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Boyle MJ, Chan JA, Handayuni I, Reiling L, Feng G, Hilton A, Kurtovic L, Oyong D, Piera KA, Barber BE, William T, Eisen DP, Minigo G, Langer C, Drew DR, de Labastida Rivera F, Amante FH, Williams TN, Kinyanjui S, Marsh K, Doolan DL, Engwerda C, Fowkes FJI, Grigg MJ, Mueller I, McCarthy JS, Anstey NM, Beeson JG. IgM in human immunity to Plasmodium falciparum malaria. Sci Adv 2019; 5:eaax4489. [PMID: 31579826 PMCID: PMC6760923 DOI: 10.1126/sciadv.aax4489] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/03/2019] [Indexed: 05/15/2023]
Abstract
Most studies on human immunity to malaria have focused on the roles of immunoglobulin G (IgG), whereas the roles of IgM remain undefined. Analyzing multiple human cohorts to assess the dynamics of malaria-specific IgM during experimentally induced and naturally acquired malaria, we identified IgM activity against blood-stage parasites. We found that merozoite-specific IgM appears rapidly in Plasmodium falciparum infection and is prominent during malaria in children and adults with lifetime exposure, together with IgG. Unexpectedly, IgM persisted for extended periods of time; we found no difference in decay of merozoite-specific IgM over time compared to that of IgG. IgM blocked merozoite invasion of red blood cells in a complement-dependent manner. IgM was also associated with significantly reduced risk of clinical malaria in a longitudinal cohort of children. These findings suggest that merozoite-specific IgM is an important functional and long-lived antibody response targeting blood-stage malaria parasites that contributes to malaria immunity.
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Affiliation(s)
- M. J. Boyle
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Corresponding author. (M.J.B.); (J.G.B.)
| | - J. A. Chan
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - I. Handayuni
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - L. Reiling
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - G. Feng
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - A. Hilton
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - L. Kurtovic
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - D. Oyong
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - K. A. Piera
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - B. E. Barber
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
| | - T. William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
- Gleneagles Hospital Kota Kinabalu Sabah, Malaysia
| | - D. P. Eisen
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - G. Minigo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - C. Langer
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - D. R. Drew
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | | | - F. H. Amante
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - T. N. Williams
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Imperial College, London, UK
| | - S. Kinyanjui
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - K. Marsh
- Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - D. L. Doolan
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - C. Engwerda
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - F. J. I. Fowkes
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Epidemiology and Preventive Medicine, Department of Infectious Diseases, Monash University, Melbourne, Victoria, Australia
| | - M. J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
| | - I. Mueller
- Walter and Eliza Hall Institute, Melbourne, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Parasites and Insect Vectors, Institute Pasteur, Paris, France
| | - J. S. McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - N. M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Charles Darwin University, Darwin, Northern Territory, Australia
| | - J. G. Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Corresponding author. (M.J.B.); (J.G.B.)
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Vaughan K, Blythe M, Greenbaum J, Zhang Q, Peters B, Doolan DL, Sette A. Meta-analysis of immune epitope data for all Plasmodia: overview and applications for malarial immunobiology and vaccine-related issues. Parasite Immunol 2009; 31:78-97. [PMID: 19149776 DOI: 10.1111/j.1365-3024.2008.01077.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We present a comprehensive meta-analysis of more than 500 references, describing nearly 5000 unique B cell and T cell epitopes derived from the Plasmodium genus, and detailing thousands of immunological assays. This is the first inventory of epitope data related to malaria-specific immunology, plasmodial pathogenesis, and vaccine performance. The survey included host and pathogen species distribution of epitopes, the number of antibody vs. CD4(+) and CD8(+) T cell epitopes, the genomic distribution of recognized epitopes, variance among epitopes from different parasite strains, and the characterization of protective epitopes and of epitopes associated with parasite evasion of the host immune response. The results identify knowledge gaps and areas for further investigation. This information has relevance to issues, such as the identification of epitopes and antigens associated with protective immunity, the design and development of candidate malaria vaccines, and characterization of immune response to strain polymorphisms.
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Affiliation(s)
- K Vaughan
- La Jolla Institute of Allergy and Immunology, La Jolla, CA 92037, USA.
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3
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Dobaño C, Doolan DL. Identification of minimal CD8+ and CD4+ T cell epitopes in the Plasmodium yoelii hepatocyte erythrocyte protein 17kDa. Mol Immunol 2007; 44:3037-48. [PMID: 17303242 DOI: 10.1016/j.molimm.2007.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 12/18/2006] [Indexed: 10/23/2022]
Abstract
Immunization of mice with subunit vaccines based on the Plasmodium yoelii 17kDa hepatocyte erythrocyte protein (PyHEP17), orthologue of Plasmodium falciparum exported protein 1 (PfExp1), induces antigen-specific immune responses and protects against sporozoite challenge. To aid in the characterization of candidate subunit vaccines based on this antigen, we have mapped the immunodominant and subdominant CD8+ and CD4+ T cell epitopes on PyHEP17. Using a panel of 29 15-mer synthetic peptides representing the complete sequence of PyHEP17 (amino acids 1-153), and overlapping each other by 10 residues, we identified an immunogenic region between amino acids 61-85. To define the minimal CD4+ and CD8+ T cell epitopes within this region, we synthesized 25 9-mer peptides overlapping each other by one residue. We screened the capacity of the 15-mer and 9-mer peptides to be recognized by splenocytes and lymph node cells from mice immunized with PyHEP17 plasmid DNA or peptides in Freund's adjuvant, as assessed by cytokine secretion, lymphoproliferation, and cytotoxicity. The profile of response to the T cell epitopes varied depending upon the immunization regimen. Antigen-specific T cell responses were detected to three 15-mer peptides (residues 61-75, 66-80 and 71-85) representing two 10-mer epitopes mapping to residues 66-75 (LTKNKKSLRK) and 71-80 (KSLRKINVAL). IFN-gamma responses after DNA immunization predominantly mapped to two overlapping 9-mer peptides (residues 73-81 and 74-82) sharing an eight amino acid overlap (residues 74-81, RKINVALA), whereas CTL responses predominantly mapped to four 9-mer peptides (residues 61-69, 70-78, 76-84, and 84-92). In addition, a subdominant 10-mer CD8+ T cell epitope recognized by peptide immunization but not DNA immunization mapped to residues 31-40 (GKYGSQNVIK). The identification of these epitopes will allow the evaluation of delivery systems for malaria vaccine candidates as well as the delineation of protective immune mechanisms.
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Affiliation(s)
- C Dobaño
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
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Dobaño C, McTague A, Sette A, Hoffman SL, Rogers WO, Doolan DL. Mutating the anchor residues associated with MHC binding inhibits and deviates CD8+ T cell mediated protective immunity against malaria. Mol Immunol 2006; 44:2235-48. [PMID: 17169429 DOI: 10.1016/j.molimm.2006.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 10/30/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
We investigated whether immune responses induced by immunization with plasmid DNA are restricted predominantly to immunodominant CD8+ T cell epitopes, or are raised against a breadth of epitopes including subdominant CD8+ and CD4+ T cell epitopes. Site-directed mutagenesis was used to change one or more primary anchor residues of the immunodominant CD8+ T cell epitope on the Plasmodium yoelii circumsporozoite protein, and in vivo protective efficacy and immune responses against defined PyCSP CD8+ and/or CD4+ epitopes were determined. Mutation of the P2 but not P9 or P10 anchor residues decreased protection and completely abrogated the antigen-specific CD8+ CTL activity and CD8+ dependent IFN-gamma responses to the immunodominant CD8+ epitope and overlapping CD8+/CD4+ epitope. Moreover, mutation deviated the immune response towards a CD4+ T cell IFN-gamma dependent profile, with enhanced lymphoproliferative responses to the immunodominant and subdominant CD4+ epitopes and enhanced antibody responses. Responses to the subdominant CD8+ epitope were not induced. Our data demonstrate that protective immunity induced by PyCSP DNA vaccination is directed predominantly against the single immunodominant CD8+ epitope, and that although responses can be induced against other epitopes, these are mediated by CD4+ T cells and are not capable of conferring optimal protection against challenge.
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Affiliation(s)
- C Dobaño
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
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5
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Abstract
Immunization with radiation-attenuated Plasmodium spp. sporozoites induces sterile protective immunity against parasite challenge. This immunity is targeted primarily against the intrahepatic parasite and appears to be sustained long term even in the absence of sporozoite exposure. It is mediated by multifactorial mechanisms, including T cells directed against parasite antigens expressed in the liver stage of the parasite life cycle and antibodies directed against sporozoite surface proteins. In rodent models, CD8+ T cells have been implicated as the principal effector cells, and IFN-gamma as a critical effector molecule. IL-4 secreting CD4+ T cells are required for induction of the CD8+ T cell responses, and Th1 CD4+ T cells provide help for optimal CD8+ T cell effector activity. Components of the innate immune system, including gamma-delta T cells, natural killer cells and natural killer T cells, also play a role. The precise nature of pre-erythrocytic stage immunity in humans, including the contribution of these immune responses to the age-dependent immunity naturally acquired by residents of malaria endemic areas, is still poorly defined. The importance of immune effector targets at the pre-erythrocytic stage of the parasite life cycle is highlighted by the fact that infection-blocking immunity in humans rarely, if ever, occurs under natural conditions. Herein, we review our current understanding of the molecular and cellular aspects of pre-erythrocytic stage immunity.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910-7500, USA.
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Doolan DL, Aguiar JC, Weiss WR, Sette A, Felgner PL, Regis DP, Quinones-Casas P, Yates JR, Blair PL, Richie TL, Hoffman SL, Carucci DJ. Utilization of genomic sequence information to develop malaria vaccines. J Exp Biol 2003; 206:3789-802. [PMID: 14506214 DOI: 10.1242/jeb.00615] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYRecent advances in the fields of genomics, proteomics and molecular immunology offer tremendous opportunities for the development of novel interventions against public health threats, including malaria. However, there is currently no algorithm that can effectively identify the targets of protective T cell or antibody responses from genomic data. Furthermore, the identification of antigens that will stimulate the most effective immunity against the target pathogen is problematic, particularly if the genome is large. Malaria is an attractive model for the development and validation of approaches to translate genomic information to vaccine development because of the critical need for effective anti-malarial interventions and because the Plasmodium parasite is a complex multistage pathogen targeted by multiple immune responses. Sterile protective immunity can be achieved by immunization with radiation-attenuated sporozoites, and anti-disease immunity can be induced in residents in malaria-endemic areas. However, the 23 Mb Plasmodium falciparum genome encodes more than 5300 proteins, each of which is a potential target of protective immune responses. The current generation of subunit vaccines is based on a single or few antigens and therefore might elicit too narrow a breadth of response. We are working towards the development of a new generation vaccine based on the presumption that duplicating the protection induced by the whole organism may require a vaccine nearly as complex as the organism itself. Here, we present our strategy to exploit the genomic sequence of P. falciparum for malaria vaccine development.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
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8
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Witney AA, Doolan DL, Anthony RM, Weiss WR, Hoffman SL, Carucci DJ. Determining liver stage parasite burden by real time quantitative PCR as a method for evaluating pre-erythrocytic malaria vaccine efficacy. Mol Biochem Parasitol 2001; 118:233-45. [PMID: 11738713 DOI: 10.1016/s0166-6851(01)00372-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The detection and quantitation of blood stage parasitaemia is typically used as a surrogate endpoint for estimating the efficacy of vaccines targeted against the hepatic stage, as well as the erythrocytic stage, of the parasite. However, this does not provide an adequate means of evaluating the efficacy of vaccines, which may be only partially effective at the liver-stage. This is a particular concern for effective evaluation of immune enhancement strategies for candidate pre-erythrocytic stage vaccines. Here, we have developed and validated a method for detecting and quantitating liver stage parasites, using the TaqMan fluorescent real-time quantitative PCR system (PE Applied Biosystems). This method uses TaqMan primers designed to the Plasmodium yoelii 18S rRNA gene and rodent GAPDH to amplify products from infected mouse liver cDNA. The technique is highly reproducible as demonstrated with plasmid controls and capable of efficiently quantitating liver-stage parasite burden following a range of sporozoite challenge doses in strains of mice, which differ in their susceptibility to sporozoite infection. We have further demonstrated the capacity of this technique to evaluate the efficacy of a range of pre-erythrocytic stage vaccines. Our data establish this quantitative real-time PCR assay to be a fast and reproducible way of accurately assessing liver stage parasite burden and vaccine efficacy in rodent malaria models.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- DNA, Ribosomal/analysis
- Erythrocytes/parasitology
- Female
- Genes, rRNA
- Immunization, Passive
- Liver/parasitology
- Malaria/parasitology
- Malaria/prevention & control
- Malaria Vaccines/administration & dosage
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Molecular Sequence Data
- Plasmodium yoelii/genetics
- Plasmodium yoelii/growth & development
- Plasmodium yoelii/immunology
- Plasmodium yoelii/pathogenicity
- RNA, Ribosomal, 18S/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Taq Polymerase/metabolism
- Vaccination
- Vaccines, DNA/administration & dosage
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Affiliation(s)
- A A Witney
- Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Room 3A4O, Silver Spring, MD 20910-7500, USA
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Brice GT, Graber NL, Hoffman SL, Doolan DL. Expression of the chemokine MIG is a sensitive and predictive marker for antigen-specific, genetically restricted IFN-gamma production and IFN-gamma-secreting cells. J Immunol Methods 2001; 257:55-69. [PMID: 11687239 DOI: 10.1016/s0022-1759(01)00446-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The evaluation of antigen-specific immune responses is critical for understanding the mechanisms of immune protection and for establishing the efficacy of candidate vaccines. Here, we describe a novel assay for IFN-gamma activity which is based on the flow cytometric detection of the chemokine, monokine induced by gamma interferon (MIG) as a sensitive and predictive measure of IFN-gamma-mediated effector function, and a surrogate marker for IFN-gamma-producing cells. Upregulation of MIG expression was demonstrated following in vitro activation of peripheral blood mononuclear cells (PBMCs) with defined CD8+ T-cell epitopes derived from influenza virus, cytomegalovirus (CMV), or Epstein-Barr virus (EBV) and was antigen-specific, genetically restricted and dependent on both CD8+ T cells and IFN-gamma. Furthermore, antigen-specific MIG expression was also demonstrated with Plasmodium falciparum circumsporozoite protein (CSP) peptides, using PBMCs from volunteers immunized with irradiated P. falciparum sporozoites. In multiple parallel experiments, the MIG assay was compared to conventional IFN-gamma ELISPOT, IFN-gamma ELISA, MIG ELISA and intracellular cytokine staining assays. The level of MIG expression was shown to be directly associated with the number of IFN-gamma spot-forming cells (SFCs) detected by ELISPOT (r2=0.94). Moreover, in all instances where cultures were considered positive by ELISPOT, a higher stimulation index was noted with the MIG assay as compared with the ELISPOT assay (on average at least threefold higher) and, in some cases, responses as detected by the MIG assay were significant, but the corresponding response as measured by ELISPOT was not significant. Finally, the flow-based MIG assay offers a number of practical and technical advantages over the ELISPOT assay. Our data validate this novel method for the detection of low as well as high levels of antigen-specific and genetically restricted IFN-gamma activity.
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Affiliation(s)
- G T Brice
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA
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Wang R, Epstein J, Baraceros FM, Gorak EJ, Charoenvit Y, Carucci DJ, Hedstrom RC, Rahardjo N, Gay T, Hobart P, Stout R, Jones TR, Richie TL, Parker SE, Doolan DL, Norman J, Hoffman SL. Induction of CD4(+) T cell-dependent CD8(+) type 1 responses in humans by a malaria DNA vaccine. Proc Natl Acad Sci U S A 2001; 98:10817-22. [PMID: 11526203 PMCID: PMC58557 DOI: 10.1073/pnas.181123498] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We assessed immunogenicity of a malaria DNA vaccine administered by needle i.m. or needleless jet injection [i.m. or i.m./intradermally (i.d.)] in 14 volunteers. Antigen-specific IFN-gamma responses were detected by enzyme-linked immunospot (ELISPOT) assays in all subjects to multiple 9- to 23-aa peptides containing class I and/or class II restricted epitopes, and were dependent on both CD8(+) and CD4(+) T cells. Overall, frequency of response was significantly greater after i.m. jet injection. CD8(+)-dependent cytotoxic T lymphocytes (CTL) were detected in 8/14 volunteers. Demonstration in humans of elicitation of the class I restricted IFN-gamma responses we believe necessary for protection against the liver stage of malaria parasites brings us closer to an effective malaria vaccine.
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Affiliation(s)
- R Wang
- Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
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Abstract
The introduction of DNA vaccine technology has facilitated an unprecedented multi-antigen approach to developing an effective vaccine against complex pathogens such as the Plasmodium spp. parasites that cause malaria. We have established the capacity of DNA vaccines encoding Plasmodium antigens to induce CD8(+) cytotoxic T lymphocyte and interferon-gamma responses in mice, monkeys and humans. However, like others, we have found that the first or second generation DNA vaccines on their own are not optimal, and have demonstrated the potential of heterologous prime/boost immunisation strategies involving priming with DNA and boosting with poxvirus or recombinant protein in adjuvant. In this review, we summarise the current status and promise of our programmatic efforts to develop a DNA-based vaccine against malaria, our Multi-Stage Malaria DNA Vaccine Operation, and illustrate the transition of promising developments in the laboratory to clinical assessment in humans.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
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Hedstrom RC, Doolan DL, Wang R, Gardner MJ, Kumar A, Sedegah M, Gramzinski RA, Sacci JB, Charoenvit Y, Weiss WR, Margalith M, Norman JA, Hobart P, Hoffman SL. The development of a multivalent DNA vaccine for malaria. Springer Semin Immunopathol 2001; 19:147-59. [PMID: 9406343 DOI: 10.1007/bf00870265] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R C Hedstrom
- Malaria Program, Naval Medical Research Institute Annex, Rockville, MD 20852, USA
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13
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Gramzinski RA, Doolan DL, Sedegah M, Davis HL, Krieg AM, Hoffman SL. Interleukin-12- and gamma interferon-dependent protection against malaria conferred by CpG oligodeoxynucleotide in mice. Infect Immun 2001; 69:1643-9. [PMID: 11179339 PMCID: PMC98068 DOI: 10.1128/iai.69.3.1643-1649.2001] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2000] [Accepted: 12/12/2000] [Indexed: 02/07/2023] Open
Abstract
Unmethylated CpG dinucleotides in bacterial DNA or synthetic oligodeoxynucleotides (ODNs) cause B-cell proliferation and immunoglobulin secretion, monocyte cytokine secretion, and activation of natural killer (NK) cell lytic activity and gamma interferon (IFN-gamma) secretion in vivo and in vitro. The potent Th1-like immune activation by CpG ODNs suggests a possible utility for enhancing innate immunity against infectious pathogens. We therefore investigated whether the innate immune response could protect against malaria. Treatment of mice with CpG ODN 1826 (TCCATGACGTTCCTGACGTT, with the CpG dinucleotides underlined) or 1585 (ggGGTCAACGTTGAgggggG, with g representing diester linkages and phosphorothioate linkages being to the right of lowercase letters) in the absence of antigen 1 to 2 days prior to challenge with Plasmodium yoelii sporozoites conferred sterile protection against infection. A higher level of protection was consistently induced by CpG ODN 1826 compared with CpG ODN 1585. The protective effects of both CpG ODNs were dependent on interleukin-12, as well as IFN-gamma. Moreover, CD8+ T cells (but not CD4+ T cells), NK cells, and nitric oxide were implicated in the CpG ODN 1585-induced protection. These data establish that the protective mechanism induced by administration of CpG ODN 1585 in the absence of parasite antigen is similar in nature to the mechanism induced by immunization with radiation-attenuated P. yoelii sporozoites or with plasmid DNA encoding preerythrocytic-stage P. yoelii antigens. We were unable to confirm whether CD8+ T cells, NK cells, or nitric oxide were required for the CpG ODN 1826-induced protection, but this may reflect differences in the potency of the ODNs rather than a real difference in the mechanism of action of the two ODNs. This is the first report that stimulation of the innate immune system by CpG immunostimulatory motifs can confer sterile protection against malaria.
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Affiliation(s)
- R A Gramzinski
- Malaria Program, Naval Medical Research Center, Silver Spring, Maryland 20910-7500, USA
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14
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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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15
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Ravichandran M, Doolan DL, Cox-Singh J, Hoffman SL, Singh B. Research note: HLA degenerate T-cell epitopes from Plasmodium falciparum liver stage-specific antigen 1 (LSA-1) are highly conserved in isolates from geographically distinct areas. Parasite Immunol 2000; 22:469-73. [PMID: 10972854 DOI: 10.1046/j.1365-3024.2000.00324.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Considerable effort is directed at the development of a malaria vaccine that elicits antigen-specific T-cell responses against pre-erythrocytic antigens of Plasmodium falciparum. Genetic restriction of host T-cell responses and polymorphism of target epitopes on parasite antigens pose obstacles to the development of such a vaccine. Liver stage-specific antigen-1 (LSA-1) is a prime candidate vaccine antigen and five T-cell epitopes that are degenerately restricted by HLA molecules common in most populations have been identified on LSA-1. To define the extent of polymorphism within these T-cell epitopes, the N-terminal non-repetitive region of the LSA-1 gene from Malaysian P. falciparum field isolates was sequenced and compared with data of isolates from Brazil, Kenya and Papua New Guinea. Three of the T-cell epitopes were completely conserved while the remaining two were highly conserved in the isolates examined. Our findings underscore the potential of including these HLA-degenerate T-cell epitopes of LSA-1 in a subunit vaccine.
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Affiliation(s)
- M Ravichandran
- Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
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16
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Abstract
Sterile protective immunity against challenge with Plasmodium spp. sporozoites can be induced in multiple model systems and humans by immunization with radiation-attenuated Plasmodium spp. sporozoites. The infected hepatocyte has been established as the primary target of this protection, but the underlying mechanisms have not been completely defined. Abs, CD8+ T cells, CD4+ T cells, cytokines (including IFN-gamma and IL-12), and NO have all been implicated as critical effectors. Here, we have investigated the mechanisms of protective immunity induced by immunization with different vaccine delivery systems (irradiated sporozoites, plasmid DNA, synthetic peptide/adjuvant, and multiple Ag peptide) in genetically distinct inbred strains, genetically modified mice, and outbred mice. We establish that there is a marked diversity of T cell-dependent immune responses that mediate sterile protective immunity against liver-stage malaria. Furthermore, we demonstrate that distinct mechanisms of protection are induced in different strains of inbred mice by a single method of immunization, and in the same strain by different methods of immunization. These data underscore the complexity of the murine host response to a parasitic infection and suggest that an outbred human population may behave similarly. Data nevertheless suggest that a pre-erythrocytic-stage vaccine should be designed to induce CD8+ T cell- and IFN-gamma-mediated immune responses and that IFN-gamma responses may represent an in vitro correlate of pre-erythrocytic-stage protective immunity.
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MESH Headings
- Amino Acid Sequence
- Animals
- Biomarkers/analysis
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Dose-Response Relationship, Immunologic
- Fas Ligand Protein
- Female
- Granzymes
- H-2 Antigens/genetics
- H-2 Antigens/immunology
- Immunity, Active
- Injections, Intramuscular
- Interferon-gamma/physiology
- Ligands
- Liver/immunology
- Liver/parasitology
- Major Histocompatibility Complex/genetics
- Major Histocompatibility Complex/immunology
- Malaria/enzymology
- Malaria/immunology
- Malaria/parasitology
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/immunology
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred A
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Sequence Data
- Perforin
- Plasmodium yoelii/growth & development
- Plasmodium yoelii/immunology
- Plasmodium yoelii/radiation effects
- Pore Forming Cytotoxic Proteins
- Serine Endopeptidases/physiology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
- fas Receptor/metabolism
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910, USA.
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17
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Doolan DL, Southwood S, Chesnut R, Appella E, Gomez E, Richards A, Higashimoto YI, Maewal A, Sidney J, Gramzinski RA, Mason C, Koech D, Hoffman SL, Sette A. HLA-DR-promiscuous T cell epitopes from Plasmodium falciparum pre-erythrocytic-stage antigens restricted by multiple HLA class II alleles. J Immunol 2000; 165:1123-37. [PMID: 10878392 DOI: 10.4049/jimmunol.165.2.1123] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previously, we identified and established the antigenicity of 17 CD8+ T cell epitopes from five P. falciparum Ags that are restricted by multiple common HLA class I alleles. Here, we report the identification of 11 peptides from the same Ags, cicumsporozoite protein, sporozoite surface protein 2, exported protein-1, and liver-stage Ag-1, that bind between at least five and up to 11 different HLA-DR molecules representative of the most common HLA-DR Ags worldwide. These peptides recall lymphoproliferative and cytokine responses in immune individuals experimentally immunized with radiation-attenuated Plasmodium falciparum sporozoites (irradiated sporozoites) or semi-immune individuals naturally exposed to malaria in Irian Jaya or Kenya. We establish that all peptides are recognized by individuals of each of the three populations, and that the frequency and magnitude of helper T lymphocyte responses to each peptide is influenced by the intensity of exposure to P. falciparum sporozoites. Mean frequencies of lymphoproliferative responses are 53.2% (irradiated sporozoites) vs 22.4% (Kenyan) vs 5.8% (Javanese), and mean frequencies of IFN-gamma responses are 66.3% (irradiated sporozoites) vs 27.3% (Kenyan) vs 8. 7% (Javanese). The identification of HLA class II degenerate T cell epitopes from P. falciparum validates our predictive strategy in a biologically relevant system and supports the potential for developing a broadly efficacious epitope-based vaccine against malaria focused on a limited number of peptide specificities.
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MESH Headings
- Adolescent
- Adult
- Aged
- Alleles
- Amino Acid Motifs/genetics
- Amino Acid Motifs/immunology
- Amino Acid Sequence
- Animals
- Antigens, Protozoan/metabolism
- Cells, Cultured
- Conserved Sequence
- Cytokines/biosynthesis
- Epitopes, T-Lymphocyte/metabolism
- Erythrocytes/immunology
- Erythrocytes/parasitology
- Female
- Gene Frequency/immunology
- HLA-DR Antigens/biosynthesis
- HLA-DR Antigens/genetics
- HLA-DR Antigens/metabolism
- Histocompatibility Testing
- Humans
- Immunity, Innate
- Immunologic Memory
- Indonesia
- Kenya
- Lymphocyte Activation/genetics
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/immunology
- Malaria, Falciparum/genetics
- Malaria, Falciparum/immunology
- Malaria, Falciparum/transmission
- Male
- Middle Aged
- Molecular Sequence Data
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Plasmodium falciparum/growth & development
- Plasmodium falciparum/immunology
- Plasmodium falciparum/metabolism
- Protein Binding/genetics
- Protein Binding/immunology
- T-Lymphocytes, Helper-Inducer/immunology
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/immunology
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910, USA.
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18
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Le TP, Coonan KM, Hedstrom RC, Charoenvit Y, Sedegah M, Epstein JE, Kumar S, Wang R, Doolan DL, Maguire JD, Parker SE, Hobart P, Norman J, Hoffman SL. Safety, tolerability and humoral immune responses after intramuscular administration of a malaria DNA vaccine to healthy adult volunteers. Vaccine 2000; 18:1893-901. [PMID: 10699338 DOI: 10.1016/s0264-410x(99)00407-7] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
DNA-based vaccines are considered to be potentially revolutionary due to their ease of production, low cost, long shelf life, lack of requirement for a cold chain and ability to induce good T-cell responses. Twenty healthy adult volunteers were enrolled in a Phase I safety and tolerability clinical study of a DNA vaccine encoding a malaria antigen. Volunteers received 3 intramuscular injections of one of four different dosages (20, 100, 500 and 2500 microg) of the Plasmodium falciparum circumsporozoite protein (PfCSP) plasmid DNA at monthly intervals and were followed for up to twelve months. Local reactogenicity and systemic symptoms were few and mild. There were no severe or serious adverse events, clinically significant biochemical or hematologic changes, or detectable anti-dsDNA antibodies. Despite induction of excellent CTL responses, intramuscular DNA vaccination via needle injection failed to induce detectable antigen-specific antibodies in any of the volunteers.
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Affiliation(s)
- T P Le
- US Army Medical Research Institute of Infectious Diseases, Ft. Detrick, MD, USA
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19
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Hoffman SL, Doolan DL. Can malaria DNA vaccines on their own be as immunogenic and protective as prime-boost approaches to immunization? Dev Biol (Basel) 2000; 104:121-32. [PMID: 11713810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
To develop a multi-stage, multi-antigen, multi-immune response-inducing vaccine against malaria we have focused on DNA vaccines because of their simplicity of construction and modification, ease of mixing, and effectiveness in inducing CD8+ T cell responses. DNA malaria vaccines induce CD8+ T cell dependent protection in mice and CD8+ CTL in rhesus monkeys and humans after intramuscular needle administration. Clinical trials in normal, healthy humans are in progress or planned, assessing alternative methods and routes of administration, and the capacity of a plasmid expressing human GM-CSF to enhance the protective efficacy of a five-gene liver-stage malaria vaccine. In mice, we have demonstrated that priming with the combination of DNA plasmids encoding a Plasmodium yoelii protein and murine GM-CSF and boosting with recombinant poxvirus expressing the same P. yoelii protein induces a 30-fold increase in antigen-specific antibodies, a 10-fold increase in antigen-specific IFN-gamma spot forming cells, a significant (p<0.05) increase in protection, and the capacity to reduce the dosage of DNA by 10-100 fold, compared to immunizing with DNA alone. In Aotus monkeys priming with DNA and boosting with recombinant protein in adjuvant is more protective than homologous priming and boosting with either DNA or recombinant protein in adjuvant. Clinical trials are now planned using these immunization strategies. Because of the complexity and cost of the heterologous regimens, we are working to make DNA vaccination alone as immunogenic and protective as the prime-boost approach. Our most encouraging findings have resulted from altering codon usage from the highly A+T rich P. falciparum native sequence to that more closely resembling mammalian sequences. Although much progress is required for the development of a vaccine that provides sustainable protective immunity against malaria, a strategy using DNA vaccine technology as a core component of such a vaccine is promising.
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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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20
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Charoenvit Y, Majam VF, Corradin G, Sacci JB, Wang R, Doolan DL, Jones TR, Abot E, Patarroyo ME, Guzman F, Hoffman SL. CD4(+) T-cell- and gamma interferon-dependent protection against murine malaria by immunization with linear synthetic peptides from a Plasmodium yoelii 17-kilodalton hepatocyte erythrocyte protein. Infect Immun 1999; 67:5604-14. [PMID: 10531206 PMCID: PMC96932 DOI: 10.1128/iai.67.11.5604-5614.1999] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most work on protective immunity against the pre-erythrocytic stages of malaria has focused on induction of antibodies that prevent sporozoite invasion of hepatocytes, and CD8(+) T-cell responses that eliminate infected hepatocytes. We recently reported that immunization of A/J mice with an 18-amino-acid synthetic linear peptide from Plasmodium yoelii sporozoite surface protein 2 (SSP2) in TiterMax adjuvant induces sterile protection that is dependent on CD4(+) T cells and gamma interferon (IFN-gamma). We now report that immunization of inbred A/J mice and outbred CD1 mice with each of two linear synthetic peptides from the 17-kDa P. yoelii hepatocyte erythrocyte protein (HEP17) in the same adjuvant also induces protection against sporozoite challenge that is dependent on CD4(+) T cells and IFN-gamma. The SSP2 peptide and the two HEP17 peptides are recognized by B cells as well as T cells, and the protection induced by these peptides appears to be directed against the infected hepatocytes. In contrast to the peptide-induced protection, immunization of eight different strains of mice with radiation-attenuated sporozoites induces protection that is absolutely dependent on CD8(+) T cells. Data represented here demonstrate that CD4(+) T-cell-dependent protection can be induced by immunization with linear synthetic peptides. These studies therefore provide the foundation for an approach to pre-erythrocytic-stage malaria vaccine development, based on the induction of protective CD4(+) T-cell responses, which will complement efforts to induce protective antibody and CD8(+) T-cell responses.
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Affiliation(s)
- Y Charoenvit
- Malaria Program, Naval Medical Research Center, Bethesda, Maryland 20814-5055, USA.
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21
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Abstract
Malaria, a disease responsible for immense human suffering, is caused by infection with Plasmodium spp. parasites, which have a very complex life cycle - antigenically unique stages infect different tissues of the body. This review details recent developments in our understanding of immunity both to pre-erythrocytic stage antigens and to erythrocytic stage antigens. The former is largely mediated via CD8(+) T cells and involves IFN-gamma, nitric oxide, IL-12 and natural killer cells; the latter varies (in different hosts and with different parasites) but is largely mediated by antibody, helper T cells, nitric oxide and gammadelta T cells. The recent progress towards clinical trials of vaccine candidates against both the pre-erythrocytic stage and erythrocytic stage is also summarized, in particular the use of heterologous prime/boost strategies for the former and the use of MSP1 as a candidate vaccine for the latter.
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Affiliation(s)
- M F Good
- The Cooperative Research Centre for Vaccine Technology, The Queensland Institute of Medical Research, PO Royal Brisbane Hospital 4029, Queensland, Australia.
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22
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Doolan DL, Hoffman SL. IL-12 and NK cells are required for antigen-specific adaptive immunity against malaria initiated by CD8+ T cells in the Plasmodium yoelii model. J Immunol 1999; 163:884-92. [PMID: 10395683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
CD8+ T cells have been implicated as critical effector cells in protection against preerythrocytic stage malaria, including the potent protective immunity of mice and humans induced by immunization with radiation-attenuated Plasmodium spp. sporozoites. This immunity is directed against the Plasmodium spp. parasite developing within the host hepatocyte and for a number of years has been presumed to be mediated directly by CD8+ CTL or indirectly by IFN-gamma released from CD8+ T cells. In this paper, in BALB/c mice, we establish that after immunization with irradiated sporozoites or DNA vaccines parasite-specific CD8+ T cells trigger a novel mechanism of adaptive immunity that is dependent on T cell- and non-T cell-derived cytokines, in particular IFN-gamma and IL-12, and requires NK cells but not CD4+ T cells. The absolute requirement for CD8+ T cells to initiate such an effector mechanism, and the requirement for IL-12 and NK cells in such vaccine-induced protective immunity, are unique and underscore the complexity of the immune responses that protect against malaria and other intracellular pathogens.
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MESH Headings
- Animals
- Antigens, Protozoan/immunology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD4-Positive T-Lymphocytes/parasitology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/parasitology
- Disease Models, Animal
- Epitopes, T-Lymphocyte/immunology
- Female
- Immunity, Cellular
- Interferon-gamma/metabolism
- Interferon-gamma/physiology
- Interleukin-12/physiology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/parasitology
- Malaria/immunology
- Malaria/parasitology
- Malaria Vaccines/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Nitric Oxide/physiology
- Plasmodium yoelii/growth & development
- Plasmodium yoelii/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/parasitology
- Vaccines, DNA/immunology
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Center, Bethesda, MD 20889, USA
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23
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Wang R, Doolan DL, Le TP, Hedstrom RC, Coonan KM, Charoenvit Y, Jones TR, Hobart P, Margalith M, Ng J, Weiss WR, Sedegah M, de Taisne C, Norman JA, Hoffman SL. Induction of antigen-specific cytotoxic T lymphocytes in humans by a malaria DNA vaccine. Science 1998; 282:476-80. [PMID: 9774275 DOI: 10.1126/science.282.5388.476] [Citation(s) in RCA: 555] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
CD8+ cytotoxic T lymphocytes (CTLs) are critical for protection against intracellular pathogens but often have been difficult to induce by subunit vaccines in animals. DNA vaccines elicit protective CD8+ T cell responses. Malaria-naïve volunteers who were vaccinated with plasmid DNA encoding a malaria protein developed antigen-specific, genetically restricted, CD8+ T cell-dependent CTLs. Responses were directed against all 10 peptides tested and were restricted by six human lymphocyte antigen (HLA) class I alleles. This first demonstration in healthy naïve humans of the induction of CD8+ CTLs by DNA vaccines, including CTLs that were restricted by multiple HLA alleles in the same individual, provides a foundation for further human testing of this potentially revolutionary vaccine technology.
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Affiliation(s)
- R Wang
- Malaria Program, Naval Medical Research Institute, Bethesda, MD 20889-5607, USA
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24
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Wang R, Doolan DL, Charoenvit Y, Hedstrom RC, Gardner MJ, Hobart P, Tine J, Sedegah M, Fallarme V, Sacci JB, Kaur M, Klinman DM, Hoffman SL, Weiss WR. Simultaneous induction of multiple antigen-specific cytotoxic T lymphocytes in nonhuman primates by immunization with a mixture of four Plasmodium falciparum DNA plasmids. Infect Immun 1998; 66:4193-202. [PMID: 9712767 PMCID: PMC108505 DOI: 10.1128/iai.66.9.4193-4202.1998] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/1998] [Accepted: 06/04/1998] [Indexed: 01/04/2023] Open
Abstract
CD8(+) T cells have been implicated as critical effector cells in protective immunity against malaria parasites developing within hepatocytes. A vaccine that protects against malaria by inducing CD8(+) T cells will probably have to include multiple epitopes on the same protein or different proteins, because of parasite polymorphism and genetic restriction of T-cell responses. To determine if CD8(+) T-cell responses against multiple P. falciparum proteins can be induced in primates by immunization with plasmid DNA, rhesus monkeys were immunized intramuscularly with a mixture of DNA plasmids encoding four P. falciparum proteins or with individual plasmids. All six monkeys immunized with PfCSP DNA, seven of nine immunized with PfSSP2 DNA, and five of six immunized with PfExp-1 or PfLSA-1 DNA had detectable antigen-specific cytotoxic T lymphocytes (CTL) after in vitro restimulation of peripheral blood mononuclear cells. CTL activity was genetically restricted and dependent on CD8(+) T cells. By providing the first evidence for primates that immunization with a mixture of DNA plasmids induces CD8(+) T-cell responses against all the components of the mixture, these studies provide the foundation for multigene immunization of humans.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- CD8-Positive T-Lymphocytes/immunology
- DNA, Protozoan/immunology
- Humans
- Interferon-gamma/genetics
- Macaca mulatta
- Malaria Vaccines/genetics
- Malaria Vaccines/immunology
- Malaria, Falciparum/genetics
- Malaria, Falciparum/immunology
- Malaria, Falciparum/prevention & control
- Molecular Sequence Data
- Plasmids
- Plasmodium falciparum/immunology
- Primates
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- RNA, Messenger
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/parasitology
- Vaccination
- Vaccines, DNA/immunology
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Affiliation(s)
- R Wang
- Malaria Program, Naval Medical Research Institute, Bethesda, Maryland 20889, USA
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25
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Hedstrom RC, Doolan DL, Wang R, Kumar A, Sacci JB, Gardner MJ, Aguiar JC, Charoenvit Y, Sedegah M, Tine JA, Margalith M, Hobart P, Hoffman SL. In vitro expression and in vivo immunogenicity of Plasmodium falciparum pre-erythrocytic stage DNA vaccines. Int J Mol Med 1998; 2:29-38. [PMID: 9854139 DOI: 10.3892/ijmm.2.1.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
DNA vaccine plasmids were constructed that encoded four pre-erythrocytic antigens from the human malaria parasite Plasmodium falciparum: circumsporozoite protein (PfCSP); sporozoite surface protein 2 (PfSSP2); carboxyl terminus of liver stage antigen 1 (PfLSA-1 c-term); and, exported protein 1 (PfExp-1). Antigen expression was evaluated in vitro by immunoblot analysis of tissue culture cells following transient transfection with each plasmid. Clearly detectable levels of expression depended upon, or were markedly enhanced by, fusion of the antigen encoding sequences in-frame with the initiation complex and peptide leader sequence of human tissue plasminogen activator protein. Mice injected with these plasmids produced antigen specific antibody and cytotoxic T lymphocyte responses. However, the magnitudes of the responses were not always predicted by the in vitro expression assay. The results of this study provided the basis for further testing of these plasmids in primates and the formulation of multi-component pre-erythrocytic DNA vaccines for efficacy testing in human volunteers.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/biosynthesis
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- DNA, Protozoan/genetics
- DNA, Protozoan/immunology
- Humans
- Malaria Vaccines/genetics
- Malaria Vaccines/immunology
- Malaria Vaccines/therapeutic use
- Malaria, Falciparum/immunology
- Malaria, Falciparum/prevention & control
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Molecular Sequence Data
- Plasmids/genetics
- Plasmodium falciparum/genetics
- T-Lymphocytes, Cytotoxic/immunology
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- Vaccines, DNA/therapeutic use
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Affiliation(s)
- R C Hedstrom
- Malaria Program, Naval Medical Research Institute, Rockville, MD 20852, USA
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26
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Doolan DL, Hedstrom RC, Gardner MJ, Sedegah M, Wang H, Gramzinski RA, Margalith M, Hobart P, Hoffman SL. DNA vaccination as an approach to malaria control: current status and strategies. Curr Top Microbiol Immunol 1998; 226:37-56. [PMID: 9479834 DOI: 10.1007/978-3-642-80475-5_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Rockville, MD 20852, USA
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27
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Abstract
The potent protective immunity against malaria induced by immunization of mice and humans with radiation-attenuated Plasmodium spp. sporozoites is thought to be mediated primarily by T-cell responses directed against infected hepatocytes. This has led to considerable efforts to develop subunit vaccines that duplicate this protective immunity, but a universally effective vaccine is still not available and in vitro correlates of protective immunity have not been established. Contributing to this delay has been a lack of understanding of the mechanisms responsible for the protection. There are now data indicating that CD8+ T cells, CD4+ T cells, cytokines, and nitric oxide can all mediate the elimination of infected hepatocytes in vitro and in vivo. By dissecting the protection induced by immunization with irradiated sporozoite, DNA and synthetic peptide-adjuvant vaccines, we have demonstrated that different T-cell-dependent immune responses mediate protective immunity in the same inbred strain of mouse, depending on the method of immunization. Furthermore, the mechanism of protection induced by a single method of immunization may vary among different strains of mice. These data have important implications for the development of pre-erythrocytic-stage vaccines designed to protect a heterogeneous human population, and of assays that predict protective immunity.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Rockville, MD 20852, USA
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28
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Doolan DL, Hedstrom RC, Wang R, Sedegah M, Scheller LF, Hobart P, Norman JA, Hoffman SL. DNA vaccines for malaria: the past, the present, & the future. Indian J Med Res 1997; 106:109-19. [PMID: 9291681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The first clinical trial of a DNA vaccine designed to protect against malaria has just commenced. This vaccine has been designed to induce protective CD8+ T cell responses against Plasmodium falciparum infected hepatocytes. Herein, we review the rationale behind the development of vaccines that induce protective CD8+ T cells, the strategy for the development of a DNA vaccine designed to protect against falciparum malaria, and the experimental data in rodent models and nonhuman primates which has provided the foundation for trials of DNA vaccines against P. falciparum malaria in humans.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Bethesda, USA
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29
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Hoffman SL, Doolan DL, Sedegah M, Wang R, Scheller LF, Kumar A, Weiss WR, Le TP, Klinman DM, Hobart P, Norman JA, Hedstrom RC. Toward clinical trials of DNA vaccines against malaria. Immunol Cell Biol 1997; 75:376-81. [PMID: 9315481 DOI: 10.1038/icb.1997.59] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In mid 1997 the first malaria DNA vaccine will enter clinical trials. This single gene DNA vaccine encoding the Plasmodium falciparum circumsporozoite protein (PfCSP) will be studied for safety and immunogenicity. If these criteria are met, a multi-gene DNA vaccine designed to induce protective CD8+ T cell responses against P. falciparum infected hepatocytes will be subsequently assessed for safety, immunogenicity and capacity to protect immunized volunteers against experimental challenge with P. falciparum sporozoites. Our perspectives on malaria vaccine development in general, and on a multi-gene DNA vaccine in particular, have been recently reviewed. Herein, we review the rationale and experimental foundation for the anticipated P. falciparum DNA vaccine trials.
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Affiliation(s)
- S L Hoffman
- Malaria Program, Naval Medical Research Institute, Bethesda, Maryland 20852, USA.
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30
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Doolan DL, Hoffman SL, Southwood S, Wentworth PA, Sidney J, Chesnut RW, Keogh E, Appella E, Nutman TB, Lal AA, Gordon DM, Oloo A, Sette A. Degenerate cytotoxic T cell epitopes from P. falciparum restricted by multiple HLA-A and HLA-B supertype alleles. Immunity 1997; 7:97-112. [PMID: 9252123 DOI: 10.1016/s1074-7613(00)80513-0] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We recently described human leukocyte antigen (HLA) A2, A3 and B7 supertypes, characterized by largely overlapping peptide-binding specificities and represented in a high percentage of different populations. Here, we identified 17 Plasmodium falciparum peptides capable of binding these supertypes and assessed antigenicity in both vaccinated and naturally exposed populations. Positive cytotoxic T lymphocyte recall and cytokine (interferon-gamma and tumor necrosis factor alpha) responses were detected for all peptides; all were recognized in the context of more than one HLA class I molecule; and at least 12 of the 17 were recognized in the context of all HLA alleles studied. These data validate the concept of HLA supertypes at the biological level, show that highly degenerate peptides are almost always recognized as epitopes, and demonstrate the feasibility of developing a universally effective vaccine by focusing on a limited number of peptide specificities.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Bethesda, Maryland 20889-5670, USA
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Hoffman SL, Doolan DL, Sedegah M, Aguiar JC, Wang R, Malik A, Gramzinski RA, Weiss WR, Hobart P, Norman JA, Margalith M, Hedstrom RC. Strategy for development of a pre-erythrocytic Plasmodium falciparum DNA vaccine for human use. Vaccine 1997; 15:842-5. [PMID: 9234529 DOI: 10.1016/s0264-410x(96)00273-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Data generated in the Plasmodium yoelii rodent model indicated that plasmid DNA vaccines encoding the P.yoelii circumsporozoite protein (PyCSP) or 17 kDa hepatocyte erythrocyte protein (PyHEP17) were potent inducers of protective CD8+ T cell responses directed against infected hepatocytes. Immunization with a mixture of these plasmids circumvented the genetic restriction of protective immunity and induced additive protection. A third DNA vaccine encoding the P. yoelii sporozoite surface protein 2 (PySSP2) also induced protection. The P. falciparum genes encoding the homologues of these three protective P. yoelii antigens as well as another P. falciparum gene encoding a protein that is expressed in infected hepatocytes have been chosen for the development of a human vaccine. The optimal plasmid constructs for human use will be selected on the basis of immunogenicity data generated in mice and nonhuman primates. We anticipate that optimization of multi-gene P. falciparum DNA vaccines designed to protect against malaria by inducing CD8+ T cells that target infected hepatocytes will require extensive clinical trials during the coming years.
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Affiliation(s)
- S L Hoffman
- Malaria Program, Naval Medical Research Institute, Bethesda, MD 20889-5607, USA.
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32
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Abstract
An ideal malaria vaccine will induce immune responses against each stage of the Plasmodium spp life cycle. During its complicated life cycle, the parasite exists extracellularly in the host's bloodstream, within cells that express major histocompatibility complex (MHC) molecules (hepatocytes), within cells that do not express MHC molecules (erythrocytes) and within the mosquito vector. Different arms of the immune system are required to attack the parasite at the different stages. Therefore, a multistage vaccine must be a multi-immune response vaccine. In addition, given the unique antigenicities of the different stages of the life cycle, implicit in this definition is that the vaccine be multivalent. Here, Denise Doolan and Stephen Hoffman present the rationale for developing a multistage, multivalent, multi-immune response malaria vaccine and explain why, among currently available technologies, DNA vaccines may offer the best prospect for success.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, 12300 Washington Avenue, Rockville, MD 20852, USA. doolan@nmripo/.nmri.nnmc.navy.mil
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33
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Gardner MJ, Doolan DL, Hedstrom RC, Wang R, Sedegah M, Gramzinski RA, Aguiar JC, Wang H, Margalith M, Hobart P, Hoffman SL. DNA vaccines against malaria: immunogenicity and protection in a rodent model. J Pharm Sci 1996; 85:1294-300. [PMID: 8961142 DOI: 10.1021/js960147h] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Since the first demonstration of the technology a few years ago, DNA vaccines have emerged as a promising method of vaccination. In a variety of experimental systems, DNA vaccines have been shown not only to induce potent immune responses, but also to offer many advantages in terms of ease of construction, testing, and production. In this article we summarize the progress achieved in development of DNA vaccines that can protect mice from infection by the rodent malaria parasite Plasmodium yoelii, describe initial studies of immunogenicity of a malaria DNA vaccine in a primate model, and outline the strategies being employed to design the next generation of malaria DNA vaccines.
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Affiliation(s)
- M J Gardner
- School of Medicine, University of Maryland, Baltimore, MD 21201, USA
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34
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Doolan DL, Wizel B, Hoffman SL. Class I HLA-restricted cytotoxic T lymphocyte responses against malaria--elucidation on the basis of HLA peptide binding motifs. Immunol Res 1996; 15:280-305. [PMID: 8988396 DOI: 10.1007/bf02935313] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In animal models, CD8+ T cells are a critical effector mechanism in the protective immunity against malaria. Conventional approaches to the development of many vaccines, including those against malaria, have however proved inadequate. In particular, an alternative approach is needed for the development of vaccines designed to induce a cellular immune response mediated by CD8+ T cells. Advances in the field of molecular immunology during the past decade have provided an insight into the presentation of peptides by MHC class I molecules and their recognition by CD8+ T cells. These studies have provided a conceptual basis for the development of efficacious parasitic and viral vaccines. By a combination of immunochemical and cellular immunologic analyses based on specific peptide binding motifs, a subunit malaria vaccine that includes CD8+ T cell epitopes restricted by the most common class I HLA alleles, including HLA-A2, can now be constructed.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Rockville, MD 20852, USA
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35
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Doolan DL, Hedstrom RC, Rogers WO, Charoenvit Y, Rogers M, de la Vega P, Hoffman SL. Identification and characterization of the protective hepatocyte erythrocyte protein 17 kDa gene of Plasmodium yoelii, homolog of Plasmodium falciparum exported protein 1. J Biol Chem 1996; 271:17861-8. [PMID: 8663412 DOI: 10.1074/jbc.271.30.17861] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We recently reported the discovery of a 17-kDa Plasmodium yoelii protein expressed in infected hepatocytes and erythrocytes, P. yoelii hepatocyte erythrocyte protein 17 (PyHEP17), and have demonstrated that this protein is a target of protective antibodies and T cells. Here, we report the identification and characterization of the gene encoding this protein and reveal that it is composed of two exons. Immunization of mice with PyHEP17 plasmid DNA induces antibodies, cytotoxic T lymphocytes, and protective immunity directed against the infected hepatocyte. Based on extensive sequence homology, expression pattern, and antigenic cross-reactivity, the Plasmodium falciparum homolog of PyHEP17 is identified as the protein known as exported protein-1 (PfExp-1), also called antigen 5.1, circumsporozoite related antigen, or QF116. Identity between PyHEP17 and PfExp-1 is 37% at the amino acid level (60/161 residues), mapping primarily to two regions within the second exon of 73% (16/22 residues) and 71% (25/35 residues) identity. On this basis, PfExp-1 is proposed as an important component of pre-erythrocytic human malaria vaccines.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Bethesda, Maryland 20889-5607, USA
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36
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Doolan DL, Sedegah M, Hedstrom RC, Hobart P, Charoenvit Y, Hoffman SL. Circumventing genetic restriction of protection against malaria with multigene DNA immunization: CD8+ cell-, interferon gamma-, and nitric oxide-dependent immunity. J Exp Med 1996; 183:1739-46. [PMID: 8666931 PMCID: PMC2192484 DOI: 10.1084/jem.183.4.1739] [Citation(s) in RCA: 203] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Despite efforts to develop vaccines that protect against malaria by inducing CD8+ T cells that kill infected hepatocytes, no subunit vaccine has been shown to circumvent the genetic restriction inherent in this approach, and little is known about the interaction of subunit vaccine-induced immune effectors and infected hepatocytes. We now report that immunization with plasmid DNA encoding the plasmodium yoelii circumsporozoite protein protected one of five strains of mice against malaria (H-2d, 75%); a PyHEP17 DNA vaccine protected three of the five strains (H-2a, 71%; H-2k, 54%; H-2d, 26%); and the combination protected 82% of H-2a, 90% of H-2k, and 88% of H-2d mice. Protection was absolutely dependent on CD8+ T cells, INF-gamma, or nitric oxide. These data introduce a new target of protective preerythrocytic immune responses, PyHEP 17 and its P. falciparum homologue, and provide a realistic perspective on the opportunities and challenges inherent in developing malaria vaccines that target the infected hepatocyte.
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Affiliation(s)
- D L Doolan
- Malaria Program, Naval Medical Research Institute, Bethesda, Maryland 20889-5607, USA
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Hoffman SL, Doolan DL, Sedegah M, Gramzinski R, Wang H, Gowda K, Hobart P, Margalith M, Norman J, Hedstrom RC. Nucleic acid malaria vaccines. Current status and potential. Ann N Y Acad Sci 1995; 772:88-94. [PMID: 8546416 DOI: 10.1111/j.1749-6632.1995.tb44734.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- S L Hoffman
- Malaria Program Naval Medical Research Institute, Bethesda, Maryland 20889-5607, USA
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38
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Argaet VP, Schmidt CW, Burrows SR, Silins SL, Kurilla MG, Doolan DL, Suhrbier A, Moss DJ, Kieff E, Sculley TB, Misko IS. Dominant selection of an invariant T cell antigen receptor in response to persistent infection by Epstein-Barr virus. J Exp Med 1994; 180:2335-40. [PMID: 7964506 PMCID: PMC2191762 DOI: 10.1084/jem.180.6.2335] [Citation(s) in RCA: 237] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
To examine T cell receptor (TCR) diversity involved in the memory response to a persistent human pathogen, we determined nucleotide sequences encoding TCR-alpha and -beta chains from HLA-B8-restricted, CD8+ cytotoxic T cell clones specific for an immunodominant epitope (FLRGRAYGL) in Epstein-Barr virus (EBV) nuclear antigen 3. Herein, we show that identical TCR protein sequences are used by clones from each of four healthy unrelated virus carriers; a clone from a fifth varied conservatively at only two residues. This dominant selection of alpha and beta chain rearrangements suggest that a persistent viral infection can select for a highly focused memory response and indicates a strong bias in gene segment usage and recombination. A novel double-step semiquantitative polymerase chain reaction (PCR) procedure and direct sequencing of amplified TCR cDNA from fresh lymphocytes derived from three HLA-B8 individuals detected transcripts specific for the conserved beta chain in an EBV-seropositive donor but not in two seronegative donors. This report describes an unprecedented degree of conservation in TCR selected in response to a natural persistent infection.
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Affiliation(s)
- V P Argaet
- Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia
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Doolan DL, Beck HP, Good MF. Evidence for limited activation of distinct CD4+ T cell subsets in response to the Plasmodium falciparum circumsporozoite protein in Papua New Guinea. Parasite Immunol 1994; 16:129-36. [PMID: 7911566 DOI: 10.1111/j.1365-3024.1994.tb00332.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Both CD4+ and CD8+ T cells, as well as antibody, are known to be important in sporozoite immunity. Data from animal studies suggest that cytokines, in particular gamma-interferon and interleukin-6, are involved. The interplay of these various factors and their importance in vaccine development has, however, not yet been elucidated. In this study, we have studied cellular and humoral responses of individuals naturally exposed to malaria in a highly endemic region of Papua New Guinea to the circumsporozoite protein of Plasmodium falciparum, a prime vaccine candidate antigen. A paucity of any CD4+ lymphoproliferative response to this protein by Papua New Guineans was notable which parallels our recent observation of a paucity of CD8+ T cell response and contrasts markedly with the responses of other endemic populations. There was nevertheless a significant antibody response to the central conserved B cell epitope, (NANP)n, as well as to other critical epitopes. An inverse relationship between gamma-interferon production and interleukin-6 production and a positive correlation between gamma-interferon production and CS peptide-specific lymphoproliferation was observed. High levels of peptide-specific IL-6 production were associated with high levels of peptide-specific serum antibodies. Our data provide evidence for the limited activation of distinct CD4+ T cell subsets and for the existence of functionally distinct subpopulations of human CD4+ T cells with respect to cytokines known to be important in sporozoite immunity.
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Affiliation(s)
- D L Doolan
- Molecular Immunology Laboratory, Queensland Institute of Medical Research, Brisbane, Australia
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Doolan DL, Khamboonruang C, Beck HP, Houghten RA, Good MF. Cytotoxic T lymphocyte (CTL) low-responsiveness to the Plasmodium falciparum circumsporozoite protein in naturally-exposed endemic populations: analysis of human CTL response to most known variants. Int Immunol 1993; 5:37-46. [PMID: 7680226 DOI: 10.1093/intimm/5.1.37] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cytotoxic T lymphocytes (CTL) specific for epitope(s) within the circumsporozoite (CS) protein of malaria sporozoites have been shown to play an important role in protective immunity against malaria, at least in murine models. Their role in sporozoite immunity in the human host has, however, not yet been elucidated. Immunological non-responsiveness and antigenic diversity within T cell epitopes of the CS protein have been identified as potential problems in producing a sporozoite vaccine. These factors may contribute to the widespread lack of sporozoite immunity in endemic populations. In this study, 137 individuals with a history of natural endemic exposure to falciparum sporozoites (119 resident in north west Thailand and 18 resident in coastal Papua New Guinea) were tested for a CTL response to the Plasmodium falciparum CS protein. Fifty-four overlapping peptides, spanning the entire sequence of the CS protein of P. falciparum including most known variants, were studied. While most individuals had antibodies to the immunodominant B cell repeat, (NANP)n, and while CTL specific for an influenza virus matrix synthetic peptide could be generated from five of 23 Karen Thai individuals tested, no CS protein-specific CTL could be detected in these populations. Our data have important implications for vaccine programs.
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Affiliation(s)
- D L Doolan
- Molecular Immunology Unit, Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia
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41
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Doolan DL, Saul AJ, Good MF. Geographically restricted heterogeneity of the Plasmodium falciparum circumsporozoite protein: relevance for vaccine development. Infect Immun 1992; 60:675-82. [PMID: 1730503 PMCID: PMC257683 DOI: 10.1128/iai.60.2.675-682.1992] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The design of a subunit vaccine against the malaria parasite relies on the epitopes recognized by T cells being identified and polymorphisms therein being defined. Here we present the analysis of a 354-bp fragment of the circumsporozoite (CS) protein encompassing defined proliferative and cytotoxic T-cell recognition regions. We reveal that the polymorphism of CS protein T-cell sites appears to be very limited among Plasmodium falciparum isolates prevalent in certain geographical regions, in particular Papua New Guinea. Furthermore, the more extensive polymorphism noted in other areas appears to be restricted. Although the extent of variation observed for the T-cell recognition domains suggests that any vaccine designed to stimulate this form of immunity will need to be polyvalent, this variation appears to be finite and the combination of peptides necessary for inclusion in a polyvalent vaccine may be small. If ways to increase immune responsiveness can be found, then a vaccine designed to stimulate CS protein-specific T-cell activity may prevent malaria.
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Affiliation(s)
- D L Doolan
- Tropical Health Program, Queensland Institute of Medical Research, Bancroft Centre, Brisbane, Australia
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42
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Doolan DL, Good MF. Plasmodium falciparum CS protein--prime malaria vaccine candidate: definition of the human CTL domain and analysis of its variation. Mem Inst Oswaldo Cruz 1992; 87 Suppl 3:241-7. [PMID: 1285314 DOI: 10.1590/s0074-02761992000700040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Studies in mice have shown that immunity to malaria sporozoites is mediated primarily by cytotoxic T lymphocytes (CTL) specific for epitopes within the circumsporozoite (CS) protein. Humans, however, had never been shown to generate CTL against any malaria or other parasite protein. The design of a sub-unit vaccine for humans relies on the epitopes recognized by CTL being identified and polymorphisms therein being defined. We have developed a novel technique using an entire series of overlapping synthetic peptides to define the epitopes of the Plasmodium falciparum CS protein recognized by human CTL and have analyzed the sequence variation of the protein with respect to the identified CTL epitopic domain. We have demonstrated that some humans can indeed generate CTL against the P. falciparum CS protein. Furthermore, the extent of variation observed for the CTL recognition domain is finite and the combination of peptides necessary for inclusion in a polyvalent vaccine may be small. If ways can be found to increase immune responsiveness, then a vaccine designed to stimulate CS protein-specific CTL activity may prevent malaria.
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Affiliation(s)
- D L Doolan
- Tropical Health Program, Queensland Institute of Medical Research, Herston, Brisbane, Australia
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43
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Doolan DL, Houghten RA, Good MF. Location of human cytotoxic T cell epitopes within a polymorphic domain of the Plasmodium falciparum circumsporozoite protein. Int Immunol 1991; 3:511-6. [PMID: 1716144 DOI: 10.1093/intimm/3.6.511] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Studies in mice have shown that cytotoxic T lymphocytes (CTL) specific for epitopes within the circumsporozoite (CS) protein of malaria sporozoites can prevent malaria probably by destroying infected hepatocytes. This has provided a model for the development of a sporozoite vaccine. It has not been shown whether humans can mount a CTL response to this protein nor what determinants on the protein could be considered as target epitopes for such cells and thus merit inclusion in a sporozoite vaccine. We have used a novel technique to study a caucasian population which would benefit from a sporozoite vaccine and have been able to demonstrate that some individuals with a history of sporozoite exposure do contain peripheral blood CTL specific for the Plasmodium falciparum CS protein. The prevalence of CTL among different individuals is low and there is evidence that recent malaria exposure may be a prerequisite for finding such CTL. In three individuals, CTL could be repeatedly found and in all cases the epitopes mapped to one of the two polymorphic C-terminal domains. Using a CTL line, we mapped a recognition site to residues 351-395 of the CS protein, overlapping the region of the protein recognized by murine CTL.
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Affiliation(s)
- D L Doolan
- Tropical Health Program, Queensland Institute of Medical Research, Brisbane, Australia
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44
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Doolan DL, Houghten RA, Good MF. Assessment of human cytotoxic T cell activity using synthetic peptides: potential for field application. Pept Res 1991; 4:125-31. [PMID: 1726648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The use of synthetic peptides to delineate epitopes recognized by major histocompatability complex-restricted cytotoxic T lymphocytes has been well documented. In the present study, we report a method for the generation and assay of peptide-specific cytotoxic T lymphocytes adapted for the field situation where quantities of blood are often limited. From a single bleed of the donor and using minimal quantities of peptide (less than 5 micrograms/ml), up to 100 potential epitopes could be screened within a short time frame. Subsequent cloning of positive cultures for further analysis of defined epitopes is permissible. The system is readily adaptable to a wide range of viral, parasitic or bacterial infections.
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Affiliation(s)
- D L Doolan
- Tropical Health Program, Queensland Institute of Medical Research, Herston, Brisbane, Australia
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45
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Abstract
The proteins of bovine ephemeral fever virus (BEFV) were examined in purified virions and in infected BHK-21 cells. Five structural proteins were named L (180K), G (81K), N (52K), M1 (43K) and M2 (29K). The 81K G protein incorporated [3H]glucosamine, was removed from virions by treatment with Triton X-100 and bound monoclonal antibodies which were both neutralizing and protective. Treatment of virions with Triton X-100 and 0.2 to 1.0 M-NaCl progressively released L, M1 and M2. The N protein remained associated with nucleocapsids in up to 2.5 M-NaCl. The glycoprotein (G), nucleoprotein (N) and matrix protein (M2) were phosphorylated. In BEFV-infected BHK-21 cells, five virus-induced proteins were detected from 12 h post-infection. The L, N, M1 and M2 proteins corresponded to those detected in virions whereas the G protein existed in two forms. In tunicamycin-treated cells these occurred as 67K and 71K non-glycosylated precursors. In the absence of tunicamycin, 77K and 79K glycosylated forms were further modified to produce the 81K virion G protein and a 90K cell-associated form. Five viral proteins were also detected in cells infected with the closely related Berrimah virus; the Berrimah virus G protein was also present in two forms.
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Affiliation(s)
- P J Walker
- CSIRO, Division of Tropical Animal Production, Indooroopilly, Queensland, Australia
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