. [PMID: 35924245 PMCID: PMC9339717 DOI: 10.3389/fimmu.2022.930956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Individuals infected with P. falciparum develop antibody responses to intra-erythrocytic gametocyte proteins and exported gametocyte proteins present on the surface of infected erythrocytes. However, there is currently limited knowledge on the immunogenicity of gametocyte antigens and the specificity of gametocyte-induced antibody responses. In this study, we assessed antibody responses in participants of two controlled human malaria infection (CHMI) studies by ELISA, multiplexed bead-based antibody assays and protein microarray. By comparing antibody responses in participants with and without gametocyte exposure, we aimed to disentangle the antibody response induced by asexual and sexual stage parasites. We showed that after a single malaria infection, a significant anti-sexual stage humoral response is induced in malaria-naïve individuals, even after exposure to relatively low gametocyte densities (up to ~1,600 gametocytes/mL). In contrast to antibody responses to well-characterised asexual blood stage antigens that were detectable by day 21 after infection, responses to sexual stage antigens (including transmission blocking vaccine candidates Pfs48/45 and Pfs230) were only apparent at 51 days after infection. We found antigens previously associated with early gametocyte or anti-gamete immunity were highly represented among responses linked with gametocyte exposure. Our data provide detailed insights on the induction and kinetics of antibody responses to gametocytes and identify novel antigens that elicit antibody responses exclusively in individuals with gametocyte exposure. Our findings provide target identification for serological assays for surveillance of the malaria infectious reservoir, and support vaccine development by describing the antibody response to leading vaccine antigens after primary infection.
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Affiliation(s)
- Roos M. de Jong
- Department of Medical Microbiology and Radboud Centre of Infectious Diseases, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Manon Alkema
- Department of Medical Microbiology and Radboud Centre of Infectious Diseases, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Tate Oulton
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Elin Dumont
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Karina Teelen
- Department of Medical Microbiology and Radboud Centre of Infectious Diseases, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Rie Nakajima
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
| | - Rafael Ramiro de Assis
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
| | | | - Priscilla Ngotho
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Kevin K.A. Tetteh
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Phil Felgner
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, United States
| | - Matthias Marti
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Katharine A. Collins
- Department of Medical Microbiology and Radboud Centre of Infectious Diseases, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology and Radboud Centre of Infectious Diseases, Radboud University Medical Centre, Nijmegen, Netherlands,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Will J.R. Stone
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom,*Correspondence: Will J.R. Stone,
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10
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Ramjith J, Alkema M, Bradley J, Dicko A, Drakeley C, Stone W, Bousema T. Quantifying Reductions in Plasmodium falciparum Infectivity to Mosquitos: A Sample Size Calculator to Inform Clinical Trials on Transmission-Reducing Interventions. Front Immunol 2022; 13:899615. [PMID: 35720362 PMCID: PMC9205189 DOI: 10.3389/fimmu.2022.899615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Malaria transmission depends on the presence of mature Plasmodium transmission stages (gametocytes) that may render blood-feeding Anopheles mosquitos infectious. Transmission-blocking antimalarial drugs and vaccines can prevent transmission by reducing gametocyte densities or infectivity to mosquitos. Mosquito infection outcomes are thereby informative biological endpoints of clinical trials with transmission blocking interventions. Nevertheless, trials are often primarily designed to determine intervention safety; transmission blocking efficacy is difficult to incorporate in sample size considerations due to variation in infection outcomes and considerable inter-study variation. Here, we use clinical trial data from studies in malaria naive and naturally exposed study participants to present an online sample size calculator tool. This sample size calculator allows studies to be powered to detect reductions in the proportion of infected mosquitos or infection burden (oocyst density) in mosquitos. The utility of this online tool is illustrated using trial data with transmission blocking malaria drugs.
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Affiliation(s)
- Jordache Ramjith
- Radboud Institute for Molecular Life Sciences, Department of Medical Microbiology, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
- Department for Health Evidence, Biostatistics Research Group, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Manon Alkema
- Radboud Institute for Molecular Life Sciences, Department of Medical Microbiology, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - John Bradley
- Medical Research Council (MRC) International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Chris Drakeley
- Medical Research Council (MRC) International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Will Stone
- Medical Research Council (MRC) International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Radboud Institute for Molecular Life Sciences, Department of Medical Microbiology, Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
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11
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Ahmad A, Prom A, Bradley J, Ndiath M, Etoketim B, Bah M, Van Geertruyden JP, Drakeley C, Bousema T, Achan J, D'Alessandro U. Gametocyte carriage after seasonal malaria chemoprevention in Plasmodium falciparum infected asymptomatic children. Malar J 2021; 20:169. [PMID: 33771166 PMCID: PMC7995796 DOI: 10.1186/s12936-021-03706-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Treatment of clinical Plasmodium falciparum malaria with sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) is associated with increased post-treatment gametocyte carriage. The effect of seasonal malaria chemoprevention (SMC) with SP and AQ on gametocyte carriage was assessed in asymptomatic P. falciparum infected children. METHODS The study was carried out in eastern Gambia. Asymptomatic P. falciparum malaria infected children aged 24-59 months old who were eligible to receive SMC (SMC group) and children 5-8 years that were not eligible to receive SMC (comparison group) were recruited. Gametocytaemia was determined by molecular methods before and after SMC administration. Gametocyte carriage between the groups was compared using the chi-squared test and within-person using conditional logistic regression. RESULTS During the 2017 and 2018 malaria transmission seasons, 65 and 75 children were recruited in the SMC and comparison groups, respectively. Before SMC administration, gametocyte prevalence was 10.7% (7/65) in the SMC group and 13.3% (10/75) in the comparison group (p = 0.64). At day 13 (IQR 12, 13) after SMC administration, this was 9.4% (5/53) in children who received at least the first dose of SMC treatment and 12.7% (9/71) for those in the comparison group (p = 0.57). Similarly, there was no difference in prevalence of gametocytes between children that adhered to all 3-day doses of SMC treatment 15.6% (5/32) and those in the comparison group (p = 0.68). In the SMC group, within-group gametocyte carriage was similar before and after SMC administration in children that received at least the first dose of SMC treatment (OR 0.6, 95% CI 0.14-2.51; p = 0.48) and in those that adhered to all 3-day doses of SMC treatment (OR 1.0, 95% CI 0.20-4.95; p = 1.0). CONCLUSION In this study with relative low gametocyte prevalence prior to SMC treatment, no evidence was observed that SMC treatment increased gametocyte carriage in asymptomatic P. falciparum malaria infected children.
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Affiliation(s)
- Abdullahi Ahmad
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia.
- Global Health Institute, University of Antwerp, Gouverneur Kinsbergencentrum, Campus Drie Eiken, Doornstraat 331, 2610, Wilrijk, Belgium.
| | - Aurelia Prom
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - John Bradley
- MRC Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Mamadou Ndiath
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Blessed Etoketim
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Mamadou Bah
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Jean-Pierre Van Geertruyden
- Global Health Institute, University of Antwerp, Gouverneur Kinsbergencentrum, Campus Drie Eiken, Doornstraat 331, 2610, Wilrijk, Belgium
| | - Chris Drakeley
- Department of Immunology and Infection, School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein 28, Microbiology 268, 6500 HB, Nijmegen, The Netherlands
| | - Jane Achan
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Umberto D'Alessandro
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia At London, School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
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12
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Woolley SD, Fernandez M, Rebelo M, Llewellyn SA, Marquart L, Amante FH, Jennings HE, Webster R, Trenholme K, Chalon S, Moehrle JJ, McCarthy JS, Barber BE. Development and evaluation of a new Plasmodium falciparum 3D7 blood stage malaria cell bank for use in malaria volunteer infection studies. Malar J 2021; 20:93. [PMID: 33593375 PMCID: PMC7885253 DOI: 10.1186/s12936-021-03627-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 02/05/2021] [Indexed: 11/23/2022] Open
Abstract
Background New anti-malarial therapeutics are required to counter the threat of increasing drug resistance. Malaria volunteer infection studies (VIS), particularly the induced blood stage malaria (IBSM) model, play a key role in accelerating anti-malarial drug development. Supply of the reference 3D7-V2 Plasmodium falciparum malaria cell bank (MCB) is limited. This study aimed to develop a new MCB, and compare the safety and infectivity of this MCB with the existing 3D7-V2 MCB, in a VIS. A second bank (3D7-V1) developed in 1995 was also evaluated. Methods The 3D7-V2 MCB was expanded in vitro using a bioreactor to produce a new MCB designated 3D7-MBE-008. This bank and 3D7-V1 were then evaluated using the IBSM model, where healthy participants were intravenously inoculated with blood-stage parasites. Participants were treated with artemether-lumefantrine when parasitaemia or clinical thresholds were reached. Safety, infectivity and parasite growth and clearance were evaluated. Results The in vitro expansion of 3D7-V2 produced 200 vials of the 3D7-MBE-008 MCB, with a parasitaemia of 4.3%. This compares to 0.1% in the existing 3D7-V2 MCB, and < 0.01% in the 3D7-V1 MCB. All four participants (two per MCB) developed detectable P. falciparum infection after inoculation with approximately 2800 parasites. For the 3D7-MBE-008 MCB, the parasite multiplication rate of 48 h (PMR48) using non-linear mixed effects modelling was 34.6 (95% CI 18.5–64.6), similar to the parental 3D7-V2 line; parasitaemia in both participants exceeded 10,000/mL by day 8. Growth of the 3D7-V1 was slower (PMR48 of 11.5 [95% CI 8.5–15.6]), with parasitaemia exceeding 10,000 parasites/mL on days 10 and 8.5. Rapid parasite clearance followed artemether-lumefantrine treatment in all four participants, with clearance half-lives of 4.01 and 4.06 (weighted mean 4.04 [95% CI 3.61–4.57]) hours for 3D7-MBE-008 and 4.11 and 4.52 (weighted mean 4.31 [95% CI 4.16–4.47]) hours for 3D7-V1. A total of 59 adverse events occurred; most were of mild severity with three being severe in the 3D7-MBE-008 study. Conclusion The safety, growth and clearance profiles of the expanded 3D7-MBE-008 MCB closely resemble that of its parent, indicating its suitability for future studies. Trial Registration: Australian New Zealand Clinical Trials registry numbers: P3487 (3D7-V1): ACTRN12619001085167. P3491 (3D7-MBE-008): ACTRN12619001079134
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Affiliation(s)
- Stephen D Woolley
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Centre for Defence Pathology, Royal Centre for Defence Medicine, Joint Hospital Group, ICT Building, Birmingham Research Park, Vincent Drive, Birmingham, UK.,Clinical Sciences Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | | | - Maria Rebelo
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | | | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Fiona H Amante
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Helen E Jennings
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Rebecca Webster
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Katharine Trenholme
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,School of Medicine, University of Queensland, Herston, QLD, Australia
| | - Stephan Chalon
- Medicines for Malaria Venture, 20 Route de Pre-Bois, PO Box 1826, 1215, Geneva 15, Switzerland
| | - Joerg J Moehrle
- Medicines for Malaria Venture, 20 Route de Pre-Bois, PO Box 1826, 1215, Geneva 15, Switzerland
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Bridget E Barber
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
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13
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Novel Method for the Separation of Male and Female Gametocytes of the Malaria Parasite Plasmodium falciparum That Enables Biological and Drug Discovery. mSphere 2020; 5:5/4/e00671-20. [PMID: 32817458 PMCID: PMC7426174 DOI: 10.1128/msphere.00671-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The protozoan Plasmodium falciparum causes the most severe form of human malaria. The development of sexual forms (so-called gametocytes) is crucial for disease transmission. However, knowledge of these forms is severely hampered by the paucity of sex-specific markers and the inability to extract single sex gametocytes in high purity. Moreover, the identification of compounds that specifically affect one sex is difficult due to the female bias of the gametocytes. We have developed a system that allows for the separation of male and female gametocytes from the same population. Applying our system, we show that male and female parasites mature at different rates, which might have implications for transmission. We also identified new sex-specific genes that can be used as sex markers or to unravel sex-specific functions. Our system will not only aid in the discovery of much needed gametocidal compounds, but it also represents a valuable tool for exploring malaria transmission biology. We developed a flow-cytometry-based method to separate and collect cocultured male and female Plasmodium falciparum gametocytes responsible for malaria transmission. The purity of the collected cells was estimated at >97% using flow cytometry, and sorted cells were observed by Giemsa-stained thin-smear and live-cell fluorescence microscopy. The expression of validated sex-specific markers corroborated the sorting strategy. Collected male and female gametocytes were used to confirm three novel sex-specific markers by quantitative real-time PCR that were more enriched in sorted male and female gametocyte populations than existing sex-specific markers. We also applied the method as a proof-of-principle drug screen that allows the identification of drugs that kill gametocytes in a sex-specific manner. Since the developed method allowed for the separation of male and female parasites from the same culture, we observed for the first time a difference in development time between the sexes: females developed faster than males. Hence, the ability to separate male and female gametocytes opens the door to a new field of sex-specific P. falciparum gametocyte biology to further our understanding of malaria transmission. IMPORTANCE The protozoan Plasmodium falciparum causes the most severe form of human malaria. The development of sexual forms (so-called gametocytes) is crucial for disease transmission. However, knowledge of these forms is severely hampered by the paucity of sex-specific markers and the inability to extract single sex gametocytes in high purity. Moreover, the identification of compounds that specifically affect one sex is difficult due to the female bias of the gametocytes. We have developed a system that allows for the separation of male and female gametocytes from the same population. Applying our system, we show that male and female parasites mature at different rates, which might have implications for transmission. We also identified new sex-specific genes that can be used as sex markers or to unravel sex-specific functions. Our system will not only aid in the discovery of much needed gametocidal compounds, but it also represents a valuable tool for exploring malaria transmission biology.
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