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Silva NDSB, Souza ADS, Andrade HDS, Pereira RN, Castro CFB, Vince N, Limou S, Naslavsky MS, Zatz M, Duarte YADO, Mendes-Junior CT, Castelli EDC. Immunogenetics of HLA-B: SNP, allele, and haplotype diversity in populations from different continents and ancestry backgrounds. HLA 2023; 101:634-646. [PMID: 37005006 DOI: 10.1111/tan.15043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 04/04/2023]
Abstract
HLA-B is among the most variable gene in the human genome. This gene encodes a key molecule for antigen presentation to CD8+ T lymphocytes and NK cell modulation. Despite the myriad of studies evaluating its coding region (with an emphasis on exons 2 and 3), few studies evaluated introns and regulatory sequences in real population samples. Thus, HLA-B variability is probably underestimated. We applied a bioinformatics pipeline tailored for HLA genes on 5347 samples from 80 different populations, which includes more than 1000 admixed Brazilians, to evaluate the HLA-B variability (SNPs, indels, MNPs, alleles, and haplotypes) in exons, introns, and regulatory regions. We observed 610 variable sites throughout HLA-B; the most frequent variants are shared worldwide. However, the haplotype distribution is geographically structured. We detected 920 full-length haplotypes (exons, introns, and untranslated regions) encoding 239 different protein sequences. HLA-B gene diversity is higher in admixed populations and Europeans while lower in African ancestry individuals. Each HLA-B allele group is associated with specific promoter sequences. This HLA-B variation resource may improve HLA imputation accuracy and disease-association studies and provide evolutionary insights regarding HLA-B genetic diversity in human populations.
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Affiliation(s)
- Nayane Dos Santos Brito Silva
- Molecular Genetics and Bioinformatics Laboratory, School of Medicine, São Paulo State University - Unesp, Botucatu, São Paulo, Brazil
- INSERM, Ecole Centrale Nantes, Center for Research in Transplantation and Translational Immunology, Nantes Université, UMR 1064, F-44000, Nantes, France
| | - Andreia da Silva Souza
- Molecular Genetics and Bioinformatics Laboratory, School of Medicine, São Paulo State University - Unesp, Botucatu, São Paulo, Brazil
| | - Heloisa de Souza Andrade
- Department of Genetics and Evolutionary Biology, Biosciences Institute, University of São Paulo (USP), São Paulo, São Paulo, Brazil
| | - Raphaela Neto Pereira
- Molecular Genetics and Bioinformatics Laboratory, School of Medicine, São Paulo State University - Unesp, Botucatu, São Paulo, Brazil
| | - Camila Ferreira Bannwart Castro
- Molecular Genetics and Bioinformatics Laboratory, School of Medicine, São Paulo State University - Unesp, Botucatu, São Paulo, Brazil
- UniFSP, Centro Universitário Sudoeste Paulista, Itapetininga, São Paulo, Brazil
| | - Nicolas Vince
- INSERM, Ecole Centrale Nantes, Center for Research in Transplantation and Translational Immunology, Nantes Université, UMR 1064, F-44000, Nantes, France
| | - Sophie Limou
- INSERM, Ecole Centrale Nantes, Center for Research in Transplantation and Translational Immunology, Nantes Université, UMR 1064, F-44000, Nantes, France
| | - Michel Satya Naslavsky
- Department of Genetics and Evolutionary Biology, Biosciences Institute, University of São Paulo (USP), São Paulo, São Paulo, Brazil
- Human Genome and Stem Cell Research Center, University of São Paulo, São Paulo, São Paulo, Brazil
- Hospital Israelita Albert Einstein, São Paulo, São Paulo, Brazil
| | - Mayana Zatz
- Department of Genetics and Evolutionary Biology, Biosciences Institute, University of São Paulo (USP), São Paulo, São Paulo, Brazil
- Human Genome and Stem Cell Research Center, University of São Paulo, São Paulo, São Paulo, Brazil
| | | | - Celso Teixeira Mendes-Junior
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Erick da Cruz Castelli
- Molecular Genetics and Bioinformatics Laboratory, School of Medicine, São Paulo State University - Unesp, Botucatu, São Paulo, Brazil
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Norin AJ, Mendoza R, Augenbraun M, Das B. HLA B53 is associated with a poor outcome in black COVID-19 patients. Hum Immunol 2021; 82:713-718. [PMID: 34303556 PMCID: PMC8266522 DOI: 10.1016/j.humimm.2021.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 06/16/2021] [Accepted: 07/06/2021] [Indexed: 01/06/2023]
Abstract
A disproportionate incidence of death has occurred in African Americans (Blacks) in the United States due to COVID-19. The reason for this disparity is likely to be multi-factorial and may involve genetic predisposition. The association of human leukocyte antigens (HLA) with severe COVID-19 was examined in a hospitalized population (89% Black, n = 36) and compared to HLA typed non-hospitalized individuals (20% Black, n = 40) who had recovered from mild disease. For additional comparison, HLA typing data was available from kidney transplant recipients and deceased donors. Hospitalized patients were followed for 45 days after admission to our medical center with death as the primary end-point. One HLA allele, B53, appeared to be more prevalent in the hospitalized COVID-19 patients (percent of positive subjects, 30.5) compared to national data in US Black populations (percent of positive subjects, 24.5). The percent B53 positive in non-hospitalized COVID-19 patients was 2.6, significantly less than the percent positive in the hospitalized COVID-19 patients (p = 0.001, Fisher’s exact test) and less than the 8 percent positive listed in national data bases for US Caucasian populations. Significantly greater deaths (73 percent) were observed in HLA B53 positive hospitalized COVID-19 patients compared to hospitalized COVID-19 patients who were B53 negative (40 percent). Multi-variate analysis indicated that HLA B53 positive Black hospitalized COVID-19 patients were at a 7.4 fold greater risk of death than Black COVID-19 patients who were B53 negative. Consideration for accelerated vaccination and treatment should be given to HLA B53 positive Black COVID19 patients.
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Affiliation(s)
- Allen J Norin
- Department of Medicine and Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, United States.
| | - Rachelle Mendoza
- Department of Pathology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, United States
| | - Michael Augenbraun
- Department of Medicine, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, United States
| | - Ballabh Das
- Department of Pathology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, United States
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3
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Digitale JC, Callaway PC, Martin M, Nelson G, Viard M, Rek J, Arinaitwe E, Dorsey G, Kamya M, Carrington M, Rodriguez-Barraquer I, Feeney ME. HLA Alleles B *53:01 and C *06:02 Are Associated With Higher Risk of P. falciparum Parasitemia in a Cohort in Uganda. Front Immunol 2021; 12:650028. [PMID: 33815410 PMCID: PMC8017319 DOI: 10.3389/fimmu.2021.650028] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/22/2021] [Indexed: 12/11/2022] Open
Abstract
Variation within the HLA locus been shown to play an important role in the susceptibility to and outcomes of numerous infections, but its influence on immunity to P. falciparum malaria is unclear. Increasing evidence indicates that acquired immunity to P. falciparum is mediated in part by the cellular immune response, including NK cells, CD4 and CD8 T cells, and semi-invariant γδ T cells. HLA molecules expressed by these lymphocytes influence the epitopes recognized by P. falciparum-specific T cells, and class I HLA molecules also serve as ligands for inhibitory receptors including KIR. Here we assessed the relationship of HLA class I and II alleles to the risk of P. falciparum infection and symptomatic malaria in a cohort of 892 Ugandan children and adults followed prospectively via both active and passive surveillance. We identified two HLA class I alleles, HLA-B*53:01 and HLA-C*06:02, that were associated with a higher prevalence of P. falciparum infection. Notably, no class I or II HLA alleles were found to be associated with protection from P. falciparum parasitemia or symptomatic malaria. These findings suggest that class I HLA plays a role in the ability to restrict parasitemia, supporting an essential role for the cellular immune response in P. falciparum immunity. Our findings underscore the need for better tools to enable mechanistic studies of the T cell response to P. falciparum at the epitope level and suggest that further study of the role of HLA in regulating pre-erythrocytic stages of the P. falciparum life cycle is warranted.
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Affiliation(s)
- Jean C. Digitale
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States
| | - Perri C. Callaway
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
- Infectious Disease and Immunity Graduate Group, University of California, Berkeley, Berkeley, CA, United States
| | - Maureen Martin
- Basic Science Program, Frederick National Laboratory for Cancer Research in the Laboratory of Integrative Cancer Immunology, National Cancer Institute, Bethesda, MD, United States
| | - George Nelson
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, MD, United States
| | - Mathias Viard
- Basic Science Program, Frederick National Laboratory for Cancer Research in the Laboratory of Integrative Cancer Immunology, National Cancer Institute, Bethesda, MD, United States
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, Kampala, Uganda
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Mary Carrington
- Basic Science Program, Frederick National Laboratory for Cancer Research in the Laboratory of Integrative Cancer Immunology, National Cancer Institute, Bethesda, MD, United States
- Ragon Institute of MGH MIT and Harvard, Cambridge, MA, United States
| | | | - Margaret E. Feeney
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, United States
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4
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Heide J, Wildner NH, Ackermann C, Wittner M, Marget M, Sette A, Sidney J, Jacobs T, Schulze Zur Wiesch J. Detection of EXP1-Specific CD4+ T Cell Responses Directed Against a Broad Range of Epitopes Including Two Promiscuous MHC Class II Binders During Acute Plasmodium falciparum Malaria. Front Immunol 2020; 10:3037. [PMID: 32038611 PMCID: PMC6993587 DOI: 10.3389/fimmu.2019.03037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/11/2019] [Indexed: 01/02/2023] Open
Abstract
Background: T cells are thought to play a major role in conferring immunity against malaria. This study aimed to comprehensively define the breadth and specificity of the Plasmodium falciparum (P. falciparum)-specific CD4+ T cell response directed against the exported protein 1 (EXP1) in a cohort of patients diagnosed with acute malaria. Methods: Peripheral blood mononuclear cells of 44 patients acutely infected with P. falciparum, and of one patient infected with P. vivax, were stimulated and cultured in vitro with an overlapping set of 31 P. falciparum-specific 13-17-mer peptides covering the entire EXP1 sequence. EXP1-specific T cell responses were analyzed by ELISPOT and intracellular cytokine staining for interferon-γ production after re-stimulation with individual peptides. For further characterization of the epitopes, in silico and in vitro human leukocyte antigen (HLA) binding studies and fine mapping assays were performed. Results: We detected one or more EXP1-specific CD4+ T cell responses (mean: 1.09, range 0–5) in 47% (21/45) of our patients. Responses were directed against 15 of the 31 EXP1 peptides. Peptides EXP1-P13 (aa60-74) and P15 (aa70-85) were detected by 18% (n = 8) and 27% (n = 12) of the 45 patients screened. The optimal length, as well as the corresponding most likely HLA-restriction, of each of these two peptides was assessed. Interestingly, we also identified one CD4+ T cell response against peptide EXP1-P15 in a patient who was infected with P. vivax but not falciparum. Conclusions: This first detailed characterization of novel EXP1-specific T cell epitopes provides important information for future analysis with major histocompatibility complex-multimer technology as well as for immunomonitoring and vaccine design.
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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
| | - Nils H Wildner
- Infectious Diseases Unit, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christin Ackermann
- Infectious Diseases Unit, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Melanie Wittner
- 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
| | - Matthias Marget
- Department of Transfusion Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States.,Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - John Sidney
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States
| | - Thomas Jacobs
- Protozoa Immunology, Bernhard-Nocht-Institute for 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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5
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Goh YS, McGuire D, Rénia L. Vaccination With Sporozoites: Models and Correlates of Protection. Front Immunol 2019; 10:1227. [PMID: 31231377 PMCID: PMC6560154 DOI: 10.3389/fimmu.2019.01227] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 05/14/2019] [Indexed: 12/14/2022] Open
Abstract
Despite continuous efforts, the century-old goal of eradicating malaria still remains. Multiple control interventions need to be in place simultaneously to achieve this goal. In addition to effective control measures, drug therapies and insecticides, vaccines are critical to reduce mortality and morbidity. Hence, there are numerous studies investigating various malaria vaccine candidates. Most of the malaria vaccine candidates are subunit vaccines. However, they have shown limited efficacy in Phase II and III studies. To date, only whole parasite formulations have been shown to induce sterile immunity in human. In this article, we review and discuss the recent developments in vaccination with sporozoites and the mechanisms of protection involved.
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Affiliation(s)
- Yun Shan Goh
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (ASTAR), Biopolis, Singapore, Singapore
| | - Daniel McGuire
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (ASTAR), Biopolis, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Laurent Rénia
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (ASTAR), Biopolis, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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6
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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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7
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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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8
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Malaria Parasite Proteins and Their Role in Alteration of the Structure and Function of Red Blood Cells. ADVANCES IN PARASITOLOGY 2015; 91:1-86. [PMID: 27015947 DOI: 10.1016/bs.apar.2015.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Malaria, caused by Plasmodium spp., continues to be a major threat to human health and a significant cause of socioeconomic hardship in many countries. Almost half of the world's population live in malaria-endemic regions and many of them suffer one or more, often life-threatening episodes of malaria every year, the symptoms of which are attributable to replication of the parasite within red blood cells (RBCs). In the case of Plasmodium falciparum, the species responsible for most malaria-related deaths, parasite replication within RBCs is accompanied by striking alterations to the morphological, biochemical and biophysical properties of the host cell that are essential for the parasites' survival. To achieve this, the parasite establishes a unique and extensive protein export network in the infected RBC, dedicating at least 6% of its genome to the process. Understanding the full gamut of proteins involved in this process and the mechanisms by which P. falciparum alters the structure and function of RBCs is important both for a more complete understanding of the pathogenesis of malaria and for development of new therapeutic strategies to prevent or treat this devastating disease. This review focuses on what is currently known about exported parasite proteins, their interactions with the RBC and their likely pathophysiological consequences.
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9
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Dalai SK, Yadav N, Patidar M, Patel H, Singh AP. Liver-Stage Specific Response among Endemic Populations: Diet and Immunity. Front Immunol 2015; 6:125. [PMID: 25852693 PMCID: PMC4367437 DOI: 10.3389/fimmu.2015.00125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/06/2015] [Indexed: 11/22/2022] Open
Abstract
Developing effective anti-malarial vaccine has been a challenge for long. Various factors including complex life cycle of parasite and lack of knowledge of stage specific critical antigens are some of the reasons. Moreover, inadequate understanding of the immune responses vis-à-vis sterile protection induced naturally by Plasmodia infection has further compounded the problem. It has been shown that people living in endemic areas take years to develop protective immunity to blood stage infection. But hardly anyone believes that immunity to liver-stage infection could be developed. Various experimental model studies using attenuated parasite suggest that liver-stage immunity might exist among endemic populations. This could be induced because of the attenuation of parasite in liver by various compounds present in the diet of endemic populations.
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Affiliation(s)
| | - Naveen Yadav
- Institute of Science, Nirma University , Ahmedabad , India
| | - Manoj Patidar
- Institute of Science, Nirma University , Ahmedabad , India
| | - Hardik Patel
- Institute of Science, Nirma University , Ahmedabad , India
| | - Agam Prasad Singh
- Infectious Diseases Laboratory, National Institute of Immunology , New Delhi , India
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10
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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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11
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Kim TS, Kim HH, Kim JY, Kong Y, Na BK, Lin K, Moon SU, Kim YJ, Kwon MH, Sohn Y, Kim H, Lee HW. Comparison of the antibody responses to Plasmodium vivax and Plasmodium falciparum antigens in residents of Mandalay, Myanmar. Malar J 2011; 10:228. [PMID: 21819610 PMCID: PMC3163629 DOI: 10.1186/1475-2875-10-228] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 08/06/2011] [Indexed: 11/18/2022] Open
Abstract
Background The aim of this study was to investigate the profile of antibodies against several antigens of Plasmodium vivax and Plasmodium falciparum in Mandalay, Myanmar. Methods Malaria parasites were identified by microscopic examination. To test the antibodies against P. vivax and P. falciparum in sera, an indirect immunofluorescence antibody test (IFAT) was performed using asexual blood parasite antigens. An enzyme-linked immunosorbent assay (ELISA) was performed with circumsporozoite protein (CSP), Pvs25 and Pvs28 recombinant proteins of transmission-blocking vaccine candidates for P. vivax, and liver stage specific antigen-1 and -3 (PfLSA-1, PfLSA-3) for P. falciparum. Results Fourteen patients among 112 were found to be infected with P. vivax and 26 with P. falciparum by thick smear examination. Twenty-three patients were found to be infected with P. vivax, 19 with P. falciparum and five with both by thin smear examination. Blood samples were divided into two groups: Group I consisted of patients who were positive for infection by microscopic examination, and Group II consisted of those who showed symptoms, but were negative in microscopic examination. In P. falciparum, IgG against the blood stage antigen in Group I (80.8%) was higher than in Group II (70.0%). In P. vivax, IgG against the blood stage antigen in Group I (53.8%) was higher than in Group II (41.7%). However, the positivity rate of the PvCSP VK210 subtype in Group II (40.0%) was higher than in Group I (23.1%). Similarly for the PvCSP VK247 subtype, Group II (21.7%) was higher than that for Group I (9.6%). A similar pattern was observed in the ELISA using Pvs25 and Pvs28: positive rates of Group II were higher than those for Group I. However, those differences were not shown significant in statistics. Conclusions The positive rates for blood stage antigens of P. falciparum were higher in Group I than in Group II, but the positive rates for antigens of other stages (PfLSA-1 and -3) showed opposite results. Similar to P. falciparum, the positive rate of pre-blood stage (CSP VK210 and 247 subtype) and post-blood stage (Pvs25 and 28) antigens of P. vivax were higher in Group II than in Group I. Therefore, sero-diagnosis is not helpful to discriminate between malaria patients and symptomatic individuals during the epidemic season in Myanmar.
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Affiliation(s)
- Tong-Soo Kim
- Department of Parasitology, College of Medicine, Inha University, Incheon405-751, Republic of Korea
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12
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Dodoo D, Hollingdale MR, Anum D, Koram KA, Gyan B, Akanmori BD, Ocran J, Adu-Amankwah S, Geneshan H, Abot E, Legano J, Banania G, Sayo R, Brambilla D, Kumar S, Doolan DL, Rogers WO, Epstein J, Richie TL, Sedegah M. Measuring naturally acquired immune responses to candidate malaria vaccine antigens in Ghanaian adults. Malar J 2011; 10:168. [PMID: 21689436 PMCID: PMC3132199 DOI: 10.1186/1475-2875-10-168] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 06/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To prepare field sites for malaria vaccine trials, it is important to determine baseline antibody and T cell responses to candidate malaria vaccine antigens. Assessing T cell responses is especially challenging, given genetic restriction, low responses observed in endemic areas, their variability over time, potential suppression by parasitaemia and the intrinsic variability of the assays. METHODS In Part A of this study, antibody titres were measured in adults from urban and rural communities in Ghana to recombinant Plasmodium falciparum CSP, SSP2/TRAP, LSA1, EXP1, MSP1, MSP3 and EBA175 by ELISA, and to sporozoites and infected erythrocytes by IFA. Positive ELISA responses were determined using two methods. T cell responses to defined CD8 or CD4 T cell epitopes from CSP, SSP2/TRAP, LSA1 and EXP1 were measured by ex vivo IFN-γ ELISpot assays using HLA-matched Class I- and DR-restricted synthetic peptides. In Part B, the reproducibility of the ELISpot assay to CSP and AMA1 was measured by repeating assays of individual samples using peptide pools and low, medium or high stringency criteria for defining positive responses, and by comparing samples collected two weeks apart. RESULTS In Part A, positive antibody responses varied widely from 17%-100%, according to the antigen and statistical method, with blood stage antigens showing more frequent and higher magnitude responses. ELISA titres were higher in rural subjects, while IFA titres and the frequencies and magnitudes of ex vivo ELISpot activities were similar in both communities. DR-restricted peptides showed stronger responses than Class I-restricted peptides. In Part B, the most stringent statistical criteria gave the fewest, and the least stringent the most positive responses, with reproducibility slightly higher using the least stringent method when assays were repeated. Results varied significantly between the two-week time-points for many participants. CONCLUSIONS All participants were positive for at least one malaria protein by ELISA, with results dependent on the criteria for positivity. Likewise, ELISpot responses varied among participants, but were relatively reproducible by the three methods tested, especially the least stringent, when assays were repeated. However, results often differed between samples taken two weeks apart, indicating significant biological variability over short intervals.
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Affiliation(s)
- Daniel Dodoo
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
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13
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Lyke KE, Fernández-Viňa MA, Cao K, Hollenbach J, Coulibaly D, Kone AK, Guindo A, Burdett LA, Hartzman RJ, Wahl AR, Hildebrand WH, Doumbo OK, Plowe CV, Sztein MB. Association of HLA alleles with Plasmodium falciparum severity in Malian children. ACTA ACUST UNITED AC 2011; 77:562-71. [PMID: 21447146 PMCID: PMC3152196 DOI: 10.1111/j.1399-0039.2011.01661.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pre-erythrocytic immunity to Plasmodium falciparum malaria is likely to be mediated by T-cell recognition of malaria epitopes presented on infected host cells via class I and II major histocompatibility complex (MHC) antigens. To test for associations of human leukocyte antigen (HLA) alleles with disease severity, we performed high-resolution typing of HLA class I and II loci and compared the distributions of alleles of HLA-A, -B, -C and -DRB1 loci in 359 Malian children of Dogon ethnicity with uncomplicated or severe malaria. We observed that alleles A*30:01 and A*33:01 had higher frequency in the group of patients with cerebral disease compared to patients with uncomplicated disease [A*30:01: gf = 0.2031 vs gf = 0.1064, odds ratio (OR) = 3.17, P = 0.004, confidence interval (CI) (1.94-5.19)] and [A*33:01: gf = 0.0781 vs gf = 0.0266, 4.21, P = 0.005, CI (1.89-9.84)], respectively. The A*30:01 and A*33:01 alleles share some sequence motifs and A*30:01 appears to have a unique peptide binding repertoire compared to other A*30 group alleles. Computer algorithms predicted malaria peptides with strong binding affinity for HLA-A*30:01 and HLA-A*33:01 but not to closely related alleles. In conclusion, we identified A*30:01 and A*33:01 as potential susceptibility factors for cerebral malaria, providing further evidence that polymorphism of MHC genes results in altered malaria susceptibility.
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Affiliation(s)
- K E Lyke
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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14
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Perlaza BL, Sauzet JP, Brahimi K, BenMohamed L, Druilhe P. Interferon-γ, a valuable surrogate marker of Plasmodium falciparum pre-erythrocytic stages protective immunity. Malar J 2011; 10:27. [PMID: 21303495 PMCID: PMC3046914 DOI: 10.1186/1475-2875-10-27] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 02/08/2011] [Indexed: 01/22/2023] Open
Abstract
Immunity against the pre-erythrocytic stages of malaria is the most promising, as it is strong and fully sterilizing. Yet, the underlying immune effectors against the human Plasmodium falciparum pre-erythrocytic stages remain surprisingly poorly known and have been little explored, which in turn prevents any rational vaccine progress. Evidence that has been gathered in vitro and in vivo, in higher primates and in humans, is reviewed here, emphasizing the significant role of IFN-γ, either as a critical immune mediator or at least as a valuable surrogate marker of protection. One may hope that these results will trigger investigations in volunteers immunized either by optimally irradiated or over-irradiated sporozoites, to quickly delineate better surrogates of protection, which are essential for the development of a successful malaria vaccine.
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Affiliation(s)
- Blanca-Liliana Perlaza
- Malaria Vaccine Development Laboratory, Pasteur Institute, 25-28 Rue du Dr, Roux, 75724 Paris, Cedex 15, France
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15
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Guilbride DL, Gawlinski P, Guilbride PDL. Why functional pre-erythrocytic and bloodstage malaria vaccines fail: a meta-analysis of fully protective immunizations and novel immunological model. PLoS One 2010; 5:e10685. [PMID: 20502667 PMCID: PMC2873430 DOI: 10.1371/journal.pone.0010685] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 04/16/2010] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Clinically protective malaria vaccines consistently fail to protect adults and children in endemic settings, and at best only partially protect infants. METHODOLOGY/PRINCIPAL FINDINGS We identify and evaluate 1916 immunization studies between 1965-February 2010, and exclude partially or nonprotective results to find 177 completely protective immunization experiments. Detailed reexamination reveals an unexpectedly mundane basis for selective vaccine failure: live malaria parasites in the skin inhibit vaccine function. We next show published molecular and cellular data support a testable, novel model where parasite-host interactions in the skin induce malaria-specific regulatory T cells, and subvert early antigen-specific immunity to parasite-specific immunotolerance. This ensures infection and tolerance to reinfection. Exposure to Plasmodium-infected mosquito bites therefore systematically triggers immunosuppression of endemic vaccine-elicited responses. The extensive vaccine trial data solidly substantiate this model experimentally. CONCLUSIONS/SIGNIFICANCE We conclude skinstage-initiated immunosuppression, unassociated with bloodstage parasites, systematically blocks vaccine function in the field. Our model exposes novel molecular and procedural strategies to significantly and quickly increase protective efficacy in both pipeline and currently ineffective malaria vaccines, and forces fundamental reassessment of central precepts determining vaccine development. This has major implications for accelerated local eliminations of malaria, and significantly increases potential for eradication.
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16
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Tsuji M. A retrospective evaluation of the role of T cells in the development of malaria vaccine. Exp Parasitol 2009; 126:421-5. [PMID: 19944099 DOI: 10.1016/j.exppara.2009.11.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 11/18/2009] [Accepted: 11/22/2009] [Indexed: 10/20/2022]
Abstract
Due to the fact that the life cycle of malaria parasites is complex, undergoing both an extracellular and intracellular phases in its host, the human immune system has to mobilize both the humoral and cellular arms of immune responses to fight against this parasitic infection. Whereas humoral immunity is directed toward the extracellular stages which include sporozoites and merozoites, cell-mediated immunity (CMI), in which T cells play a major role, targets hepatic stages - liver stages - of the parasites. In this review, the role of T cells in protective immunity against liver stages of the malaria infection is being re-evaluated. Furthermore, this review intends to address how to translate the findings regarding the role of T cells obtained in experimental systems to actual development of malaria vaccine for humans.
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Affiliation(s)
- Moriya Tsuji
- HIV and Malaria Vaccine Program, Aaron Diamond AIDS Research Center, New York, NY 10016, USA.
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17
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Prieur E, Druilhe P. The malaria candidate vaccine liver stage antigen-3 is highly conserved in Plasmodium falciparum isolates from diverse geographical areas. Malar J 2009; 8:247. [PMID: 19874576 PMCID: PMC2774867 DOI: 10.1186/1475-2875-8-247] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 10/29/2009] [Indexed: 01/13/2023] Open
Abstract
Background A high level of genetic stability has been formerly identified in segments of the gene coding for the liver stage antigen-3 (LSA-3), a subunit vaccine candidate against Plasmodium falciparum. The exploration of lsa-3 polymorphisms was extended to the whole sequence of this large antigen in 20 clinical isolates from four geographical areas; Senegal, Comoro islands, Brazil and Thailand. Methods The whole 4680 bp genomic sequence of lsa-3 was amplified by polymerase chain reaction and sequenced. The clinical isolate sequences were aligned on the sequence of the laboratory reference P. falciparum strain 3D7. Results The non-repeated sequence of lsa-3 was very well conserved with only a few allelic variations scattered along the sequence. Interestingly, a formerly identified immunodominant region, employed for the majority of pre-clinical vaccine development, was totally conserved at the genetic level. The most significant variations observed were in the number and organization of tetrapeptide repeated units, but not in their composition, resulting in different lengths of these repeated regions. The shorter repeated regions were from Brazilian origin. A correlation between the geographical distribution of the parasites with single nucleotide polymorphisms was not detected. Conclusion The lack of correlation between allelic polymorphisms with a specific transmission pressure suggests that LSA-3 is a structurally constrained molecule. The unusual characteristics of the lsa-3 gene make the molecule an interesting candidate for a subunit vaccine against malaria.
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Affiliation(s)
- Eric Prieur
- Biochemical Parasitology Unit, Institut Pasteur, Paris, France.
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18
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Nguyen TV, Sacci JB, de la Vega P, John CC, James AA, Kang AS. Characterization of immunoglobulin G antibodies to Plasmodium falciparum sporozoite surface antigen MB2 in malaria exposed individuals. Malar J 2009; 8:235. [PMID: 19852802 PMCID: PMC2772840 DOI: 10.1186/1475-2875-8-235] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 10/23/2009] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND MB2 protein is a sporozoite surface antigen on the human malaria parasite Plasmodium falciparum. MB2 was identified by screening a P. falciparum sporozoite cDNA expression library using immune sera from a protected donor immunized via the bites of P. falciparum-infected irradiated mosquitoes. It is not known whether natural exposure to P. falciparum also induces the anti-MB2 response and if this response differs from that in protected individuals immunized via the bites of P. falciparum infected irradiated mosquitoes. The anti-MB2 antibody response may be part of a robust protective response against the sporozoite. METHODS Fragments of polypeptide regions of MB2 were constructed as recombinant fusions sandwiched between glutathione S-transferase and a hexa histidine tag for bacterial expression. The hexa histidine tag affinity purified proteins were used to immunize rabbits and the polyclonal sera evaluated in an in vitro inhibition of sporozoite invasion assay. The proteins were also used in immunoblots with sera from a limited number of donors immunized via the bites of P. falciparum infected irradiated mosquitoes and plasma and serum obtained from naturally exposed individuals in Kenya. RESULTS Rabbit polyclonal antibodies targeting the non-repeat region of the basic domain of MB2 inhibited sporozoites entry into HepG2-A16 cells in vitro. Analysis of serum from five human volunteers that were immunized via the bites of P. falciparum infected irradiated mosquitoes that developed immunity and were completely protected against subsequent challenge with non-irradiated parasite also had detectable levels of antibody against MB2 basic domain. In contrast, in three volunteers not protected, anti-MB2 antibodies were below the level of detection. Sera from protected volunteers preferentially recognized a non-repeat region of the basic domain of MB2, whereas plasma from naturally-infected individuals also had antibodies that recognize regions of MB2 that contain a repeat motif in immunoblots. Sequence analysis of eleven field isolates and four laboratory strains showed that these antigenic regions of the basic domain of the MB2 gene are highly conserved in parasites obtained from different parts of the world. Moreover, anti-MB2 antibodies also were detected in the plasma of 83% of the individuals living in a malaria endemic area of Kenya (n = 41). CONCLUSION A preliminary analysis of the human humoral response against MB2 indicates that it may be an additional highly conserved target for immune intervention at the pre-erythrocytic stage of P. falciparum life cycle.
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Affiliation(s)
- Thanh V Nguyen
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
- NeoGenomics California, 6 Morgan, Suite 150, Irvine, CA 92618, USA
| | - John B Sacci
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Room 324 660 W Redwood Street, Baltimore, MD 21201, USA
| | - Patricia de la Vega
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Room 324 660 W Redwood Street, Baltimore, MD 21201, USA
- Department of Cell Mediated Immunity, Division of Malaria Vaccine Development, US Military Malaria Vaccine Program, Walter Reed Army Institute of Research, USA
| | - Chandy C John
- Global Pediatrics Program and Division of Pediatric Infectious Diseases, University of MN Medical School, 420 Delaware Street, SE, MMC #296, 850-Mayo, Minneapolis, MN 55455, USA
| | - Anthony A James
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697-3900, USA
| | - Angray S Kang
- The School of Life Sciences, Department of Molecular and Applied Biosciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK
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19
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Takala SL, Plowe CV. Genetic diversity and malaria vaccine design, testing and efficacy: preventing and overcoming 'vaccine resistant malaria'. Parasite Immunol 2009; 31:560-73. [PMID: 19691559 DOI: 10.1111/j.1365-3024.2009.01138.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of effective malaria vaccines may be hindered by extensive genetic diversity in the surface proteins being employed as vaccine antigens. Understanding of the extent and dynamics of genetic diversity in vaccine antigens is needed to guide rational vaccine design and to interpret the results of vaccine efficacy trials conducted in malaria endemic areas. Molecular epidemiological, population genetic, and structural approaches are being employed to try to identify immunologically relevant polymorphism in vaccine antigens. The results of these studies will inform choices of which alleles to include in multivalent or chimeric vaccines; however, additional molecular and immuno-epidemiological studies in a variety of geographic locations will be necessary for these approaches to succeed. Alternative means of overcoming antigenic diversity are also being explored, including boosting responses to critical conserved regions of current vaccine antigens, identifying new, more conserved and less immunodominant antigens, and developing whole-organism vaccines. Continued creative application and integration of tools from multiple disciplines, including epidemiology, immunology, molecular biology, and evolutionary genetics and genomics, will likely be required to develop broadly protective vaccines against Plasmodium and other antigenically complex pathogens.
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Affiliation(s)
- S L Takala
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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20
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Moyano EM, González LM, Arahuetes S, Benito A. Liver stage antigen 3 isolated from a cDNA library of Plasmodium falciparum erythrocytic stages. Parasitol Res 2007; 102:111-5. [PMID: 17828606 DOI: 10.1007/s00436-007-0737-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 08/21/2007] [Indexed: 11/25/2022]
Abstract
An expression library of P. falciparum erythrocyte stages (clon Dd2) was constructed and immunoscreened with a sera pool from malaria patients. Isolated clones were analysed, and the liver stage antigen 3 (LSA-3) antigen was identified. The partial nucleotide sequence of LSA-3 has 1,623 bp. The open reading frame coded for the putative protein with 541 amino acid residues. We have demonstrated by reverse transcriptase polymerase chain reaction the transcription of the LSA-3 gene in ring form, trophozoite, and schizont, stages of asexual erythrocyte cycle.
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Affiliation(s)
- Eva M Moyano
- Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III, Sinesio Delgado, 6, Pabellózn 13, 28020, Madrid, Spain
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21
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Garcia JE, Puentes A, Patarroyo ME. Developmental biology of sporozoite-host interactions in Plasmodium falciparum malaria: implications for vaccine design. Clin Microbiol Rev 2006; 19:686-707. [PMID: 17041140 PMCID: PMC1592691 DOI: 10.1128/cmr.00063-05] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum sporozoite infects different types of cells in a mosquito's salivary glands and human epithelial and Kuppfer cells and hepatocytes. These become differentiated later on, transforming themselves into the invasive red blood cell form, the merozoite. The ability of sporozoites to interact with different types of cells requires a wide variety of mechanisms allowing them to survive in both hosts: mobility, receptor-ligand interactions with different cellular receptors, and transformation and development into other invasive parasite forms, which are vitally important for parasite survival. Sporozoite complexity is reflected in the large quantity of proteins that can be expressed. Some of them have been extensively studied, such as CSP, TRAP, STARP, LSA-1, LSA-3, SALSA, SPECT1, SPECT2, MAEBL, and SPATR, due to their importance in infection and their potential use as vaccines. Our work has been focused on the search for the molecular mechanisms of parasite-host cellular receptor-ligand interactions by identifying amino acid sequences and the critical binding residues from these proteins relevant to parasite invasion. Once such sequences have been identified, it will be possible to modify them to induce a strong immune response against P. falciparum in the experimental Aotus monkey model. This all leads towards developing multistage, multicomponent, subunit-based vaccines that will be effective in eradicating or controlling malaria caused by P. falciparum.
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Affiliation(s)
- Javier E Garcia
- Fundacion Instituto de Immunología de Colombia, Carrera 50 #26-00, Bogotá, Colombia
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22
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Girard MP, Reed ZH, Friede M, Kieny MP. A review of human vaccine research and development: malaria. Vaccine 2006; 25:1567-80. [PMID: 17045367 DOI: 10.1016/j.vaccine.2006.09.074] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2006] [Accepted: 09/25/2006] [Indexed: 11/18/2022]
Abstract
The last several years have seen significant progress in the development of vaccines against malaria. Most recently, proof-of-concept of vaccine-induced protection from malaria infection and disease was demonstrated in African children. Pursued by various groups and on many fronts, several other candidate vaccines are in early clinical trials. Yet, despite the optimism and promise, an effective malaria vaccine is not yet available, in part because of the lack of understanding of the types of immune responses needed for protection, added to the difficulty of identifying, selecting and producing the appropriate protective antigens from a parasite with a genome of well over five thousand genes and to the frequent need to enhance the immunogenicity of purified antigens through the use of novel adjuvants or delivery systems. Insufficient clinical trial capacity and normative research functions such as local ethical committee reviews also contribute to slow down the development process. This article attempts to summarize the state of the art of malaria vaccine development.
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Affiliation(s)
- Marc P Girard
- University Paris 7, 39 rue Seignemartin, FR-69008 Lyon, France.
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23
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Lee HW, Moon SU, Ryu HS, Kim YJ, Cho SH, Chung GT, Lin K, Na BK, Kong Y, Chung KS, Kim TS. Usefulness of the recombinant liver stage antigen-3 for an early serodiagnosis of Plasmodium falciparum infection. THE KOREAN JOURNAL OF PARASITOLOGY 2006; 44:49-54. [PMID: 16514282 PMCID: PMC2532649 DOI: 10.3347/kjp.2006.44.1.49] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In order to develop tools for an early serodiagnosis of Plasmodium falciparum infection, we evaluated the usefulness of P. falciparum liver stage antigen-3 (LSA-3) as a serodiagnostic antigen. A portion of LSA-3 gene was cloned, and its recombinant protein (rLSA-3) was expressed in Escherichia coli and purified by column chromatography. The purified rLSA-3 and 120 test blood/serum samples collected from inhabitants in malaria-endemic areas of Mandalay, Myanmar were used for this study. In microscopic examinations of blood samples, P. falciparum positive rate was 39.1% (47/120) in thin smear trials, and 33.3% (40/120) in thick smear trials. Although the positive rate associated with the rLSA-3 (30.8%) was lower than that of the blood stage antigens (70.8%), rLSA-3 based enzyme-linked immunosorbent assay could detect 12 seropositive cases (10.0%), in which blood stage antigens were not detected. These results indicate that the LSA-3 is a useful antigen for an early serodiagnosis of P. falciparum infection.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Protozoan/biosynthesis
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Base Sequence
- Cloning, Molecular/methods
- DNA Primers/chemistry
- DNA, Protozoan/chemistry
- Early Diagnosis
- Enzyme-Linked Immunosorbent Assay/methods
- Escherichia coli/genetics
- Fluorescent Antibody Technique, Direct/methods
- Genes, Protozoan/genetics
- Genes, Protozoan/immunology
- Humans
- Malaria, Falciparum/blood
- Malaria, Falciparum/diagnosis
- Molecular Sequence Data
- Plasmodium falciparum/immunology
- Plasmodium vivax/isolation & purification
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
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Affiliation(s)
- Hyeong-Woo Lee
- Division of Tropical and Endemic Parasitic Diseases, National Institute of Health, Korea Center for Disease Control and Prevention, Seoul
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24
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Hafalla JCR, Cockburn IA, Zavala F. Protective and pathogenic roles of CD8+ T cells during malaria infection. Parasite Immunol 2006; 28:15-24. [PMID: 16438672 DOI: 10.1111/j.1365-3024.2006.00777.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
CD8+ T cells play a key role in protection against pre-erythrocytic stages of malaria infection. Many vaccine strategies are based on the idea of inducing a strong infection-blocking CD8+ T cell response. Here, we summarize what is known about the development, specificity and protective effect of malaria-specific CD8+ T cells and report on recent developments in the field. Although work in mouse models continues to make progress in our understanding of the basic biology of these cells, many questions remain to be answered - particularly on the roles of these cells in human infections. Increasing evidence is also emerging of a harmful role for CD8+ T cells in the pathology of cerebral malaria in rodent systems. Once again, the relevance of these results to human disease is one of the primary questions facing workers in this field.
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Affiliation(s)
- J C R Hafalla
- Department of Medical Parasitology, New York University School of Medicine, New York, NY, USA
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25
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Abstract
Multiple injections of gamma-radiation-attenuated Plasmodium sporozoites (gamma-spz) can induce long-lived, sterile immunity against pre-erythrocytic stages of malaria. Malaria antigen (Ag)-specific CD8 T cells that produce IFN-gamma are key effector cells in this model of protection. Although there have been numerous reports dealing with gamma-spz-induced CD8 T cells in the spleen, CD8 T cells most likely confer protection by targeting infected hepatocytes. Consequently, in this chapter we discuss observations and hypotheses concerning CD8 T cell responses that occur in the liver after an encounter with the Plasmodium parasite. Protracted protection against pre-erythrocytic stages requires memory CD8 T cells and we discuss evidence that gamma-spz-induced immunity is indeed accompanied by the presence of intrahepatic CD44hi CD45RBlo CD62lo CD122lo effector memory (EM) CD8 T cells and CD44hi CD45RBhi CD621hi CD122hi central memory (CM) CD8 T cells. In addition, the EM CD8 T cells rapidly release IFN-gamma in response to spz challenge. The possible role of Kupffer cells in the processing of spz Ags and the production of cytokines is also considered. Finally, we discuss evidence that is consistent with a model whereby intrahepatic CM CD8 T cells are maintained by IL-15 mediated-homeostatic proliferation while the EM CD8 T cells are conscripted from the CM pool in response to a persisting depot of liver-stage Ag.
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Affiliation(s)
- U Krzych
- Department of Immunology, Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
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Lyke KE, Burges RB, Cissoko Y, Sangare L, Kone A, Dao M, Diarra I, Fernández-Vina MA, Plowe CV, Doumbo OK, Sztein MB. HLA-A2 supertype-restricted cell-mediated immunity by peripheral blood mononuclear cells derived from Malian children with severe or uncomplicated Plasmodium falciparum malaria and healthy controls. Infect Immun 2005; 73:5799-808. [PMID: 16113298 PMCID: PMC1231120 DOI: 10.1128/iai.73.9.5799-5808.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Understanding HLA-restricted adaptive host immunity to defined epitopes of malarial antigens may be required for the development of successful malaria vaccines. Fourteen epitopes of preerythrocytic malarial antigens known to mediate cytotoxic T-lymphocyte responses against target cells expressing HLA-A2-restricted epitopes were synthesized and pooled based on antigen: thrombospondin-related anonymous protein (TRAP), circumsporozoite protein (CSP), and export protein 1 (Exp-1) peptides. HLA-A2 supertype (*0201, *0202, *0205, *6802) peripheral blood mononuclear cells collected from 774 Malian children, aged 3 months to 14 years, with severe Plasmodium falciparum malaria matched to uncomplicated malaria or healthy controls were stimulated with the HLA-A2-restricted peptide pools. Significant gamma interferon production, determined by enzyme-linked immunospot assay to at least one of the three peptide pools, was observed in 24/58 (41%) of the severe malaria cases, 24/57 (42%) of the uncomplicated malaria cases, and 34/51 (67%) of the healthy controls. Significant lymphoproliferation to these peptides was observed in 12/44 (27%) of the severe malaria cases, 13/55 (24%) of the uncomplicated malaria cases, and 18/50 (36%) of the healthy controls. Responses to individual peptide pools were limited. These studies confirm the presence of adaptive cell-mediated immunity to preerythrocytic malaria antigens in volunteers from Mali and demonstrate that suballeles of the HLA-A2 supertype can effectively present antigenic epitopes. However, whether these immune responses to TRAP, CSP, and Exp-1 malarial proteins play a substantial role in protection remains a matter of controversy.
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Affiliation(s)
- Kirsten E Lyke
- The University of Maryland at Baltimore, Center for Vaccine Development, 685 W. Baltimore St., HSF 480, Baltimore, MD 21201, USA
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Wang R, Richie TL, Baraceros MF, Rahardjo N, Gay T, Banania JG, Charoenvit Y, Epstein JE, Luke T, Freilich DA, Norman J, Hoffman SL. Boosting of DNA vaccine-elicited gamma interferon responses in humans by exposure to malaria parasites. Infect Immun 2005; 73:2863-72. [PMID: 15845492 PMCID: PMC1087336 DOI: 10.1128/iai.73.5.2863-2872.2005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A mixture of DNA plasmids expressing five Plasmodium falciparum pre-erythrocyte-stage antigens was administered with or without a DNA plasmid encoding human granulocyte-macrophage colony-stimulating factor (hGM-CSF) as an immune enhancer. After DNA immunization, antigen-specific gamma interferon (IFN-gamma) responses were detected by ELISPOT in 15/31 volunteers to multiple class I- and/or class II-restricted T-cell epitopes derived from all five antigens. Responses to multiple epitopes (</=7) were detected simultaneously in some volunteers. By 4 weeks after challenge with P. falciparum parasites, 23/31 volunteers had positive IFN-gamma responses and the magnitude of responses was increased from 2- to 143-fold. Nonetheless, none was protected against malaria. Volunteers who received hGM-CSF had a reduced frequency of IFN-gamma responses to class I peptides compared to those who only received plasmids expressing P. falciparum proteins before challenge (3/23 versus 3/8; P = 0.15) or after parasite challenge (4/23 versus 5/8; P = 0.015) but not to class II peptides before or after challenge. The responses to one antigen (P. falciparum circumsporozoite protein [PfCSP]) were similar among volunteers who received the five-gene mixture compared to volunteers who only received the PfCSP DNA plasmid in a previous study. In summary, DNA-primed IFN-gamma responses were boosted in humans by exposure to native antigen on parasites, coadministration of a plasmid expressing hGM-CSF had a negative effect on boosting of class I-restricted IFN-gamma responses, and there was no evidence that immunization with PfCSP DNA in the mixture reduced T-cell responses to PfCSP compared to when it was administered alone.
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Affiliation(s)
- Ruobing Wang
- Sanaria, Inc., 12115 Parklawn Drive, Suite L, Rockville, MD 20852, USA
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Abstract
Transgenic (Tg) mice carrying a T-cell receptor (TCR) specific for a CD8(+) T-cell epitope expressed in pre-erythrocytic stages of Plasmodium yoelii has proven to be a valuable tool to advance our understanding of this anti-parasite T-cell response, as it occurs in vivo. The visualization of CD8(+) T cells in vivo and ex vivo greatly facilitated research aimed at characterizing basic features of this T-cell response such as the kinetics of differentiation and proliferation and the in vivo antigen presentation. Importantly, this research unveiled the existence of early self-regulatory mechanisms controlling the magnitude of the CD8(+) T-cell response and also identified CD4(+) T cells as critical elements in the development of memory populations. This review discusses our recent research using Tg mice and highlights our progress in understanding the CD8(+) T-cell-mediated immunity against malaria liver stages.
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Affiliation(s)
- Alexandre Morrot
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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BenMohamed L, Thomas A, Druilhe P. Long-term multiepitopic cytotoxic-T-lymphocyte responses induced in chimpanzees by combinations of Plasmodium falciparum liver-stage peptides and lipopeptides. Infect Immun 2004; 72:4376-84. [PMID: 15271893 PMCID: PMC470687 DOI: 10.1128/iai.72.8.4376-4384.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Preclinical immunogenicity studies of 12 malaria peptides, selected from four Plasmodium falciparum antigens (Ags), namely, LSA1, LSA3, SALSA, and STARP, that are expressed at the pre-erythrocytic (sporozoite and liver) stages of the human parasite were carried out in chimpanzees. To strengthen their immunogenicity, six of these synthetic peptides were modified by the C-terminal addition of a single palmitoyl chain (lipopeptides) and delivered without adjuvant, whereas the remaining six unmodified peptides were emulsified and delivered by using Montanide ISA51 adjuvant. We have previously reported that these peptides and lipopeptides induce high B-cell and CD4(+)-T-helper responses in chimpanzees. In this report, we show their ability to induce multiepitopic and long-lasting antigen-specific CD8(+) cytotoxic-T-lymphocyte (CTL) responses. The magnitude, consistency, and memory of CTL responses generated by LSA3 peptides point to the strong immunogenicity of this liver-stage Ag. These findings support the screening strategy used to select the four P. falciparum pre-erythrocytic Ags and emphasize their valuable immunogenic properties. The successful immunization of nonhuman primates with combinations of corresponding peptides in a mineral oil emulsion (ISA51) and lipopeptides in saline provide a vaccine formulation that can be tested in humans.
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Affiliation(s)
- Lbachir BenMohamed
- Unité de Parasitologie Bio-Médicale, Institut Pasteur, 75015 Paris, France
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Prieur E, Gilbert SC, Schneider J, Moore AC, Sheu EG, Goonetilleke N, Robson KJH, Hill AVS. A Plasmodium falciparum candidate vaccine based on a six-antigen polyprotein encoded by recombinant poxviruses. Proc Natl Acad Sci U S A 2003; 101:290-5. [PMID: 14694197 PMCID: PMC314178 DOI: 10.1073/pnas.0307158101] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To generate broadly protective T cell responses more similar to those acquired after vaccination with radiation-attenuated Plasmodium falciparum sporozoites, we have constructed candidate subunit malaria vaccines expressing six preerythrocytic antigens linked together to produce a 3240-aa-long polyprotein (L3SEPTL). This polyprotein was expressed by a plasmid DNA vaccine vector (DNA) and by two attenuated poxvirus vectors, modified vaccinia virus Ankara (MVA) and fowlpox virus of the FP9 strain. MVAL3SEPTL boosted anti-thrombospondin-related adhesive protein (anti-TRAP) and anti-liver stage antigen 1 (anti-LSA1) CD8(+) T cell responses when primed by single antigen TRAP- or LSA1-expressing DNAs, respectively, but not by DNA-L3SEPTL. However, prime boost regimes involving two heterologous viral vectors expressing L3SEPTL induced a strong cellular response directed against an LSA1 peptide located in the C-terminal region of the polyprotein. Peptide-specific T cells secreted IFN-gamma and were cytotoxic. IFN-gamma-secreting T cells specific for each of the six antigens were induced after vaccination with L3SEPTL, supporting the use of polyprotein inserts to induce multispecific T cells against P. falciparum. The use of polyprotein constructs in nonreplicating poxviruses should broaden the target antigen range of vaccine-induced immunity and increase the number of potential epitopes available for immunogenetically diverse human populations.
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Affiliation(s)
- Eric Prieur
- Weatherall Institute of Molecular Medicine and Cellular Immunology, Nuffield Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom.
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Chelimo K, Sumba PO, Kazura JW, Ofula AV, John CC. Interferon-gamma responses to Plasmodium falciparum liver-stage antigen-1 and merozoite-surface protein-1 increase with age in children in a malaria holoendemic area of western Kenya. Malar J 2003; 2:37. [PMID: 14613510 PMCID: PMC280688 DOI: 10.1186/1475-2875-2-37] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Accepted: 11/05/2003] [Indexed: 11/24/2022] Open
Abstract
Background In areas of high-level, year-round malaria transmission, morbidity and mortality due to malaria decrease after the first two to three years of life. This reduction may be related to the development of cellular immunity to specific antigens expressed in the different life-cycle stages of Plasmodium falciparum. Methods A cross sectional study was conducted to evaluate T cell cytokine responses to the P. falciparum pre-erythrocytic antigen liver-stage antigen-1 (LSA-1) and the blood-stage antigen merozoite-surface protein-1 (MSP-1) in children under five years of age residing in a malaria holoendemic region of western Kenya. Interferon-γ (IFN-γ) and interleukin-10 (IL-10) responses to the LSA-1 T3 peptide (aa 1813–1835) and the MSP-1 aa20–39 peptide were tested in 48 children. Results The proportion of children producing IFN-γ to LSA-1 and to MSP-1 increased with age: in the 0–12, 13–24, 25–36 and 37–48 month age groups, zero, 11.1, 36.4 and 40% of children had IFN-γ responses to LSA-1 (p = 0.019), and 10, 10, 27.7 and 40% of children had IFN-γ responses to MSP-1 (p = 0.07), respectively. In contrast, the proportion of children producing IL-10 to LSA-1 and MSP-1 was similar in all age groups. Conclusion The data suggest that development of IFN-γ responses to LSA-1 and MSP-1 requires increased age and/or repeated exposure, whereas IL-10 responses to these antigens may occur at any age and with limited exposure. The data also demonstrate that by the age of 4 years, children in a malaria holoendemic area develop frequencies of IFN-γ responses to LSA-1 and MSP-1 similar to those seen in adults in the area.
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Affiliation(s)
- Kiprotich Chelimo
- Maseno University, P.O Box 333, Maseno, Kenya
- Kenya Medical Research Institute, P.O Box, 1578, Kisumu, Kenya
| | - Peter O Sumba
- Kenya Medical Research Institute, P.O Box, 1578, Kisumu, Kenya
| | - James W Kazura
- Center for Global Health and Disease, Case Western Reserve University and Rainbow Babies and Children's Hospital, Cleveland, Ohio, USA
| | | | - Chandy C John
- Center for Global Health and Disease, Case Western Reserve University and Rainbow Babies and Children's Hospital, Cleveland, Ohio, USA
- Rainbow Center for International Child Health and Division of Pediatric Infectious Diseases, Case Western Reserve University and Rainbow Babies and Children's Hospital, Cleveland, Ohio, USA
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Abstract
Malaria is the world's deadliest parasitic disease and effective control measures are a public health priority. Most deaths in humans from malaria are caused by one species of the protozoa, Plasmodium falciparum. An efficacious and cost-effective vaccine against this parasite is considered a holy grail of modern molecular medicine. A vaccine that targets liver stage parasites would prevent infection from reaching the blood and causing clinical disease. Among known P. falciparum antigens, liver stage antigen-1 (LSA-1) is the only protein expressed exclusively by infected hepatocytes. Several independent studies in humans have consistently related immune responses to LSA-1 with resistance to infection or disease, providing a powerful rationale for the development of liver stage vaccines. Investigations by ourselves and others aim to dissect the mechanism of cellular immunity to LSA-1 and to evaluate in different delivery systems epitopes associated with protection as components of a multiantigen malaria vaccine. The first clinical trials are already being conducted, the results of which are eagerly awaited.
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Ong'echa JMO, Lal AA, Terlouw DJ, Ter Kuile FO, Kariuki SK, Udhayakumar V, Orago ASS, Hightower AW, Nahlen BL, Shi YP. Association of interferon-gamma responses to pre-erythrocytic stage vaccine candidate antigens of Plasmodium falciparum in young Kenyan children with improved hemoglobin levels: XV. Asembo Bay Cohort Project. Am J Trop Med Hyg 2003; 68:590-7. [PMID: 12812352 DOI: 10.4269/ajtmh.2003.68.590] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Previous studies in animal models have revealed an association between interferon-gamma (IFN-gamma), produced by CD8+ T cells and irradiated sporozoite-induced sterile immunity. To determine whether IFN-gamma can serve as a marker of pre-erythrocytic protective immunity in individuals naturally exposed to malaria, we characterized IFN-gamma and lymphocyte proliferative responses to previously defined CD8+ cytotoxic T lymphocyte (CTL) epitopes from six pre-erythrocytic stage antigens in 107 children six months to two years old from a community-based birth cohort in western Kenya. We found that IFN-gamma positive responders had higher hemoglobin (Hb) levels and significantly reduced prevalence of severe malarial anemia one month after the test compared with IFN-gamma non-responders, suggesting that IFN-gamma immune responses to these pre-erythrocytic antigens were associated with protection against malarial anemia. Children who responded by lymphocyte proliferation had a significantly longer time to first documented malaria parasitemia after birth; however, there was no correlation between the presence of lymphocyte proliferative response and higher Hb levels. We propose that IFN-gamma production could be used as a potential marker of protective immunity against malaria associated anemia in young children living in malaria holoendemic areas.
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Affiliation(s)
- John M O Ong'echa
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, Kenya
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Grüner AC, Snounou G, Brahimi K, Letourneur F, Rénia L, Druilhe P. Pre-erythrocytic antigens of Plasmodium falciparum: from rags to riches? Trends Parasitol 2003; 19:74-8. [PMID: 12586475 DOI: 10.1016/s1471-4922(02)00067-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A growing number of Plasmodium genomes have joined the sequencing treadmill, and the genome of Plasmodium falciparum has recently been published. Most malaria vaccinologists will soon be confronted by a bewildering array of new potential antigens from the recently completed genome of this parasite. However, for those aiming to target the pre-erythrocytic stages of the hepatic parasite, the wait might be long. In the absence of readily available materials and specific reagents, the selection of pre-erythrocytic antigens from raw sequence data is likely to prove difficult. Here, current knowledge of pre-erythrocytic antigens is updated in the light of recent results, and the post-genomic prospects of completing the antigenic repertoire of these immunologically important and intriguing stages is discussed.
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Affiliation(s)
- Anne Charlotte Grüner
- Unité de Parasitologie Biomédicale, Institut Pasteur, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
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Abstract
T cells from different subsets play a major role in protective immunity against pre-erythrocytic stages of malaria parasites. Exposure of humans and animals to malaria sporozoites induces (alphabeta CD8(+) and CD4(+) T cells specific for antigens expressed in pre-erythrocytic stages of Plasmodium. These T cells inhibit parasite development in the liver, and immunization with subunit vaccines expressing the respective antigenic moieties confers protection against sporozoite challenge. gammadelta and natural killer T cells can also play a role in protective immunity. Recent studies with mice transgenic for the alphabeta T-cell receptor have revealed the existence of complex mechanisms regulating the induction and development of these responses.
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Affiliation(s)
- Moriya Tsuji
- Department of Medical and Molecular Parasitology, New York University School of Medicine, 341 East 25th Street, New York, NY 10010, USA
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36
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Lipsitch M, Bergstrom CT, Antia R. Effect of human leukocyte antigen heterozygosity on infectious disease outcome: the need for allele-specific measures. BMC MEDICAL GENETICS 2003; 4:2. [PMID: 12542841 PMCID: PMC149356 DOI: 10.1186/1471-2350-4-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2002] [Accepted: 01/24/2003] [Indexed: 11/23/2022]
Abstract
BACKGROUND Doherty and Zinkernagel, who discovered that antigen presentation is restricted by the major histocompatibility complex (MHC, called HLA in humans), hypothesized that individuals heterozygous at particular MHC loci might be more resistant to particular infectious diseases than the corresponding homozygotes because heterozygotes could present a wider repertoire of antigens. The superiority of heterozygotes over either corresponding homozygote, which we term allele-specific overdominance, is of direct biological interest for understanding the mechanisms of immune response; it is also a leading explanation for the observation that MHC loci are extremely polymorphic and that these polymorphisms have been maintained through extremely long evolutionary periods. Recent studies have shown that in particular viral infections, heterozygosity at HLA loci was associated with a favorable disease outcome, and such findings have been interpreted as supporting the allele-specific overdominance hypothesis in humans. METHODS An algebraic model is used to define the expected population-wide findings of an epidemiologic study of HLA heterozygosity and disease outcome as a function of allele-specific effects and population genetic parameters of the study population. RESULTS We show that overrepresentation of HLA heterozygotes among individuals with favorable disease outcomes (which we term population heterozygote advantage) need not indicate allele-specific overdominance. On the contrary, partly due to a form of confounding by allele frequencies, population heterozygote advantage can occur under a very wide range of assumptions about the relationship between homozygote risk and heterozygote risk. In certain extreme cases, population heterozygote advantage can occur even when every heterozygote is at greater risk of being a case than either corresponding homozygote. CONCLUSION To demonstrate allele-specific overdominance for specific infections in human populations, improved analytic tools and/or larger studies (or studies in populations with limited HLA diversity) are necessary.
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Affiliation(s)
- Marc Lipsitch
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Carl T Bergstrom
- Department of Zoology, University of Washington, Seattle, WA 98195, USA
| | - Rustom Antia
- Department of Biology, Emory University, Atlanta, GA 30322, USA
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Meraldi V, Nebié I, Moret R, Cuzin-Ouattara N, Thiocone A, Doumbo O, Esposito F, Traoré AS, Corradin G, Terenzi S. Recognition of synthetic polypeptides corresponding to the N- and C-terminal fragments of Plasmodium falciparum Exp-1 by T-cells and plasma from human donors from African endemic areas. Parasite Immunol 2002; 24:141-50. [PMID: 11982859 DOI: 10.1046/j.1365-3024.2002.00447.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present work describes the recognition of three synthetic polypeptides encompassing the N- and C-terminal regions of the transmembrane Exp-1 protein of the parasite Plasmodium falciparum by plasma and peripheral blood mononuclear cells from naturally exposed individuals living in African endemic areas. The three polypeptides comprise the sequences 23-105, 73-162 and 101-162, and overlap at the transmembrane domain (73-105). Thus, they permitted characterization of the immune response specific to the N- and C-terminal domains in an independent fashion. Two different populations were evaluated, one in the village of Safo in Mali and the other in the villages of Somnaway, Kabortenga and Toussouktenga in Burkina Faso. Antibodies to the sequence 73-162 of Pf Exp-1 were found in 70% of adult Mali donors and in all of the donors tested from Burkina Faso. Strikingly, the N-terminal fragment Pf Exp-1 23-105 was only weakly recognized by a few donors. Evaluation of the T-cell response indicated that the peptide Pf Exp-1 23-105 was more potent than Pf Exp-1 73-162 in inducing a proliferative response. A correlation between peptide-specific interferon-gamma and interleukin-6 production and proliferation to peptide Pf Exp-1 23-105 was observed. Further studies are needed to evaluate this molecule as a vaccine candidate.
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Affiliation(s)
- Valentin Meraldi
- Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland
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38
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Affiliation(s)
- S L Hoffman
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
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39
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Daubersies P, Thomas AW, Millet P, Brahimi K, Langermans JA, Ollomo B, BenMohamed L, Slierendregt B, Eling W, Van Belkum A, Dubreuil G, Meis JF, Guérin-Marchand C, Cayphas S, Cohen J, Gras-Masse H, Druilhe P, Mohamed LB. Protection against Plasmodium falciparum malaria in chimpanzees by immunization with the conserved pre-erythrocytic liver-stage antigen 3. Nat Med 2000; 6:1258-63. [PMID: 11062538 DOI: 10.1038/81366] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In humans, sterile immunity against malaria can be consistently induced through exposure to the bites of thousands of irradiated infected mosquitoes. The same level of protection has yet to be achieved using subunit vaccines. Recent studies have indicated an essential function for intrahepatic parasites, the stage after the mosquito bite, and thus for antigens expressed during this stage. We report here the identification of liver-stage antigen 3, which is expressed both in the mosquito and liver-stage parasites. This Plasmodium falciparum 200-kilodalton protein is highly conserved, and showed promising antigenic and immunogenic properties. In chimpanzees (Pan troglodytes), the primates most closely related to humans and that share a similar susceptibility to P. falciparum liver-stage infection, immunization with LSA-3 induced protection against successive heterologous challenges with large numbers of P. falciparum sporozoites.
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Affiliation(s)
- P Daubersies
- Unité de Parasitologie Biomédicale, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France.
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Perlmann P, Björkman A. Malaria research: host-parasite interactions and new developments in chemotherapy, immunology and vaccinology. Curr Opin Infect Dis 2000; 13:431-443. [PMID: 11964811 DOI: 10.1097/00001432-200010000-00002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Malaria remains the major parasitic disease, with 300-500 million new infections each year. This survey covers recent advances in the field of parasite-host interactions, focusing on Plasmodium falciparum, the most virulent of the human parasites. Rapid progress in genomic research is creating a basis for the development of new drugs and vaccines. Identification of drug-resistance mutations facilitates evaluation of improved drug policies, and attempts are being made to develop new compounds that inhibit metabolic pathways that are specific to the parasite. Cytoadherence of parasitized erythrocytes to microvascular endothelium is responsible for the sequestration of parasites, causing pathology and severe disease. Newly identified molecular fine structures that mediate cytoadherence may provide new targets for specific therapies. Humoral and cell-mediated immunity induced by the parasite may be protective, but may also be harmful by generating imbalance in cytokine responses. Efforts are made to determine the pathways that give rise to protection, with vaccination being the principal goal for achieving malaria control. Different vaccine constructs are being evaluated in preclinical and clinical trials, including modified viral vectors, synthetic peptides, DNA and new adjuvants.
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Affiliation(s)
- Peter Perlmann
- aDepartment of Immunology, Stockholm University, and bKarolinska Institute, Infectious Diseases Unit, Karolinska Hospital, Stockholm, Sweden
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41
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Abstract
As global malaria mortality increases the urgency for vaccine development, analysis of immune responses in naturally exposed populations is providing clues to the nature of protective immunity. Recently, sophisticated immune evasion strategies adopted by the parasite have been analysed at the molecular level. More immunogenic vaccination strategies have been identified, providing renewed optimism that effective malaria control through vaccination should be feasible.
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Affiliation(s)
- M Plebanski
- Vaccine Development and Infectious Diseases Unit, The Austin Research Institute, Heidelberg, VA 3084, Australia.
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