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Ofori EA, Tetteh JKA, Frimpong A, Ganeshan H, Belmonte M, Peters B, Villasante E, Sedegah M, Ofori MF, Kusi KA. Comparison of the impact of allelic polymorphisms in PfAMA1 on the induction of T Cell responses in high and low malaria endemic communities in Ghana. Malar J 2021; 20:367. [PMID: 34507582 PMCID: PMC8431259 DOI: 10.1186/s12936-021-03900-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/28/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria eradication requires a combined effort involving all available control tools, and these efforts would be complemented by an effective vaccine. The antigen targets of immune responses may show polymorphisms that can undermine their recognition by immune effectors and hence render vaccines based on antigens from a single parasite variant ineffective against other variants. This study compared the influence of allelic polymorphisms in Plasmodium falciparum apical membrane antigen 1 (PfAMA1) peptide sequences from three strains of P. falciparum (3D7, 7G8 and FVO) on their function as immunodominant targets of T cell responses in high and low malaria transmission communities in Ghana. METHODS Peripheral blood mononuclear cells (PBMCs) from 10 subjects from a high transmission area (Obom) and 10 subjects from a low transmission area (Legon) were tested against 15 predicted CD8 + T cell minimal epitopes within the PfAMA1 antigen of multiple parasite strains using IFN-γ ELISpot assay. The peptides were also tested in similar assays against CD8 + enriched PBMC fractions from the same subjects in an effort to characterize the responding T cell subsets. RESULTS In assays using unfractionated PBMCs, two subjects from the high transmission area, Obom, responded positively to four (26.7%) of the 15 tested peptides. None of the Legon subject PBMCs yielded positive peptide responses using unfractionated PBMCs. In assays with CD8 + enriched PBMCs, three subjects from Obom made positive recall responses to six (40%) of the 15 tested peptides, while only one subject from Legon made a positive recall response to a single peptide. Overall, 5 of the 20 study subjects who had positive peptide-specific IFN-γ recall responses were from the high transmission area, Obom. Furthermore, while subjects from Obom responded to peptides in PfAMA1 from multiple parasite strains, one subject from Legon responded to a peptide from 3D7 strain only. CONCLUSIONS The current data demonstrate the possibility of a real effect of PfAMA1 polymorphisms on the induction of T cell responses in malaria exposed subjects, and this effect may be more pronounced in communities with higher parasite exposure.
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Affiliation(s)
- Ebenezer A Ofori
- West Africa Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana.,Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - John K A Tetteh
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Augustina Frimpong
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Harini Ganeshan
- Malaria Department, Naval Medical Research Center, Silver Spring, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Maria Belmonte
- Malaria Department, Naval Medical Research Center, Silver Spring, USA.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Bjoern Peters
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
| | - Eileen Villasante
- Malaria Department, Naval Medical Research Center, Silver Spring, USA
| | - Martha Sedegah
- Malaria Department, Naval Medical Research Center, Silver Spring, USA
| | - Michael F Ofori
- West Africa Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana.,Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Kwadwo A Kusi
- West Africa Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana. .,Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
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IMRAS-Immunization with radiation-attenuated Plasmodium falciparum sporozoites by mosquito bite: Cellular immunity to sporozoites, CSP, AMA1, TRAP and CelTOS. PLoS One 2021; 16:e0256396. [PMID: 34415964 PMCID: PMC8378721 DOI: 10.1371/journal.pone.0256396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/21/2021] [Indexed: 11/19/2022] Open
Abstract
Background Immunization with radiation-attenuated sporozoites (RAS) by mosquito bites provides >90% sterile protection against Plasmodium falciparum malaria in humans. We conducted a clinical trial based on data from previous RAS clinical trials that suggested that 800–1200 infected bites should induce ~50% protective vaccine efficacy (VE) against controlled human malaria infection (CHMI) administered three weeks after the final immunization. Two cohorts were immunized separately. VE was 55% in Cohort 1 but 90% in Cohort 2, the cohort that received a higher first dose and a reduced (fractional) fifth dose. Immune responses were better boosted by the fractional fifth dose in Cohort 2 and suggested the importance of the fractional fifth dose for increased protection in Cohort 2 responses. Three protected subjects were later boosted and were protected suggesting that protection could be extended to at least 67 weeks. Methods The ex vivo FluoroSpot assay was used to measure peripheral IFN-γ, IL2, and IFN-γ+IL2 responses to PfNF54 sporozoites and malaria antigens CSP, AMA1, TRAP, and CelTOS using pools of synthetic overlapping 15mer peptides spanning each antigen. Results There was no correlation between IFN-γ, IL2, and IFN-γ+IL2 responses to sporozoites and protection, but fold-increases between post-4th and post-5th responses greater than 1.0 occurred mostly in protected subjects. IFN-γ and IL2 responses to TRAP, CelTOS and CSP occurred only in protected subjects. Peripheral IFN-γ, IL2, and IFN-γ+IL2 responses were short-lived and low by 27 weeks post-CHMI but were restored by boosting. Conclusions These studies highlight the importance of vaccine dose and schedule for vaccine efficacy, and suggest that CSP, TRAP, AMA1 and CelTOS may be targets of protective immunity. The correlation between fold-increases in responses and protection should be explored in other vaccine trials. Trial registration ClinicalTrials.gov NCT01994525.
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Raissi V, Etemadi S, Getso MI, Mehravaran A, Raiesi O. Structure-genetic diversity and recombinant protein of circumsporozoite protein (CSP) of vivax malaria antigen: A potential malaria vaccine candidate. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Importance of the Immunodominant CD8 + T Cell Epitope of Plasmodium berghei Circumsporozoite Protein in Parasite- and Vaccine-Induced Protection. Infect Immun 2020; 88:IAI.00383-20. [PMID: 32719159 DOI: 10.1128/iai.00383-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 07/22/2020] [Indexed: 12/15/2022] Open
Abstract
The circumsporozoite protein (CSP) builds up the surface coat of sporozoites and is the leading malaria pre-erythrocytic-stage vaccine candidate. CSP has been shown to induce robust CD8+ T cell responses that are capable of eliminating developing parasites in hepatocytes, resulting in protective immunity. In this study, we characterized the importance of the immunodominant CSP-derived epitope SYIPSAEKI of Plasmodium berghei in both sporozoite- and vaccine-induced protection in murine infection models. In BALB/c mice, where SYIPSAEKI is efficiently presented in the context of the major histocompatibility complex class I (MHC-I) molecule H-2-Kd, we established that epitope-specific CD8+ T cell responses contribute to parasite killing following sporozoite immunization. Yet, sterile protection was achieved in the absence of this epitope, substantiating the concept that other antigens can be sufficient for parasite-induced protective immunity. Furthermore, we demonstrated that SYIPSAEKI-specific CD8+ T cell responses elicited by viral-vectored CSP-expressing vaccines effectively targeted parasites in hepatocytes. The resulting sterile protection strictly relied on the expression of SYIPSAEKI. In C57BL/6 mice, which are unable to present the immunodominant epitope, CSP-based vaccines did not confer complete protection, despite the induction of high levels of CSP-specific antibodies. These findings underscore the significance of CSP in protection against malaria pre-erythrocytic stages and demonstrate that a significant proportion of the protection against the parasite is mediated by CD8+ T cells specific for the immunodominant CSP-derived epitope.
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Kusi KA, Aggor FE, Amoah LE, Anum D, Nartey Y, Amoako-Sakyi D, Obiri-Yeboah D, Hollingdale M, Ganeshan H, Belmonte M, Peters B, Kim Y, Tetteh J, Kyei-Baafour E, Dodoo D, Villasante E, Sedegah M. Identification of Plasmodium falciparum circumsporozoite protein-specific CD8+ T cell epitopes in a malaria exposed population. PLoS One 2020; 15:e0228177. [PMID: 32040522 PMCID: PMC7010280 DOI: 10.1371/journal.pone.0228177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/08/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Sterile protection against malaria, most likely mediated by parasite-specific CD8+ T cells, has been achieved by attenuated sporozoite vaccination of animals as well as malaria-naïve and malaria-exposed subjects. The circumsporozoite protein (CSP)-based vaccine, RTS,S, shows low efficacy partly due to limited CD8+ T cell induction, and inclusion of such epitopes could improve RTS,S. This study assessed 8-10mer CSP peptide epitopes, present in predicted or previously positive P. falciparum 3D7 CSP 15mer overlapping peptide pools, for their ability to induce CD8+ T cell IFN-γ responses in natural malaria-exposed subjects. METHODS Cryopreserved PBMCs from nine HLA-typed subjects were stimulated with 23 8-10mer CSP peptides from the 3D7 parasite in IFN-ɣ ELISpot assays. The CD8+ T cell specificity of IFN-γ responses was confirmed in ELISpot assays using CD8+ T cell-enriched PBMC fractions after CD4+ cell depletion. RESULTS Ten of 23 peptide epitopes elicited responses in whole PBMCs from five of the nine subjects. Four peptides tested positive in CD8+ T cell-enriched PBMCs from two previously positive responders and one new subject. All four immunodominant peptides are restricted by globally common HLA supertypes (A02, A03, B07) and mapped to regions of the CSP antigen with limited or no reported polymorphism. Association of these peptide-specific responses with anti-malarial protection remains to be confirmed. CONCLUSIONS The relatively conserved nature of the four identified epitopes and their binding to globally common HLA supertypes makes them good candidates for inclusion in potential multi-epitope malaria vaccines.
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Affiliation(s)
- Kwadwo A. Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
- * E-mail:
| | - Felix E. Aggor
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Linda E. Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Dorothy Anum
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Yvonne Nartey
- Department of Microbiology and Immunology, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Daniel Amoako-Sakyi
- Department of Microbiology and Immunology, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Dorcas Obiri-Yeboah
- Department of Microbiology and Immunology, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Michael Hollingdale
- Malaria Department, Naval Medical Research Center, Silver Springs, MD, United States of America
| | - Harini Ganeshan
- Malaria Department, Naval Medical Research Center, Silver Springs, MD, United States of America
| | - Maria Belmonte
- Malaria Department, Naval Medical Research Center, Silver Springs, MD, United States of America
| | - Bjoern Peters
- La Jolla Institute for Immunology, La Jolla, CA, United States of America
| | - Yohan Kim
- La Jolla Institute for Immunology, La Jolla, CA, United States of America
| | - John Tetteh
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Eric Kyei-Baafour
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Daniel Dodoo
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Eileen Villasante
- Malaria Department, Naval Medical Research Center, Silver Springs, MD, United States of America
| | - Martha Sedegah
- Malaria Department, Naval Medical Research Center, Silver Springs, MD, United States of America
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Proietti C, Krause L, Trieu A, Dodoo D, Gyan B, Koram KA, Rogers WO, Richie TL, Crompton PD, Felgner PL, Doolan DL. Immune Signature Against Plasmodium falciparum Antigens Predicts Clinical Immunity in Distinct Malaria Endemic Communities. Mol Cell Proteomics 2020; 19:101-113. [PMID: 31658979 PMCID: PMC6944240 DOI: 10.1074/mcp.ra118.001256] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 10/23/2019] [Indexed: 01/14/2023] Open
Abstract
A large body of evidence supports the role of antibodies directed against the Plasmodium spp. parasite in the development of naturally acquired immunity to malaria, however an antigen signature capable of predicting protective immunity against Plasmodium remains to be identified. Key challenges for the identification of a predictive immune signature include the high dimensionality of data produced by high-throughput technologies and the limitation of standard statistical tests in accounting for synergetic interactions between immune responses to multiple targets. In this study, using samples collected from young children in Ghana at multiple time points during a longitudinal study, we adapted a predictive modeling framework which combines feature selection and machine learning techniques to identify an antigen signature of clinical immunity to malaria. Our results show that an individual's immune status can be accurately predicted by measuring antibody responses to a small defined set of 15 target antigens. We further demonstrate that the identified immune signature is highly versatile and capable of providing precise and accurate estimates of clinical protection from malaria in an independent geographic community. Our findings pave the way for the development of a robust point-of-care test to identify individuals at high risk of disease and which could be applied to monitor the impact of vaccinations and other interventions. This approach could be also translated to biomarker discovery for other infectious diseases.
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Affiliation(s)
- Carla Proietti
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia; QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Lutz Krause
- The University of Queensland Diamantina Institute, Brisbane, QLD, Australia
| | - Angela Trieu
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Ben Gyan
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Kwadwo A Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | | | | | - Peter D Crompton
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Philip L Felgner
- Department of Medicine, Division of Infectious Diseases, University of California Irvine, Irvine, California
| | - Denise L Doolan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia; QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
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Gbedande K, Stephens R. Initiating the T Cell Response to Liver-Stage Malaria. Trends Parasitol 2019; 35:489-490. [PMID: 31129040 DOI: 10.1016/j.pt.2019.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 10/26/2022]
Abstract
Kurup et al. (Cell Host Microbe 2019;25:565-577.e6) define the liver-based antigen-presenting cell driving CD8 T cell responses to mosquito transmission of Plasmodium spp., and show direct interaction of CD11c+ cells with infected hepatocytes. We discuss this work in context, highlighting gaps and new approaches suggested by the work to target liver-stage vaccine antigens.
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Affiliation(s)
- Komi Gbedande
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0435, USA
| | - Robin Stephens
- Department of Internal Medicine, Division of Infectious Diseases, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0435, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0435, USA.
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Jaenisch T, Heiss K, Fischer N, Geiger C, Bischoff FR, Moldenhauer G, Rychlewski L, Sié A, Coulibaly B, Seeberger PH, Wyrwicz LS, Breitling F, Loeffler FF. High-density Peptide Arrays Help to Identify Linear Immunogenic B-cell Epitopes in Individuals Naturally Exposed to Malaria Infection. Mol Cell Proteomics 2019; 18:642-656. [PMID: 30630936 PMCID: PMC6442360 DOI: 10.1074/mcp.ra118.000992] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/28/2018] [Indexed: 01/31/2023] Open
Abstract
High-density peptide arrays are an excellent means to profile anti-plasmodial antibody responses. Different protein intrinsic epitopes can be distinguished, and additional insights are gained, when compared with assays involving the full-length protein. Distinct reactivities to specific epitopes within one protein may explain differences in published results, regarding immunity or susceptibility to malaria. We pursued three approaches to find specific epitopes within important plasmodial proteins, (1) twelve leading vaccine candidates were mapped as overlapping 15-mer peptides, (2) a bioinformatical approach served to predict immunogenic malaria epitopes which were subsequently validated in the assay, and (3) randomly selected peptides from the malaria proteome were screened as a control. Several peptide array replicas were prepared, employing particle-based laser printing, and were used to screen 27 serum samples from a malaria-endemic area in Burkina Faso, West Africa. The immunological status of the individuals was classified as "protected" or "unprotected" based on clinical symptoms, parasite density, and age. The vaccine candidate screening approach resulted in significant hits in all twelve proteins and allowed us (1) to verify many known immunogenic structures, (2) to map B-cell epitopes across the entire sequence of each antigen and (3) to uncover novel immunogenic epitopes. Predicting immunogenic regions in the proteome of the human malaria parasite Plasmodium falciparum, via the bioinformatics approach and subsequent array screening, confirmed known immunogenic sequences, such as in the leading malaria vaccine candidate CSP and discovered immunogenic epitopes derived from hypothetical or unknown proteins.
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Affiliation(s)
- Thomas Jaenisch
- From the ‡Center for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Im Neuenheimer Feld 324, D 69120 Heidelberg, Germany;; §German Center for Infectious Disease Research, Heidelberg (DZIF);; ¶HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University, Karlsruhe Institute of Technology (KIT), Germany;.
| | - Kirsten Heiss
- From the ‡Center for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Im Neuenheimer Feld 324, D 69120 Heidelberg, Germany;; §German Center for Infectious Disease Research, Heidelberg (DZIF)
| | - Nico Fischer
- From the ‡Center for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Im Neuenheimer Feld 324, D 69120 Heidelberg, Germany;; §German Center for Infectious Disease Research, Heidelberg (DZIF);; ¶HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University, Karlsruhe Institute of Technology (KIT), Germany
| | - Carolin Geiger
- From the ‡Center for Infectious Diseases, Parasitology Unit, Heidelberg University Hospital, Im Neuenheimer Feld 324, D 69120 Heidelberg, Germany;; §German Center for Infectious Disease Research, Heidelberg (DZIF)
| | - F Ralf Bischoff
- ‖German Cancer Research Center, Im Neuenheimer Feld 280, D 69120 Heidelberg, Germany
| | - Gerhard Moldenhauer
- ‖German Cancer Research Center, Im Neuenheimer Feld 280, D 69120 Heidelberg, Germany
| | - Leszek Rychlewski
- BioInfoBank Institute, Św. Marcin 80/82 lok. 355, 61-809 Poznań, Poland
| | - Ali Sié
- Centre de Recherche en Santé de Nouna, BP 02 Nouna, Rue Namory Keita, Burkina Faso
| | - Boubacar Coulibaly
- Centre de Recherche en Santé de Nouna, BP 02 Nouna, Rue Namory Keita, Burkina Faso
| | - Peter H Seeberger
- §§Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, D 14476 Potsdam, Germany
| | - Lucjan S Wyrwicz
- Department of Oncology and Radiotherapy, M Sklodowska Curie Memorial Cancer Center, Wawelska 15, 02-034 Warsaw, Poland
| | - Frank Breitling
- ‖‖Institute of Microstructure Technology, Karlsruhe Institute of Technology, Germany Hermann-von-Helmholtz-Platz 1, D 76344 Eggenstein-Leopoldshafen, Germany
| | - Felix F Loeffler
- ¶HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University, Karlsruhe Institute of Technology (KIT), Germany;; §§Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, D 14476 Potsdam, Germany;.
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Heide J, Vaughan KC, Sette A, Jacobs T, Schulze Zur Wiesch J. Comprehensive Review of Human Plasmodium falciparum-Specific CD8+ T Cell Epitopes. Front Immunol 2019; 10:397. [PMID: 30949162 PMCID: PMC6438266 DOI: 10.3389/fimmu.2019.00397] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/15/2019] [Indexed: 12/16/2022] Open
Abstract
Control of malaria is an important global health issue and there is still an urgent need for the development of an effective prophylactic vaccine. Multiple studies have provided strong evidence that Plasmodium falciparum-specific MHC class I-restricted CD8+ T cells are important for sterile protection against Plasmodium falciparum infection. Here, we present an interactive epitope map of all P. falciparum-specific CD8+ T cell epitopes published to date, based on a comprehensive data base (IEDB), and literature search. The majority of the described P. falciparum-specific CD8+ T cells were directed against the antigens CSP, TRAP, AMA1, and LSA1. Notably, most of the epitopes were discovered in vaccine trials conducted with malaria-naïve volunteers. Only few immunological studies of P. falciparum-specific CD8+ T cell epitopes detected in patients suffering from acute malaria or in people living in malaria endemic areas have been published. Further detailed immunological mappings of P. falciparum-specific epitopes of a broader range of P. falciparum proteins in different settings and with different disease status are needed to gain a more comprehensive understanding of the role of CD8+ T cell responses for protection, and to better guide vaccine design and to study their efficacy.
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Affiliation(s)
- Janna Heide
- Infectious Diseases Unit, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Kerrie C Vaughan
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States
| | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States.,Department of Medicine, Division of Infectious Diseases, University of California, San Diego (UCSD), La Jolla, CA, United States
| | - Thomas Jacobs
- Protozoa Immunology, Bernhard-Nocht-Institute of Tropical Medicine, Hamburg, Germany
| | - Julian Schulze Zur Wiesch
- Infectious Diseases Unit, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
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Abstract
The enzyme-linked immunosorbent assay (ELISA) is a reliable and relatively low-cost method for measuring soluble ligands such as antibodies and proteins in biological samples. For analysis of specific antibodies in serum, a capture antigen is immobilized onto a solid polystyrene surface from which it can capture the antibodies. The captured antibodies are subsequently detected using a secondary antibody conjugated to an enzyme. Detection is accomplished by addition of a colorimetric substrate, and the readout is absorbance (optical density). Here, we provide a detailed standardized ELISA protocol for the quantification of antibodies against malaria antigens.
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Pratt-Riccio LR, De Souza Perce-Da-Silva D, Da Costa Lima-Junior J, Pratt Riccio EK, Ribeiro-Alves M, Santos F, Arruda M, Camus D, Druilhe P, Oliveira-Ferreira J, Daniel-Ribeiro CT, Banic DM. Synthetic Antigens Derived from Plasmodium falciparum Sporozoite, Liver, and Blood Stages: Naturally Acquired Immune Response and Human Leukocyte Antigen Associations in Individuals Living in a Brazilian Endemic Area. Am J Trop Med Hyg 2017; 97:1581-1592. [PMID: 29016339 DOI: 10.4269/ajtmh.17-0359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Peptide vaccine strategies using Plasmodium-derived antigens have emerged as an attractive approach against malaria. However, relatively few studies have been conducted with malaria-exposed populations from non-African countries. Herein, the seroepidemiological profile against Plasmodium falciparum of naturally exposed individuals from a Brazilian malaria-endemic area against synthetic peptides derived from vaccine candidates circumsporozoite protein (CSP), liver stage antigen-1 (LSA-1), erythrocyte binding antigen-175 (EBA-175), and merozoite surface protein-3 (MSP-3) was investigated. Moreover, human leukocyte antigen (HLA)-DRB1* and HLA-DQB1* were evaluated to characterize genetic modulation of humoral responsiveness to these antigens. The study was performed using blood samples from 187 individuals living in rural malaria-endemic villages situated near Porto Velho, Rondônia State. Specific IgG and IgM antibodies and IgG subclasses were detected by enzyme-linked immunosorbent assay, and HLA-DRB1* and HLA-DQB1* low-resolution typing was performed by PCR-SSP. All four synthetic peptides were broadly recognized by naturally acquired antibodies. Regarding the IgG subclass profile, only CSP induced IgG1 and IgG3 antibodies, which is an important fact given that the acquisition of protective immunity appears to be associated with the cytophilicity of IgG1 and IgG3 antibodies. HLA-DRB1*11 and HLA-DQB1*7 had the lowest odds of responding to EBA-175. Our results showed that CSP, LSA-1, EBA, and MSP-3 are immunogenic in natural conditions of exposure and that anti-EBA antibody responses appear to be modulated by HLA class II antigens.
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Affiliation(s)
| | | | | | | | - Marcelo Ribeiro-Alves
- Laboratório de Pesquisa Clínica em DST/AIDS, Instituto Nacional de Infectologia Evandro Chagas, Fiocruz, Rio de Janeiro, Brazil
| | - Fátima Santos
- Laboratório Central de Saúde Pública (LACEN), Rondônia, Brazil
| | - Mercia Arruda
- Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fiocruz, Recife, Brazil
| | - Daniel Camus
- Service de Parasitologie-Mycologie, Faculte de Médecine, Lille, France
| | | | | | | | - Dalma Maria Banic
- Laboratório de Imunologia Clínica, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
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Lima-Junior JDC, Morgado FN, Conceição-Silva F. How Can Elispot Add Information to Improve Knowledge on Tropical Diseases? Cells 2017; 6:cells6040031. [PMID: 28961208 PMCID: PMC5755491 DOI: 10.3390/cells6040031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 01/04/2023] Open
Abstract
Elispot has been used as an important tool for detecting immune cells' products and functions and has facilitated the understanding of host-pathogen interaction. Despite the incredible diversity of possibilities, two main approaches have been developed: the immunopathogenesis and diagnosis/prognosis of infectious diseases as well as cancer research. Much has been described on the topics of allergy, autoimmune diseases, and HIV-Aids, however, Elispot can also be applied to other infectious diseases, mainly leishmaniasis, malaria, some viruses, helminths and mycosis usually classified as tropical diseases. The comprehension of the function, concentration and diversity of the immune response in the infectious disease is pointed out as crucial to the development of infection or disease in humans and animals. In this review we will describe the knowledge already obtained using Elispot as a method for accessing the profile of immune response as well as the recent advances in information about host-pathogen interaction in order to better understand the clinical outcome of a group of tropical and neglected diseases.
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Affiliation(s)
- Josué da Costa Lima-Junior
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz/FIOCRUZ, Pavilhão 26-4° andar, sala 406-C, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil.
| | - Fernanda Nazaré Morgado
- Laboratório de Pesquisa em Leishmaniose, Instituto Oswaldo Cruz/FIOCRUZ, Pavilhão 26-5° andar, sala 509, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil.
| | - Fátima Conceição-Silva
- Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz/FIOCRUZ, Pavilhão 26-4° andar, sala 406-C, Av. Brasil 4365, Manguinhos, 21045-900 Rio de Janeiro, Brazil.
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Nazeri S, Zakeri S, Mehrizi AA, Djadid ND. Naturally acquired immune responses to thrombospondin-related adhesion protein (TRAP) of Plasmodium vivax in patients from areas of unstable malaria transmission. Acta Trop 2017; 173:45-54. [PMID: 28549910 DOI: 10.1016/j.actatropica.2017.05.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/20/2017] [Accepted: 05/20/2017] [Indexed: 10/19/2022]
Abstract
A key tool for the control, elimination, and eradication of Plasmodium vivax is the development of an effective vaccine. The thrombospondin-related adhesion protein (TRAP) is one of the major sporozoite antigens that plays an important role in the invasion of mosquito salivary glands and hepatocytes by sporozoites. The main goal of this study was to evaluate the naturally acquired antibodies to the P. vivax TRAP (PvTRAP) in patients from malaria-endemic areas of Iran (n=116), Afghanistan (n=50), and Pakistan (n=50). The PvTRAP gene was expressed in Escherichia coli Rosetta (DE3)-pET23a and used as antigen in enzyme-linked immunosorbent assay (ELISA). The profile of immunoglobulin G (IgG) isotype and the avidity of IgG, IgG1, and IgG3 to PvTRAP, as well as the association between anti-PvTRAP isotype responses and host age were evaluated. Only 42.24% of Iranian, 38% of Afghani, and 44% of Pakistani patients infected with P. vivax had positive anti-PvTRAP IgG, and the prevalence of responders in the three countries did not differ significantly (P>0.05). Moreover, the prevalence of IgG1 and IgG3 antibody responses to PvTRAP showed no significant correlation with age (P>0.05). Individuals exposed to vivax malaria in the unstable malaria transmission areas are able to produce antibodies to the TRAP antigen at all ages in response to P. vivax infections. Finally, the presence of mature IgG1 and IgG3 antibodies with high to intermediate avidity against PvTRAP antigen (>60%) provide more information to understand the interactions between the host and P. vivax parasite. In summary, the present study provides data that support the rational development of an effective pre-erythrocytic stage vaccine based on PvTRAP antigen.
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Spencer AJ, Longley RJ, Gola A, Ulaszewska M, Lambe T, Hill AVS. The Threshold of Protection from Liver-Stage Malaria Relies on a Fine Balance between the Number of Infected Hepatocytes and Effector CD8 + T Cells Present in the Liver. THE JOURNAL OF IMMUNOLOGY 2017; 198:2006-2016. [PMID: 28087668 PMCID: PMC5318841 DOI: 10.4049/jimmunol.1601209] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/16/2016] [Indexed: 12/20/2022]
Abstract
Since the demonstration of sterile protection afforded by injection of irradiated sporozoites, CD8+ T cells have been shown to play a significant role in protection from liver-stage malaria. This is, however, dependent on the presence of an extremely high number of circulating effector cells, thought to be necessary to scan, locate, and kill infected hepatocytes in the short time that parasites are present in the liver. We used an adoptive transfer model to elucidate the kinetics of the effector CD8+ T cell response in the liver following Plasmodium berghei sporozoite challenge. Although effector CD8+ T cells require <24 h to find, locate, and kill infected hepatocytes, active migration of Ag-specific CD8+ T cells into the liver was not observed during the 2-d liver stage of infection, as divided cells were only detected from day 3 postchallenge. However, the percentage of donor cells recruited into division was shown to indicate the level of Ag presentation from infected hepatocytes. By titrating the number of transferred Ag-specific effector CD8+ T cells and sporozoites, we demonstrate that achieving protection toward liver-stage malaria is reliant on CD8+ T cells being able to locate infected hepatocytes, resulting in a protection threshold dependent on a fine balance between the number of infected hepatocytes and CD8+ T cells present in the liver. With such a fine balance determining protection, achieving a high number of CD8+ T cells will be critical to the success of a cell-mediated vaccine against liver-stage malaria.
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Affiliation(s)
| | - Rhea J Longley
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Anita Gola
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Marta Ulaszewska
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Teresa Lambe
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Adrian V S Hill
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom
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15
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Hickey BW, Lumsden JM, Reyes S, Sedegah M, Hollingdale MR, Freilich DA, Luke TC, Charoenvit Y, Goh LM, Berzins MP, Bebris L, Sacci JB, De La Vega P, Wang R, Ganeshan H, Abot EN, Carucci DJ, Doolan DL, Brice GT, Kumar A, Aguiar J, Nutman TB, Leitman SF, Hoffman SL, Epstein JE, Richie TL. Mosquito bite immunization with radiation-attenuated Plasmodium falciparum sporozoites: safety, tolerability, protective efficacy and humoral immunogenicity. Malar J 2016; 15:377. [PMID: 27448805 PMCID: PMC4957371 DOI: 10.1186/s12936-016-1435-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/09/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In this phase 1 clinical trial, healthy adult, malaria-naïve subjects were immunized with radiation-attenuated Plasmodium falciparum sporozoites (PfRAS) by mosquito bite and then underwent controlled human malaria infection (CHMI). The PfRAS model for immunization against malaria had previously induced >90 % sterile protection against homologous CHMI. This study was to further explore the safety, tolerability and protective efficacy of the PfRAS model and to provide biological specimens to characterize protective immune responses and identify protective antigens in support of malaria vaccine development. METHODS Fifty-seven subjects were screened, 41 enrolled and 30 received at least one immunization. The true-immunized subjects received PfRAS via mosquito bite and the mock-immunized subjects received mosquito bites from irradiated uninfected mosquitoes. Sera and peripheral blood mononuclear cells (PBMCs) were collected before and after PfRAS immunizations. RESULTS Immunization with PfRAS was generally safe and well tolerated, and repeated immunization via mosquito bite did not appear to increase the risk or severity of AEs. Local adverse events (AEs) of true-immunized and mock-immunized groups consisted of erythaema, papules, swelling, and induration and were consistent with reactions from mosquito bites seen in nature. Two subjects, one true- and one mock-immunized, developed large local reactions that completely resolved, were likely a result of mosquito salivary antigens, and were withdrawn from further participation as a safety precaution. Systemic AEs were generally rare and mild, consisting of headache, myalgia, nausea, and low-grade fevers. Two true-immunized subjects experienced fever, malaise, myalgia, nausea, and rigours approximately 16 h after immunization. These symptoms likely resulted from pre-formed antibodies interacting with mosquito salivary antigens. Ten subjects immunized with PfRAS underwent CHMI and five subjects (50 %) were sterilely protected and there was a significant delay to parasitaemia in the other five subjects. All ten subjects developed humoral immune responses to whole sporozoites and to the circumsporozoite protein prior to CHMI, although the differences between protected and non-protected subjects were not statistically significant for this small sample size. CONCLUSIONS The protective efficacy of this clinical trial (50 %) was notably less than previously reported (>90 %). This may be related to differences in host genetics or the inherent variability in mosquito biting behavior and numbers of sporozoites injected. Differences in trial procedures, such as the use of leukapheresis prior to CHMI and of a longer interval between the final immunization and CHMI in these subjects compared to earlier trials, may also have reduced protective efficacy. This trial has been retrospectively registered at ISRCTN ID 17372582, May 31, 2016.
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Affiliation(s)
- Bradley W. Hickey
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Joanne M. Lumsden
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Sharina Reyes
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Martha Sedegah
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Michael R. Hollingdale
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Daniel A. Freilich
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Thomas C. Luke
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Yupin Charoenvit
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Lucy M. Goh
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Mara P. Berzins
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Lolita Bebris
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - John B. Sacci
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Patricia De La Vega
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Ruobing Wang
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Harini Ganeshan
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Esteban N. Abot
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD USA
| | - Daniel J. Carucci
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Denise L. Doolan
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Gary T. Brice
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Anita Kumar
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Joao Aguiar
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Thomas B. Nutman
- />Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD USA
| | - Susan F. Leitman
- />Department of Transfusion Medicine, National Institutes of Health Clinical Center, Bethesda, MD USA
| | - Stephen L. Hoffman
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Sanaria Inc., Rockville, MD USA
| | - Judith E. Epstein
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
| | - Thomas L. Richie
- />US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD USA
- />Sanaria Inc., Rockville, MD USA
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16
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Abstract
The quantification of single cell interferon-gamma (IFN-γ) release for assessing cellular immune responses using the Enzyme-linked immunospot (ELISPOT) assay is an invaluable technique in immunology. Peripheral blood mononuclear cells (PBMC) are stimulated in vitro with recombinant proteins, peptides and recently whole malaria organisms. Stimulation may be short term (20-36 h) or long term (cultured ELISpot, up to 7 days). ELISpot is also able to quantify other cytokines secreted by antigen-specific T-cells, such as interleukin-2, interleukin-5, and other interleukins. ELISpot is playing an important role especially in vaccine research studies.
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Affiliation(s)
- Martha Sedegah
- Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA.
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17
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Mbengue B, Kpodji P, Sylla Niang M, Varela ML, Thiam A, Sow A, Ndiaye K, Aidara M, Thiam F, Ndiaye R, Diop G, Nguer CM, Perraut R, Dièye A. [Profiles of IgG responses against CSP, GLURP and LSA-3NR2 in urban malaria (Dakar): relations with haemoglobin levels and parasite densities]. BULLETIN DE LA SOCIETE DE PATHOLOGIE EXOTIQUE (1990) 2016; 109:91-98. [PMID: 27100862 DOI: 10.1007/s13149-016-0485-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/23/2016] [Indexed: 06/05/2023]
Abstract
Malaria remains a major health problem in sub- Saharan African countries despite substantial decreases in morbidity and mortality due to sustained control programs. Vaccines candidates were mainly tested in rural endemic setting; however increasing proportion of the population is living in urban area. Evaluation of the qualitative or quantitative immune responses to key targets of anti-Plasmodium immunity requires further investigation in urban area. In a cohort of 144 patients with mild malaria living in Dakar, we analyzed IgG responses against target antigens of P. falciparum: CSP, LSA-3NR2 and GLURP by ELISA. A mean age of 15 yrs (4-65 yrs) was found and patients were separated in 59 adults (<15yrs) and 85 children (≤15 yrs). Parasites densities (0,01-15%) did not differ between the two age groups. In contrast, haemoglobin levels appeared lower in children (4.5-16.6 g/dl) (p<0.01). For the immune results, the most recognized antigens were GLURP and CSP compared to LSA-3NR2. Levels of IgG against these antigens were significantly different between the two age groups and they were positively correlated (rho = 0.32; p<0.001). In addition, levels of IgG anti-GLURP were associated with low parasitemia (≤1%) and absence of anemia (≥11g/dl), particularly in adults (p<0.001). In a multiple regression analysis, no significant relationship was found between parasite densities and IgG responses against all the tested antigens. Our study shows the implication of IgG anti-GLURP in humoral immune response against the parasite. The present work contributes to determine IgG levels that can be used as relevant immunologic biomarkers in urban clinical malaria.
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Affiliation(s)
- B Mbengue
- Service d'immunologie FMPO, Université Cheikh Anta Diop, Dakar, Sénégal.
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal.
| | - P Kpodji
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - M Sylla Niang
- Service d'immunologie FMPO, Université Cheikh Anta Diop, Dakar, Sénégal
| | - M L Varela
- Unité d'immunologie, Institut Pasteur de Dakar, Dakar, Sénégal
| | - A Thiam
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - A Sow
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - K Ndiaye
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - M Aidara
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - F Thiam
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - R Ndiaye
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - G Diop
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
| | - C M Nguer
- Département génie chimique et biologie appliquée, ESP, Université Cheikh Anta Diop, Dakar, Sénégal
| | - R Perraut
- Unité d'immunologie, Institut Pasteur de Dakar, Dakar, Sénégal
| | - A Dièye
- Unité d'immunogénétique, Institut Pasteur de Dakar, Dakar, Sénégal
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18
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Addai-Mensah O, Seidel M, Amidu N, Maskus DJ, Kapelski S, Breuer G, Franken C, Owusu-Dabo E, Frempong M, Rakotozandrindrainy R, Schinkel H, Reimann A, Klockenbring T, Barth S, Fischer R, Fendel R. Acquired immune responses to three malaria vaccine candidates and their relationship to invasion inhibition in two populations naturally exposed to malaria. Malar J 2016; 15:65. [PMID: 26850066 PMCID: PMC4743426 DOI: 10.1186/s12936-016-1112-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 01/19/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria still represents a major cause of morbidity and mortality predominantly in several developing countries, and remains a priority in many public health programmes. Despite the enormous gains made in control and prevention the development of an effective vaccine represents a persisting challenge. Although several parasite antigens including pre-erythrocytic antigens and blood stage antigens have been thoroughly investigated, the identification of solid immune correlates of protection against infection by Plasmodium falciparum or clinical malaria remains a major hurdle. In this study, an immuno-epidemiological survey was carried out between two populations naturally exposed to P. falciparum malaria to determine the immune correlates of protection. Methods Plasma samples of immune adults from two countries (Ghana and Madagascar) were tested for their reactivity against the merozoite surface proteins MSP1-19, MSP3 and AMA1 by ELISA. The antigens had been selected on the basis of cumulative evidence of their role in anti-malarial immunity. Additionally, reactivity against crude P. falciparum lysate was investigated. Purified IgG from these samples were furthermore tested in an invasion inhibition assay for their antiparasitic activity. Results Significant intra- and inter- population variation of the reactivity of the samples to the tested antigens were found, as well as a significant positive correlation between MSP1-19 reactivity and invasion inhibition (p < 0.05). Interestingly, male donors showed a significantly higher antibody response to all tested antigens than their female counterparts. In vitro invasion inhibition assays comparing the purified antibodies from the donors from Ghana and Madagascar did not show any statistically significant difference. Although in vitro invasion inhibition increased with breadth of antibody response, the increase was not statistically significant. Conclusions The findings support the fact that the development of semi-immunity to malaria is probably contingent on the development of antibodies to not only one, but a range of antigens and that invasion inhibition in immune adults may be a function of antibodies to various antigens. This supports strategies of vaccination including multicomponent vaccines as well as passive vaccination strategies with antibody cocktails.
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Affiliation(s)
- Otchere Addai-Mensah
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany. .,RWTH Aachen University, Institute for Molecular Biotechnology, Worringerweg 1, 52074, Aachen, Germany. .,Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Melanie Seidel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Nafiu Amidu
- Department of Biomedical Laboratory Science, School of Medicine and Health Science, University for Development Studies, Tamale, Ghana.
| | - Dominika J Maskus
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Stephanie Kapelski
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Gudrun Breuer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Carmen Franken
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Ellis Owusu-Dabo
- Kumasi Centre for Collaborative Research, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Margaret Frempong
- Department of Molecular Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Raphaël Rakotozandrindrainy
- Laboratoire de Microbiologie et de Parasitologie, ESSAGRO-Faculté de Médecine, Université d'Antananarivo, Antananarivo, Madagascar.
| | - Helga Schinkel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Torsten Klockenbring
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany.
| | - Stefan Barth
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany. .,Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering at RWTH Aachen University and Hospital, Pauwelsstraße 20, 52074, Aachen, Germany. .,South African Research Chair in Cancer Biotechnology, Institute of Infectious Disease and Molecular Medicine (IDM), Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, 7925, South Africa.
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany. .,RWTH Aachen University, Institute for Molecular Biotechnology, Worringerweg 1, 52074, Aachen, Germany.
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Forckenbeckstraße 6, 52074, Aachen, Germany. .,RWTH Aachen University, Institute for Molecular Biotechnology, Worringerweg 1, 52074, Aachen, Germany. .,Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering at RWTH Aachen University and Hospital, Pauwelsstraße 20, 52074, Aachen, Germany.
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19
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Ganeshan H, Kusi KA, Anum D, Hollingdale MR, Peters B, Kim Y, Tetteh JKA, Ofori MF, Gyan BA, Koram KA, Huang J, Belmonte M, Banania JG, Dodoo D, Villasante E, Sedegah M. Measurement of ex vivo ELISpot interferon-gamma recall responses to Plasmodium falciparum AMA1 and CSP in Ghanaian adults with natural exposure to malaria. Malar J 2016; 15:55. [PMID: 26830334 PMCID: PMC4736649 DOI: 10.1186/s12936-016-1098-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 01/12/2016] [Indexed: 12/17/2022] Open
Abstract
Background Malaria eradication requires a concerted approach involving all available control tools, and an effective vaccine would complement these efforts. An effective malaria vaccine should be able to induce protective immune responses in a genetically diverse population. Identification of immunodominant T cell epitopes will assist in determining if candidate vaccines will be immunogenic in malaria-endemic areas. This study therefore investigated whether class I-restricted T cell epitopes of two leading malaria vaccine antigens, Plasmodium falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1), could recall T cell interferon-γ responses from naturally exposed subjects using ex vivo ELISpot assays. Methods Thirty-five subjects aged between 24 and 43 years were recruited from a malaria-endemic urban community of Ghana in 2011, and their peripheral blood mononuclear cells (PBMCs) were tested in ELISpot IFN-γ assays against overlapping 15mer peptide pools spanning the entire CSP and AMA1 antigens, and 9–10mer peptide epitope mixtures that included previously identified and/or predicted human leukocyte antigen (HLA) class 1-restricted epitopes from same two antigens. Results For CSP, 26 % of subjects responded to at least one of the nine 15mer peptide pools whilst 17 % responded to at least one of the five 9–10mer HLA-restricted epitope mixtures. For AMA1, 63 % of subjects responded to at least one of the 12 AMA1 15mer peptide pools and 51 % responded to at least one of the six 9–10mer HLA-restricted epitope mixtures. Following analysis of data from the two sets of peptide pools, along with bioinformatics predictions of class I-restricted epitopes and the HLA supertypes expressed by a subset of study subjects, peptide pools that may contain epitopes recognized by multiple HLA supertypes were identified. Collectively, these results suggest that natural transmission elicits ELISpot IFN-γ activities to class 1-restricted epitopes that are largely HLA-promiscuous. Conclusions These results generally demonstrate that CSP and AMA1 peptides recalled ELISpot IFN-γ responses from naturally exposed individuals and that both CSP and AMA1 contain diverse class 1-restricted epitopes that are HLA-promiscuous and are widely recognized in this population. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1098-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Harini Ganeshan
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, USA.
| | - Kwadwo A Kusi
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Dorothy Anum
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | | | - Bjoern Peters
- La Jolla Institute for Allergy and Immunology, La Jolla, San Diego, CA, USA.
| | - Yohan Kim
- La Jolla Institute for Allergy and Immunology, La Jolla, San Diego, CA, USA.
| | - John K A Tetteh
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Michael F Ofori
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Ben A Gyan
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Kwadwo A Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Jun Huang
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, USA.
| | - Maria Belmonte
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, USA.
| | - Jo Glenna Banania
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, USA.
| | - Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Eileen Villasante
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, USA.
| | - Martha Sedegah
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, USA.
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20
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Abstract
The development of an efficacious and practicable vaccine conferring sterile immunity towards a Plasmodium infection represents a not yet achieved goal. A crucial factor for the impact of a given anti-plasmodial subunit vaccine is the identification of the most potent parasitic components required to induce protection from both infection and disease. Here, we present a method based on a novel high-density peptide array technology that allows for a flexible readout of malaria antibodies. Peptide arrays applied as a screening method can be used to identify novel immunogenic antibody epitopes under a large number of potential antigens/peptides. Ultimately, discovered antigen candidates and/or epitope sequences can be translated into vaccine prototype design. The technology can be further utilized to unravel antibody-mediated immune responses (e.g., involved in the establishment of semi-immunity) and moreover to confirm vaccine potency during the process of clinical development by verifying the induced antibody responses following vaccination.
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Flanagan KL, Wilson KL, Plebanski M. Polymorphism in liver-stage malaria vaccine candidate proteins: immune evasion and implications for vaccine design. Expert Rev Vaccines 2015; 15:389-99. [PMID: 26610026 DOI: 10.1586/14760584.2016.1125785] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The pre-erythrocytic stage of infection by malaria parasites represents a key target for vaccines that aim to eradicate malaria. Two important broad immune evasion strategies that can interfere with vaccine efficacy include the induction of dendritic cell (DC) dysfunction and regulatory T cells (Tregs) by blood-stage malaria parasites, leading to inefficient priming of T cells targeting liver-stage infections. The parasite also uses 'surgical strike' strategies, whereby polymorphism in pre-erythrocytic antigens can interfere with host immunity. Specifically, we review how even single amino acid changes in T cell epitopes can lead to loss of binding to major histocompatibility complex (MHC), lack of cross-reactivity, or antagonism and immune interference, where simultaneous or sequential stimulation with related variants of the same T cell epitope can cause T cell anergy or the conversion of effector to immunosuppressive T cell phenotypes.
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Affiliation(s)
- Katie L Flanagan
- a Vaccine and Infectious Diseases Laboratory, Department of Immunology , Monash University , Melbourne , VIC , Australia
| | - Kirsty L Wilson
- a Vaccine and Infectious Diseases Laboratory, Department of Immunology , Monash University , Melbourne , VIC , Australia
| | - Magdalena Plebanski
- a Vaccine and Infectious Diseases Laboratory, Department of Immunology , Monash University , Melbourne , VIC , Australia
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Acquisition and Longevity of Antibodies to Plasmodium vivax Preerythrocytic Antigens in Western Thailand. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 23:117-24. [PMID: 26656115 PMCID: PMC4744911 DOI: 10.1128/cvi.00501-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/25/2015] [Indexed: 12/31/2022]
Abstract
Plasmodium vivax is now the dominant Plasmodium species causing malaria in Thailand, yet little is known about naturally acquired immune responses to this parasite in this low-transmission region. The preerythrocytic stage of the P. vivax life cycle is considered an excellent target for a malaria vaccine, and in this study, we assessed the stability of the seropositivity and the magnitude of IgG responses to three different preerythrocytic P. vivax proteins in two groups of adults from a region of western Thailand where malaria is endemic. These individuals were enrolled in a yearlong cohort study, which comprised one group that remained P. vivax free (by quantitative PCR [qPCR] detection, n = 31) and another that experienced two or more blood-stage P. vivax infections during the year of follow up (n = 31). Despite overall low levels of seropositivity, IgG positivity and magnitude were long-lived over the 1-year period in the absence of qPCR-detectable blood-stage P. vivax infections. In contrast, in the adults with two or more P. vivax infections during the year, IgG positivity was maintained, but the magnitude of the response to P. vivax circumsporozoite protein 210 (CSP210) decreased over time. These findings demonstrate that long-term humoral immunity can develop in low-transmission regions.
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Immune protection-inducing protein structures (IMPIPS) against malaria: the weapons needed for beating Odysseus. Vaccine 2015; 33:7525-37. [DOI: 10.1016/j.vaccine.2015.09.109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 08/04/2015] [Accepted: 09/28/2015] [Indexed: 11/19/2022]
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Aguiar JC, Bolton J, Wanga J, Sacci JB, Iriko H, Mazeika JK, Han ET, Limbach K, Patterson NB, Sedegah M, Cruz AM, Tsuboi T, Hoffman SL, Carucci D, Hollingdale MR, Villasante ED, Richie TL. Discovery of Novel Plasmodium falciparum Pre-Erythrocytic Antigens for Vaccine Development. PLoS One 2015; 10:e0136109. [PMID: 26292257 PMCID: PMC4546230 DOI: 10.1371/journal.pone.0136109] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 07/29/2015] [Indexed: 02/07/2023] Open
Abstract
Background Nearly 100% protection against malaria infection can be achieved in humans by immunization with P. falciparum radiation-attenuated sporozoites (RAS). Although it is thought that protection is mediated by T cell and antibody responses, only a few of the many pre-erythrocytic (sporozoite and liver stage) antigens that are targeted by these responses have been identified. Methodology Twenty seven P. falciparum pre-erythrocytic antigens were selected using bioinformatics analysis and expression databases and were expressed in a wheat germ cell-free protein expression system. Recombinant proteins were recognized by plasma from RAS-immunized subjects, and 21 induced detectable antibody responses in mice and rabbit and sera from these immunized animals were used to characterize these antigens. All 21 proteins localized to the sporozoite: five localized to the surface, seven localized to the micronemes, cytoplasm, endoplasmic reticulum or nucleus, two localized to the surface and cytoplasm, and seven remain undetermined. PBMC from RAS-immunized volunteers elicited positive ex vivo or cultured ELISpot responses against peptides from 20 of the 21 antigens. Conclusions These T cell and antibody responses support our approach of using reagents from RAS-immunized subjects to screen potential vaccine antigens, and have led to the identification of a panel of novel P. falciparum antigens. These results provide evidence to further evaluate these antigens as vaccine candidates. Trial Registration ClinicalTrials.gov NCT00870987 ClinicalTrials.gov NCT00392015
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Affiliation(s)
- Joao C. Aguiar
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- Camris International, Bethesda, MD 20814, United States of America
- * E-mail:
| | - Jessica Bolton
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD 20817, United States of America
| | - Joyce Wanga
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- Technical Resources International, Inc., Bethesda, MD 20817, United States of America
| | - John B. Sacci
- Department of Microbiology and Immunology, The University of Maryland School of Medicine, Baltimore, MD 21201, United States of America
| | - Hideyuki Iriko
- Department of International Health, Kobe University Graduate School of Health Science, Kobe 654-0142, Japan
| | - Julie K. Mazeika
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- EMD Millipore Corporation, North Andover, MA 01845, United States of America
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea
| | - Keith Limbach
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD 20817, United States of America
| | - Noelle B. Patterson
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD 20817, United States of America
| | - Martha Sedegah
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
| | - Ann-Marie Cruz
- PATH Malaria Vaccine Initiative, Washington, DC 20001, United States of America
| | - Takafumi Tsuboi
- Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Stephen L. Hoffman
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
| | - Daniel Carucci
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
| | - Michael R. Hollingdale
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD 20817, United States of America
| | - Eileen D. Villasante
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
| | - Thomas L. Richie
- Malaria Department, Naval Medical Research Center, Silver Spring, MD 20910, United States of America
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Mbengue B, Sylla Niang M, Ndiaye Diallo R, Diop G, Thiam A, Ka O, Touré A, Tall A, Perraut R, Dièye A. [IgG responses to candidate malaria vaccine antigens in the urban area of Dakar (Senegal): evolution according to age and parasitemia in patients with mild symptoms]. ACTA ACUST UNITED AC 2015; 108:94-101. [PMID: 25925805 DOI: 10.1007/s13149-015-0419-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/25/2014] [Indexed: 12/22/2022]
Abstract
Malaria remains a major problem in African countries despite substantial decreases in morbidity and mortality due to sustained control programs. Studies for the evaluation of qualitative or quantitative Ab responses to key targets of anti-plasmodium immunity were mostly done in rural endemic setting compared to urban area. In a cohort of 200 patients with mild malaria and living in Dakar, we analyze total and subclasses IgG responses to a panel of P. falciparum blood stage antigens: MSP1p19, MSP3, EB200, GST-5 and R23. A mean age of 15 yrs (4 to 56 yrs) and parasitemia between 0.1 to 17% were found. Levels of IgG anti-MSP3 were higher in patients with low parasitemia (≤1%) and appear negatively correlated to parasite densities (Rho =. 0.54; p= 0.021). This correlation is more significant in children (≤ 15 yrs). In addition, an increase of IgG responses against MSP1p19 is highly observed in adults having a parasitemia less than 1%. In those patients, we find that IgG1 subclasses were predominant (p <0.01). Our study shows an association between Ab responses and parasitemia. This association is dependant to IgG anti-MSP3 in children and IgG anti-MSP1p19 in adults living in urban area.
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Affiliation(s)
- B Mbengue
- Service d'immunologie UCAD FMPO, Dakar, Sénégal,
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26
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Anum D, Kusi KA, Ganeshan H, Hollingdale MR, Ofori MF, Koram KA, Gyan BA, Adu-Amankwah S, Badji E, Huang J, Belmonte M, Banania GJ, Kwofie TB, Villasante E, Dodoo D, Sedegah M. Measuring naturally acquired ex vivo IFN-γ responses to Plasmodium falciparum cell-traversal protein for ookinetes and sporozoites (CelTOS) in Ghanaian adults. Malar J 2015; 14:20. [PMID: 25604473 PMCID: PMC4308902 DOI: 10.1186/s12936-014-0539-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/29/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A malaria vaccine that targets the sporozoite/liver stage parasites could potentially prevent blood stage infection and the associated clinical symptoms. Identification of sporozoite/liver stage antigens is, therefore, crucial for the development of effective vaccines. Cell-traversal protein for ookinetes and sporozoites (CelTOS) is a highly conserved antigen involved in sporozoite motility and hepatocyte invasion and has been shown to induce significant IFN-γ production in PBMCs from radiation-attenuated sporozoite-immunized malaria-naïve individuals. The aim of this study was to ascertain whether such CelTOS-specific recall responses are also induced in individuals with natural exposure to Plasmodium falciparum. METHODS Ex vivo IFN-γ responses to 15mer overlapping peptide pools covering the entire sequence of CelTOS and five other candidate antigens, CSP, AMA1, MSP1, TRAP and LSA1, were characterized using PBMCs from 35 malaria exposed adults. Responses to four CelTOS peptide pools (CelTp1, CelTp2, CelTp3 and CelTp4), a pool containing peptides from the entire CelTOS antigen (CelTTp), and pools comprised of overlapping peptides from each of the other five malaria antigens were assessed by ex vivo ELISpot assay. A positive IFN-γ response for stimulants was defined by two criteria; a stimulation index of two or greater relative to the unstimulated control, and a difference of 10 or greater in spot forming cells between stimulant and the unstimulated control. RESULTS Of the 35 volunteers tested, five had positive IFN-γ recall responses against the four different CelTOS pools while four volunteers made responses against the CelTTp pool; six volunteers were, therefore, positive with CelTOS. By contrast, six volunteers responded to AMA1, seven to LSA1, 15 to MSP1 and two volunteers responded against CSP and TRAP. CONCLUSIONS These results suggest natural malaria transmission induces CelTOS-specific ex vivo IFN-γ in Ghanaian adults and that the frequency of these responses was similar to those of other previously characterized malaria antigens. These findings support the further evaluation of CelTOS as a pre-erythrocytic candidate antigen for inclusion in a potential multi-antigen vaccine.
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Affiliation(s)
| | - Kwadwo A Kusi
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
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27
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Ondigo BN, Hodges JS, Ireland KF, Magak NG, Lanar DE, Dutta S, Narum DL, Park GS, Ofulla AV, John CC. Estimation of recent and long-term malaria transmission in a population by antibody testing to multiple Plasmodium falciparum antigens. J Infect Dis 2014; 210:1123-32. [PMID: 24737801 DOI: 10.1093/infdis/jiu225] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Tools that estimate recent and long-term malaria transmission in a population would be highly useful for malaria elimination programs. METHODS The prevalence of antibodies to 11 Plasmodium falciparum antigens was assessed by cytometric bead assay or enzyme-linked immunosorbent assay in 1000 people in a highland area of Kenya over 14 months, during a period of interrupted malaria transmission. RESULTS Antibodies differed by antigen in acquisition with age: rapid (>80% antibody positive by age 20 years, 5 antigens), moderate (>40% positive by age 20 years, 3 antigens), or slow (<40% positive by age 20 years, 3 antigens). Antibody seroreversion rates in the 14 months between samples decreased with age rapidly (7 antigens), slowly (3 antigens), or remained high at all ages (schizont extract). Estimated antibody half-lives in individuals >10 years of age were long (40 to >80 years) for 5 antigens, moderate (5-20 years) for 3 antigens, and short (<1 year) for 3 antigens. CONCLUSIONS Antibodies to P. falciparum antigens in malaria-endemic areas vary by age, antigen, and time since last exposure to P. falciparum. Multiplex P. falciparum antibody testing could provide estimates of long-term and recent malaria transmission and potentially of a population's susceptibility to future clinical malaria.
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Affiliation(s)
- Bartholomew N Ondigo
- Department of Biomedical Science and Technology, Maseno University Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - James S Hodges
- Division of Biostatistics, School of Public Health, University of Minnesota
| | | | | | - David E Lanar
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Sheetij Dutta
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - David L Narum
- Malaria Vaccine Branch, Walter Reed Army Institute for Research, Silver Spring
| | - Gregory S Park
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Health, Rockville, Maryland
| | - Ayub V Ofulla
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Health, Rockville, Maryland
| | - Chandy C John
- Department of Pediatrics, University of Minnesota Medical School Center for Global Health Research, Kenya Medical Research Institute, Kisumu
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28
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Kusi KA, Bosomprah S, Dodoo D, Kyei-Baafour E, Dickson EK, Mensah D, Angov E, Dutta S, Sedegah M, Koram KA. Anti-sporozoite antibodies as alternative markers for malaria transmission intensity estimation. Malar J 2014; 13:103. [PMID: 24635830 PMCID: PMC3995447 DOI: 10.1186/1475-2875-13-103] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/05/2014] [Indexed: 11/10/2022] Open
Abstract
Background Reported malaria cases continue to decline globally, and this has been attributed to strategic implementation of multiple malaria control tools. Gains made would however need to be sustained through continuous monitoring to ensure malaria elimination and eradication. Entomological inoculation rate (EIR) is currently the standard tool for transmission monitoring but this is not sensitive enough, especially in areas of very low transmission. Transmission estimation models based on seroconversion rates (λ) of antibodies to Plasmodium falciparum blood stage antigens are gaining relevance. Estimates of λ, which is the measure of transmission intensity, correlate with EIR but are limited by long-term persistence of antibodies to blood stage antigens. Seroprevalence of antibodies to sporozoite antigens may be better alternatives since these antigens usually have shorter immune exposure times. The aim of this study was to develop transmission estimation models based on the seroprevalence of antibodies to two P. falciparum sporozoite antigens (CSP, CelTOS) and compare with models based on the classical blood stage antigen AMA1. Methods Antibody levels in archived plasma from three cross-sectional surveys conducted in 2009 in a low transmission area of Southern Ghana were assessed by indirect ELISA. Seroprevalence of antibodies against CSP, CelTOS and AMA1 were fitted to reversible catalytic models to estimate λ and corresponding seroreversion rates (ρ) for each antibody. Results Of the three models developed, the anti-CSP model predicted a 13-fold decrease in λ four years prior to the time of sampling (2009). Anti-AMA1 antibodies formed at a four-fold greater rate compared to that of anti-CelTOS antibodies, and anti-CSP antibodies during the period of decreased λ. In contrast, anti-AMA1 antibodies decayed at a five-fold slower rate relative to that of anti-CSP antibodies while anti-AMA1 and anti-CelTOS antibody decay rates were not significantly different. Anti-CSP antibodies were relatively short-lived as they formed at an 11.6-fold slower rate relative to their decay during the period of decreased λ. Conclusions These features of anti-CSP antibodies can be exploited for the development of models for predicting seasonal, short-term changes in transmission intensity in malaria-endemic areas, especially as the elimination phase of malaria control is approached.
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Affiliation(s)
- Kwadwo A Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.
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29
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Efficacy of a Plasmodium vivax malaria vaccine using ChAd63 and modified vaccinia Ankara expressing thrombospondin-related anonymous protein as assessed with transgenic Plasmodium berghei parasites. Infect Immun 2013; 82:1277-86. [PMID: 24379295 PMCID: PMC3957994 DOI: 10.1128/iai.01187-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plasmodium vivax is the world's most widely distributed malaria parasite and a potential cause of morbidity and mortality for approximately 2.85 billion people living mainly in Southeast Asia and Latin America. Despite this dramatic burden, very few vaccines have been assessed in humans. The clinically relevant vectors modified vaccinia virus Ankara (MVA) and the chimpanzee adenovirus ChAd63 are promising delivery systems for malaria vaccines due to their safety profiles and proven ability to induce protective immune responses against Plasmodium falciparum thrombospondin-related anonymous protein (TRAP) in clinical trials. Here, we describe the development of new recombinant ChAd63 and MVA vectors expressing P. vivax TRAP (PvTRAP) and show their ability to induce high antibody titers and T cell responses in mice. In addition, we report a novel way of assessing the efficacy of new candidate vaccines against P. vivax using a fully infectious transgenic Plasmodium berghei parasite expressing P. vivax TRAP to allow studies of vaccine efficacy and protective mechanisms in rodents. Using this model, we found that both CD8+ T cells and antibodies mediated protection against malaria using virus-vectored vaccines. Our data indicate that ChAd63 and MVA expressing PvTRAP are good preerythrocytic-stage vaccine candidates with potential for future clinical application.
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30
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Medeiros MM, Fotoran WL, dalla Martha RC, Katsuragawa TH, Pereira da Silva LH, Wunderlich G. Natural antibody response to Plasmodium falciparum merozoite antigens MSP5, MSP9 and EBA175 is associated to clinical protection in the Brazilian Amazon. BMC Infect Dis 2013; 13:608. [PMID: 24373342 PMCID: PMC3880555 DOI: 10.1186/1471-2334-13-608] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/23/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Antibodies have an essential role in the acquired immune response against blood stage P. falciparum infection. Although several antigens have been identified as important antibody targets, it is still elusive which antigens have to be recognized for clinical protection. Herein, we analyzed antibodies from plasmas from symptomatic or asymptomatic individuals living in the same geographic area in the Western Amazon, measuring their recognition of multiple merozoite antigens. METHODS Specific fragments of genes encoding merozoite proteins AMA1 and members of MSP and EBL families from circulating P. falciparum field isolates present in asymptomatic and symptomatic patients were amplified by PCR. After cloning and expression of different versions of the antigens as recombinant GST-fusion peptides, we tested the reactivity of patients' plasmas by ELISA and the presence of IgG subclasses in the most reactive plasmas. RESULTS 11 out of 24 recombinant antigens were recognized by plasmas from either symptomatic or asymptomatic infections. Antibodies to MSP9 (X2(DF=1) = 9.26/p = 0.0047) and MSP5 (X2(DF=1) = 8.29/p = 0.0069) were more prevalent in asymptomatic individuals whereas the opposite was observed for MSP1 block 2-MAD20 (X2(DF=1) = 6.41/p = 0.0206, Fisher's exact test). Plasmas from asymptomatic individuals reacted more intensely against MSP4 (U = 210.5, p < 0.03), MSP5 (U = 212, p < 0.004), MSP9 (U = 189.5, p < 0.002) and EBA175 (U = 197, p < 0.014, Mann-Whitney's U test). IgG1 and IgG3 were predominant for all antigens, but some patients also presented with IgG2 and IgG4. The recognition of MSP5 (OR = 0.112, IC95% = 0.021-0.585) and MSP9 (OR = 0.125, IC95% = 0.030-0.529, cross tab analysis) predicted 8.9 and 8 times less chances, respectively, to present symptoms. Higher antibody levels against MSP5 and EBA175 were associated by odds ratios of 9.4 (IC95% = 1.29-69.25) and 5.7 (IC95% = 1.12-29.62, logistic regression), respectively, with an asymptomatic status. CONCLUSIONS Merozoite antigens were targets of cytophilic antibodies and antibodies against MSP5, MSP9 and EBA175 were independently associated with decreased symptoms.
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Affiliation(s)
| | | | | | | | | | - Gerhard Wunderlich
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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31
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Sheehy SH, Spencer AJ, Douglas AD, Sim BKL, Longley RJ, Edwards NJ, Poulton ID, Kimani D, Williams AR, Anagnostou NA, Roberts R, Kerridge S, Voysey M, James ER, Billingsley PF, Gunasekera A, Lawrie AM, Hoffman SL, Hill AVS. Optimising Controlled Human Malaria Infection Studies Using Cryopreserved P. falciparum Parasites Administered by Needle and Syringe. PLoS One 2013; 8:e65960. [PMID: 23823332 PMCID: PMC3688861 DOI: 10.1371/journal.pone.0065960] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 04/29/2013] [Indexed: 11/18/2022] Open
Abstract
Background Controlled human malaria infection (CHMI) studies have become a routine tool to evaluate efficacy of candidate anti-malarial drugs and vaccines. To date, CHMI trials have mostly been conducted using the bite of infected mosquitoes, restricting the number of trial sites that can perform CHMI studies. Aseptic, cryopreserved P. falciparum sporozoites (PfSPZ Challenge) provide a potentially more accurate, reproducible and practical alternative, allowing a known number of sporozoites to be administered simply by injection. Methodology We sought to assess the infectivity of PfSPZ Challenge administered in different dosing regimens to malaria-naive healthy adults (n = 18). Six participants received 2,500 sporozoites intradermally (ID), six received 2,500 sporozoites intramuscularly (IM) and six received 25,000 sporozoites IM. Findings Five out of six participants receiving 2,500 sporozoites ID, 3/6 participants receiving 2,500 sporozoites IM and 6/6 participants receiving 25,000 sporozoites IM were successfully infected. The median time to diagnosis was 13.2, 17.8 and 12.7 days for 2,500 sporozoites ID, 2,500 sporozoites IM and 25,000 sporozoites IM respectively (Kaplan Meier method; p = 0.024 log rank test). Conclusions 2,500 sporozoites ID and 25,000 sporozoites IM have similar infectivities. Given the dose response in infectivity seen with IM administration, further work should evaluate increasing doses of PfSPZ Challenge IM to identify a dosing regimen that reliably infects 100% of participants. Trial Registration ClinicalTrials.gov NCT01465048
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Affiliation(s)
- Susanne H. Sheehy
- Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
- The Jenner Institute Laboratories, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | | | | | - B. Kim Lee Sim
- Sanaria Inc., Rockville, Maryland, United States of America
| | - Rhea J. Longley
- The Jenner Institute Laboratories, University of Oxford, Oxford, United Kingdom
| | - Nick J. Edwards
- The Jenner Institute Laboratories, University of Oxford, Oxford, United Kingdom
| | - Ian D. Poulton
- Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | - Domtila Kimani
- Centre for Geographical Medical Research (Coast), Kenya Medical Research Institute, Kilifi, Kenya
| | - Andrew R. Williams
- The Jenner Institute Laboratories, University of Oxford, Oxford, United Kingdom
| | - Nicholas A. Anagnostou
- Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | - Rachel Roberts
- Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon Kerridge
- Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | - Merryn Voysey
- Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom
| | - Eric R. James
- Sanaria Inc., Rockville, Maryland, United States of America
| | | | | | - Alison M. Lawrie
- Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Adrian V. S. Hill
- The Jenner Institute Laboratories, University of Oxford, Oxford, United Kingdom
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Sedegah M, Kim Y, Ganeshan H, Huang J, Belmonte M, Abot E, Banania JG, Farooq F, McGrath S, Peters B, Sette A, Soisson L, Diggs C, Doolan DL, Tamminga C, Villasante E, Hollingdale MR, Richie TL. Identification of minimal human MHC-restricted CD8+ T-cell epitopes within the Plasmodium falciparum circumsporozoite protein (CSP). Malar J 2013; 12:185. [PMID: 23738590 PMCID: PMC3683343 DOI: 10.1186/1475-2875-12-185] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 05/23/2013] [Indexed: 01/14/2023] Open
Abstract
Background Plasmodium falciparum circumsporozoite protein (CSP) is a leading malaria vaccine candidate antigen, known to elicit protective antibody responses in humans (RTS,S vaccine). Recently, a DNA prime / adenovirus (Ad) vector boost vaccine encoding CSP and a second P. falciparum antigen, apical membrane antigen-1, also elicited sterile protection, but in this case associated with interferon gamma ELISpot and CD8+ T cell but not antibody responses. The finding that CSP delivered by an appropriate vaccine platform likely elicits protective cell-mediated immunity provided a rationale for identifying class I-restricted epitopes within this leading vaccine candidate antigen. Methods Limited samples of peripheral blood mononuclear cells from clinical trials of the Ad vaccine were used to identify CD8+ T cell epitopes within pools of overlapping 15mer peptides spanning portions of CSP that stimulated recall responses. Computerized algorithms (NetMHC) predicted 17 minimal class I-restricted 9-10mer epitopes within fifteen 15mers positive in ELISpot assay using PBMC from 10 HLA-matched study subjects. Four additional epitopes were subsequently predicted using NetMHC, matched to other study subjects without initial 15mer ELISpot screening. Nine of the putative epitopes were synthesized and tested by ELISpot assay, and six of these nine were further tested for CD8+ T cell responses by ELISpot CD4+ and CD8+ T cell-depletion and flow cytometry assays for evidence of CD8+ T cell dependence. Results Each of the nine putative epitopes, all sequence-conserved, recalled responses from HLA-matched CSP-immunized research subjects. Four shorter sequences contained within these sequences were identified using NetMHC predictions and may have contributed to recall responses. Five (9-10mer) epitopes were confirmed to be targets of CD8+ T cell responses using ELISpot depletion and ICS assays. Two 9mers among these nine epitopes were each restricted by two HLA supertypes (A01/B07; A01A24/A24) and one 9mer was restricted by three HLA supertypes (A01A24/A24/B27) indicating that some CSP class I-restricted epitopes, like DR epitopes, may be HLA-promiscuous. Conclusions This study identified nine and confirmed five novel class I epitopes restricted by six HLA supertypes, suggesting that an adenovirus-vectored CSP vaccine would be immunogenic and potentially protective in genetically diverse populations.
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Affiliation(s)
- Martha Sedegah
- US Military Malaria Vaccine Program, Naval Medical Research Center, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
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Howland SW, Poh CM, Gun SY, Claser C, Malleret B, Shastri N, Ginhoux F, Grotenbreg GM, Rénia L. Brain microvessel cross-presentation is a hallmark of experimental cerebral malaria. EMBO Mol Med 2013; 5:984-99. [PMID: 23681698 PMCID: PMC3721469 DOI: 10.1002/emmm.201202273] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 01/02/2023] Open
Abstract
Cerebral malaria is a devastating complication of Plasmodium falciparum infection. Its pathogenesis is complex, involving both parasite- and immune-mediated events. CD8+ T cells play an effector role in murine experimental cerebral malaria (ECM) induced by Plasmodium berghei ANKA (PbA) infection. We have identified a highly immunogenic CD8 epitope in glideosome-associated protein 50 that is conserved across rodent malaria species. Epitope-specific CD8+ T cells are induced during PbA infection, migrating to the brain just before neurological signs manifest. They are functional, cytotoxic and can damage the blood–brain barrier in vivo. Such CD8+ T cells are also found in the brain during infection with parasite strains/species that do not induce neuropathology. We demonstrate here that PbA infection causes brain microvessels to cross-present parasite antigen, while non-ECM-causing parasites do not. Further, treatment with fast-acting anti-malarial drugs before the onset of ECM reduces parasite load and thus antigen presentation in the brain, preventing ECM death. Thus our data suggest that combined therapies targeting both the parasite and host antigen-presenting cells may improve the outcome of CM patients.
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Affiliation(s)
- Shanshan W Howland
- Singapore Immunology Network, Agency for Science, Technology and Research A*STAR, Singapore, Singapore
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Ndungu FM, Mwacharo J, Kimani D, Kai O, Moris P, Jongert E, Vekemans J, Olotu A, Bejon P. A statistical interaction between circumsporozoite protein-specific T cell and antibody responses and risk of clinical malaria episodes following vaccination with RTS,S/AS01E. PLoS One 2012; 7:e52870. [PMID: 23300801 PMCID: PMC3531328 DOI: 10.1371/journal.pone.0052870] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/21/2012] [Indexed: 11/19/2022] Open
Abstract
The candidate malaria vaccine RTS,S/AS01E provides significant but partial protection from clinical malaria. On in vitro circumsporozoite protein (CSP) peptide stimulation and intra-cellular cytokine staining of whole blood taken from 407 5–17 month-old children in a phase IIb trial of RTS,S/AS01E, we identified significantly increased frequencies of two CSP-specific CD4+ T cells phenotypes among RTS,S/AS01E vaccinees (IFNγ-IL2+TNF− and IFNγ-IL2+TNF+ CD4+ T cells), and increased frequency of IFNγ-IL2-TNF+ CD4+ T cells after natural exposure. All these T cells phenotypes were individually associated with reductions in the risk of clinical malaria, but IFNγ-IL2-TNF+ CD4+ T cells independently predicted reduced risk of clinical malaria on multi-variable analysis (HR = 0.29, 95% confidence intervals 0.15–0.54, p<0.0005). Furthermore, there was a strongly significant synergistic interaction between CSP-specific IFNγ-IL2-TNF+ CD4+ T cells and anti-CSP antibodies in determining protection against clinical malaria (p = 0.002). Vaccination strategies that combine potent cellular and antibody responses may enhance protection against malaria.
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Affiliation(s)
- Francis M Ndungu
- Kenya Medical Research Institute, Centre for Geographical Medical Research-Coast, Kilifi, Kenya.
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Ajua A, Engleitner T, Esen M, Theisen M, Issifou S, Mordmüller B. A flow cytometry-based workflow for detection and quantification of anti-plasmodial antibodies in vaccinated and naturally exposed individuals. Malar J 2012; 11:367. [PMID: 23130649 PMCID: PMC3545855 DOI: 10.1186/1475-2875-11-367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/30/2012] [Indexed: 11/14/2022] Open
Abstract
Background Antibodies play a central role in naturally acquired immunity against Plasmodium falciparum. Current assays to detect anti-plasmodial antibodies against native antigens within their cellular context are prone to bias and cannot be automated, although they provide important information about natural exposure and vaccine immunogenicity. A novel, cytometry-based workflow for quantitative detection of anti-plasmodial antibodies in human serum is presented. Methods Fixed red blood cells (RBCs), infected with late stages of P. falciparum were utilized to detect malaria-specific antibodies by flow cytometry with subsequent automated data analysis. Available methods for data-driven analysis of cytometry data were assessed and a new overlap subtraction algorithm (OSA) based on open source software was developed. The complete workflow was evaluated using sera from two GMZ2 malaria vaccine trials in semi-immune adults and pre-school children residing in a malaria endemic area. Results Fixation, permeabilization, and staining of infected RBCs were adapted for best operation in flow cytometry. As asexual blood-stage vaccine candidates are designed to induce antibody patterns similar to those in semi-immune adults, serial dilutions of sera from heavily exposed individuals were compared to naïve controls to determine optimal antibody dilutions. To eliminate investigator effects introduced by manual gating, a non-biased algorithm (OSA) for data-driven gating was developed. OSA-derived results correlated well with those obtained by manual gating (r between 0.79 and 0.99) and outperformed other model-driven gating methods. Bland-Altman plots confirmed the agreement of manual gating and OSA-derived results. A 1.33-fold increase (p=0.003) in the number of positive cells after vaccination in a subgroup of pre-school children vaccinated with 100 μg GMZ2 was present and in vaccinated adults from the same region we measured a baseline-corrected 1.23-fold, vaccine-induced increase in mean fluorescence intensity of positive cells (p=0.03). Conclusions The current workflow advances detection and quantification of anti-plasmodial antibodies through improvement of a bias-prone, low-throughput to an unbiased, semi-automated, scalable method. In conclusion, this work presents a novel method for immunofluorescence assays in malaria research.
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Affiliation(s)
- Anthony Ajua
- Institute of Tropical Medicine, University of Tübingen, Wilhelmstraße 27, Tübingen D-72074, Germany
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Richie TL, Charoenvit Y, Wang R, Epstein JE, Hedstrom RC, Kumar S, Luke TC, Freilich DA, Aguiar JC, Sacci JB, Sedegah M, Nosek RA, De La Vega P, Berzins MP, Majam VF, Abot EN, Ganeshan H, Richie NO, Banania JG, Baraceros MFB, Geter TG, Mere R, Bebris L, Limbach K, Hickey BW, Lanar DE, Ng J, Shi M, Hobart PM, Norman JA, Soisson LA, Hollingdale MR, Rogers WO, Doolan DL, Hoffman SL. Clinical trial in healthy malaria-naïve adults to evaluate the safety, tolerability, immunogenicity and efficacy of MuStDO5, a five-gene, sporozoite/hepatic stage Plasmodium falciparum DNA vaccine combined with escalating dose human GM-CSF DNA. Hum Vaccin Immunother 2012; 8:1564-84. [PMID: 23151451 PMCID: PMC3601132 DOI: 10.4161/hv.22129] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
When introduced in the 1990s, immunization with DNA plasmids was considered potentially revolutionary for vaccine development, particularly for vaccines intended to induce protective CD8 T cell responses against multiple antigens. We conducted, in 1997−1998, the first clinical trial in healthy humans of a DNA vaccine, a single plasmid encoding Plasmodium falciparum circumsporozoite protein (PfCSP), as an initial step toward developing a multi-antigen malaria vaccine targeting the liver stages of the parasite. As the next step, we conducted in 2000–2001 a clinical trial of a five-plasmid mixture called MuStDO5 encoding pre-erythrocytic antigens PfCSP, PfSSP2/TRAP, PfEXP1, PfLSA1 and PfLSA3. Thirty-two, malaria-naïve, adult volunteers were enrolled sequentially into four cohorts receiving a mixture of 500 μg of each plasmid plus escalating doses (0, 20, 100 or 500 μg) of a sixth plasmid encoding human granulocyte macrophage-colony stimulating factor (hGM-CSF). Three doses of each formulation were administered intramuscularly by needle-less jet injection at 0, 4 and 8 weeks, and each cohort had controlled human malaria infection administered by five mosquito bites 18 d later. The vaccine was safe and well-tolerated, inducing moderate antigen-specific, MHC-restricted T cell interferon-γ responses but no antibodies. Although no volunteers were protected, T cell responses were boosted post malaria challenge. This trial demonstrated the MuStDO5 DNA and hGM-CSF plasmids to be safe and modestly immunogenic for T cell responses. It also laid the foundation for priming with DNA plasmids and boosting with recombinant viruses, an approach known for nearly 15 y to enhance the immunogenicity and protective efficacy of DNA vaccines.
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Freimanis G, Sedegah M, Owusu-Ofori S, Kumar S, Allain JP. Investigating the prevalence of transfusion transmission ofPlasmodiumwithin a hyperendemic blood donation system. Transfusion 2012; 53:1429-41. [DOI: 10.1111/j.1537-2995.2012.03943.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 07/25/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
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