1
|
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.
Collapse
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
| | | |
Collapse
|
2
|
Walker IS, Rogerson SJ. Pathogenicity and virulence of malaria: Sticky problems and tricky solutions. Virulence 2023; 14:2150456. [PMID: 36419237 PMCID: PMC9815252 DOI: 10.1080/21505594.2022.2150456] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/25/2022] Open
Abstract
Infections with Plasmodium falciparum and Plasmodium vivax cause over 600,000 deaths each year, concentrated in Africa and in young children, but much of the world's population remain at risk of infection. In this article, we review the latest developments in the immunogenicity and pathogenesis of malaria, with a particular focus on P. falciparum, the leading malaria killer. Pathogenic factors include parasite-derived toxins and variant surface antigens on infected erythrocytes that mediate sequestration in the deep vasculature. Host response to parasite toxins and to variant antigens is an important determinant of disease severity. Understanding how parasites sequester, and how antibody to variant antigens could prevent sequestration, may lead to new approaches to treat and prevent disease. Difficulties in malaria diagnosis, drug resistance, and specific challenges of treating P. vivax pose challenges to malaria elimination, but vaccines and other preventive strategies may offer improved disease control.
Collapse
Affiliation(s)
- Isobel S Walker
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
| |
Collapse
|
3
|
Surit T, Sripoorote P, Kumpitak C, Suansomjit C, Maneechai N, Cui L, Sattabongkot J, Roobsoong W, Nguitragool W. Transmission efficiency of Plasmodium vivax at low parasitaemia. Malar J 2023; 22:22. [PMID: 36658583 PMCID: PMC9854148 DOI: 10.1186/s12936-022-04435-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/27/2022] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Plasmodium vivax is responsible for much of malaria outside Africa. Although most P. vivax infections in endemic areas are asymptomatic and have low parasite densities, they are considered a potentially important source of transmission. Several studies have demonstrated that asymptomatic P. vivax carriers can transmit the parasite to mosquitoes, but the efficiency has not been well quantified. The aim of this study is to determine the relationship between parasite density and mosquito infectivity, particularly at low parasitaemia. METHODS Membrane feeding assays were performed using serial dilutions of P. vivax-infected blood to define the relationship between parasitaemia and mosquito infectivity. RESULTS The infection rate (oocyst prevalence) and intensity (oocyst load) were positively correlated with the parasite density in the blood. There was a broad case-to-case variation in parasite infectivity. The geometric mean parasite density yielding a 10% mosquito infection rate was 33 (CI 95 9-120) parasites/µl or 4 (CI 95 1-17) gametocytes/µl. The geometric mean parasite density yielding a 50% mosquito infection rate was 146 (CI 95 36-586) parasites/µl or 13 (CI 95 3-49) gametocytes/µl. CONCLUSION This study quantified the ability of P. vivax to infect Anopheles dirus at over a broad range of parasite densities. It provides important information about parasite infectivity at low parasitaemia common among asymptomatic P. vivax carriers.
Collapse
Affiliation(s)
- Thitiporn Surit
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Piyarat Sripoorote
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand
| | - Chalermpon Kumpitak
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand
| | - Chayanut Suansomjit
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand
| | - Nongnuj Maneechai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand.
| | - Wang Nguitragool
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Rd, Ratchathewi, Bangkok, 10400, Thailand.
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| |
Collapse
|
4
|
Tebeje SK, Chali W, Hailemeskel E, Ramjith J, Gashaw A, Ashine T, Nebret D, Esayas E, Emiru T, Tsegaye T, Teelen K, Lanke K, Takashima E, Tsuboi T, Salinas ND, Tolia NH, Narum D, Drakeley C, Witkowski B, Vantaux A, Jore MM, Stone WJR, Hansen IS, Tadesse FG, Bousema T. Naturally acquired antibodies to gametocyte antigens are associated with reduced transmission of Plasmodium vivax gametocytes to Anopheles arabiensis mosquitoes. Front Cell Infect Microbiol 2023; 12:1106369. [PMID: 36726645 PMCID: PMC9885094 DOI: 10.3389/fcimb.2022.1106369] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 12/28/2022] [Indexed: 01/17/2023] Open
Abstract
Naturally acquired antibodies may reduce the transmission of Plasmodium gametocytes to mosquitoes. Here, we investigated associations between antibody prevalence and P. vivax infectivity to mosquitoes. A total of 368 microscopy confirmed P. vivax symptomatic patients were passively recruited from health centers in Ethiopia and supplemented with 56 observations from asymptomatic P. vivax parasite carriers. Direct membrane feeding assays (DMFA) were performed to assess mosquito infectivity; for selected feeds these experiments were also performed after replacing autologous plasma with malaria naïve control serum (n=61). The prevalence of antibodies against 6 sexual stage antigens (Pvs47, Pvs48/45, Pvs230, PvsHAP2, Pvs25 and PvCelTOS) and an array of asexual antigens was determined by ELISA and multiplexed bead-based assays. Gametocyte (ρ< 0.42; p = 0.0001) and parasite (ρ = 0.21; p = 0.0001) densities were positively associated with mosquito infection rates. Antibodies against Pvs47, Pvs230 and Pvs25 were associated with 23 and 34% reductions in mosquito infection rates (p<0.0001), respectively. Individuals who showed evidence of transmission blockade in serum-replacement DMFAs (n=8) were significantly more likely to have PvsHAP2 or Pvs47 antibodies. Further studies may demonstrate causality for the observed associations, improve our understanding of the natural transmission of P. vivax and support vaccine development.
Collapse
Affiliation(s)
- Surafel K. Tebeje
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Wakweya Chali
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Elifaged Hailemeskel
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands,Department of Biology, College of Natural and Computational Sciences, Wollo University, Dessie, Ethiopia
| | - Jordache Ramjith
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Abrham Gashaw
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia
| | - Temesgen Ashine
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia
| | - Desalegn Nebret
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia
| | - Endashaw Esayas
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia
| | - Tadele Emiru
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia
| | - Tizita Tsegaye
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia
| | - Karina Teelen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Nichole D. Salinas
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
| | - Niraj H. Tolia
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
| | - David Narum
- Laboratory of Malaria Immunology and Vaccinology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
| | - Chris Drakeley
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Pasteur Institute of Cambodia, Phnom Penh, Cambodia
| | - Amelie Vantaux
- Malaria Molecular Epidemiology Unit, Pasteur Institute of Cambodia, Phnom Penh, Cambodia
| | - Matthijs M. Jore
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Ivo S. Hansen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Fitsum G. Tadesse
- Armauer Hansen Research Institute, Malaria and Neglected Tropical Disease Directorate, Addis Ababa, Ethiopia,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands,London School of Hygiene & Tropical Medicine, London, United Kingdom,*Correspondence: Teun Bousema,
| |
Collapse
|
5
|
Muthui MK, Takashima E, Omondi BR, Kinya C, Muasya WI, Nagaoka H, Mwai KW, Orindi B, Wambua J, Bousema T, Drakeley C, Blagborough AM, Marsh K, Bejon P, Kapulu MC. Characterization of Naturally Acquired Immunity to a Panel of Antigens Expressed in Mature P. falciparum Gametocytes. Front Cell Infect Microbiol 2021; 11:774537. [PMID: 34869075 PMCID: PMC8633105 DOI: 10.3389/fcimb.2021.774537] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction Naturally acquired immune responses against antigens expressed on the surface of mature gametocytes develop in individuals living in malaria-endemic areas. Evidence suggests that such anti-gametocyte immunity can block the development of the parasite in the mosquito, thus playing a role in interrupting transmission. A better comprehension of naturally acquired immunity to these gametocyte antigens can aid the development of transmission-blocking vaccines and improve our understanding of the human infectious reservoir. Methods Antigens expressed on the surface of mature gametocytes that had not previously been widely studied for evidence of naturally acquired immunity were identified for protein expression alongside Pfs230-C using either the mammalian HEK293E or the wheat germ cell-free expression systems. Where there was sequence variation in the candidate antigens (3D7 vs a clinical isolate PfKE04), both variants were expressed. ELISA was used to assess antibody responses against these antigens, as well as against crude stage V gametocyte extract (GE) and AMA1 using archived plasma samples from individuals recruited to participate in malaria cohort studies. We analyzed antibody levels (estimated from optical density units using a standardized ELISA) and seroprevalence (defined as antibody levels greater than three standard deviations above the mean levels of a pool of malaria naïve sera). We described the dynamics of antibody responses to these antigens by identifying factors predictive of antibody levels using linear regression models. Results Of the 25 antigens selected, seven antigens were produced successfully as recombinant proteins, with one variant antigen, giving a total of eight proteins for evaluation. Antibodies to the candidate antigens were detectable in the study population (N = 216), with seroprevalence ranging from 37.0% (95% CI: 30.6%, 43.9%) for PSOP1 to 77.8% (95% CI: 71.6%, 83.1%) for G377 (3D7 variant). Responses to AMA1 and GE were more prevalent than those to the gametocyte proteins at 87.9% (95% CI: 82.8%, 91.9%) and 88.3% (95% CI: 83.1%, 92.4%), respectively. Additionally, both antibody levels and breadth of antibody responses were associated with age and concurrent parasitaemia. Conclusion Age and concurrent parasitaemia remain important determinants of naturally acquired immunity to gametocyte antigens. Furthermore, we identify novel candidates for transmission-blocking activity evaluation.
Collapse
Affiliation(s)
- Michelle K Muthui
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Brian R Omondi
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya
| | - Christine Kinya
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya
| | - William I Muasya
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Kennedy W Mwai
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Benedict Orindi
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya
| | - Juliana Wambua
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Andrew M Blagborough
- Division of Microbiology and Parasitology, Department of Pathology, Cambridge University, Tennis Court Road, Cambridge, United Kingdom
| | - Kevin Marsh
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Philip Bejon
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Melissa C Kapulu
- Department of Biosciences, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
6
|
Bantuchai S, Imad H, Nguitragool W. Plasmodium vivax gametocytes and transmission. Parasitol Int 2021; 87:102497. [PMID: 34748969 DOI: 10.1016/j.parint.2021.102497] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/14/2021] [Accepted: 10/30/2021] [Indexed: 10/19/2022]
Abstract
Malaria elimination means cessation of parasite transmission. At present, the declining malaria incidence in many countries has made elimination a feasible goal. Transmission control has thus been placed at the center of the national malaria control programs. The efficient transmission of Plasmodium vivax from humans to mosquitoes is a key factor that helps perpetuate malaria in endemic areas. A better understanding of transmission is crucial to the success of elimination efforts. Biological delineation of the parasite transmission process is important for identifying and prioritizing new targets of intervention. Identification of the infectious parasite reservoir in the community is key to devising an effective elimination strategy. Here we describe the fundamental characteristics of P. vivax gametocytes - the dynamics of their production, longevity, and the relationship with the total parasitemia - as well as recent advances in the molecular understanding of parasite sexual development. In relation to malaria elimination, factors influencing the human infectivity and the current evidence for a role of asymptomatic carriers in transmission are presented.
Collapse
Affiliation(s)
- Sirasate Bantuchai
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| | - Hisham Imad
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| | - Wang Nguitragool
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand; Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
| |
Collapse
|
7
|
Healy SA, Anderson C, Swihart BJ, Mwakingwe A, Gabriel EE, Decederfelt H, Hobbs CV, Rausch KM, Zhu D, Muratova O, Herrera R, Scaria PV, MacDonald NJ, Lambert LE, Zaidi I, Coelho CH, Renn JP, Wu Y, Narum DL, Duffy PE. Pfs230 yields higher malaria transmission-blocking vaccine activity than Pfs25 in humans but not mice. J Clin Invest 2021; 131:146221. [PMID: 33561016 PMCID: PMC8011888 DOI: 10.1172/jci146221] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/03/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUNDVaccines that block human-to-mosquito Plasmodium transmission are needed for malaria eradication, and clinical trials have targeted zygote antigen Pfs25 for decades. We reported that a Pfs25 protein-protein conjugate vaccine formulated in alum adjuvant induced serum functional activity in both US and Malian adults. However, antibody levels declined rapidly, and transmission-reducing activity required 4 vaccine doses. Functional immunogenicity and durability must be improved before advancing transmission-blocking vaccines further in clinical development. We hypothesized that the prefertilization protein Pfs230 alone or in combination with Pfs25 would improve functional activity.METHODSTransmission-blocking vaccine candidates based on gamete antigen Pfs230 or Pfs25 were conjugated with Exoprotein A, formulated in Alhydrogel, and administered to mice, rhesus macaques, and humans. Antibody levels were measured by ELISA and transmission-reducing activity was assessed by the standard membrane feeding assay.RESULTSPfs25-EPA/Alhydrogel and Pfs230D1-EPA/Alhydrogel induced similar serum functional activity in mice, but Pfs230D1-EPA induced significantly greater activity in rhesus monkeys that was enhanced by complement. In US adults, 2 vaccine doses induced complement-dependent activity in 4 of 5 Pfs230D1-EPA/Alhydrogel recipients but no significant activity in 5 Pfs25-EPA recipients, and combination with Pfs25-EPA did not increase activity over Pfs230D1-EPA alone.CONCLUSIONThe complement-dependent functional immunogenicity of Pfs230D1-EPA represents a significant improvement over Pfs25-EPA in this comparative study. The rhesus model is more predictive of the functional human immune response to Pfs230D1 than is the mouse model.TRIAL REGISTRATIONClinicalTrials.gov NCT02334462.FUNDINGIntramural Research Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health.
Collapse
Affiliation(s)
- Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, and
| | | | - Bruce J Swihart
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Erin E Gabriel
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.,Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
| | - Hope Decederfelt
- Pharmacy Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | | | | | - Daming Zhu
- Laboratory of Malaria Immunology and Vaccinology, and
| | - Olga Muratova
- Laboratory of Malaria Immunology and Vaccinology, and
| | - Raul Herrera
- Laboratory of Malaria Immunology and Vaccinology, and
| | | | | | | | - Irfan Zaidi
- Laboratory of Malaria Immunology and Vaccinology, and
| | | | | | - Yimin Wu
- Laboratory of Malaria Immunology and Vaccinology, and
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, and
| | | |
Collapse
|
8
|
Chawla J, Oberstaller J, Adams JH. Targeting Gametocytes of the Malaria Parasite Plasmodium falciparum in a Functional Genomics Era: Next Steps. Pathogens 2021; 10:346. [PMID: 33809464 PMCID: PMC7999360 DOI: 10.3390/pathogens10030346] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/25/2021] [Accepted: 03/03/2021] [Indexed: 02/04/2023] Open
Abstract
Mosquito transmission of the deadly malaria parasite Plasmodium falciparum is mediated by mature sexual forms (gametocytes). Circulating in the vertebrate host, relatively few intraerythrocytic gametocytes are picked up during a bloodmeal to continue sexual development in the mosquito vector. Human-to-vector transmission thus represents an infection bottleneck in the parasite's life cycle for therapeutic interventions to prevent malaria. Even though recent progress has been made in the identification of genetic factors linked to gametocytogenesis, a plethora of genes essential for sexual-stage development are yet to be unraveled. In this review, we revisit P. falciparum transmission biology by discussing targetable features of gametocytes and provide a perspective on a forward-genetic approach for identification of novel transmission-blocking candidates in the future.
Collapse
Affiliation(s)
- Jyotsna Chawla
- Molecular Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, MDC 7, Tampa, FL 33612, USA;
| | - Jenna Oberstaller
- Center for Global Health and Infectious Diseases Research and USF Genomics Program, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 404, Tampa, FL 33612, USA;
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research and USF Genomics Program, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 404, Tampa, FL 33612, USA;
| |
Collapse
|
9
|
Cozzarolo CS, Glaizot O, Christe P, Pigeault R. Enhanced Attraction of Arthropod Vectors to Infected Vertebrates: A Review of Empirical Evidence. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.568140] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
10
|
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: 57] [Impact Index Per Article: 14.3] [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.
Collapse
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
Collapse
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
| |
Collapse
|
11
|
Kurtovic L, Boyle MJ, Opi DH, Kennedy AT, Tham WH, Reiling L, Chan JA, Beeson JG. Complement in malaria immunity and vaccines. Immunol Rev 2019; 293:38-56. [PMID: 31556468 PMCID: PMC6972673 DOI: 10.1111/imr.12802] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/03/2019] [Indexed: 12/20/2022]
Abstract
Developing efficacious vaccines for human malaria caused by Plasmodium falciparum is a major global health priority, although this has proven to be immensely challenging over the decades. One major hindrance is the incomplete understanding of specific immune responses that confer protection against disease and/or infection. While antibodies to play a crucial role in malaria immunity, the functional mechanisms of these antibodies remain unclear as most research has primarily focused on the direct inhibitory or neutralizing activity of antibodies. Recently, there is a growing body of evidence that antibodies can also mediate effector functions through activating the complement system against multiple developmental stages of the parasite life cycle. These antibody‐complement interactions can have detrimental consequences to parasite function and viability, and have been significantly associated with protection against clinical malaria in naturally acquired immunity, and emerging findings suggest these mechanisms could contribute to vaccine‐induced immunity. In order to develop highly efficacious vaccines, strategies are needed that prioritize the induction of antibodies with enhanced functional activity, including the ability to activate complement. Here we review the role of complement in acquired immunity to malaria, and provide insights into how this knowledge could be used to harness complement in malaria vaccine development.
Collapse
Affiliation(s)
- Liriye Kurtovic
- Burnet Institute, Melbourne, Vic., Australia.,Central Clinical School, Monash University, Melbourne, Vic., Australia
| | | | | | - Alexander T Kennedy
- Walter and Eliza Hall Institute, Melbourne, Vic., Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Vic., Australia
| | - Wai-Hong Tham
- Walter and Eliza Hall Institute, Melbourne, Vic., Australia
| | | | - Jo-Anne Chan
- Burnet Institute, Melbourne, Vic., Australia.,Central Clinical School, Monash University, Melbourne, Vic., Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Vic., Australia.,Central Clinical School, Monash University, Melbourne, Vic., Australia.,Department of Microbiology, Monash University, Clayton, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| |
Collapse
|
12
|
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.
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Stone W, Bousema T, Sauerwein R, Drakeley C. Two-Faced Immunity? The Evidence for Antibody Enhancement of Malaria Transmission. Trends Parasitol 2018; 35:140-153. [PMID: 30573175 DOI: 10.1016/j.pt.2018.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022]
Abstract
Plasmodium gametocytes can induce an immune response in humans that interferes with the development of sexual-stage parasites in the mosquito gut. Many early studies of the sexual-stage immune response noted that mosquito infection could be enhanced as well as reduced by immune sera. For Plasmodium falciparum, these reports are scarce, and the phenomenon is generally regarded as a methodological artefact. Plasmodium transmission enhancement (TE) remains contentious, but the clinical development of transmission-blocking vaccines based on sexual-stage antigens requires that it is further studied. In this essay, we review the early literature on the sexual-stage immune response and transmission-modulating immunity. We discuss hypotheses for the mechanism of TE, suggest experiments to prove or disprove its existence, and discuss its possible implications.
Collapse
Affiliation(s)
- Will Stone
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| |
Collapse
|
15
|
White SE, Harvey SA, Meza G, Llanos A, Guzman M, Gamboa D, Vinetz JM. Acceptability of a herd immunity-focused, transmission-blocking malaria vaccine in malaria-endemic communities in the Peruvian Amazon: an exploratory study. Malar J 2018; 17:179. [PMID: 29703192 PMCID: PMC5921293 DOI: 10.1186/s12936-018-2328-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/18/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A transmission-blocking vaccine (TBV) to prevent malaria-infected humans from infecting mosquitoes has been increasingly considered as a tool for malaria control and elimination. This study tested the hypothesis that a malaria TBV would be acceptable among residents of a malaria-hypoendemic region. METHODS The study was carried out in six Spanish-speaking rural villages in the Department of Loreto in the Peruvian Amazon. These villages comprise a cohort of 430 households associated with the Peru-Brazil International Centre for Excellence in Malaria Research. Individuals from one-third (143) of enrolled households in an ongoing longitudinal, prospective cohort study in 6 communities in Loreto, Peru, were randomly selected to participate by answering a pre-validated questionnaire. RESULTS All 143 participants expressed desire for a malaria vaccine in general; only 1 (0.7%) expressed unwillingness to receive a transmission-blocking malaria vaccine. Injection was considered most acceptable for adults (97.2%); for children drops in the mouth were preferred (96.8%). Acceptability waned marginally with the prospect of multiple injections (83.8%) and different projected efficacies at 70 and 50% (90.1 and 71.8%, respectively). Respondents demonstrated clear understanding that the vaccine was for community, rather than personal, protection against malaria infection. DISCUSSION In this setting of the Peruvian Amazon, a transmission-blocking malaria vaccine was found to be almost universally acceptable. This study is the first to report that residents of a malaria-endemic region have been queried regarding a malaria vaccine strategy that policy-makers in the industrialized world often dismiss as altruistic.
Collapse
Affiliation(s)
- Sara E White
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego School of Medicine, 9500 Gilman Drive 0760, Biomedical Research Facility Room 4A16, La Jolla, CA, 92093-0760, USA
| | - Steven A Harvey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St. E5030, Baltimore, MD, 21205, USA.
| | - Graciela Meza
- Facultad de Medicina Humana, Universidad Nacional de la Amazonia Peruana, Iquitos, Peru
| | - Alejandro Llanos
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Mitchel Guzman
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Dionicia Gamboa
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru.,Department of Cellular and Molecular Sciences, Faculty of Sciences and Laboratory of Research and Development, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego School of Medicine, 9500 Gilman Drive 0760, Biomedical Research Facility Room 4A16, La Jolla, CA, 92093-0760, USA. .,Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru. .,Department of Cellular and Molecular Sciences, Faculty of Sciences and Laboratory of Research and Development, Universidad Peruana Cayetano Heredia, Lima, Peru.
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
Sinden RE. Antimalarial transmission-blocking vaccines. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1997.11813242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
18
|
Rosas-Aguirre A, Gamboa D, Manrique P, Conn JE, Moreno M, Lescano AG, Sanchez JF, Rodriguez H, Silva H, Llanos-Cuentas A, Vinetz JM. Epidemiology of Plasmodium vivax Malaria in Peru. Am J Trop Med Hyg 2016; 95:133-144. [PMID: 27799639 PMCID: PMC5201219 DOI: 10.4269/ajtmh.16-0268] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/29/2016] [Indexed: 01/01/2023] Open
Abstract
Malaria in Peru, dominated by Plasmodium vivax, remains a public health problem. The 1990s saw newly epidemic malaria emerge, primarily in the Loreto Department in the Amazon region, including areas near to Iquitos, the capital city, but sporadic malaria transmission also occurred in the 1990s–2000s in both north-coastal Peru and the gold mining regions of southeastern Peru. Although a Global Fund-supported intervention (PAMAFRO, 2005–2010) was temporally associated with a decrease of malaria transmission, from 2012 to the present, both P. vivax and Plasmodium falciparum malaria cases have rapidly increased. The Peruvian Ministry of Health continues to provide artemesinin-based combination therapy for microscopy-confirmed cases of P. falciparum and chloroquine–primaquine for P. vivax. Malaria transmission continues in remote areas nonetheless, where the mobility of humans and parasites facilitates continued reintroduction outside of ongoing surveillance activities, which is critical to address for future malaria control and elimination efforts. Ongoing P. vivax research gaps in Peru include the following: identification of asymptomatic parasitemics, quantification of the contribution of patent and subpatent parasitemics to mosquito transmission, diagnosis of nonparasitemic hypnozoite carriers, and implementation of surveillance for potential emergence of chloroquine- and 8-aminoquinoline-resistant P. vivax. Clinical trials of tafenoquine in Peru have been promising, and glucose-6-phosphate dehydrogenase deficiency in the region has not been observed to be a limitation to its use. Larger-scale challenges for P. vivax (and malaria in general) in Peru include logistical difficulties in accessing remote riverine populations, consequences of government policy and poverty trends, and obtaining international funding for malaria control and elimination.
Collapse
Affiliation(s)
- Angel Rosas-Aguirre
- Research Institute of Health and Society, Université Catholique de Louvain, Brussels, Belgium.,Instituto de Medicina Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Dionicia Gamboa
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.,Instituto de Medicina Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Paulo Manrique
- Instituto de Medicina Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Albany, New York.,Department of Biomedical Sciences, School of Public Health, University at Albany (State University of New York), Albany, New York
| | - Marta Moreno
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, San Diego, California
| | - Andres G Lescano
- Facultad de Salud Pública, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Juan F Sanchez
- Facultad de Salud Pública, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Hugo Rodriguez
- Dirección Regional de Salud Loreto, Ministerio de Salud, Iquitos, Peru
| | - Hermann Silva
- Dirección Regional de Salud Loreto, Ministerio de Salud, Iquitos, Peru
| | - Alejandro Llanos-Cuentas
- Instituto de Medicina Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M Vinetz
- Instituto de Medicina Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru.,Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.,Division of Infectious Diseases, Department of Medicine, University of California San Diego, San Diego, California
| |
Collapse
|
19
|
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.
Collapse
|
20
|
Abstract
SUMMARYPlasmodium vivaxis the most geographically widespread of the malaria parasites causing human disease, yet it is comparatively understudied compared withPlasmodium falciparum.In this article we review what is known about naturally acquired immunity toP. vivax, and importantly, how this differs to that acquired againstP. falciparum.Immunity to clinicalP. vivaxinfection is acquired more quickly than toP. falciparum, and evidence suggests humans in endemic areas also have a greater capacity to mount a successful immunological memory response to this pathogen. Both of these factors give promise to the idea of a successfulP. vivaxvaccine. We review what is known about both the cellular and humoral immune response, including the role of cytokines, antibodies, immunoregulation, immune memory and immune dysfunction. Furthermore, we discuss where the future lies in terms of advancing our understanding of naturally acquired immunity toP. vivax, through the use of well-designed longitudinal epidemiological studies and modern tools available to immunologists.
Collapse
|
21
|
Wu Y, Sinden RE, Churcher TS, Tsuboi T, Yusibov V. Development of malaria transmission-blocking vaccines: from concept to product. ADVANCES IN PARASITOLOGY 2015; 89:109-52. [PMID: 26003037 DOI: 10.1016/bs.apar.2015.04.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Despite decades of effort battling against malaria, the disease is still a major cause of morbidity and mortality. Transmission-blocking vaccines (TBVs) that target sexual stage parasite development could be an integral part of measures for malaria elimination. In the 1950s, Huff et al. first demonstrated the induction of transmission-blocking immunity in chickens by repeated immunizations with Plasmodium gallinaceum-infected red blood cells. Since then, significant progress has been made in identification of parasite antigens responsible for transmission-blocking activity. Recombinant technologies accelerated evaluation of these antigens as vaccine candidates, and it is possible to induce effective transmission-blocking immunity in humans both by natural infection and now by immunization with recombinant vaccines. This chapter reviews the efforts to produce TBVs, summarizes the current status and advances and discusses the remaining challenges and approaches.
Collapse
Affiliation(s)
- Yimin Wu
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Rockville, MD, USA
| | | | - Thomas S Churcher
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK
| | - Takafumi Tsuboi
- Division of Malaria Research, Ehime University, Matsuyama, Ehime, Japan
| | - Vidadi Yusibov
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
| |
Collapse
|
22
|
Arévalo-Herrera M, Vallejo AF, Rubiano K, Solarte Y, Marin C, Castellanos A, Céspedes N, Herrera S. Recombinant Pvs48/45 antigen expressed in E. coli generates antibodies that block malaria transmission in Anopheles albimanus mosquitoes. PLoS One 2015; 10:e0119335. [PMID: 25775466 PMCID: PMC4361554 DOI: 10.1371/journal.pone.0119335] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 01/23/2015] [Indexed: 11/23/2022] Open
Abstract
Transmission of malaria parasites from humans to Anopheles mosquitoes can be inhibited by specific antibodies elicited during malaria infection, which target surface Plasmodium gametocyte/gamete proteins. Some of these proteins may have potential for vaccine development. Pvs48/45 is a P. vivax gametocyte surface antigen orthologous to Pfs48/45, which may play a role during parasite fertilization and thus has potential for transmission blocking (TB) activity. Here we describe the expression of a recombinant Pvs48/45 protein expressed in Escherichia coli as a ∼60kDa construct which we tested for antigenicity using human sera and for its immunogenicity and transmission blocking activity of specific anti-mouse and anti-monkey Pvs48/45 antibodies. The protein reacted with sera of individuals from malaria-endemic areas and in addition induced specific IgG antibody responses in BALB/c mice and Aotus l. griseimembra monkeys. Sera from both immunized animal species recognized native P. vivax protein in Western blot (WB) and immunofluorescence assays. Moreover, sera from immunized mice and monkeys produced significant inhibition of parasite transmission to An. Albimanus mosquitoes as shown by membrane feeding assays. Results indicate the presence of reactive epitopes in the Pvs48/45 recombinant product that induce antibodies with TB activity. Further testing of this protein is ongoing to determine its vaccine potential.
Collapse
Affiliation(s)
- Myriam Arévalo-Herrera
- Malaria Vaccine and Drug Development Center, Cali, Colombia
- School of Health, Universidad del Valle, Cali, Colombia
- * E-mail:
| | | | - Kelly Rubiano
- Malaria Vaccine and Drug Development Center, Cali, Colombia
- Caucaseco Scientific Research Center, Cali, Colombia
| | - Yezid Solarte
- School of Health, Universidad del Valle, Cali, Colombia
| | | | | | - Nora Céspedes
- Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Sócrates Herrera
- Malaria Vaccine and Drug Development Center, Cali, Colombia
- Caucaseco Scientific Research Center, Cali, Colombia
- Primates Center Foundation, Cali, Colombia
| |
Collapse
|
23
|
Tachibana M, Suwanabun N, Kaneko O, Iriko H, Otsuki H, Sattabongkot J, Kaneko A, Herrera S, Torii M, Tsuboi T. Plasmodium vivax gametocyte proteins, Pvs48/45 and Pvs47, induce transmission-reducing antibodies by DNA immunization. Vaccine 2015; 33:1901-8. [PMID: 25765968 DOI: 10.1016/j.vaccine.2015.03.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 02/13/2015] [Accepted: 03/02/2015] [Indexed: 11/18/2022]
Abstract
Malaria transmission-blocking vaccines (TBV) aim to interfere with the development of the malaria parasite in the mosquito vector, and thus prevent spread of transmission in a community. To date three TBV candidates have been identified in Plasmodium vivax; namely, the gametocyte/gamete protein Pvs230, and the ookinete surface proteins Pvs25 and Pvs28. The Plasmodium falciparum gametocyte/gamete stage proteins Pfs48/45 and Pfs47 have been studied as TBV candidates, and Pfs48/45 shown to induce transmission-blocking antibodies, but the candidacy of their orthologs in P. vivax, Pvs48/45 (PVX_083235) and Pvs47 (PVX_083240), for vivax TBV have not been tested. Herein we investigated whether targeting Pvs48/45 and Pvs47 can inhibit parasite transmission to mosquitoes, using P. vivax isolates obtained in Thailand. Mouse antisera directed against the products from plasmids expressing Pvs48/45 and Pvs47 detected proteins of approximately 45- and 40-kDa, respectively, in the P. vivax gametocyte lysate, by Western blot analysis under non-reducing conditions. In immunofluorescence assays Pvs48/45 was detected predominantly on the surface and Pvs47 was detected in the cytoplasm of gametocytes. Membrane feeding transmission assays demonstrated that anti-Pvs48/45 and -Pvs47 mouse sera significantly reduced the number of P. vivax oocysts developing in the mosquito midgut. Limited amino acid polymorphism of these proteins was observed among 27 P. vivax isolates obtained from Thailand, Vanuatu, and Colombia; suggesting that polymorphism may not be an impediment for the utilization of Pvs48/45 and Pvs47 as TBV antigens. In one Thai isolate we found that the fourth cysteine residue in the Pvs47 cysteine-rich domain (CRD) III (amino acid position 337) is substituted to phenylalanine. However, antibodies targeting Pvs47 CRDI-III showed a significant transmission-reducing activity against this isolate, suggesting that this substitution in Pvs47 was not critical for recognition by the generated antibodies. In conclusion, our results indicate that Pvs48/45 and Pvs47 are potential transmission-blocking vaccine candidates of P. vivax.
Collapse
Affiliation(s)
- Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Nantavadee Suwanabun
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Sakamoto, Nagasaki 852-8523, Japan
| | - Hideyuki Iriko
- Department of Parasitology, Faculty of Health Sciences, Kobe University Graduate School of Health Sciences, Kobe 654-0142, Japan
| | - Hitoshi Otsuki
- Division of Medical Zoology, Faculty of Medicine, Tottori University, Yonago, Tottori 683-8503, Japan
| | - Jetsumon Sattabongkot
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | - Akira Kaneko
- Department of Parasitology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; Island Malaria Group, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Socrates Herrera
- Malaria Vaccine and Drug Development Center, Cali AA 25574, Colombia
| | - Motomi Torii
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan.
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan.
| |
Collapse
|
24
|
GRAHAM CHRISTINEB, WOODS MICHAELE, VETTER SARAM, PETERSEN JEANNINEM, MONTENIERI JOHNA, HOLMES JENNIFERL, MAES SARAHE, BEARDEN SCOTTW, GAGE KENNETHL, EISEN REBECCAJ. Evaluation of the effect of host immune status on short-term Yersinia pestis infection in fleas with implications for the enzootic host model for maintenance of Y. pestis during interepizootic periods. JOURNAL OF MEDICAL ENTOMOLOGY 2014; 51:1079-86. [PMID: 25276941 PMCID: PMC4636331 DOI: 10.1603/me14080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Plague, a primarily flea-borne disease caused by Yersinia pestis, is characterized by rapidly spreading epizootics separated by periods of quiescence. Little is known about how and where Y. pestis persists between epizootics. It is commonly proposed, however, that Y pestis is maintained during interepizootic periods in enzootic cycles involving flea vectors and relatively resistant host populations. According to this model, while susceptible individuals serve as infectious sources for feeding fleas and subsequently die of infection, resistant hosts survive infection, develop antibodies to the plague bacterium, and continue to provide bloodmeals to infected fleas. For Y. pestis to persist under this scenario, fleas must remain infected after feeding on hosts carrying antibodies to Y. pestis. Studies of other vector-borne pathogens suggest that host immunity may negatively impact pathogen survival in the vector. Here, we report infection rates and bacterial loads for fleas (both Xenopsylla cheopis (Rothschild) and Oropsylla montana (Baker)) that consumed an infectious bloodmeal and subsequently fed on an immunized or age-matched naive mouse. We demonstrate that neither the proportion of infected fleas nor the bacterial loads in infected fleas were significantly lower within 3 d of feeding on immunized versus naive mice. Our findings thus provide support for one assumption underlying the enzootic host model of interepizootic maintenance of Y. pestis.
Collapse
Affiliation(s)
- CHRISTINE B. GRAHAM
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - MICHAEL E. WOODS
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - SARA M. VETTER
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - JEANNINE M. PETERSEN
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - JOHN A. MONTENIERI
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - JENNIFER L. HOLMES
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - SARAH E. MAES
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - SCOTT W. BEARDEN
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - KENNETH L. GAGE
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| | - REBECCA J. EISEN
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521
| |
Collapse
|
25
|
Abstract
Vector-borne pathogens may alter traits of their primary hosts in ways that influence the frequency and nature of interactions between hosts and vectors. Previous work has reported enhanced mosquito attraction to host organisms infected with malaria parasites but did not address the mechanisms underlying such effects. Here we document malaria-induced changes in the odor profiles of infected mice (relative to healthy individuals) over the course of infection, as well as effects on the attractiveness of infected hosts to mosquito vectors. We observed enhanced mosquito attraction to infected mice during a key period after the subsidence of acute malaria symptoms, but during which mice remained highly infectious. This attraction corresponded to an overall elevation in the volatile emissions of infected mice observed during this period. Furthermore, data analyses--using discriminant analysis of principal components and random forest approaches--revealed clear differences in the composition of the volatile blends of infected and healthy individuals. Experimental manipulation of individual compounds that exhibited altered emission levels during the period when differential vector attraction was observed also elicited enhanced mosquito attraction, indicating that compounds being influenced by malaria infection status also mediate vector host-seeking behavior. These findings provide important insights into the cues that mediate vector attraction to hosts infected with transmissible stages of malaria parasites, as well as documenting characteristic changes in the odors of infected individuals that may have potential value as diagnostic biomarkers of infection.
Collapse
|
26
|
McQueen PG, Williamson KC, McKenzie FE. Host immune constraints on malaria transmission: insights from population biology of within-host parasites. Malar J 2013; 12:206. [PMID: 23767770 PMCID: PMC3691866 DOI: 10.1186/1475-2875-12-206] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/30/2013] [Indexed: 02/07/2023] Open
Abstract
Background Plasmodium infections trigger complex immune reactions from their hosts against several life stages of the parasite, including gametocytes. These immune responses are highly variable, depending on age, genetics, and exposure history of the host as well as species and strain of parasite. Although the effects of host antibodies that act against gamete stages in the mosquito (due to uptake in the blood meal) are well documented, the effects of host immunity upon within-host gametocytes are not as well understood. This report consists of a theoretical population biology-based analysis to determine constraints that host immunity impose upon gametocyte population growth. The details of the mathematical models used for the analysis were guided by published reports of clinical and animal studies, incorporated plausible modalities of immune reactions to parasites, and were tailored to the life cycl es of the two most widespread human malaria pathogens, Plasmodium falciparum and Plasmodium vivax. Results For the same ability to bind and clear a target, the model simulations suggest that an antibody attacking immature gametocytes would tend to lower the overall density of transmissible mature gametocytes more than an antibody attacking the mature forms directly. Transmission of P. falciparum would be especially vulnerable to complete blocking by antibodies to its immature forms since its gametocytes take much longer to reach maturity than those of P. vivax. On the other hand, antibodies attacking the mature gametocytes directly would reduce the time the mature forms can linger in the host. Simulation results also suggest that varying the standard deviation in the time necessary for individual asexual parasites to develop and produce schizonts can affect the efficiency of production of transmissible gametocytes. Conclusions If mature gametocyte density determines the probability of transmission, both Plasmodium species, but especially P. falciparum, could bolster this probability through evasion or suppression of host immune responses against the immature gametocytes. However, if the long term lingering of mature gametocytes at low density in the host is also important to ensure transmission, then evasion or suppression of antibodies against the mature stages would bolster probability of transmission as well.
Collapse
Affiliation(s)
- Philip G McQueen
- Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, USA.
| | | | | |
Collapse
|
27
|
Céspedes N, Vallejo A, Arévalo-Herrera M, Herrera S. Malaria vaccines: high-throughput tools for antigens discovery with potential for their development. Colomb Med (Cali) 2013; 44:121-8. [PMID: 24892459 PMCID: PMC4002024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 09/20/2012] [Accepted: 01/15/2013] [Indexed: 11/17/2022] Open
Abstract
Malaria is a disease induced by parasites of the Plasmodium genus, which are transmitted by Anopheles mosquitoes and represents a great socio-economic burden Worldwide. Plasmodium vivax is the second species of malaria Worldwide, but it is the most prevalent in Latin America and other regions of the planet. It is currently considered that vaccines represent a cost-effective strategy for controlling transmissible diseases and could complement other malaria control measures; however, the chemical and immunological complexity of the parasite has hindered development of effective vaccines. Recent availability of several genomes of Plasmodium species, as well as bioinformatic tools are allowing the selection of large numbers of proteins and analysis of their immune potential. Herein, we review recently developed strategies for discovery of novel antigens with potential for malaria vaccine development.
Collapse
|
28
|
Mueller I, Galinski MR, Tsuboi T, Arevalo-Herrera M, Collins WE, King CL. Natural acquisition of immunity to Plasmodium vivax: epidemiological observations and potential targets. ADVANCES IN PARASITOLOGY 2013; 81:77-131. [PMID: 23384622 DOI: 10.1016/b978-0-12-407826-0.00003-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Population studies show that individuals acquire immunity to Plasmodium vivax more quickly than Plasmodium falciparum irrespective of overall transmission intensity, resulting in the peak burden of P. vivax malaria in younger age groups. Similarly, actively induced P. vivax infections in malaria therapy patients resulted in faster and generally more strain-transcending acquisition of immunity than P. falciparum infections. The mechanisms behind the more rapid acquisition of immunity to P. vivax are poorly understood. Natural acquired immune responses to P. vivax target both pre-erythrocytic and blood-stage antigens and include humoral and cellular components. To date, only a few studies have investigated the association of these immune responses with protection, with most studies focussing on a few merozoite antigens (such as the Pv Duffy binding protein (PvDBP), the Pv reticulocyte binding proteins (PvRBPs), or the Pv merozoite surface proteins (PvMSP1, 3 & 9)) or the circumsporozoite protein (PvCSP). Naturally acquired transmission-blocking (TB) immunity (TBI) was also found in several populations. Although limited, these data support the premise that developing a multi-stage P. vivax vaccine may be feasible and is worth pursuing.
Collapse
Affiliation(s)
- Ivo Mueller
- Walter + Eliza Hall Institute, Infection & Immunity Division, Parkville, Victoria, Australia
| | | | | | | | | | | |
Collapse
|
29
|
Tyagi RK, Garg NK, Sahu T. Vaccination Strategies against Malaria: novel carrier(s) more than a tour de force. J Control Release 2012; 162:242-54. [PMID: 22564369 DOI: 10.1016/j.jconrel.2012.04.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/20/2012] [Accepted: 04/23/2012] [Indexed: 02/07/2023]
Abstract
The introduction of vaccine technology has facilitated an unprecedented multi-antigen approach to develop an effective vaccine against complex systemic inflammatory pathogens such as Plasmodium spp. that cause severe malaria. The capacity of multi subunit DNA vaccine encoding different stage Plasmodium antigens to induce CD8(+) cytotoxic T lymphocytes and interferon-γ responses in mice, monkeys and humans has been observed. Moreover, genetic vaccination may be capable of eliciting both cell mediated and humoral immune responses. The cytotoxic T cell responses are categorically needed against intracellular hepatic stage and humoral response with antibodies targeted against antigens from all stages of malaria parasite life cycle. Therefore, the key to success for any DNA based vaccine is to design a vector able to serve as a safe and efficient delivery system. This has encouraged the development of non-viral DNA-mediated gene transfer techniques such as liposome, virosomes, microsphere and nanoparticles. Efficient and relatively safe DNA transfection using lipoplexes makes them an appealing alternative to be explored for gene delivery. Also, liposome-entrapped DNA has been shown to enhance the potency of DNA vaccines, possibly by facilitating uptake of the plasmid by antigen-presenting cells (APC). Another recent technology using cationic lipids has been deployed and has generated substantial interest in this approach to gene transfer. In this review we discussed various aspects that could be decisive in the formulation of efficient and stable carrier system(s) for the development of malaria vaccine.
Collapse
Affiliation(s)
- Rajeev K Tyagi
- Global Health Infectious Disease Research Program, Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa, FL 33612-9415, USA.
| | | | | |
Collapse
|
30
|
Corradin G, Céspedes N, Verdini A, Kajava AV, Arévalo-Herrera M, Herrera S. Malaria vaccine development using synthetic peptides as a technical platform. Adv Immunol 2012; 114:107-49. [PMID: 22449780 DOI: 10.1016/b978-0-12-396548-6.00005-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The review covers the development of synthetic peptides as vaccine candidates for Plasmodium falciparum- and Plasmodium vivax-induced malaria from its beginning up to date and the concomitant progress of solid phase peptide synthesis (SPPS) that enables the production of long peptides in a routine fashion. The review also stresses the development of other complementary tools and actions in order to achieve the long sought goal of an efficacious malaria vaccine.
Collapse
|
31
|
Débarre F, Lion S, van Baalen M, Gandon S. Evolution of host life-history traits in a spatially structured host-parasite system. Am Nat 2011; 179:52-63. [PMID: 22173460 DOI: 10.1086/663199] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Most models for the evolution of host defense against parasites assume that host populations are not spatially structured. Yet local interactions and limited dispersal can strongly affect the evolutionary outcome, because they significantly alter epidemiological feedbacks and the spatial genetic structuring of the host and pathogen populations. We provide a general framework to study the evolution of a number of host life-history traits in a spatially structured host population infected by a horizontally transmitted parasite. Our analysis teases apart the selective pressures on hosts and helps disentangle the direct fitness effect of mutations and their indirect effects via the influence of spatial structure on the genetic, demographic, and epidemiological structure of the host population. We then illustrate the evolutionary consequences of spatial structure by focusing on the evolution of two host defense strategies against parasitism: suicide upon infection and reduced transmission. Because they bring no direct fitness benefit, these strategies are counterselected or selectively neutral in a nonspatial setting, but we show that they can be selected for in a spatially structured environment. Our study thus sheds light on the evolution of altruistic defense mechanisms that have been observed in various biological systems.
Collapse
Affiliation(s)
- F Débarre
- Centre d'Écologie Fonctionnelle et Évolutive, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 5175, F-34293 Montpellier Cedex 5, France.
| | | | | | | |
Collapse
|
32
|
Naturally acquired immune responses to Plasmodium falciparum sexual stage antigens Pfs48/45 and Pfs230 in an area of seasonal transmission. Infect Immun 2011; 79:4957-64. [PMID: 21969000 DOI: 10.1128/iai.05288-11] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Acquisition of immunity to Plasmodium falciparum sexual stages is a key determinant for reducing human-mosquito transmission by preventing the fertilization and the development of the parasite in the mosquito midgut. Naturally acquired immunity against sexual stages may therefore form the basis for the development of transmission-blocking vaccines, but studies conducted to date offer little in the way of consistent findings. Here, we describe the acquisition of antigametocyte immune responses in malaria-exposed individuals in Burkina Faso. A total of 719 blood samples were collected in a series of three cross-sectional surveys at the start, peak, and end of the wet season. The seroprevalence of antibodies with specificity for the sexual stage antigens Pfs48/45 and Pfs230 was 2-fold lower (22 to 28%) than that for an asexual blood stage antigen glutamate-rich protein (GLURP) (65%) or for the preerythrocytic stage antigen circumsporozoite protein (CSP) (54%). The youngest children responded at frequencies similar to those for all four antigens but, in contrast with the immune responses to GLURP and CSP that increased with age independently of season and area of residence, there was no evidence for a clear age dependence of responses to Pfs48/45 and Pfs230. Anti-Pfs230 antibodies were most prevalent at the peak of the wet season (P < 0.001). Our findings suggest that naturally acquired immunity against Pfs48/45 and Pfs230 is a function of recent exposure rather than of cumulative exposure to gametocytes.
Collapse
|
33
|
Arévalo-Herrera M, Solarte Y, Marin C, Santos M, Castellanos J, Beier JC, Valencia SH. Malaria transmission blocking immunity and sexual stage vaccines for interrupting malaria transmission in Latin America. Mem Inst Oswaldo Cruz 2011; 106 Suppl 1:202-11. [PMID: 21881775 PMCID: PMC4830685 DOI: 10.1590/s0074-02762011000900025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 07/13/2011] [Indexed: 11/22/2022] Open
Abstract
Malaria is a vector-borne disease that is considered to be one of the most serious public health problems due to its high global mortality and morbidity rates. Although multiple strategies for controlling malaria have been used, many have had limited impact due to the appearance and rapid dissemination of mosquito resistance to insecticides, parasite resistance to multiple antimalarial drug, and the lack of sustainability. Individuals in endemic areas that have been permanently exposed to the parasite develop specific immune responses capable of diminishing parasite burden and the clinical manifestations of the disease, including blocking of parasite transmission to the mosquito vector. This is referred to as transmission blocking (TB) immunity (TBI) and is mediated by specific antibodies and other factors ingested during the blood meal that inhibit parasite development in the mosquito. These antibodies recognize proteins expressed on either gametocytes or parasite stages that develop in the mosquito midgut and are considered to be potential malaria vaccine candidates. Although these candidates, collectively called TB vaccines (TBV), would not directly stop malaria from infecting individuals, but would stop transmission from infected person to non-infected person. Here, we review the progress that has been achieved in TBI studies and the development of TBV and we highlight their potential usefulness in areas of low endemicity such as Latin America.
Collapse
|
34
|
Valencia SH, Rodríguez DC, Acero DL, Ocampo V, Arévalo-Herrera M. Platform for Plasmodium vivax vaccine discovery and development. Mem Inst Oswaldo Cruz 2011; 106 Suppl 1:179-92. [PMID: 21881773 PMCID: PMC4832982 DOI: 10.1590/s0074-02762011000900023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 06/15/2011] [Indexed: 01/17/2023] Open
Abstract
Plasmodium vivax is the most prevalent malaria parasite on the American continent. It generates a global burden of 80-100 million cases annually and represents a tremendous public health problem, particularly in the American and Asian continents. A malaria vaccine would be considered the most cost-effective measure against this vector-borne disease and it would contribute to a reduction in malaria cases and to eventual eradication. Although significant progress has been achieved in the search for Plasmodium falciparum antigens that could be used in a vaccine, limited progress has been made in the search for P. vivax components that might be eligible for vaccine development. This is primarily due to the lack of in vitro cultures to serve as an antigen source and to inadequate funding. While the most advanced P. falciparum vaccine candidate is currently being tested in Phase III trials in Africa, the most advanced P. vivax candidates have only advanced to Phase I trials. Herein, we describe the overall strategy and progress in P. vivax vaccine research, from antigen discovery to preclinical and clinical development and we discuss the regional potential of Latin America to develop a comprehensive platform for vaccine development.
Collapse
|
35
|
A plant-produced Pfs230 vaccine candidate blocks transmission of Plasmodium falciparum. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:1351-7. [PMID: 21715576 DOI: 10.1128/cvi.05105-11] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Plasmodium falciparum is transmitted to a new host after completing its sexual cycle within a mosquito. Developing vaccines against the parasite sexual stages is a critical component in the fight against malaria. We are targeting multiple proteins of P. falciparum which are found only on the surfaces of the sexual forms of the parasite and where antibodies against these proteins have been shown to block the progression of the parasite's life cycle in the mosquito and thus block transmission to the next human host. We have successfully produced a region of the Pfs230 antigen in our plant-based transient-expression system and evaluated this vaccine candidate in an animal model. This plant-produced protein, 230CMB, is expressed at approximately 800 mg/kg in fresh whole leaf tissue and is 100% soluble. Administration of 230CMB with >90% purity induces strong immune responses in rabbits with high titers of transmission-blocking antibodies, resulting in a greater than 99% reduction in oocyst counts in the presence of complement, as determined by a standard membrane feeding assay. Our data provide a clear perspective on the clinical development of a Pfs230-based transmission-blocking malaria vaccine.
Collapse
|
36
|
Abstract
Malaria is a vector-borne infectious disease caused by unicellular parasites of the genus Plasmodium. These obligate intracellular parasites have the unique capacity to infect and replicate within erythrocytes, which are terminally differentiated host cells that lack antigen presentation pathways. Prior to the cyclic erythrocytic infections that cause the characteristic clinical symptoms of malaria, the parasite undergoes an essential and clinically silent expansion phase in the liver. By infecting privileged host cells, employing programs of complex life stage conversions and expressing varying immunodominant antigens, Plasmodium parasites have evolved mechanisms to downmodulate protective immune responses against ongoing and even future infections. Consequently, anti-malaria immunity develops only gradually over many years of repeated and multiple infections in endemic areas. The identification of immune correlates of protection among the abundant non-protective host responses remains a research priority. Understanding the molecular and immunological mechanisms of the crosstalk between the parasite and the host is a prerequisite for the rational discovery and development of a safe, affordable, and protective anti-malaria vaccine.
Collapse
Affiliation(s)
- Julius Clemence Hafalla
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | | | | |
Collapse
|
37
|
Arévalo-Herrera M, Solarte Y, Rocha L, Alvarez D, Beier JC, Herrera S. Characterization of Plasmodium vivax transmission-blocking activity in low to moderate malaria transmission settings of the Colombian Pacific coast. Am J Trop Med Hyg 2011; 84:71-7. [PMID: 21292881 DOI: 10.4269/ajtmh.2011.10-0085] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Malaria infection induces antibodies capable of suppressing the infectivity of gametocytes and gametes, however, little is known about the duration of the antibody response, the parasite specificity, and the role of complement. We report the analyses of the transmission-blocking (TB) activity of sera collected from 105 Plasmodium vivax-infected and 44 non-infected individuals from a malaria endemic region of Colombia, using a membrane feeding assay in Anopheles albimanus mosquitoes. In infected donors we found that TB activity was antibody dose dependent (35%), lasted for 2-4 months after infection, and in 70% of the cases different P. vivax wild isolates displayed differential susceptibility to blocking antibodies. Additionally, in a number of assays TB was complement-dependent. Twenty-seven percent of non-infected individuals presented TB activity that correlated with antibody titers. Studies here provide preliminary data on factors of great importance for further work on the development of TB vaccines.
Collapse
|
38
|
Sex and Death: The Effects of Innate Immune Factors on the Sexual Reproduction of Malaria Parasites. PLoS Pathog 2011; 7:e1001309. [PMID: 21408620 PMCID: PMC3048364 DOI: 10.1371/journal.ppat.1001309] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 02/01/2011] [Indexed: 12/31/2022] Open
Abstract
Malaria parasites must undergo a round of sexual reproduction in the blood meal of a mosquito vector to be transmitted between hosts. Developing a transmission-blocking intervention to prevent parasites from mating is a major goal of biomedicine, but its effectiveness could be compromised if parasites can compensate by simply adjusting their sex allocation strategies. Recently, the application of evolutionary theory for sex allocation has been supported by experiments demonstrating that malaria parasites adjust their sex ratios in response to infection genetic diversity, precisely as predicted. Theory also predicts that parasites should adjust sex allocation in response to host immunity. Whilst data are supportive, the assumptions underlying this prediction – that host immune responses have differential effects on the mating ability of males and females – have not yet been tested. Here, we combine experimental work with theoretical models in order to investigate whether the development and fertility of male and female parasites is affected by innate immune factors and develop new theory to predict how parasites' sex allocation strategies should evolve in response to the observed effects. Specifically, we demonstrate that reactive nitrogen species impair gametogenesis of males only, but reduce the fertility of both male and female gametes. In contrast, tumour necrosis factor-α does not influence gametogenesis in either sex but impairs zygote development. Therefore, our experiments demonstrate that immune factors have complex effects on each sex, ranging from reducing the ability of gametocytes to develop into gametes, to affecting the viability of offspring. We incorporate these results into theory to predict how the evolutionary trajectories of parasite sex ratio strategies are shaped by sex differences in gamete production, fertility and offspring development. We show that medical interventions targeting offspring development are more likely to be ‘evolution-proof’ than interventions directed at killing males or females. Given the drive to develop medical interventions that interfere with parasite mating, our data and theoretical models have important implications. Malaria and related parasites cause some of the most serious infectious diseases of humans, domestic animals and wildlife. To be transmitted, these parasites produce male and female sexual stages that differentiate into gametes and mate when taken up in a mosquito blood meal. Despite the need to develop a transmission-blocking intervention, remarkably little is understood about the evolution of parasite mating strategies. However, recent research demonstrates that producing the right ratio of male to female stages is central to mating success. Evolutionary theory predicts that sex ratios are adjusted in line with a variety of factors that affect mating success, including host immunity. We test this theory by investigating whether ubiquitous immune factors differentially affect the production and fertility of males and females. Our experiments demonstrate that immune factors have complex, sex-specific effects, from reducing gamete production to affecting offspring viability. We use these results to generate theory predicting how such effects shape the evolutionary trajectories of parasite sex ratio strategies. Given the drive to develop medical interventions that prevent transmission by blocking parasite mating, our results have important implications. Specifically, we suggest that medical interventions targeting offspring development are more likely to be ‘evolution-proof’ than interventions with sex-specific effects.
Collapse
|
39
|
Saeed M, Roeffen W, Alexander N, Drakeley CJ, Targett GAT, Sutherland CJ. Plasmodium falciparum Antigens on the Surface of the Gametocyte-Infected Erythrocyte. PLoS One 2008; 3:e2280. [PMID: 18509532 PMCID: PMC2386550 DOI: 10.1371/journal.pone.0002280] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 04/07/2008] [Indexed: 11/17/2022] Open
Affiliation(s)
- Maha Saeed
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Will Roeffen
- Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Neal Alexander
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christopher J. Drakeley
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Geoffrey A. T. Targett
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Colin J. Sutherland
- Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail:
| |
Collapse
|
40
|
Tyagi RK, Sharma PK, Vyas SP, Mehta A. Various carrier system(s)- mediated genetic vaccination strategies against malaria. Expert Rev Vaccines 2008; 7:499-520. [PMID: 18444895 DOI: 10.1586/14760584.7.4.499] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The introduction of vaccine technology has facilitated an unprecedented multiantigen approach to develop an effective vaccine against complex pathogens, such as Plasmodium spp., that cause severe malaria. The capacity of multisubunit DNA vaccines encoding different stage Plasmodium antigens to induce CD8(+) cytotoxic T lymphocytes and IFN-gamma responses in mice, monkeys and humans has been observed. Moreover, genetic vaccination may be multi-immune (i.e., capable of eliciting more than one type of immune response, including cell-mediated and humoral). In the case of malaria parasites, a cytotoxic T-lymphocyte response is categorically needed against the intracellular hepatocyte stage while a humoral response, with antibodies targeted against antigens from all stages of the life cycle, is also needed. Therefore, the key to success for any DNA-based therapy is to design a vector able to serve as a safe and efficient delivery system. This has encouraged the development of nonviral DNA-mediated gene-transfer techniques, such as liposomes, virosomes, microspheres and nanoparticles. Efficient and relatively safe DNA transfection using lipoplexes makes them an appealing alternative to be explored for gene delivery. In addition, liposome-entrapped DNA has been shown to enhance the potency of DNA vaccines, possibly by facilitating uptake of the plasmid by antigen-presenting cells. Another recent technology using cationic lipids has been deployed and has generated substantial interest in this approach to gene transfer. This review comprises various aspects that could be decisive in the formulation of efficient and stable carrier system(s) for the development of malaria vaccines.
Collapse
Affiliation(s)
- Rajeev K Tyagi
- Biomedical Parasitology Unit, Pasteur Institute, 25-28 Rue Du Dr Roux, 75724 Paris Cedex 15, France.
| | | | | | | |
Collapse
|
41
|
Vaughan JA. Population dynamics of Plasmodium sporogony. Trends Parasitol 2006; 23:63-70. [PMID: 17188574 DOI: 10.1016/j.pt.2006.12.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 11/02/2006] [Accepted: 12/11/2006] [Indexed: 11/20/2022]
Abstract
Malaria transmission relies on the sporogonic development of Plasmodium parasites within insect vectors. Sporogony is a complex process that involves several morphologically distinct life-stages and can be described in terms of population dynamics: changes in the abundance and distribution of successive life-stages throughout development. Recent publications on the population dynamics of sporogony are reviewed, with special attention to the differences and similarities among the parasite-vector systems examined thus far. Understanding the population dynamics of malaria parasites within their natural vectors will lead to a better understanding of how malaria parasites survive and are maintained within mosquitoes.
Collapse
Affiliation(s)
- Jefferson A Vaughan
- Department of Biology, University of North Dakota, Grand Forks, ND 58201-9019, USA.
| |
Collapse
|
42
|
Bharti AR, Chuquiyauri R, Brouwer KC, Stancil J, Lin J, Llanos-Cuentas A, Vinetz JM. Experimental infection of the neotropical malaria vector Anopheles darlingi by human patient-derived Plasmodium vivax in the Peruvian Amazon. Am J Trop Med Hyg 2006; 75:610-6. [PMID: 17038681 PMCID: PMC1630632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
Malaria transmission from humans to mosquitoes is modulated by human host immune factors. Understanding mechanisms by which the human host response may impair parasite infectivity for mosquitoes has direct implications for the development of transmission-blocking vaccines. We hypothesized that despite a low transmission intensity of malaria in the Peruvian Amazon region of Iquitos, transmission-blocking immunity against Plasmodium vivax might be common, given an unexpectedly high proportion of asymptomatic parasitemic individuals in this region. To test this hypothesis, the ability of symptomatic P. vivax malaria patients to experimentally infect wild-caught outbred Anopheles darlingi mosquitoes was tested using the indirect membrane feeding technique. Only half (52/102) of P. vivax parasitemic patients successfully infected mosquitoes. Transmitters were more likely to have gametocytes (OR 6.35, P = 0.003), high parasitemia (OR 3.79, P = 0.024), and, in terms of basic clinical parameters, a slower pulse rate (mean +/- SD: 82.3 +/- 12.3 versus 88.7 +/- 13.5, P = 0.016) than non-transmitters. Log(10) gametocytemia and log(10) real-time reverse transcriptase Pvs25 PCR quantifying gametocytes were significantly and positively correlated with oocyst counts (correlation coefficient 0.505, R2 = 0.26, P = 0.001). These experiments are the first to establish a system of determining transmission patterns in experimental infection of outbred natural neotropical malaria vectors in the Amazon region. Patients with P. vivax inefficiently infect outbred An. darlingi mosquitoes, raising the possibility that some degree of naturally occurring transmission-blocking immunity is present on a population basis in the Peruvian Amazon, an area of low intensity of malaria transmission.
Collapse
Affiliation(s)
- Ajay R Bharti
- University of California San Diego School of Medicine, La Jolla, CA 92093-0741, USA.
| | | | | | | | | | | | | |
Collapse
|
43
|
van der Kolk M, de Vlas SJ, Sauerwein RW. Reduction and enhancement of Plasmodium falciparum transmission by endemic human sera. Int J Parasitol 2006; 36:1091-5. [PMID: 16790244 DOI: 10.1016/j.ijpara.2006.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 04/14/2006] [Accepted: 05/05/2006] [Indexed: 11/30/2022]
Abstract
Transmission of Plasmodium falciparum from man to mosquito can be affected by human sera. Whereas serum-dependent reduction of transmission has been shown to be reproducible, there is limited evidence for enhancement of transmission. We aimed to assess the prevalence and reproducibility of transmission enhancement (TE) by human sera from different geographic areas (n = 642), in comparison with the capacity for transmission reduction (TR). The overall prevalence of TE (7%) was lower than that of TR (48%) and its effect generally weaker but reproducible in repeated measurements. TR but not TE showed a significant association with the presence of serum antibodies against Pfs48/45 and a non-significant trend to the presence of anti-Pfs230 antibodies.
Collapse
Affiliation(s)
- Mike van der Kolk
- Radboud University Nijmegen Medical Centre, MMB 268, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
| | | | | |
Collapse
|
44
|
Haddad D, Maciel J, Kumar N. Infection with Plasmodium berghei boosts antibody responses primed by a DNA vaccine encoding gametocyte antigen Pbs48/45. Infect Immun 2006; 74:2043-51. [PMID: 16552033 PMCID: PMC1418885 DOI: 10.1128/iai.74.4.2043-2051.2006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An important consideration in the development of a malaria vaccine for individuals living in areas of endemicity is whether vaccine-elicited immune responses can be boosted by natural infection. To investigate this question, we used Plasmodium berghei ANKA blood-stage parasites for the infection of mice that were previously immunized with a DNA vaccine encoding the P. berghei sexual-stage antigen Pbs48/45. Intramuscular immunization in mice with one or two doses of DNA-Pbs48/45 or of empty DNA vaccine as control did not elicit detectable anti-Pbs48/45 antibodies as determined by enzyme-linked immunosorbent assay. An infection with P. berghei ANKA 6 weeks after DNA vaccination elicited comparable anti-Pbs48/45 antibody levels in mice which had been primed with DNA-Pbs48/45 or with empty DNA vaccine. However, a repeat infection with P. berghei ANKA resulted in significantly higher anti-Pbs48/45 antibody levels in mice which had been primed with the DNA-Pbs48/45 vaccine than the levels in the mock DNA-vaccinated mice. In parallel and as an additional control to distinguish the boosting of Pbs48/45 antibodies exclusively by gametocytes during infection, a separate group of mice primed with DNA-Pbs48/45 received an infection with P. berghei ANKA clone 2.33, which was previously described as a "nongametocyte producer." To our surprise, this parasite clone too elicited antibody levels comparable to those induced by the P. berghei gametocyte producer clone. We further demonstrate that the nongametocyte producer P. berghei clone is in fact a defective gametocyte producer that expresses Pbs48/45, much like the gametocyte producer clone, and is therefore capable of boosting antibody levels to Pbs48/45. Taken together, these results indicate that vaccine-primed antibodies can be boosted during repeat infections and warrant further investigation with additional malaria antigens.
Collapse
Affiliation(s)
- Diana Haddad
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, The Johns Hopkins University, Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD 21205, USA
| | | | | |
Collapse
|
45
|
Arévalo-Herrera M, Solarte Y, Zamora F, Mendez F, Yasnot MF, Rocha L, Long C, Miller LH, Herrera S. Plasmodium vivax: transmission-blocking immunity in a malaria-endemic area of Colombia. Am J Trop Med Hyg 2006; 73:38-43. [PMID: 16291765 DOI: 10.4269/ajtmh.2005.73.5_suppl.0730038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Plasmodium vivax transmission-blocking activity was assessed in sera from acutely infected patients from a malaria-endemic area in Colombia. We measured reduction in the number of oocysts that developed in the midguts of Anopheles albimanus mosquitoes artificially fed with blood from these patients. Of 88 mosquito batches that developed infections when parasites were mixed with normal AB human serum, one-third (36.4%) showed full transmission-blocking activity (>or= 90% inhibition) when mixed with autologous sera, 29.6% showed partial activity (50-89%), 17.0% did not block transmission (0-50%), and 17% did not enhance transmission. Transmission-blocking activity correlated with antibody titer by an immunofluorescent antibody test and decreased with the serial dilution of the sera. This activity disappeared at a 1:4 dilution in most sera tested. Afro-Colombian individuals showed lower activity than other ethnic groups and febrile patients produced stronger inhibition than those without fever.
Collapse
|
46
|
Torres JA, Rodriguez MH, Rodriguez MC, de la Cruz Hernandez-Hernandez F. Plasmodium berghei: effect of protease inhibitors during gametogenesis and early zygote development. Exp Parasitol 2005; 111:255-9. [PMID: 16198343 DOI: 10.1016/j.exppara.2005.08.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 08/11/2005] [Accepted: 08/13/2005] [Indexed: 11/18/2022]
Abstract
Plasmodium berghei: The effect of five protease inhibitors, TPCK, TLCK, PMSF, leupeptin, and 1,10-phenanthroline on in vitro gametogenesis and early zygote development of P. berghei was investigated. PMSF and leupeptin showed no effect. Cysteine/serine protease inhibitors TPCK/TLCK at concentrations of 75 and 100 microM were effective on inhibiting exflagellation center formation, and this effect was reversible with the addition of l-cysteine. Exflagellation center formation was most effectively blocked by 1,10-phenanthroline (1mM), and exflagellation center numbers were restored by the addition of Zn(2+). A reduction of ookinete production was observed when TPCK/TLCK (100 microM) was added at 2h after gametogenesis, but no effect was observed with 1,10-phenanthroline (1mM). Our results suggest that proteolysis is important in both gametocyte activation and sexual development of P. berghei.
Collapse
Affiliation(s)
- Jorge A Torres
- Department of Experimental Parasitology, CINVESTAV-IPN, Av. IPN 2508, Col. San Pedro Zacatenco Delegacion G.A. Madero, Mexico 07360 DF, Mexico
| | | | | | | |
Collapse
|
47
|
Abstract
The sexual stages of the malaria parasite are highly specialized cells adapted to withstand major environmental changes during their development. They also induce immune responses that may affect the outcome of the infection in the mosquito. In this review Pietro Alano considers the nature and the role of the antigens expressed by Plasmodium sexual stages.
Collapse
Affiliation(s)
- P Alano
- Laboratorio di Biologia Cellulare, Istituto Superiore di Sanita, viale Regina Elena 299, 00161 Rome, Italy
| |
Collapse
|
48
|
Taylor LH, Read AF. Why so few transmission stages? Reproductive restraint by malaria parasites. ACTA ACUST UNITED AC 2005; 13:135-40. [PMID: 15275099 DOI: 10.1016/s0169-4758(97)89810-9] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Vast numbers of malaria parasites exist in a population: perhaps 10(10) in just one vertebrate host. Yet gametocytes, the only stage capable of transmission, usually constitute just a few percent or even less of the circulating parasites. Why? Parasite fitness should be intimately linked with transmission probability and infectiousness rises with gametocyte density. Here, Louise Taylor and Andrew Read propose several testable hypotheses that might explain why natural selection has not favoured variants producing more transmission stages.
Collapse
Affiliation(s)
- L H Taylor
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, UK.
| | | |
Collapse
|
49
|
Abstract
Malaria represents a complex system. Transmission depends on a multitude of factors - of which vector density may not be the most important (see Box 1). The classical Ross-Macdonald model of malaria transmission (Box 2) reveals two dominant factors: the probability that a mosquito will survive long enough for the parasite to develop to its infective stage, and the likelihood that the mosquito will feed on man. An important assumption however, is that all individuals will be at equal risk from mosquito attack. In fact, host-vector contact is far from randomly distributed. In this review, Tom Burkot explains the biological causes of non-random host selection by anopheline vectors, and Chris Dye discusses some of the epidemiological implications of this selection for malaria transmission (Box 3).
Collapse
Affiliation(s)
- T R Burkot
- Tropical Health Program Queensland Institute of Medical Research Bramston Terrace, Herston Brisbane Queensland 4006 Australia
| |
Collapse
|
50
|
Drakeley CJ, Eling W, Teelen K, Bousema JT, Sauerwein R, Greenwood BM, Targett GAT. Parasite infectivity and immunity to Plasmodium falciparum gametocytes in Gambian children. Parasite Immunol 2004; 26:159-65. [PMID: 15367293 DOI: 10.1111/j.0141-9838.2004.00696.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Immunity to the sexual stages of Plasmodium falciparum can be induced during natural infections. Characterization of this immunity may facilitate the design of a transmission-blocking vaccine (TBV). This study aimed to assess the prevalence and serological correlates of functional transmission-blocking immunity in Gambian children (aged 1-4 years old) who were P. falciparum gametocyte carriers. Serological assays showed 100% response to fixed, whole parasites but only 42% to live gametes. Responses to the antigens Pfs230 and Pfs48/45 were 54.1% and 37.3%, respectively, in an IgG1 ELISA. 14/55 sera were capable of reducing the infectivity of laboratory isolate NF54 in a standard membrane-feeding assay (SMFA). This activity was strongly correlated with IgG1 responses to Pfs48/45 (r = 0.49, P < 0.001) and to a serological reaction with epitopes of the same molecule (r = 0.38, P = 0.003). A weaker correlation was observed with IgG1 to Pfs230 (r = 0.29, P = 0.03). In direct membrane feeding assays (DMFA) with autologous isolates, sera from 4/29 children showed transmission-blocking activity. There was no correlation with serological assays and the DMFA or between the SMFA and DMFA. This may be caused by variation in sexual stage antigens and/or alternative modes of transmission-blocking immunity, both of which have implications for vaccine implementation.
Collapse
Affiliation(s)
- C J Drakeley
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel St., London WC1E 7HT, UK.
| | | | | | | | | | | | | |
Collapse
|