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Thongpoon S, Roobsoong W, Nguitragool W, Chotirat S, Tsuboi T, Takashima E, Cui L, Ishino T, Tachibana M, Miura K, Sattabongkot J. Naturally Acquired Transmission-Blocking Immunity Against Different Strains of Plasmodium vivax in a Malaria-Endemic Area in Thailand. J Infect Dis 2024; 229:567-575. [PMID: 37943633 PMCID: PMC10873188 DOI: 10.1093/infdis/jiad469] [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] [Revised: 09/30/2023] [Accepted: 11/04/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Human immunity triggered by natural malaria infections impedes parasite transmission from humans to mosquitoes, leading to interest in transmission-blocking vaccines. However, immunity characteristics, especially strain specificity, remain largely unexplored. We investigated naturally acquired transmission-blocking immunity (TBI) against Plasmodium vivax, a major malaria parasite. METHODS Using the direct membrane-feeding assay, we assessed TBI in plasma samples and examined the role of antibodies by removing immunoglobulins through protein G/L adsorption before mosquito feeding. Strain specificity was evaluated by conducting a direct membrane-feeding assay with plasma exchange. RESULTS Blood samples from 47 patients with P vivax were evaluated, with 37 plasma samples successfully infecting mosquitoes. Among these, 26 showed inhibition before immunoglobulin depletion. Despite substantial immunoglobulin removal, 4 samples still exhibited notable inhibition, while 22 had reduced blocking activity. Testing against heterologous strains revealed some plasma samples with broad TBI and others with strain-specific TBI. CONCLUSIONS Our findings indicate that naturally acquired TBI is mainly mediated by antibodies, with possible contributions from other serum factors. The transmission-blocking activity of plasma samples varied by the tested parasite strain, suggesting single polymorphic or multiple targets for naturally acquired TBI. These observations improve understanding of immunity against P vivax and hold implications for transmission-blocking vaccine development.
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Affiliation(s)
| | | | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Tomoko Ishino
- Department of Parasitology and Tropical Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, Japan
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
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Dinko B, Awuah D, Boampong K, Larbi JA, Bousema T, Sutherland CJ. Prevalence of Plasmodium falciparum gametocytaemia in asymptomatic school children before and after treatment with dihydroartemisinin-piperaquine (DP). Parasite Epidemiol Control 2023; 21:e00292. [PMID: 36860282 PMCID: PMC9969054 DOI: 10.1016/j.parepi.2023.e00292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/12/2023] [Accepted: 02/15/2023] [Indexed: 02/19/2023] Open
Abstract
Background Asymptomatic Plasmodium carriers form the majority of malaria-infected individuals in most endemic areas. A proportion of these asymptomatically infected individuals carry gametocytes, the transmissible stages of malaria parasites, that sustain human to mosquito transmission. Few studies examine gametocytaemia in asymptomatic school children who may form an important reservoir for transmission. We assessed the prevalence of gametocytaemia before antimalarial treatment and monitored clearance of gametocytes after treatment in asymptomatic malaria children. Methods A total of 274 primary school children were screened for P. falciparum parasitaemia by microscopy. One hundred and fifty-five (155) parasite positive children were treated under direct observation with dihydroartemisinin-piperaquine (DP). Gametocyte carriage was determined by microscopy seven days prior to treatment, day 0 before treatment, and on days 7, 14 and 21 post initiation of treatment. Results The prevalence of microscopically-detectable gametocytes at screening (day -7) and enrolment (day 0) were 9% (25/274) and 13.6% (21/155) respectively. Following DP treatment, gametocyte carriage dropped to 4% (6/135), 3% (5/135) and 6% (10/151) on days 7, 14 and 21 respectively. Asexual parasites persisted in a minority of treated children, resulting in microscopically detectable parasites on days 7 (9%, 12/135), 14 (4%, 5/135) and 21 (7%, 10/151). Gametocyte carriage was inversely correlated with the age of the participants (p = 0.05) and asexual parasite density (p = 0.08). In a variate analysis, persistent gametocytaemia 7 or more days after treatment was significantly associated with post-treatment asexual parasitaemia at day 7 (P = 0.027) and presence of gametocytes on the day of treatment (P < 0.001). Conclusions Though DP provides both excellent cure rates for clinical malaria and a long prophylactic half-life, our findings suggest that after treatment of asymptomatic infections, both asexual parasites and gametocytes may persist in a minority of individuals during the first 3 weeks after treatment. This indicates DP may be unsuitable for use in mass drug administration strategies towards malaria elimination in Africa.
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Affiliation(s)
- Bismarck Dinko
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Dennis Awuah
- Department of Theoretical and Applied Biology, Faculty of Biosciences, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Kwadwo Boampong
- Department of Theoretical and Applied Biology, Faculty of Biosciences, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - John A. Larbi
- Department of Theoretical and Applied Biology, Faculty of Biosciences, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Teun Bousema
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
- Department of Medical Microbiology, Nijmegen Medical Centre, Radboud University, Nijmegen, the Netherlands
| | - Colin J. Sutherland
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
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3
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Mulamba C, Williams C, Kreppel K, Ouedraogo JB, Olotu AI. Evaluation of the Pfs25-IMX313/Matrix-M malaria transmission-blocking candidate vaccine in endemic settings. Malar J 2022; 21:159. [PMID: 35655174 PMCID: PMC9161629 DOI: 10.1186/s12936-022-04173-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/02/2022] [Indexed: 11/10/2022] Open
Abstract
Malaria control relies heavily on the use of anti-malarial drugs and insecticides against malaria parasites and mosquito vectors. Drug and insecticide resistance threatens the effectiveness of conventional malarial interventions; alternative control approaches are, therefore, needed. The development of malaria transmission-blocking vaccines that target the sexual stages in humans or mosquito vectors is among new approaches being pursued. Here, the immunological mechanisms underlying malaria transmission blocking, status of Pfs25-based vaccines are viewed, as well as approaches and capacity for first in-human evaluation of a transmission-blocking candidate vaccine Pfs25-IMX313/Matrix-M administered to semi-immune healthy individuals in endemic settings. It is concluded that institutions in low and middle income settings should be supported to conduct first-in human vaccine trials in order to stimulate innovative research and reduce the overdependence on developed countries for research and local interventions against many diseases of public health importance.
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Affiliation(s)
- Charles Mulamba
- Interventions & Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania.,Nelson Mandela African Institution of Science and Technology, Tengeru, P. O. Box 447, Arusha, Tanzania
| | - Chris Williams
- The Jenner Institute, University of Oxford, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Katharina Kreppel
- Nelson Mandela African Institution of Science and Technology, Tengeru, P. O. Box 447, Arusha, Tanzania
| | | | - Ally I Olotu
- Interventions & Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania.
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4
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O’Flaherty K, Chan JA, Cutts JC, Zaloumis SG, Ashley EA, Phyo AP, Drew DR, Dondorp AM, Day NP, Dhorda M, Fairhurst RM, Lim P, Amaratunga C, Pukrittayakamee S, Hien TT, Htut Y, Mayxay M, Faiz MA, Mokuolu OA, Onyamboko MA, Fanello C, Takashima E, Tsuboi T, Theisen M, Nosten F, Beeson JG, Simpson JA, White NJ, Fowkes FJI. Anti-Gametocyte Antigen Humoral Immunity and Gametocytemia During Treatment of Uncomplicated Falciparum Malaria: A Multi-National Study. Front Cell Infect Microbiol 2022; 12:804470. [PMID: 35463638 PMCID: PMC9022117 DOI: 10.3389/fcimb.2022.804470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/11/2022] [Indexed: 11/16/2022] Open
Abstract
Introduction Understanding the human immune response to Plasmodium falciparum gametocytes and its association with gametocytemia is essential for understanding the transmission of malaria as well as progressing transmission blocking vaccine candidates. Methods In a multi-national clinical efficacy trial of artemisinin therapies (13 sites of varying transmission over South-East Asia and Africa), we measured Immunoglobulin G (IgG) responses to recombinant P. falciparum gametocyte antigens expressed on the gametocyte plasma membrane and leading transmission blocking vaccine candidates Pfs230 (Pfs230c and Pfs230D1M) and Pfs48/45 at enrolment in 1,114 participants with clinical falciparum malaria. Mixed effects linear and logistic regression were used to determine the association between gametocyte measures (gametocytemia and gametocyte density) and antibody outcomes at enrolment. Results Microscopy detectable gametocytemia was observed in 11% (127/1,114) of participants at enrolment, and an additional 9% (95/1,114) over the follow-up period (up to day 42) (total 20% of participants [222/1,114]). IgG levels in response to Pfs230c, Pfs48/45 and Pfs230D1M varied across study sites at enrolment (p < 0.001), as did IgG seroprevalence for anti-Pfs230c and D1M IgG (p < 0.001), but not for anti-Pfs48/45 IgG (p = 0.159). In adjusted analyses, microscopy detectable gametocytemia at enrolment was associated with an increase in the odds of IgG seropositivity to the three gametocyte antigens (Pfs230c OR [95% CI], p: 1.70 [1.10, 2.62], 0.017; Pfs48/45: 1.45 [0.85, 2.46], 0.174; Pfs230D1M: 1.70 [1.03, 2.80], 0.037), as was higher gametocyte density at enrolment (per two-fold change in gametocyte density Pfs230c OR [95% CI], p: 1.09 [1.02, 1.17], 0.008; Pfs48/45: 1.05 [0.98, 1.13], 0.185; Pfs230D1M: 1.07 [0.99, 1.14], 0.071). Conclusion Pfs230 and Pfs48/45 antibodies are naturally immunogenic targets associated with patent gametocytemia and increasing gametocyte density across multiple malaria endemic settings, including regions with emerging artemisinin-resistant P. falciparum.
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Affiliation(s)
| | - Jo-Anne Chan
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Julia C. Cutts
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Sophie G. Zaloumis
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Elizabeth A. Ashley
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Damien R. Drew
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
| | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mehul Dhorda
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- WorldWide Antimalarial Resistance Network, Asia-Pacific Regional Centre, Bangkok, Thailand
| | - Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Pharath Lim
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Chanaki Amaratunga
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | | | - Tran Tinh Hien
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Ye Htut
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust-Research Unit, Mahosot Hospital, Vientiane, Laos
- Institute of Research and Education Development, University of Health Sciences, Vientiane, Laos
| | - M. Abul Faiz
- Malaria Research Group and Dev Care Foundation, Chittagong, Bangladesh
| | - Olugbenga A. Mokuolu
- Department of Paediatrics and Child Health, University of Ilorin, Ilorin, Nigeria
| | - Marie A. Onyamboko
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Caterina Fanello
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Francois Nosten
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - James G. Beeson
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
- Department of Microbiology and Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Nicholas J. White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Freya J. I. Fowkes
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
- Department of Infectious Diseases and Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, VIC, Australia
- *Correspondence: Freya J. I. Fowkes,
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5
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High Plasmodium infection intensity in naturally infected malaria vectors in Africa. Int J Parasitol 2020; 50:985-996. [PMID: 32681932 DOI: 10.1016/j.ijpara.2020.05.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/14/2020] [Accepted: 05/17/2020] [Indexed: 01/18/2023]
Abstract
The population dynamics of human to mosquito malaria transmission in the field has important implications for the genetics, epidemiology and control of malaria. The number of oocysts in oocyst-positive mosquitoes developing from a single, naturally acquired infectious blood meal (herein referred to as a single-feed infection load) greatly influences the efficacy of transmission blocking interventions but still remains poorly documented. During a year-long analysis of malaria parasite transmission in Burkina Faso we caught and dissected wild malaria vectors to assess Plasmodium oocyst prevalence and load (the number of oocysts counted in mosquitoes with detectable oocysts) and the prevalence of salivary gland sporozoites. This was compared with malaria endemicity in the human population, assessed in cross-sectional surveys. Data were analysed using a novel transmission mathematical model to estimate the per bite transmission probability and the average single-feed infection load for each location. The observed oocyst load and the estimated single-feed infection load in naturally infected mosquitoes were substantially higher than previous estimates (means ranging from 3.2 to 24.5 according to seasons and locations) and indicate a strong positive association between the single-feed infection load and parasite prevalence in humans. This work suggests that highly infected mosquitoes are not rare in the field and might have a greater influence on the epidemiology and genetics of the parasite, and on the efficacy of novel transmission blocking interventions.
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6
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Mhamilawa LE, Ngasala B, Morris U, Kitabi EN, Barnes R, Soe AP, Mmbando BP, Björkman A, Mårtensson A. Parasite clearance, cure rate, post-treatment prophylaxis and safety of standard 3-day versus an extended 6-day treatment of artemether-lumefantrine and a single low-dose primaquine for uncomplicated Plasmodium falciparum malaria in Bagamoyo district, Tanzania: a randomized controlled trial. Malar J 2020; 19:216. [PMID: 32576258 PMCID: PMC7310382 DOI: 10.1186/s12936-020-03287-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 06/12/2020] [Indexed: 11/19/2022] Open
Abstract
Background Artemisinin-based combination therapy (ACT) resistant Plasmodium falciparum represents an increasing threat to Africa. Extended ACT regimens from standard 3 to 6 days may represent a means to prevent its development and potential spread in Africa. Methods Standard 3-day treatment with artemether–lumefantrine (control) was compared to extended 6-day treatment and single low-dose primaquine (intervention); in a randomized controlled, parallel group, superiority clinical trial of patients aged 1–65 years with microscopy confirmed uncomplicated P. falciparum malaria, enrolled in Bagamoyo district, Tanzania. The study evaluated parasite clearance, including proportion of PCR detectable P. falciparum on days 5 and 7 (primary endpoint), cure rate, post-treatment prophylaxis, safety and tolerability. Clinical, and laboratory assessments, including ECG were conducted during 42 days of follow-up. Blood samples were collected for parasite detection (by microscopy and PCR), molecular genotyping and pharmacokinetic analyses. Kaplan–Meier survival analyses were done for both parasite clearance and recurrence. Results A total of 280 patients were enrolled, 141 and 139 in the control and intervention arm, respectively, of whom 121 completed 42 days follow-up in each arm. There was no difference in proportion of PCR positivity across the arms at day 5 (80/130 (61.5%) vs 89/134 (66.4%), p = 0.44), or day 7 (71/129 (55.0%) vs 70/134 (52.2%), p = 0.71). Day 42 microscopy determined cure rates (PCR adjusted) were 97.4% (100/103) and 98.3% (110/112), p = 0.65, in the control and intervention arm, respectively. Microscopy determined crude recurrent parasitaemia during follow-up was 21/121 (17.4%) in the control and 14/121 (11.6%) in the intervention arm, p = 0.20, and it took 34 days and 42 days in the respective arms for 90% of the patients to remain without recurrent parasitaemia. Lumefantrine exposure was significantly higher in intervention arm from D3 to D42, but cardiac, biochemical and haematological safety was high and similar in both arms. Conclusion Extended 6-day artemether–lumefantrine treatment and a single low-dose of primaquine was not superior to standard 3-day treatment for ACT sensitive P. falciparum infections but, importantly, equally efficacious and safe. Thus, extended artemether–lumefantrine treatment may be considered as a future treatment regimen for ACT resistant P. falciparum, to prolong the therapeutic lifespan of ACT in Africa. Trial registration ClinicalTrials.gov, NCT03241901. Registered July 27, 2017 https://clinicaltrials.gov/show/NCT03241901
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Affiliation(s)
- Lwidiko E Mhamilawa
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden. .,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
| | - Billy Ngasala
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Ulrika Morris
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Eliford Ngaimisi Kitabi
- Office of Clinical Pharmacology, Division of Pharmacometrics, Food and Drugs Administration, Silver Spring, MD, USA
| | - Rory Barnes
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Aung Paing Soe
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bruno P Mmbando
- Tanga Centre, National Institute for Medical Research, Tanga, Tanzania
| | - Anders Björkman
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
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7
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de Jong RM, Tebeje SK, Meerstein‐Kessel L, Tadesse FG, Jore MM, Stone W, Bousema T. Immunity against sexual stage Plasmodium falciparum and Plasmodium vivax parasites. Immunol Rev 2020; 293:190-215. [PMID: 31840844 PMCID: PMC6973022 DOI: 10.1111/imr.12828] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 12/25/2022]
Abstract
The efficient spread of malaria from infected humans to mosquitoes is a major challenge for malaria elimination initiatives. Gametocytes are the only Plasmodium life stage infectious to mosquitoes. Here, we summarize evidence for naturally acquired anti-gametocyte immunity and the current state of transmission blocking vaccines (TBV). Although gametocytes are intra-erythrocytic when present in infected humans, developing Plasmodium falciparum gametocytes may express proteins on the surface of red blood cells that elicit immune responses in naturally exposed individuals. This immune response may reduce the burden of circulating gametocytes. For both P. falciparum and Plasmodium vivax, there is a solid evidence that antibodies against antigens present on the gametocyte surface, when co-ingested with gametocytes, can influence transmission to mosquitoes. Transmission reducing immunity, reducing the burden of infection in mosquitoes, is a well-acknowledged but poorly quantified phenomenon that forms the basis for the development of TBV. Transmission enhancing immunity, increasing the likelihood or intensity of transmission to mosquitoes, is more speculative in nature but is convincingly demonstrated for P. vivax. With the increased interest in malaria elimination, TBV and monoclonal antibodies have moved to the center stage of malaria vaccine development. Methodologies to prioritize and evaluate products are urgently needed.
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MESH Headings
- Antibodies, Blocking/immunology
- Antibodies, Protozoan/immunology
- Host-Parasite Interactions/immunology
- Humans
- Immunity
- Immunomodulation
- Life Cycle Stages
- Malaria Vaccines/immunology
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Malaria, Falciparum/prevention & control
- Malaria, Falciparum/transmission
- Malaria, Vivax/immunology
- Malaria, Vivax/parasitology
- Malaria, Vivax/prevention & control
- Malaria, Vivax/transmission
- Plasmodium falciparum/growth & development
- Plasmodium falciparum/immunology
- Plasmodium vivax/growth & development
- Plasmodium vivax/immunology
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Affiliation(s)
- Roos M. de Jong
- Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | | | - Lisette Meerstein‐Kessel
- Radboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Centre for Molecular and Biomolecular InformaticsRadboud Institute for Molecular Life SciencesNijmegenThe Netherlands
| | - Fitsum G. Tadesse
- Armauer Hansen Research InstituteAddis AbabaEthiopia
- Radboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Matthijs M. Jore
- Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Will Stone
- Department of Immunology and InfectionLondon School of Hygiene and Tropical MedicineLondonUK
| | - Teun Bousema
- Radboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Department of Immunology and InfectionLondon School of Hygiene and Tropical MedicineLondonUK
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8
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Abstract
In the progression of the life cycle of Plasmodium falciparum, a small proportion of asexual parasites differentiate into male or female sexual forms called gametocytes. Just like their asexual counterparts, gametocytes are contained within the infected host's erythrocytes (RBCs). However, unlike their asexual partners, they do not exit the RBC until they are taken up in a blood meal by a mosquito. In the mosquito midgut, they are stimulated to emerge from the RBC, undergo fertilization, and ultimately produce tens of thousands of sporozoites that are infectious to humans. This transmission cycle can be blocked by antibodies targeting proteins exposed on the parasite surface in the mosquito midgut, a process that has led to the development of candidate transmission-blocking vaccines (TBV), including some that are in clinical trials. Here we review the leading TBV antigens and highlight the ongoing search for additional gametocyte/gamete surface antigens, as well as antigens on the surfaces of gametocyte-infected erythrocytes, which can potentially become a new group of TBV candidates.
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9
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Kengne-Ouafo JA, Sutherland CJ, Binka FN, Awandare GA, Urban BC, Dinko B. Immune Responses to the Sexual Stages of Plasmodium falciparum Parasites. Front Immunol 2019; 10:136. [PMID: 30804940 PMCID: PMC6378314 DOI: 10.3389/fimmu.2019.00136] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 01/16/2019] [Indexed: 11/13/2022] Open
Abstract
Malaria infections remain a serious global health problem in the world, particularly among children and pregnant women in Sub-Saharan Africa. Moreover, malaria control and elimination is hampered by rapid development of resistance by the parasite and the vector to commonly used antimalarial drugs and insecticides, respectively. Therefore, vaccine-based strategies are sorely needed, including those designed to interrupt disease transmission. However, a prerequisite for such a vaccine strategy is the understanding of both the human and vector immune responses to parasite developmental stages involved in parasite transmission in both man and mosquito. Here, we review the naturally acquired humoral and cellular responses to sexual stages of the parasite while in the human host and the Anopheles vector. In addition, updates on current anti-gametocyte, anti-gamete, and anti-mosquito transmission blocking vaccines are given. We conclude with our views on some important future directions of research into P. falciparum sexual stage immunity relevant to the search for the most appropriate transmission-blocking vaccine.
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Affiliation(s)
- Jonas A Kengne-Ouafo
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Colin J Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Fred N Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Ghana
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Britta C Urban
- Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
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10
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Chan JA, Drew DR, Reiling L, Lisboa-Pinto A, Dinko B, Sutherland CJ, Dent AE, Chelimo K, Kazura JW, Boyle MJ, Beeson JG. Low Levels of Human Antibodies to Gametocyte-Infected Erythrocytes Contrasts the PfEMP1-Dominant Response to Asexual Stages in P. falciparum Malaria. Front Immunol 2019; 9:3126. [PMID: 30692996 PMCID: PMC6340286 DOI: 10.3389/fimmu.2018.03126] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 12/18/2018] [Indexed: 11/13/2022] Open
Abstract
Vaccines that target Plasmodium falciparum gametocytes have the potential to reduce malaria transmission and are thus attractive targets for malaria control. However, very little is known about human immune responses to gametocytes present in human hosts. We evaluated naturally-acquired antibodies to gametocyte-infected erythrocytes (gametocyte-IEs) of different developmental stages compared to other asexual parasite stages among naturally-exposed Kenyan residents. We found that acquired antibodies strongly recognized the surface of mature asexual-IEs, but there was limited reactivity to the surface of gametocyte-IEs of different stages. We used genetically-modified P. falciparum with suppressed expression of PfEMP1, the major surface antigen of asexual-stage IEs, to demonstrate that PfEMP1 is a dominant target of antibodies to asexual-IEs, in contrast to gametocyte-IEs. Antibody reactivity to gametocyte-IEs was similar to asexual-IEs lacking PfEMP1. Significant antibody reactivity to the surface of gametocytes was observed when outside of the host erythrocyte, including recognition of the major gametocyte antigen, Pfs230. This indicates that there is a deficiency of acquired antibodies to gametocyte-IEs despite the acquisition of antibodies to gametocyte antigens and asexual IEs. Our findings suggest that the acquisition of substantial immunity to the surface of gametocyte-IEs is limited, which may facilitate immune evasion to enable malaria transmission even in the face of substantial host immunity to malaria. Further studies are needed to understand the basis for the limited acquisition of antibodies to gametocytes and whether vaccine strategies can generate substantial immunity.
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Affiliation(s)
- Jo-Anne Chan
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Linda Reiling
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Ashley Lisboa-Pinto
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Colin J Sutherland
- Department of Immunology and InfectionLondon School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Arlene E Dent
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, United States
| | - Kiprotich Chelimo
- Department of Biomedical Science and Technology Maseno University, Kisumu, Kenya
| | - James W Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, United States
| | - Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - James G Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia.,Department of Medicine, University of Melbourne Parkville, VIC, Australia.,Department of Microbiology and Central Clinical School, Monash University Melbourne, VIC, Australia
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11
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Dinko B, Ansah F, Agyare-Kwabi C, Tagboto S, Amoah LE, Urban BC, Sutherland CJ, Awandare GA, Williamson KC, Binka FN, Deitsch KW. Gametocyte Development and Carriage in Ghanaian Individuals with Uncomplicated Plasmodium falciparum Malaria. Am J Trop Med Hyg 2018; 99:57-64. [PMID: 29692310 DOI: 10.4269/ajtmh.18-0077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Plasmodium falciparum gametocytes develop over 9-12 days while sequestered in deep tissues. On emergence into the bloodstream, they circulate for varied amounts of time during which certain host factors might influence their further development. We aimed to evaluate the potential association of patient clinical parameters with gametocyte development and carriage via in vivo methods. Seventy-two patients were enrolled from three hospitals in the Volta region of Ghana in 2016. Clinical parameters were documented for all patients, and gametocyte prevalence by microscopy was estimated at 12.5%. By measuring RNA transcripts representing two distinct gametocyte developmental stages using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), we obtained a more precise estimate of gametocyte carriage while also inferring gametocyte maturation. Fifty-three percent of the study participants harbored parasites expressing transcripts of the immature gametocyte-specific gene (PF3D7_1477700), whereas 36% harbored PF3D7_1438800 RNA-positive parasites, which is enriched in mid and mature gametocytes, suggesting the presence of more immature stages. Linear logistic regression showed that patients older than 5 years but less than 16 years were more likely to carry gametocytes expressing both PF3D7_1477700 and PF3D7_1438800 compared with younger participants, and gametocytemia was more likely in mildly anemic individuals compared with those with severe/moderate anemia. These data provide further evidence that a greater number of malaria patients harbor gametocytes than typically estimated by microscopy and suggest a possible association between age, fever, anemia, and gametocytemia.
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Affiliation(s)
- Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Comfort Agyare-Kwabi
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Senyo Tagboto
- Department of Internal Medicine, School of Medicine, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Linda Eva Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Britta C Urban
- Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Colin J Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Kim C Williamson
- Microbiology and Immunology Department, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Fred N Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York
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12
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Stone WJR, Campo JJ, Ouédraogo AL, Meerstein-Kessel L, Morlais I, Da D, Cohuet A, Nsango S, Sutherland CJ, van de Vegte-Bolmer M, Siebelink-Stoter R, van Gemert GJ, Graumans W, Lanke K, Shandling AD, Pablo JV, Teng AA, Jones S, de Jong RM, Fabra-García A, Bradley J, Roeffen W, Lasonder E, Gremo G, Schwarzer E, Janse CJ, Singh SK, Theisen M, Felgner P, Marti M, Drakeley C, Sauerwein R, Bousema T, Jore MM. Unravelling the immune signature of Plasmodium falciparum transmission-reducing immunity. Nat Commun 2018; 9:558. [PMID: 29422648 PMCID: PMC5805765 DOI: 10.1038/s41467-017-02646-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 12/15/2017] [Indexed: 02/02/2023] Open
Abstract
Infection with Plasmodium can elicit antibodies that inhibit parasite survival in the mosquito, when they are ingested in an infectious blood meal. Here, we determine the transmission-reducing activity (TRA) of naturally acquired antibodies from 648 malaria-exposed individuals using lab-based mosquito-feeding assays. Transmission inhibition is significantly associated with antibody responses to Pfs48/45, Pfs230, and to 43 novel gametocyte proteins assessed by protein microarray. In field-based mosquito-feeding assays the likelihood and rate of mosquito infection are significantly lower for individuals reactive to Pfs48/45, Pfs230 or to combinations of the novel TRA-associated proteins. We also show that naturally acquired purified antibodies against key transmission-blocking epitopes of Pfs48/45 and Pfs230 are mechanistically involved in TRA, whereas sera depleted of these antibodies retain high-level, complement-independent TRA. Our analysis demonstrates that host antibody responses to gametocyte proteins are associated with reduced malaria transmission efficiency from humans to mosquitoes.
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Affiliation(s)
- Will J R Stone
- Radboud Institute for Health Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. .,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | | | | | - Lisette Meerstein-Kessel
- Radboud Institute for Health Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Isabelle Morlais
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, BP 288, Yaoundé, Cameroon.,Institut de Recherche pour le Développement, MIVEGEC (IRD, CNRS, Univ. Montpellier), 911 Avenue Agropolis, 34394, Montpellier, France
| | - Dari Da
- Institut de Recherche en Sciences de la Santé, 399 Avenue de la Liberté, 01 BP 545, Bobo-Dioulasso, Burkina Faso
| | - Anna Cohuet
- Institut de Recherche pour le Développement, MIVEGEC (IRD, CNRS, Univ. Montpellier), 911 Avenue Agropolis, 34394, Montpellier, France.,Institut de Recherche en Sciences de la Santé, 399 Avenue de la Liberté, 01 BP 545, Bobo-Dioulasso, Burkina Faso
| | - Sandrine Nsango
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, BP 288, Yaoundé, Cameroon.,Faculty of Medecine and Pharmaceutical Science, PO Box 2701, Douala, Cameroon
| | - Colin J Sutherland
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Marga van de Vegte-Bolmer
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Rianne Siebelink-Stoter
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Geert-Jan van Gemert
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Wouter Graumans
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Kjerstin Lanke
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | | | | | - Andy A Teng
- Antigen Discovery Inc., Irvine, CA, 92618, USA
| | - Sophie Jones
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Roos M de Jong
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Amanda Fabra-García
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - John Bradley
- Medical Research Council Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Will Roeffen
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Edwin Lasonder
- School of Biomedical and Healthcare Sciences, Plymouth University, Drakes Circus, Plymouth, PL4 8AA, UK
| | - Giuliana Gremo
- Department of Oncology, University of Torino, Via Santena 5bis, 10126, Torino, Italy
| | - Evelin Schwarzer
- Department of Oncology, University of Torino, Via Santena 5bis, 10126, Torino, Italy
| | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center (LUMC), Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Susheel K Singh
- Department for Congenital Diseases, Statens Serum Institut, Copenhagen, DK 2300, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, DK 2200, Denmark
| | - Michael Theisen
- Department for Congenital Diseases, Statens Serum Institut, Copenhagen, DK 2300, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, DK 2200, Denmark
| | - Phil Felgner
- Department of Medicine, University of California Irvine, Irvine, CA, 92697, USA
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, 02115, USA.,Wellcome Center for Molecular Parasitology, University of Glasgow, Glasgow, G12 8TA, UK
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Robert Sauerwein
- Radboud Institute for Health Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. .,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Matthijs M Jore
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
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13
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Meerstein-Kessel L, van der Lee R, Stone W, Lanke K, Baker DA, Alano P, Silvestrini F, Janse CJ, Khan SM, van de Vegte-Bolmer M, Graumans W, Siebelink-Stoter R, Kooij TWA, Marti M, Drakeley C, Campo JJ, van Dam TJP, Sauerwein R, Bousema T, Huynen MA. Probabilistic data integration identifies reliable gametocyte-specific proteins and transcripts in malaria parasites. Sci Rep 2018; 8:410. [PMID: 29323249 PMCID: PMC5765010 DOI: 10.1038/s41598-017-18840-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/15/2017] [Indexed: 12/02/2022] Open
Abstract
Plasmodium gametocytes are the sexual forms of the malaria parasite essential for transmission to mosquitoes. To better understand how gametocytes differ from asexual blood-stage parasites, we performed a systematic analysis of available ‘omics data for P. falciparum and other Plasmodium species. 18 transcriptomic and proteomic data sets were evaluated for the presence of curated “gold standards” of 41 gametocyte-specific versus 46 non-gametocyte genes and integrated using Bayesian probabilities, resulting in gametocyte-specificity scores for all P. falciparum genes. To illustrate the utility of the gametocyte score, we explored newly predicted gametocyte-specific genes as potential biomarkers of gametocyte carriage and exposure. We analyzed the humoral immune response in field samples against 30 novel gametocyte-specific antigens and found five antigens to be differentially recognized by gametocyte carriers as compared to malaria-infected individuals without detectable gametocytes. We also validated the gametocyte-specificity of 15 identified gametocyte transcripts on culture material and samples from naturally infected individuals, resulting in eight transcripts that were >1000-fold higher expressed in gametocytes compared to asexual parasites and whose transcript abundance allowed gametocyte detection in naturally infected individuals. Our integrated genome-wide gametocyte-specificity scores provide a comprehensive resource to identify targets and monitor P. falciparum gametocytemia.
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Affiliation(s)
- Lisette Meerstein-Kessel
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Robin van der Lee
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands.,Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Will Stone
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands.,Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - David A Baker
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Pietro Alano
- Dipartimento Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | | | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Shahid M Khan
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Wouter Graumans
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Rianne Siebelink-Stoter
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Taco W A Kooij
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Matthias Marti
- Wellcome Trust Center for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Teunis J P van Dam
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands.,Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Teun Bousema
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands.
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14
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Amoah LE, Acquah FK, Ayanful-Torgby R, Oppong A, Abankwa J, Obboh EK, Singh SK, Theisen M. Dynamics of anti-MSP3 and Pfs230 antibody responses and multiplicity of infection in asymptomatic children from southern Ghana. Parasit Vectors 2018; 11:13. [PMID: 29304870 PMCID: PMC5755320 DOI: 10.1186/s13071-017-2607-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/25/2017] [Indexed: 11/25/2022] Open
Abstract
Background During a Plasmodium infection, exposure of human host immune cells to both the asexual and the sexual stages of the parasite elicit immune responses. These responses may be protective and prevent the development of high parasitaemia and its associated clinical symptoms, or block the transmission of malaria to an uninfected person. This study aimed at examining the dynamics of naturally acquired immune responses against the asexual and sexual forms of Plasmodium falciparum as well as assessing differences in the multiplicity of infection (MOI) in asymptomatic Ghanaian children living in two communities with varying malaria transmission intensities. Methods School children aged between 6 and 12 years were recruited from Obom, a high malaria prevalence setting and Abura, a low malaria prevalence setting and enrolled in monthly multiple cross sectional surveys between February and May 2015. Filter paper blood blots (DBS) as well as thick and thin blood smears were made from finger-pricked blood at each visit. Plasmodium falciparum parasite prevalence was determined by microscopy and PCR. Serum eluted from the DBS were used to assess anti-Pfs230 (sexual stage) and anti-MSP3 (asexual stage) antibody levels using indirect ELISA and DNA extracted from the DBS used to assess MOI. Results Malaria parasite point prevalence and MOI throughout the study was higher in Obom than Abura. The trend of parasite prevalence estimated by microscopy was similar to that determined by PCR in Obom but not in Abura. The trend of MSP3 antibody seroprevalence followed that of PCR-estimated parasite prevalence in Obom, while in Abura the trend of Pfs230 antibody seroprevalence followed that of PCR-estimated parasite prevalence. Conclusions Microscopy can more accurately predict changes in parasite prevalence in high transmission settings than low transmission settings. In high transmission settings, P. falciparum parasite prevalence can predict antibody seroprevalence to MSP3, whilst in low transmission settings, seroprevalence against Pfs230 may be a useful predictor of parasite prevalence. Electronic supplementary material The online version of this article (10.1186/s13071-017-2607-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Linda E Amoah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
| | - Festus K Acquah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Ruth Ayanful-Torgby
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Akua Oppong
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joana Abankwa
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Evans K Obboh
- School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Susheel K Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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15
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Assadou MH, Sagara I, Healy SA, Guindo MA, Kone M, Sanogo S, Doucoure M, Keita S, Ellis RD, Wu Y, Omaswa F, Duffy PE, Doumbo OK. Malaria Infection and Gametocyte Carriage Rates in Preparation for Transmission Blocking Vaccine Trials in Bancoumana, Mali. Am J Trop Med Hyg 2017; 97:183-187. [PMID: 28719292 DOI: 10.4269/ajtmh.15-0845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The epidemiological characterization of transmission reservoirs is a critical step in preparation for interventional trials for malaria elimination/eradication. Using cluster sampling and households/compounds as units of sampling, we recruited and followed monthly, from June 2011 to June 2012, 250 volunteers 3 months to 50 years of age in Bancoumana, Mali. In July 2012, only participants 5-35 years of age (N = 121) were reenrolled and followed for an additional year. Malaria infection prevalence was highest in October in both 2011 (21.5%, 50/233) and 2012 (38.2%, 26/68). During both years, malaria infection prevalence was highest in children 5-14 years of age (P = 0.01 and P = 0.02, respectively). The gametocyte carriage prevalence was highest in November 2011 (7.6%, 17/225) and in October 2012 (16.2%, 11/68). Gametocyte carriage rates by age did not significantly differ in 2011 and 2012. In Bancoumana, the asexual and sexual parasite carriage rates are relatively high and highly seasonal. Seasonal variation and age differences in parasite and gametocyte carriage provide essential knowledge for the design of transmission blocking assay and vaccine studies in the field.
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Affiliation(s)
- Mahamadoun Hamady Assadou
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Issaka Sagara
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Merepen Agnes Guindo
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mamady Kone
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sintry Sanogo
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - M'Bouye Doucoure
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekouba Keita
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ruth D Ellis
- Biologics Consulting Group Inc., Alexandria, Virginia
| | - Yimin Wu
- PATH-Malaria Vaccine Initiative, Washington, District of Columbia
| | - Freda Omaswa
- University of British Columbia, Vancouver, Canada
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Ogobara K Doumbo
- Malaria Research and Training Center, FMOS-FAPH, Mali-NIAID-ICER, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
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16
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Bompard A, Da DF, Yerbanga RS, Biswas S, Kapulu M, Bousema T, Lefèvre T, Cohuet A, Churcher TS. Evaluation of two lead malaria transmission blocking vaccine candidate antibodies in natural parasite-vector combinations. Sci Rep 2017; 7:6766. [PMID: 28754921 PMCID: PMC5533793 DOI: 10.1038/s41598-017-06130-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/08/2017] [Indexed: 12/25/2022] Open
Abstract
Transmission blocking vaccines (TBV) which aim to control malaria by inhibiting human-to-mosquito transmission show considerable promise though their utility against naturally circulating parasites remains unknown. The efficacy of two lead candidates targeting Pfs25 and Pfs230 antigens to prevent onwards transmission of naturally occurring parasites to a local mosquito strain is assessed using direct membrane feeding assays and murine antibodies in Burkina Faso. The transmission blocking activity of both candidates depends on the level of parasite exposure (as assessed by the mean number of oocysts in control mosquitoes) and antibody titers. A mathematical framework is devised to allow the efficacy of different candidates to be directly compared and determine the minimal antibody titers required to halt transmission in different settings. The increased efficacy with diminishing parasite exposure indicates that the efficacy of vaccines targeting either Pfs25 or Pfs230 may increase as malaria transmission declines. This has important implications for late-stage candidate selection and assessing how they can support the drive for malaria elimination.
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Affiliation(s)
- Anais Bompard
- MRC Centre for Outbreak Analysis and Modelling, Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, W2 1PG, United Kingdom.
| | - Dari F Da
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Unité MIVEGEC, IRD 224-CNRS 5290-Université Montpellier, Montpellier, France
| | | | - Sumi Biswas
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Melissa Kapulu
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Thierry Lefèvre
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.,Unité MIVEGEC, IRD 224-CNRS 5290-Université Montpellier, Montpellier, France.,Laboratoire mixte international sur les vecteurs (LAMIVECT), Bobo Dioulasso, Burkina Faso
| | - Anna Cohuet
- Unité MIVEGEC, IRD 224-CNRS 5290-Université Montpellier, Montpellier, France
| | - Thomas S Churcher
- MRC Centre for Outbreak Analysis and Modelling, Infectious Disease Epidemiology, Imperial College London, Norfolk Place, London, W2 1PG, United Kingdom
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Chaturvedi N, Bharti PK, Tiwari A, Singh N. Strategies & recent development of transmission-blocking vaccines against Plasmodium falciparum. Indian J Med Res 2017; 143:696-711. [PMID: 27748294 PMCID: PMC5094109 DOI: 10.4103/0971-5916.191927] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Transmission blocking malaria vaccines are aimed to block the development and maturity of sexual stages of parasite within mosquitoes. The vaccine candidate antigens (Pfs25, Pfs48/45, Pfs230) that have shown transmission blocking immunity in model systems are in different stages of development. These antigens are immunogenic with limited genetic diversity. Pfs25 is a leading candidate and currently in phase I clinical trial. Efforts are now focused on the cost-effective production of potent antigens using safe adjuvants and optimization of vaccine delivery system that are capable of inducing strong immune responses. This review addresses the potential usefulness, development strategies, challenges, clinical trials and current status of Plasmodium falciparum sexual stage malaria vaccine candidate antigens for the development of transmission-blocking vaccines.
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Affiliation(s)
- Neha Chaturvedi
- National Institute for Research in Tribal Health (ICMR), Jabalpur, School of Biotechnology, Rajiv Gandhi Proudyogiki Vishwavidyalaya (State Technological University of Madhya Pradesh), Bhopal, India
| | - Praveen K Bharti
- National Institute for Research in Tribal Health (ICMR), Jabalpur, India
| | - Archana Tiwari
- School of Biotechnology, Rajiv Gandhi Proudyogiki Vishwavidyalaya (State Technological University of Madhya Pradesh), Bhopal, India
| | - Neeru Singh
- National Institute for Research in Tribal Health (ICMR), Jabalpur, India
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18
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Gebru T, Ajua A, Theisen M, Esen M, Ngoa UA, Issifou S, Adegnika AA, Kremsner PG, Mordmüller B, Held J. Recognition of Plasmodium falciparum mature gametocyte-infected erythrocytes by antibodies of semi-immune adults and malaria-exposed children from Gabon. Malar J 2017; 16:176. [PMID: 28446190 PMCID: PMC5406886 DOI: 10.1186/s12936-017-1827-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transmission of malaria from man to mosquito depends on the presence of gametocytes, the sexual stage of Plasmodium parasites in the infected host. Naturally acquired antibodies against gametocytes exist and may play a role in controlling transmission by limiting the gametocyte development in the circulation or by interrupting gamete development and fertilization in the mosquito following ingestion. So far, most studies on antibody responses to sexual stage antigens have focused on a subset of gametocyte-surface antigens, even though inhibitory Ab responses to other gametocyte antigens might also play a role in controlling gametocyte density and fertility. Limited information is available on natural antibody response to the surfaces of gametocyte-infected erythrocytes. METHODS Ab responses to surface antigens of erythrocytes infected by in vitro differentiated Plasmodium falciparum mature gametocytes were investigated in sera of semi-immune adults and malaria-exposed children. In addition, the effect of immunization with GMZ2, a blood stage malaria vaccine candidate, and the effect of intestinal helminth infection on the development of immunity to gametocytes of P. falciparum was evaluated in malaria-exposed children and adults from Gabon. Serum samples from two Phase I clinical trials conducted in Gabon were analysed by microscopic and flow-cytometric immunofluorescence assay. RESULTS Adults had a higher Ab response compared to children. Ab reactivity was significantly higher after fixation and permeabilization of parasitized erythrocytes. Following vaccination with the malaria vaccine candidate GMZ2, anti-gametocyte Ab concentration decreased in adults compared to baseline. Ab response to whole asexual stage antigens had a significant but weak positive correlation to anti-gametocyte Ab responses in adults, but not in children. Children infected with Ascaris lumbricoides had a significantly higher anti-gametocyte Ab response compared to non-infected children. CONCLUSION The current data suggest that antigens exposed on the gametocyte-infected red blood cells are recognized by serum antibodies from malaria-exposed children and semi-immune adults. This anti-gametocyte immune response may be influenced by natural exposure and vaccination. Modulation of the natural immune response to gametocytes by co-infecting parasites should be investigated further and may have an important impact on malaria control strategies.
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Affiliation(s)
- Tamirat Gebru
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.,Department of Medical Laboratory Sciences, College of Medical and Health Sciences, Haramaya University, Harar, Ethiopia
| | - Anthony Ajua
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Center for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Meral Esen
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon
| | - Ulysse Ateba Ngoa
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Saadou Issifou
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Fondation pour la Recherche Scientifique (FORS), Cotonou, Benin
| | - Ayola A Adegnika
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, 72074, Tübingen, Germany. .,German Centre for Infection Research (DZIF), Partner Site Tübingen, Germany. .,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon. .,German Centre for Infection Research (DZIF), Partner Site Lambaréné, Gabon.
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19
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The s48/45 six-cysteine proteins: mediators of interaction throughout the Plasmodium life cycle. Int J Parasitol 2016; 47:409-423. [PMID: 27899328 DOI: 10.1016/j.ijpara.2016.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/01/2016] [Accepted: 10/05/2016] [Indexed: 01/05/2023]
Abstract
During their life cycle Plasmodium parasites rely upon an arsenal of proteins that establish key interactions with the host and vector, and between the parasite sexual stages, with the purpose of ensuring infection, reproduction and proliferation. Among these is a group of secreted or membrane-anchored proteins known as the six-cysteine (6-cys) family. This is a small but important family with only 14 members thus far identified, each stage-specifically expressed during the parasite life cycle. 6-cys proteins often localise at the parasite surface or interface with the host and vector, and are conserved in different Plasmodium species. The unifying feature of the family is the s48/45 domain, presumably involved in adhesion and structurally related to Ephrins, the ligands of Eph receptors. The most prominent s48/45 members are currently under functional investigation and are being pursued as vaccine candidates. In this review, we examine what is known about the 6-cys family, their structure and function, and discuss future research directions.
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20
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Abstract
Gametocytes are the specialized form of Plasmodium parasites that are responsible for human-to-mosquito transmission of malaria. Transmission of gametocytes is highly effective, but represents a biomass bottleneck for the parasite that has stimulated interest in strategies targeting the transmission stages separately from those responsible for clinical disease. Studying targets of naturally acquired immunity against transmission-stage parasites may reveal opportunities for novel transmission reducing interventions, particularly the development of a transmission blocking vaccine (TBV). In this review, we summarize the current knowledge on immunity against the transmission stages of Plasmodium. This includes immune responses against epitopes on the gametocyte-infected erythrocyte surface during gametocyte development, as well as epitopes present upon gametocyte activation in the mosquito midgut. We present an analysis of historical data on transmission reducing immunity (TRI), as analysed in mosquito feeding assays, and its correlation with natural recognition of sexual stage specific proteins Pfs48/45 and Pfs230. Although high antibody titres towards either one of these proteins is associated with TRI, the presence of additional, novel targets is anticipated. In conclusion, the identification of novel gametocyte-specific targets of naturally acquired immunity against different gametocyte stages could aid in the development of potential TBV targets and ultimately an effective transmission blocking approach.
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21
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Smith RC, Vega-Rodríguez J, Jacobs-Lorena M. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector. Mem Inst Oswaldo Cruz 2015. [PMID: 25185005 PMCID: PMC4156458 DOI: 10.1590/0074-0276130597] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.
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Affiliation(s)
- Ryan C Smith
- Department of Molecular Microbiology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health and Immunology, Baltimore, MD, USA
| | - Joel Vega-Rodríguez
- Department of Molecular Microbiology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health and Immunology, Baltimore, MD, USA
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health and Immunology, Baltimore, MD, USA
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22
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Jones S, Grignard L, Nebie I, Chilongola J, Dodoo D, Sauerwein R, Theisen M, Roeffen W, Singh SK, Singh RK, Singh S, Kyei-Baafour E, Tetteh K, Drakeley C, Bousema T. Naturally acquired antibody responses to recombinant Pfs230 and Pfs48/45 transmission blocking vaccine candidates. J Infect 2015; 71:117-27. [PMID: 25869538 DOI: 10.1016/j.jinf.2015.03.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 03/13/2015] [Accepted: 03/28/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Pfs48/45 and Pfs230 are Plasmodium falciparum sexual stage proteins and promising malaria transmission-blocking vaccine candidates. Antibody responses against these proteins may be naturally acquired and target antigens may be under selective pressure. This has consequences for the future evaluation of vaccine immunogenicity and efficacy in populations naturally exposed to malaria. METHODS We determined naturally acquired antibody responses to the recombinant proteins Pfs48/45-10C and Pfs230-230CMB in children from three malaria endemic settings in Ghana, Tanzania and Burkina Faso. We also examined genetic polymorphisms in the P. falciparum gene pfs48/45. RESULTS Antibody prevalence was 1.1-18.2% for 10C and 6.7-18.9% for 230CMB. In Burkina Faso we observed evidence of an age-dependent acquisition pattern for both 10C (p < 0.001) and 230CMB (p = 0.031). Membrane feeding assays on a separate dataset demonstrated an association between functional transmission reducing activity and antibody prevalence for both 10C (p = 0.017) and 230CMB (p = 0.049). 17 single nucleotide polymorphisms were found in pfs48/45 (from 126 samples), with 5 non-synonymous SNPs in the Pfs48/45 10C region. CONCLUSIONS We conclude there are naturally acquired antibody responses to both vaccine candidates which have functional relevance by reducing the transmissibility of infected individuals. We identified genetic polymorphisms, in pfs48/45 which exhibited geographical specificity.
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Affiliation(s)
- Sophie Jones
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Lynn Grignard
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Issa Nebie
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | | | - Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michael Theisen
- Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen, Denmark; Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology, University of Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Will Roeffen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Sanjay Singh
- Gennova Bio Pharmaceuticals Limited, Pune, India
| | - Eric Kyei-Baafour
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Kevin Tetteh
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom; Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
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23
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Human-to-mosquito transmission efficiency increases as malaria is controlled. Nat Commun 2015; 6:6054. [PMID: 25597498 PMCID: PMC4309425 DOI: 10.1038/ncomms7054] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/09/2014] [Indexed: 11/28/2022] Open
Abstract
The efficiency of malaria transmission between human and mosquito has been shown to be influenced by many factors in the laboratory, although their impact in the field and how this changes with disease endemicity are unknown. Here we estimate how human–mosquito transmission changed as malaria was controlled in Dielmo, Senegal. Mathematical models were fit to data collected between 1990 and the start of vector control in 2008. Results show that asexual parasite slide prevalence in humans has reduced from 70 to 20%, but that the proportion of infectious mosquitoes has remained roughly constant. Evidence suggests that this is due to an increase in transmission efficiency caused by a rise in gametocyte densities, although the uneven distribution of mosquito bites between hosts could also contribute. The resilience of mosquito infection to changes in endemicity will have important implications for planning disease control, and the development and deployment of transmission-reducing interventions. Understanding the epidemiology of malaria transmission between humans and mosquitoes is crucial for successful disease control. Analysing data from an 18-year malaria control programme, Churcher et al. show that decreased parasite prevalence in humans can be found concurrently with an increase in transmission efficiency.
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24
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Miura K, Deng B, Tullo G, Diouf A, Moretz SE, Locke E, Morin M, Fay MP, Long CA. Qualification of standard membrane-feeding assay with Plasmodium falciparum malaria and potential improvements for future assays. PLoS One 2013; 8:e57909. [PMID: 23483940 PMCID: PMC3590281 DOI: 10.1371/journal.pone.0057909] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/29/2013] [Indexed: 11/18/2022] Open
Abstract
Vaccines that interrupt malaria transmission are of increasing interest and a robust functional assay to measure this activity would promote their development by providing a biologically relevant means of evaluating potential vaccine candidates. Therefore, we aimed to qualify the standard membrane-feeding assay (SMFA). The assay measures the transmission-blocking activity of antibodies by feeding cultured P. falciparum gametocytes to Anopheles mosquitoes in the presence of the test antibodies and measuring subsequent mosquito infection. The International Conference on Harmonisation (ICH) Harmonised Tripartite Guideline Q2(R1) details characteristics considered in assay validation. Of these characteristics, we decided to qualify the SMFA for Precision, Linearity, Range and Specificity. The transmission-blocking 4B7 monoclonal antibody was tested over 6 feeding experiments at several concentrations to determine four suitable concentrations that were tested in triplicate in the qualification experiments (3 additional feeds) to evaluate Precision, Linearity and Range. For Specificity, 4B7 was tested in the presence of normal mouse IgG. We determined intra- and inter-assay variability of % inhibition of mean oocyst intensity at each concentration of 4B7 (lower concentrations showed higher variability). We also showed that % inhibition was dependent on 4B7 concentration and the activity is specific to 4B7. Since obtaining empirical data is time-consuming, we generated a model using data from all 9 feeds and simulated the effects of different parameters on final readouts to improve the assay procedure and analytical methods for future studies. For example, we estimated the effect of number of mosquitoes dissected on variability of % inhibition, and simulated the relationship between % inhibition in oocyst intensity and % inhibition of prevalence of infected mosquitos at different mean oocysts in the control. SMFA is one of the few biological assays used in preclinical and early clinical development of transmission-blocking vaccines, and this study strongly supports its further development and application.
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Affiliation(s)
- Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, USA.
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25
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Bousema T, Dinglasan RR, Morlais I, Gouagna LC, van Warmerdam T, Awono-Ambene PH, Bonnet S, Diallo M, Coulibaly M, Tchuinkam T, Mulder B, Targett G, Drakeley C, Sutherland C, Robert V, Doumbo O, Touré Y, Graves PM, Roeffen W, Sauerwein R, Birkett A, Locke E, Morin M, Wu Y, Churcher TS. Mosquito feeding assays to determine the infectiousness of naturally infected Plasmodium falciparum gametocyte carriers. PLoS One 2012; 7:e42821. [PMID: 22936993 PMCID: PMC3425579 DOI: 10.1371/journal.pone.0042821] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 07/11/2012] [Indexed: 12/27/2022] Open
Abstract
Introduction In the era of malaria elimination and eradication, drug-based and vaccine-based approaches to reduce malaria transmission are receiving greater attention. Such interventions require assays that reliably measure the transmission of Plasmodium from humans to Anopheles mosquitoes. Methods We compared two commonly used mosquito feeding assay procedures: direct skin feeding assays and membrane feeding assays. Three conditions under which membrane feeding assays are performed were examined: assays with i) whole blood, ii) blood pellets resuspended with autologous plasma of the gametocyte carrier, and iii) blood pellets resuspended with heterologous control serum. Results 930 transmission experiments from Cameroon, The Gambia, Mali and Senegal were included in the analyses. Direct skin feeding assays resulted in higher mosquito infection rates compared to membrane feeding assays (odds ratio 2.39, 95% confidence interval 1.94–2.95) with evident heterogeneity between studies. Mosquito infection rates in membrane feeding assays and direct skin feeding assays were strongly correlated (p<0.0001). Replacing the plasma of the gametocyte donor with malaria naïve control serum resulted in higher mosquito infection rates compared to own plasma (OR 1.92, 95% CI 1.68–2.19) while the infectiousness of gametocytes may be reduced during the replacement procedure (OR 0.60, 95% CI 0.52–0.70). Conclusions Despite a higher efficiency of direct skin feeding assays, membrane feeding assays appear suitable tools to compare the infectiousness between individuals and to evaluate transmission-reducing interventions. Several aspects of membrane feeding procedures currently lack standardization; this variability makes comparisons between laboratories challenging and should be addressed to facilitate future testing of transmission-reducing interventions.
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Affiliation(s)
- Teun Bousema
- Department of Immunity and Infection, London School of Hygiene & Tropical Medicine, London, United Kingdom.
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26
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Patra KP, Vinetz JM. New ultrastructural analysis of the invasive apparatus of the Plasmodium ookinete. Am J Trop Med Hyg 2012; 87:412-7. [PMID: 22802443 DOI: 10.4269/ajtmh.2012.11-0609] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Invasion of the mosquito midgut by the Plasmodium ookinete determines the success of transmission of malaria parasites from humans to mosquitoes and therefore, is a potential target for molecular intervention. Here, we show higher-resolution ultrastructural details of developing and mature P. gallinaceum ookinetes than previously available. Improved fixation and processing methods yielded substantially improved transmission electron micrographs of ookinetes, particularly with regard to visualization of subcellular secretory and other organelles. These new images provide new insights into the synthesis and function of vital invasive machinery focused on the following features: apical membrane protrusions presumptively used for attachment and protein secretion, dark spherical bodies at the apical end of the mature ookinete, and the presence of a dense array of micronemes apposed to microtubules at the apical end of the ookinete involved in constitutive secretion. This work advances understanding of the molecular and cellular details of the Plasmodium ookinete and provides the basis of future, more detailed mechanistic experimentation on the biology of the Plasmodium ookinete.
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Affiliation(s)
- Kailash P Patra
- Division of Infectious Diseases, Department of Medicine, University of California at San Diego, La Jolla, CA 92093-0741, USA.
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27
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Quantitative assessment of Plasmodium falciparum sexual development reveals potent transmission-blocking activity by methylene blue. Proc Natl Acad Sci U S A 2011; 108:E1214-23. [PMID: 22042867 DOI: 10.1073/pnas.1112037108] [Citation(s) in RCA: 242] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Clinical studies and mathematical models predict that, to achieve malaria elimination, combination therapies will need to incorporate drugs that block the transmission of Plasmodium falciparum sexual stage parasites to mosquito vectors. Efforts to measure the activity of existing antimalarials on intraerythrocytic sexual stage gametocytes and identify transmission-blocking agents have, until now, been hindered by a lack of quantitative assays. Here, we report an experimental system using P. falciparum lines that stably express gametocyte-specific GFP-luciferase reporters, which enable the assessment of dose- and time-dependent drug action on gametocyte maturation and transmission. These studies reveal activity of the first-line antimalarial dihydroartemisinin and the partner drugs lumefantrine and pyronaridine against early gametocyte stages, along with moderate inhibition of mature gametocyte transmission to Anopheles mosquitoes. The other partner agents monodesethyl-amodiaquine and piperaquine showed activity only against immature gametocytes. Our data also identify methylene blue as a potent inhibitor of gametocyte development across all stages. This thiazine dye almost fully abolishes P. falciparum transmission to mosquitoes at concentrations readily achievable in humans, highlighting the potential of this chemical class to reduce the spread of malaria.
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28
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Bousema T, Drakeley C. Epidemiology and infectivity of Plasmodium falciparum and Plasmodium vivax gametocytes in relation to malaria control and elimination. Clin Microbiol Rev 2011; 24:377-410. [PMID: 21482730 PMCID: PMC3122489 DOI: 10.1128/cmr.00051-10] [Citation(s) in RCA: 505] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed.
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Affiliation(s)
- Teun Bousema
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, United Kingdom
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, United Kingdom
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29
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Bousema T, Sutherland CJ, Churcher TS, Mulder B, Gouagna LC, Riley EM, Targett GA, Drakeley CJ. Human immune responses that reduce the transmission of Plasmodium falciparum in African populations. Int J Parasitol 2011; 41:293-300. [PMID: 20974145 PMCID: PMC3052432 DOI: 10.1016/j.ijpara.2010.09.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 09/20/2010] [Accepted: 09/21/2010] [Indexed: 12/04/2022]
Abstract
Malaria-infected individuals can develop antibodies which reduce the infectiousness of Plasmodium gametocytes to biting Anopheles mosquitoes. When ingested in a bloodmeal together with gametocytes, these antibodies reduce or prevent subsequent parasite maturation in the insect host. This transmission-blocking immunity is usually measured in human sera by testing its effect on the infectivity of gametocytes grown in vitro. Here we evaluate evidence of transmission-blocking immunity in eight studies conducted in three African countries. Plasmodium falciparum gametocytes isolated from each individual were fed to mosquitoes in both autologous plasma collected with the parasites, and permissive serum from non-exposed donors. Evidence of transmission reducing effects of autologous plasma was found in all countries. Experiments involving 116 Gambian children (aged 0.5-15 years) were combined to determine which factors were associated with transmission reducing immune responses. The chances of infecting at least one mosquito and the average proportion of infected mosquitoes were negatively associated with recent exposure to gametocytes and sampling late in the season. These results suggest that effective malaria transmission-reducing antibodies do not commonly circulate in African children, and that recent gametocyte carriage is required to initiate and/or boost such responses.
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Affiliation(s)
- Teun Bousema
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Colin J. Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas S. Churcher
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK
| | - Bert Mulder
- Microbiology Laboratory Twente, Enschede, The Netherlands
| | | | - Eleanor M. Riley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Geoffrey A.T. Targett
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris J. Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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30
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Bousema T, Roeffen W, Meijerink H, Mwerinde H, Mwakalinga S, van Gemert GJ, van de Vegte-Bolmer M, Mosha F, Targett G, Riley EM, Sauerwein R, Drakeley C. The dynamics of naturally acquired immune responses to Plasmodium falciparum sexual stage antigens Pfs230 & Pfs48/45 in a low endemic area in Tanzania. PLoS One 2010; 5:e14114. [PMID: 21124765 PMCID: PMC2993929 DOI: 10.1371/journal.pone.0014114] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 09/16/2010] [Indexed: 11/23/2022] Open
Abstract
Background Naturally acquired immune responses against sexual stages of P. falciparum can reduce the transmission of malaria from humans to mosquitoes. These antigens are candidate transmission-blocking vaccines but little is known about the acquisition of sexual stage immunity after exposure to gametocytes, or their longevity and functionality. We conducted a longitudinal study on functional sexual stage immune responses. Methodology/Principal Findings Parasitaemic individuals (n = 116) were recruited at a health centre in Lower Moshi, Tanzania. Patients presented with gametocytes (n = 16), developed circulating gametocytes by day 7 (n = 69) or between day 7 and 14 (n = 10) after treatment or did not develop gametocytes (n = 21). Serum samples were collected on the first day of gametocytaemia and 28 and 84 days post-enrolment (or d7, 28, 84 after enrolment from gametocyte-negative individuals). Antibody responses to sexual stage antigens Pfs230 and Pfs48/45 were detected in 20.7% (72/348) and 15.2% (53/348) of the samples, respectively, and were less prevalent than antibodies against asexual stage antigens MSP-119 (48.1%; 137/285) and AMA-1 (52.4%; 129/246)(p<0.001). The prevalence of anti-Pfs230 (p = 0.026) and anti-Pfs48/45 antibodies (p = 0.017) increased with longer duration of gametocyte exposure and had an estimated half-life of approximately 3 months. Membrane feeding experiments demonstrated a strong association between the prevalence and concentration of Pfs230 and Pfs48/45 antibodies and transmission reducing activity (TRA, p<0.01). Conclusions/Significance In a longitudinal study, anti-Pfs230 and Pf48/45 antibodies developed rapidly after exposure to gametocytes and were strongly associated with transmission-reducing activity. Our data indicate that the extent of antigen exposure is important in eliciting functional transmission-reducing immune responses.
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Affiliation(s)
- Teun Bousema
- Department of Immunology & Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Joint Malaria Programme, Moshi, Tanzania
| | - Will Roeffen
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Hinta Meijerink
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Harry Mwerinde
- TPC District Designated Hospital, Tanzania Plantation Company, Lower Moshi, Tanzania
| | - Steve Mwakalinga
- Joint Malaria Programme, Moshi, Tanzania
- Department of International Health, Immunology, and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Marga van de Vegte-Bolmer
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Frank Mosha
- Joint Malaria Programme, Moshi, Tanzania
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Geoffrey Targett
- Department of Immunology & Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Eleanor M. Riley
- Department of Immunology & Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology & Infection, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Joint Malaria Programme, Moshi, Tanzania
- * E-mail:
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31
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van Dijk MR, van Schaijk BCL, Khan SM, van Dooren MW, Ramesar J, Kaczanowski S, van Gemert GJ, Kroeze H, Stunnenberg HG, Eling WM, Sauerwein RW, Waters AP, Janse CJ. Three members of the 6-cys protein family of Plasmodium play a role in gamete fertility. PLoS Pathog 2010; 6:e1000853. [PMID: 20386715 PMCID: PMC2851734 DOI: 10.1371/journal.ppat.1000853] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 03/09/2010] [Indexed: 01/16/2023] Open
Abstract
The process of fertilization is critically dependent on the mutual recognition of gametes and in Plasmodium, the male gamete surface protein P48/45 is vital to this process. This protein belongs to a family of 10 structurally related proteins, the so called 6-cys family. To identify the role of additional members of this family in Plasmodium fertilisation, we performed genetic and functional analysis on the five members of the 6-cys family that are transcribed during the gametocyte stage of P. berghei. This analysis revealed that in addition to P48/45, two members (P230 and P47) also play an essential role in the process of parasite fertilization. Mating studies between parasites lacking P230, P48/45 or P47 demonstrate that P230, like P48/45, is a male fertility factor, consistent with the previous demonstration of a protein complex containing both P48/45 and P230. In contrast, disruption of P47 results in a strong reduction of female fertility, while males remain unaffected. Further analysis revealed that gametes of mutants lacking expression of p48/45 or p230 or p47 are unable to either recognise or attach to each other. Disruption of the paralog of p230, p230p, also specifically expressed in gametocytes, had no observable effect on fertilization. These results indicate that the P. berghei 6-cys family contains a number of proteins that are either male or female specific ligands that play an important role in gamete recognition and/or attachment. The implications of low levels of fertilisation that exist even in the absence of these proteins, indicating alternative pathways of fertilisation, as well as positive selection acting on these proteins, are discussed in the context of targeting these proteins as transmission blocking vaccine candidates. Sexual reproduction for malaria parasites is an essential process and is necessary for parasite transmission between hosts. Fertilisation between female and male gametes occurs in the midgut of the mosquito and proteins on the surface of gametes are principle targets in transmission blocking strategies. Despite their importance, relatively little is known about the malaria proteins involved in fertilisation. In this study we show that two gamete proteins, one expressed on the surface of males, the other on the surface of females, have important roles in the mutual recognition and attachment of gametes. Mutant parasites that lack the presence of these surface proteins show a strong reduction in fertility. Comparison of these gamete surface proteins in different malaria parasites showed that these proteins are evolving rapidly either across their length or at discreet regions/domains. We found, that despite the drastic reduction in zygote formation, low levels of fertilisation can still occur in the absence of these surface proteins, indicating that gametes can use alternative proteins to recognize each other. Both genetic variation of gamete surface proteins and the presence of different fertilisation pathways have important implications for transmission blocking vaccines targeting gamete surface proteins.
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Affiliation(s)
- Melissa R. van Dijk
- Laboratory for Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Ben C. L. van Schaijk
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Shahid M. Khan
- Laboratory for Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Maaike W. van Dooren
- Laboratory for Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jai Ramesar
- Laboratory for Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Szymon Kaczanowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Hans Kroeze
- Laboratory for Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Hendrik G. Stunnenberg
- Department of Molecular Biology, NCMLS, University of Nijmegen, Nijmegen, The Netherlands
| | - Wijnand M. Eling
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Robert W. Sauerwein
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Andrew P. Waters
- Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, Scotland
| | - Chris J. Janse
- Laboratory for Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
- * E-mail:
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32
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Miura K, Keister DB, Muratova OV, Sattabongkot J, Long CA, Saul A. Transmission-blocking activity induced by malaria vaccine candidates Pfs25/Pvs25 is a direct and predictable function of antibody titer. Malar J 2007; 6:107. [PMID: 17686163 PMCID: PMC1971714 DOI: 10.1186/1475-2875-6-107] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 08/08/2007] [Indexed: 11/30/2022] Open
Abstract
Background Mosquito stage malaria vaccines are designed to induce an immune response in the human host that will block the parasite's growth in the mosquito and consequently block transmission of the parasite. A mosquito membrane-feeding assay (MFA) is used to test transmission-blocking activity (TBA), but in this technique cannot accommodate many samples. A clear understanding of the relationship between antibody levels and TBA may allow ELISA determinations to be used to predict TBA and assist in planning vaccine development. Methods Rabbit anti-Pfs25 sera and monkey anti-Pvs25 sera were generated and the antibody titers were determined by a standardized ELISA. The biological activity of the same sera was tested by MFA using Plasmodium gametocytes (cultured Plasmodium falciparum or Plasmodium vivax from malaria patients) and Anopheles mosquitoes. Results Anti-Pfs25 and anti-Pvs25 sera showed that ELISA antibody units correlate with the percent reduction in the oocyst density per mosquito (Spearman Rank correlations: 0.934 and 0.616, respectively), and fit a hyperbolic curve when percent reduction in oocyst density is plotted against antibody units of the tested sample. Antibody levels also correlated with the number of mosquitoes that failed to become infected, and this proportion can be calculated from the reduction in oocyst numbers and the distribution of oocysts per infected mosquito in control group. Conclusion ELISA data may be used as a surrogate for the MFA to evaluate transmission-blocking vaccine efficacy. This will facilitate the evaluation of transmission-blocking vaccines and implementation of this malaria control strategy.
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MESH Headings
- Animals
- Anopheles/parasitology
- Anopheles/physiology
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/physiology
- Antigens, Protozoan/immunology
- Antigens, Surface/immunology
- Cell Count
- Culicidae/parasitology
- Culicidae/physiology
- Disease Transmission, Infectious/prevention & control
- Female
- Humans
- Immunization
- Immunization Schedule
- Injections, Intramuscular
- Macaca mulatta
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/immunology
- Malaria, Falciparum/blood
- Malaria, Falciparum/prevention & control
- Malaria, Falciparum/transmission
- Malaria, Vivax/blood
- Malaria, Vivax/prevention & control
- Malaria, Vivax/transmission
- Male
- Oocytes/cytology
- Plasmodium falciparum/immunology
- Plasmodium vivax/immunology
- Protozoan Proteins/immunology
- Rabbits
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/immunology
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Affiliation(s)
- Kazutoyo Miura
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
| | - David B Keister
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
| | - Olga V Muratova
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
| | - Jetsumon Sattabongkot
- Department of Entomology, United States Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Carole A Long
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
| | - Allan Saul
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA
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33
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Drakeley CJ, Bousema JT, Akim NIJ, Teelen K, Roeffen W, Lensen AH, Bolmer M, Eling W, Sauerwein RW. Transmission-reducing immunity is inversely related to age in Plasmodium falciparum gametocyte carriers. Parasite Immunol 2006; 28:185-90. [PMID: 16629703 DOI: 10.1111/j.1365-3024.2005.00818.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Immunity to the sexual stages of Plasmodium falciparum is induced during natural infections and can significantly reduce the transmission of parasites to mosquitoes (transmission reducing activity; TRA) but little is known about how these responses develop with increasing age/exposure to malaria. Routinely TRA is measured in the standard membrane feeding assay (SMFA). Sera were collected from a total of 199 gametocyte carriers (median age 4 years, quartiles 2 and 9 years) near Ifakara, Tanzania; 128 samples were tested in the SMFA and generated TRA data classified as a reduction of > 50% and > 90% of transmission. TRA of > 50% was highest in young children (aged 1-2) with a significant decline with age (chi(2) trend = 5.79, P = 0.016) and in logistic regression was associated with prevalence of antibodies to both Pfs230 and Pfs48/45 (OR 4.03, P = 0.011 and OR 2.43 P = 0.059, respectively). A TRA of > 90% reduction in transmission was not age related but was associated with antibodies to Pfs48/45 (OR 2.36, P = 0.055). Our data confirm that antibodies are an important component of naturally induced TRA. However, whilst a similar but small proportion of individuals at all ages have TRA > 90%, the gradual deterioration of TRA > 50% with age suggests decreased antibody concentration or affinity. This may be due to decreased exposure to gametocytes, probably as a result of increased asexual and/or gametocyte specific immunity.
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Affiliation(s)
- C J Drakeley
- Ifakara Health Research and Development Centre, Ifakara, Tanzania.
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