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Silk SE, Kalinga WF, Mtaka IM, Lilolime NS, Mpina M, Milando F, Ahmed S, Diouf A, Mkwepu F, Simon B, Athumani T, Rashid M, Mohammed L, Lweno O, Ali AM, Nyaulingo G, Mwalimu B, Mswata S, Mwamlima TG, Barrett JR, Wang LT, Themistocleous Y, King LDW, Hodgson SH, Payne RO, Nielsen CM, Lawrie AM, Nugent FL, Cho JS, Long CA, Miura K, Draper SJ, Minassian AM, Olotu AI. Superior antibody immunogenicity of a viral-vectored RH5 blood-stage malaria vaccine in Tanzanian infants as compared to adults. MED 2023; 4:668-686.e7. [PMID: 37572659 DOI: 10.1016/j.medj.2023.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/23/2023] [Accepted: 07/11/2023] [Indexed: 08/14/2023]
Abstract
BACKGROUND RH5 is a leading blood-stage candidate antigen for a Plasmodium falciparum vaccine; however, its safety and immunogenicity in malaria-endemic populations are unknown. METHODS A phase 1b, single-center, dose-escalation, age-de-escalation, double-blind, randomized, controlled trial was conducted in Bagamoyo, Tanzania (NCT03435874). Between 12th April and 25th October 2018, 63 healthy adults (18-35 years), young children (1-6 years), and infants (6-11 months) received a priming dose of viral-vectored ChAd63 RH5 or rabies control vaccine. Sixty participants were boosted with modified vaccinia virus Ankara (MVA) RH5 or rabies control vaccine 8 weeks later and completed 6 months of follow-up post priming. Primary outcomes were the number of solicited and unsolicited adverse events post vaccination and the number of serious adverse events over the study period. Secondary outcomes included measures of the anti-RH5 immune response. FINDINGS Vaccinations were well tolerated, with profiles comparable across groups. No serious adverse events were reported. Vaccination induced RH5-specific cellular and humoral responses. Higher anti-RH5 serum immunoglobulin G (IgG) responses were observed post boost in young children and infants compared to adults. Vaccine-induced antibodies showed growth inhibition activity (GIA) in vitro against P. falciparum blood-stage parasites; their highest levels were observed in infants. CONCLUSIONS The ChAd63-MVA RH5 vaccine shows acceptable safety and reactogenicity and encouraging immunogenicity in children and infants residing in a malaria-endemic area. The levels of functional GIA observed in RH5-vaccinated infants are the highest reported to date following human vaccination. These data support onward clinical development of RH5-based blood-stage vaccines to protect against clinical malaria in young African infants. FUNDING Medical Research Council, London, UK.
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Affiliation(s)
- Sarah E Silk
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Wilmina F Kalinga
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Ivanny M Mtaka
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Nasoro S Lilolime
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Maximillian Mpina
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Florence Milando
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Saumu Ahmed
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Fatuma Mkwepu
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Beatus Simon
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Thabit Athumani
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Mohammed Rashid
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Latipha Mohammed
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Omary Lweno
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Ali M Ali
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Gloria Nyaulingo
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Bakari Mwalimu
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Sarah Mswata
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Tunu G Mwamlima
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
| | - Jordan R Barrett
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Lawrence T Wang
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Yrene Themistocleous
- Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK
| | - Lloyd D W King
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Susanne H Hodgson
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Ruth O Payne
- Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK
| | - Carolyn M Nielsen
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Alison M Lawrie
- Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK
| | - Fay L Nugent
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK
| | - Jee-Sun Cho
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK
| | - Carole A Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, MD 20852, USA
| | - Simon J Draper
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Angela M Minassian
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; Centre for Clinical Vaccinology and Tropical Medicine, Jenner Institute, University of Oxford, Old Road Campus, Oxford OX3 7LE, UK; Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, Oxford OX1 3QU, UK; NIHR Oxford Biomedical Research Centre, Oxford, UK.
| | - Ally I Olotu
- Interventions and Clinical Trials Department, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania
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A Chimeric Plasmodium vivax Merozoite Surface Protein Antibody Recognizes and Blocks Erythrocytic P. cynomolgi Berok Merozoites In Vitro. Infect Immun 2021; 89:IAI.00645-20. [PMID: 33199351 DOI: 10.1128/iai.00645-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 01/22/2023] Open
Abstract
Research on erythrocytic Plasmodium vivax merozoite antigens is critical for identifying potential vaccine candidates in reducing P. vivax disease. However, many P. vivax studies are constrained by its inability to undergo long-term culture in vitro Conserved across all Plasmodium spp., merozoite surface proteins are essential for invasion into erythrocytes and highly expressed on erythrocytic merozoites, thus making it an ideal vaccine candidate. In clinical trials, the P. vivax merozoite surface protein 1 (PvMSP1-19) vaccine candidate alone has shown to have limited immunogenicity in patients; hence, we incorporate the highly conserved and immunogenic C terminus of both P. vivax merozoite surface protein 8 (PvMSP8) and PvMSP1-19 to develop a multicomponent chimeric protein rPvMSP8+1 for immunization of mice. The resulted chimeric rPvMSP8+1 antibody was shown to recognize native protein MSP8 and MSP1-19 of mature P. vivax schizonts. In the immunized mice, an elevated antibody response was observed in the rPvMSP8+1-immunized group compared to that immunized with single-antigen components. In addition, we examined the growth inhibition of these antibodies against Plasmodium cynomolgi (Berok strain) parasites, which is phylogenetically close to P. vivax and sustains long-term culture in vitro Similarly, the chimeric anti-rPvMSP8+1 antibodies recognize P. cynomolgi MSP8 and MSP1-19 on mature schizonts and showed strong inhibition in vitro via growth inhibition assay. This study provides support for a new multiantigen-based paradigm rPvMSP8+1 to explore potential chimeric vaccine candidates against P. vivax malaria using sister species P. cynomolgi.
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Immunization with full-length Plasmodium falciparum merozoite surface protein 1 is safe and elicits functional cytophilic antibodies in a randomized first-in-human trial. NPJ Vaccines 2020; 5:10. [PMID: 32025341 PMCID: PMC6994672 DOI: 10.1038/s41541-020-0160-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/14/2020] [Indexed: 12/20/2022] Open
Abstract
A vaccine remains a priority in the global fight against malaria. Here, we report on a single-center, randomized, double-blind, placebo and adjuvant-controlled, dose escalation phase 1a safety and immunogenicity clinical trial of full-length Plasmodium falciparum merozoite surface protein 1 (MSP1) in combination with GLA-SE adjuvant. Thirty-two healthy volunteers were vaccinated at least three times with MSP1 plus adjuvant, adjuvant alone, or placebo (24:4:4) to evaluate the safety and immunogenicity. MSP1 was safe, well tolerated and immunogenic, with all vaccinees sero-converting independent of the dose. The MSP1-specific IgG and IgM titers persisted above levels found in malaria semi-immune humans for at least 6 months after the last immunization. The antibodies were variant- and strain-transcending and stimulated respiratory activity in granulocytes. Furthermore, full-length MSP1 induced memory T-cells. Our findings encourage challenge studies as the next step to evaluate the efficacy of full-length MSP1 as a vaccine candidate against falciparum malaria (EudraCT 2016-002463-33).
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Rühl J, Citterio C, Engelmann C, Haigh T, Dzionek A, Dreyer J, Khanna R, Taylor GS, Wilson JB, Leung CS, Münz C. Heterologous prime-boost vaccination protects against EBV antigen-expressing lymphomas. J Clin Invest 2019; 129:2071-2087. [PMID: 31042161 DOI: 10.1172/jci125364] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 03/05/2019] [Indexed: 02/06/2023] Open
Abstract
The Epstein-Barr virus (EBV) is one of the predominant tumor viruses in humans, but so far no therapeutic or prophylactic vaccination against this transforming pathogen is available. We demonstrated that heterologous prime-boost vaccination with the nuclear antigen 1 of EBV (EBNA1), either targeted to the DEC205 receptor on DCs or expressed from a recombinant modified vaccinia virus Ankara (MVA) vector, improved priming of antigen-specific CD4+ T cell help. This help supported the expansion and maintenance of EBNA1-specific CD8+ T cells that are most efficiently primed by recombinant adenoviruses that encode EBNA1. These combined CD4+ and CD8+ T cell responses protected against EBNA1-expressing T and B cell lymphomas, including lymphoproliferations that emerged spontaneously after EBNA1 expression. In particular, the heterologous EBNA1-expressing adenovirus, boosted by EBNA1-encoding MVA vaccination, demonstrated protection as a prophylactic and therapeutic treatment for the respective lymphoma challenges. Our study shows that such heterologous prime-boost vaccinations against EBV-associated malignancies as well as symptomatic primary EBV infection should be further explored for clinical development.
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Affiliation(s)
- Julia Rühl
- Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Carmen Citterio
- Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Christine Engelmann
- Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Tracey Haigh
- Cancer Immunology and Immunotherapy Centre, University of Birmingham, Birmingham, United Kingdom
| | | | - Johannes Dreyer
- Institute for Pathology, Unfallkrankenhaus Berlin, Berlin, Germany
| | - Rajiv Khanna
- QIMR Berghofer Centre for Immunotherapy and Vaccine Development and Tumour Immunology Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Graham S Taylor
- Cancer Immunology and Immunotherapy Centre, University of Birmingham, Birmingham, United Kingdom
| | - Joanna B Wilson
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Carol S Leung
- University of Oxford, Nuffield Department of Medicine, Ludwig Institute for Cancer Research, Oxford, United Kingdom
| | - Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
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Payne RO, Silk SE, Elias SC, Miura K, Diouf A, Galaway F, de Graaf H, Brendish NJ, Poulton ID, Griffiths OJ, Edwards NJ, Jin J, Labbé GM, Alanine DG, Siani L, Di Marco S, Roberts R, Green N, Berrie E, Ishizuka AS, Nielsen CM, Bardelli M, Partey FD, Ofori MF, Barfod L, Wambua J, Murungi LM, Osier FH, Biswas S, McCarthy JS, Minassian AM, Ashfield R, Viebig NK, Nugent FL, Douglas AD, Vekemans J, Wright GJ, Faust SN, Hill AV, Long CA, Lawrie AM, Draper SJ. Human vaccination against RH5 induces neutralizing antimalarial antibodies that inhibit RH5 invasion complex interactions. JCI Insight 2017; 2:96381. [PMID: 29093263 PMCID: PMC5752323 DOI: 10.1172/jci.insight.96381] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/05/2017] [Indexed: 11/17/2022] Open
Abstract
The development of a highly effective vaccine remains a key strategic goal to aid the control and eventual eradication of Plasmodium falciparum malaria. In recent years, the reticulocyte-binding protein homolog 5 (RH5) has emerged as the most promising blood-stage P. falciparum candidate antigen to date, capable of conferring protection against stringent challenge in Aotus monkeys. We report on the first clinical trial to our knowledge to assess the RH5 antigen - a dose-escalation phase Ia study in 24 healthy, malaria-naive adult volunteers. We utilized established viral vectors, the replication-deficient chimpanzee adenovirus serotype 63 (ChAd63), and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA), encoding RH5 from the 3D7 clone of P. falciparum. Vaccines were administered i.m. in a heterologous prime-boost regimen using an 8-week interval and were well tolerated. Vaccine-induced anti-RH5 serum antibodies exhibited cross-strain functional growth inhibition activity (GIA) in vitro, targeted linear and conformational epitopes within RH5, and inhibited key interactions within the RH5 invasion complex. This is the first time to our knowledge that substantial RH5-specific responses have been induced by immunization in humans, with levels greatly exceeding the serum antibody responses observed in African adults following years of natural malaria exposure. These data support the progression of RH5-based vaccines to human efficacy testing.
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Affiliation(s)
- Ruth O. Payne
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Sarah E. Silk
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Sean C. Elias
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Francis Galaway
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Hans de Graaf
- NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton NHS Foundation Trust and Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Nathan J. Brendish
- NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton NHS Foundation Trust and Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Ian D. Poulton
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Nick J. Edwards
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jing Jin
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Loredana Siani
- ReiThera SRL (formerly Okairos SRL), Viale Città d’Europa, Rome, Italy
| | - Stefania Di Marco
- ReiThera SRL (formerly Okairos SRL), Viale Città d’Europa, Rome, Italy
| | - Rachel Roberts
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Nicky Green
- Clinical Biomanufacturing Facility, University of Oxford, Oxford, United Kingdom
| | - Eleanor Berrie
- Clinical Biomanufacturing Facility, University of Oxford, Oxford, United Kingdom
| | | | | | - Martino Bardelli
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Frederica D. Partey
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Michael F. Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Lea Barfod
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Juliana Wambua
- KEMRI Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Linda M. Murungi
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
- KEMRI Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Faith H. Osier
- KEMRI Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Sumi Biswas
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - James S. McCarthy
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | | | - Rebecca Ashfield
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Nicola K. Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Heidelberg, Germany
| | - Fay L. Nugent
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Gavin J. Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Saul N. Faust
- NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton NHS Foundation Trust and Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Adrian V.S. Hill
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, NIAID/NIH, Rockville, Maryland, USA
| | - Alison M. Lawrie
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Simon J. Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
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Healer J, Cowman AF, Kaslow DC, Birkett AJ. Vaccines to Accelerate Malaria Elimination and Eventual Eradication. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025627. [PMID: 28490535 DOI: 10.1101/cshperspect.a025627] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Remarkable progress has been made in coordinated malaria control efforts with substantial reductions in malaria-associated deaths and morbidity achieved through mass administration of drugs and vector control measures including distribution of long-lasting insecticide-impregnated bednets and indoor residual spraying. However, emerging resistance poses a significant threat to the sustainability of these interventions. In this light, the malaria research community has been charged with the development of a highly efficacious vaccine to complement existing malaria elimination measures. As the past 40 years of investment in this goal attests, this is no small feat. The malaria parasite is a highly complex organism, exquisitely adapted for survival under hostile conditions within human and mosquito hosts. Here we review current vaccine strategies to accelerate elimination and the potential for novel and innovative approaches to vaccine design through a better understanding of the host-parasite interaction.
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Affiliation(s)
- Julie Healer
- Walter & Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia
| | - Alan F Cowman
- Walter & Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia
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Amorim KNS, Rampazo EV, Antonialli R, Yamamoto MM, Rodrigues MM, Soares IS, Boscardin SB. The presence of T cell epitopes is important for induction of antibody responses against antigens directed to DEC205 + dendritic cells. Sci Rep 2016; 6:39250. [PMID: 28000705 PMCID: PMC5175286 DOI: 10.1038/srep39250] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/22/2016] [Indexed: 11/08/2022] Open
Abstract
In vivo antigen targeting to dendritic cells (DCs) has been used as a way to improve immune responses. Targeting is accomplished with the use of monoclonal antibodies (mAbs) to receptors present on the DC surface fused with the antigen of interest. An anti-DEC205 mAb has been successfully used to target antigens to the DEC205+CD8α+ DC subset. The administration of low doses of the hybrid mAb together with DC maturation stimuli is able to activate specific T cells and induce production of high antibody titres for a number of different antigens. However, it is still not known if this approach would work with any fused protein. Here we genetically fused the αDEC205 mAb with two fragments (42-kDa and 19-kDa) derived from the ~200 kDa Plasmodium vivax merozoite surface protein 1 (MSP1), known as MSP142 and MSP119, respectively. The administration of two doses of αDEC-MSP142, but not of αDEC-MSP119 mAb, together with an adjuvant to two mouse strains induced high anti-MSP119 antibody titres that were dependent on CD4+ T cells elicited by peptides present in the MSP133 sequence, indicating that the presence of T cell epitopes in antigens targeted to DEC205+ DCs increases antibody responses.
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Affiliation(s)
- Kelly N. S. Amorim
- Laboratory of Antigen Targeting to Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Eline V. Rampazo
- Laboratory of Antigen Targeting to Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Renan Antonialli
- Laboratory of Antigen Targeting to Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Marcio M. Yamamoto
- Laboratory of Antigen Targeting to Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Mauricio M. Rodrigues
- CTCMol, Federal University of São Paulo, São Paulo, 04044-010, Brazil
- National Institute for Science and Technology in Vaccines, Belo Horizonte, 31270-910, Brazil
| | - Irene S. Soares
- National Institute for Science and Technology in Vaccines, Belo Horizonte, 31270-910, Brazil
- Department of Clinical and Toxicological Analysis, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, 05508-900, Brazil
| | - Silvia B. Boscardin
- Laboratory of Antigen Targeting to Dendritic Cells, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, 05508-000, Brazil
- National Institute for Science and Technology in Vaccines, Belo Horizonte, 31270-910, Brazil
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8
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A chimeric protein-based malaria vaccine candidate induces robust T cell responses against Plasmodium vivax MSP1 19. Sci Rep 2016; 6:34527. [PMID: 27708348 PMCID: PMC5052570 DOI: 10.1038/srep34527] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 09/15/2016] [Indexed: 01/06/2023] Open
Abstract
The most widespread Plasmodium species, Plasmodium vivax, poses a significant public health threat. An effective vaccine is needed to reduce global malaria burden. Of the erythrocytic stage vaccine candidates, the 19 kDa fragment of the P. vivax Merozoite Surface Protein 1 (PvMSP119) is one of the most promising. Our group has previously defined several promiscuous T helper epitopes within the PvMSP1 protein, with features that allow them to bind multiple MHC class II alleles. We describe here a P. vivax recombinant modular chimera based on MSP1 (PvRMC-MSP1) that includes defined T cell epitopes genetically fused to PvMSP119. This vaccine candidate preserved structural elements of the native PvMSP119 and elicited cytophilic antibody responses, and CD4+ and CD8+ T cells capable of recognizing PvMSP119. Although CD8+ T cells that recognize blood stage antigens have been reported to control blood infection, CD8+ T cell responses induced by P. falciparum or P. vivax vaccine candidates based on MSP119 have not been reported. To our knowledge, this is the first time a protein based subunit vaccine has been able to induce CD8+ T cell against PvMSP119. The PvRMC-MSP1 protein was also recognized by naturally acquired antibodies from individuals living in malaria endemic areas with an antibody profile associated with protection from infection. These features make PvRMC-MSP1 a promising vaccine candidate.
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Blagborough AM, Musiychuk K, Bi H, Jones RM, Chichester JA, Streatfield S, Sala KA, Zakutansky SE, Upton LM, Sinden RE, Brian I, Biswas S, Sattabonkot J, Yusibov V. Transmission blocking potency and immunogenicity of a plant-produced Pvs25-based subunit vaccine against Plasmodium vivax. Vaccine 2016; 34:3252-9. [PMID: 27177945 PMCID: PMC4915602 DOI: 10.1016/j.vaccine.2016.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 04/06/2016] [Accepted: 05/03/2016] [Indexed: 01/18/2023]
Abstract
Malaria transmission blocking (TB) vaccines (TBVs) directed against proteins expressed on the sexual stages of Plasmodium parasites are a potentially effective means to reduce transmission. Antibodies induced by TBVs block parasite development in the mosquito, and thus inhibit transmission to further human hosts. The ookinete surface protein P25 is a primary target for TBV development. Recently, transient expression in plants using hybrid viral vectors has demonstrated potential as a strategy for cost-effective and scalable production of recombinant vaccines. Using a plant virus-based expression system, we produced recombinant P25 protein of Plasmodium vivax (Pvs25) in Nicotiana benthamiana fused to a modified lichenase carrier protein. This candidate vaccine, Pvs25-FhCMB, was purified, characterized and evaluated for immunogenicity and efficacy using multiple adjuvants in a transgenic rodent model. An in vivo TB effect of up to a 65% reduction in intensity and 54% reduction in prevalence was observed using Abisco-100 adjuvant. The ability of this immunogen to induce a TB response was additionally combined with heterologous prime-boost vaccination with viral vectors expressing Pvs25. Significant blockade was observed when combining both platforms, achieving a 74% and 68% reduction in intensity and prevalence, respectively. This observation was confirmed by direct membrane feeding on field P. vivax samples, resulting in reductions in intensity/prevalence of 85.3% and 25.5%. These data demonstrate the potential of this vaccine candidate and support the feasibility of expressing Plasmodium antigens in a plant-based system for the production of TBVs, while demonstrating the potential advantages of combining multiple vaccine delivery systems to maximize efficacy.
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Affiliation(s)
- A M Blagborough
- Department of Life Sciences, Sir Alexander Fleming Building, Imperial College London, Imperial College Road, South Kensington, London SW7 2AZ, UK.
| | - K Musiychuk
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
| | - H Bi
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
| | - R M Jones
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
| | - J A Chichester
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
| | - S Streatfield
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
| | - K A Sala
- Department of Life Sciences, Sir Alexander Fleming Building, Imperial College London, Imperial College Road, South Kensington, London SW7 2AZ, UK
| | - S E Zakutansky
- Department of Life Sciences, Sir Alexander Fleming Building, Imperial College London, Imperial College Road, South Kensington, London SW7 2AZ, UK
| | - L M Upton
- Department of Life Sciences, Sir Alexander Fleming Building, Imperial College London, Imperial College Road, South Kensington, London SW7 2AZ, UK
| | - R E Sinden
- Jenner Institute, The University of Oxford, Roosevelt Road, Oxford OX9 2PP, UK
| | - I Brian
- Jenner Institute, The University of Oxford, Roosevelt Road, Oxford OX9 2PP, UK
| | - S Biswas
- Jenner Institute, The University of Oxford, Roosevelt Road, Oxford OX9 2PP, UK
| | - J Sattabonkot
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
| | - V Yusibov
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE, USA
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Tailoring a Combination Preerythrocytic Malaria Vaccine. Infect Immun 2015; 84:622-34. [PMID: 26667840 PMCID: PMC4771343 DOI: 10.1128/iai.01063-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/27/2015] [Indexed: 12/20/2022] Open
Abstract
The leading malaria vaccine candidate, RTS,S, based on the Plasmodium falciparum circumsporozoite protein (CSP), will likely be the first publicly adopted malaria vaccine. However, this and other subunit vaccines, such as virus-vectored thrombospondin-related adhesive protein (TRAP), provide only intermediate to low levels of protection. In this study, the Plasmodium berghei homologues of antigens CSP and TRAP are combined. TRAP is delivered using adenovirus- and vaccinia virus-based vectors in a prime-boost regime. Initially, CSP is also delivered using these viral vectors; however, a reduction of anti-CSP antibodies is seen when combined with virus-vectored TRAP, and the combination is no more protective than either subunit vaccine alone. Using an adenovirus-CSP prime, protein-CSP boost regime, however, increases anti-CSP antibody titers by an order of magnitude, which is maintained when combined with virus-vectored TRAP. This combination regime using protein CSP provided 100% protection in C57BL/6 mice compared to no protection using virus-vectored TRAP alone and 40% protection using adenovirus-CSP prime and protein-CSP boost alone. This suggests that a combination of CSP and TRAP subunit vaccines could enhance protection against malaria.
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Abstract
A safe and effective malaria vaccine is a crucial part of the roadmap to malaria elimination/eradication by the year 2050. Viral-vectored vaccines based on adenoviruses and modified vaccinia virus Ankara (MVA) expressing malaria immunogens are currently being used in heterologous prime-boost regimes in clinical trials for induction of strong antigen-specific T-cell responses and high-titer antibodies. Recombinant MVA is a safe and well-tolerated attenuated vector that has consistently shown significant boosting potential. Advances have been made in large-scale MVA manufacture as high-yield producer cell lines and high-throughput purification processes have recently been developed. This review describes the use of MVA as malaria vaccine vector in both preclinical and clinical studies in the past 5 years.
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12
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Nahrendorf W, Scholzen A, Sauerwein RW, Langhorne J. Cross-stage immunity for malaria vaccine development. Vaccine 2015; 33:7513-7. [PMID: 26469724 PMCID: PMC4687527 DOI: 10.1016/j.vaccine.2015.09.098] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 09/11/2015] [Accepted: 09/28/2015] [Indexed: 11/17/2022]
Abstract
A vaccine against malaria is urgently needed for control and eventual eradication. Different approaches are pursued to induce either sterile immunity directed against pre-erythrocytic parasites or to mimic naturally acquired immunity by controlling blood-stage parasite densities and disease severity. Pre-erythrocytic and blood-stage malaria vaccines are often seen as opposing tactics, but it is likely that they have to be combined into a multi-stage malaria vaccine to be optimally safe and effective. Since many antigenic targets are shared between liver- and blood-stage parasites, malaria vaccines have the potential to elicit cross-stage protection with immune mechanisms against both stages complementing and enhancing each other. Here we discuss evidence from pre-erythrocytic and blood-stage subunit and whole parasite vaccination approaches that show that protection against malaria is not necessarily stage-specific. Parasites arresting at late liver-stages especially, can induce powerful blood-stage immunity, and similarly exposure to blood-stage parasites can afford pre-erythrocytic immunity. The incorporation of a blood-stage component into a multi-stage malaria vaccine would hence not only combat breakthrough infections in the blood should the pre-erythrocytic component fail to induce sterile protection, but would also actively enhance the pre-erythrocytic potency of this vaccine. We therefore advocate that future studies should concentrate on the identification of cross-stage protective malaria antigens, which can empower multi-stage malaria vaccine development.
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Affiliation(s)
- Wiebke Nahrendorf
- Mill Hill Laboratory, The Francis Crick Institute, London, United Kingdom; Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Anja Scholzen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Jean Langhorne
- Mill Hill Laboratory, The Francis Crick Institute, London, United Kingdom.
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13
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Abstract
The development of a highly effective malaria vaccine remains a key goal to aid in the control and eventual eradication of this devastating parasitic disease. The field has made huge strides in recent years, with the first-generation vaccine RTS,S showing modest efficacy in a Phase III clinical trial. The updated 2030 Malaria Vaccine Technology Roadmap calls for a second generation vaccine to achieve 75% efficacy over two years for both Plasmodium falciparum and Plasmodium vivax, and for a vaccine that can prevent malaria transmission. Whole-parasite immunisation approaches and combinations of pre-erythrocytic subunit vaccines are now reporting high-level efficacy, whilst exciting new approaches to the development of blood-stage and transmission-blocking vaccine subunit components are entering clinical development. The development of a highly effective multi-component multi-stage subunit vaccine now appears to be a realistic ambition. This review will cover these recent developments in malaria vaccinology.
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Assessment of humoral immune responses to blood-stage malaria antigens following ChAd63-MVA immunization, controlled human malaria infection and natural exposure. PLoS One 2014; 9:e107903. [PMID: 25254500 PMCID: PMC4177865 DOI: 10.1371/journal.pone.0107903] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 08/17/2014] [Indexed: 11/19/2022] Open
Abstract
The development of protective vaccines against many difficult infectious pathogens will necessitate the induction of effective antibody responses. Here we assess humoral immune responses against two antigens from the blood-stage merozoite of the Plasmodium falciparum human malaria parasite--MSP1 and AMA1. These antigens were delivered to healthy malaria-naïve adult volunteers in Phase Ia clinical trials using recombinant replication-deficient viral vectors--ChAd63 to prime the immune response and MVA to boost. In subsequent Phase IIa clinical trials, immunized volunteers underwent controlled human malaria infection (CHMI) with P. falciparum to assess vaccine efficacy, whereby all but one volunteer developed low-density blood-stage parasitemia. Here we assess serum antibody responses against both the MSP1 and AMA1 antigens following i) ChAd63-MVA immunization, ii) immunization and CHMI, and iii) primary malaria exposure in the context of CHMI in unimmunized control volunteers. Responses were also assessed in a cohort of naturally-immune Kenyan adults to provide comparison with those induced by a lifetime of natural malaria exposure. Serum antibody responses against MSP1 and AMA1 were characterized in terms of i) total IgG responses before and after CHMI, ii) responses to allelic variants of MSP1 and AMA1, iii) functional growth inhibitory activity (GIA), iv) IgG avidity, and v) isotype responses (IgG1-4, IgA and IgM). These data provide the first in-depth assessment of the quality of adenovirus-MVA vaccine-induced antibody responses in humans, along with assessment of how these responses are modulated by subsequent low-density parasite exposure. Notable differences were observed in qualitative aspects of the human antibody responses against these malaria antigens depending on the means of their induction and/or exposure of the host to the malaria parasite. Given the continued clinical development of viral vectored vaccines for malaria and a range of other diseases targets, these data should help to guide further immuno-monitoring studies of vaccine-induced human antibody responses.
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15
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Carey JB, Vrdoljak A, O'Mahony C, Hill AVS, Draper SJ, Moore AC. Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route. Sci Rep 2014; 4:6154. [PMID: 25142082 PMCID: PMC4139947 DOI: 10.1038/srep06154] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/04/2014] [Indexed: 11/28/2022] Open
Abstract
Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP142, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP142 also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP142 using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies.
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Affiliation(s)
- John B Carey
- School of Pharmacy, University College Cork, Cork, Ireland
| | - Anto Vrdoljak
- School of Pharmacy, University College Cork, Cork, Ireland
| | - Conor O'Mahony
- The Tyndall National Institute, University College Cork, Cork, Ireland
| | | | | | - Anne C Moore
- 1] School of Pharmacy, University College Cork, Cork, Ireland [2] Dept. of Pharmacology and Therapeutics, University College Cork, Cork, Ireland
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16
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de Cassan SC, Draper SJ. Recent advances in antibody-inducing poxviral and adenoviral vectored vaccine delivery platforms for difficult disease targets. Expert Rev Vaccines 2014; 12:365-78. [DOI: 10.1586/erv.13.11] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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17
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Efficacy of a Plasmodium vivax malaria vaccine using ChAd63 and modified vaccinia Ankara expressing thrombospondin-related anonymous protein as assessed with transgenic Plasmodium berghei parasites. Infect Immun 2013; 82:1277-86. [PMID: 24379295 PMCID: PMC3957994 DOI: 10.1128/iai.01187-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plasmodium vivax is the world's most widely distributed malaria parasite and a potential cause of morbidity and mortality for approximately 2.85 billion people living mainly in Southeast Asia and Latin America. Despite this dramatic burden, very few vaccines have been assessed in humans. The clinically relevant vectors modified vaccinia virus Ankara (MVA) and the chimpanzee adenovirus ChAd63 are promising delivery systems for malaria vaccines due to their safety profiles and proven ability to induce protective immune responses against Plasmodium falciparum thrombospondin-related anonymous protein (TRAP) in clinical trials. Here, we describe the development of new recombinant ChAd63 and MVA vectors expressing P. vivax TRAP (PvTRAP) and show their ability to induce high antibody titers and T cell responses in mice. In addition, we report a novel way of assessing the efficacy of new candidate vaccines against P. vivax using a fully infectious transgenic Plasmodium berghei parasite expressing P. vivax TRAP to allow studies of vaccine efficacy and protective mechanisms in rodents. Using this model, we found that both CD8+ T cells and antibodies mediated protection against malaria using virus-vectored vaccines. Our data indicate that ChAd63 and MVA expressing PvTRAP are good preerythrocytic-stage vaccine candidates with potential for future clinical application.
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18
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Cheong FW, Fong MY, Lau YL, Mahmud R. Immunogenicity of bacterial-expressed recombinant Plasmodium knowlesi merozoite surface protein-142 (MSP-142). Malar J 2013; 12:454. [PMID: 24354660 PMCID: PMC3878241 DOI: 10.1186/1475-2875-12-454] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 12/17/2013] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium knowlesi is the fifth Plasmodium species that can infect humans. The Plasmodium merozoite surface protein-142 (MSP-142) is a potential candidate for malaria vaccine. However, limited studies have focused on P. knowlesi MSP-142. Methods A ~42 kDa recombinant P. knowlesi MSP-142 (pkMSP-142) was expressed using an Escherichia coli system. The purified pkMSP-142 was evaluated with malaria and non-malaria human patient sera (n = 189) using Western blots and ELISA. The immunogenicity of pkMSP-142 was evaluated in mouse model. Results The purified pkMSP-142 had a sensitivity of 91.0% for detection of human malaria in both assays. Specificity was 97.5 and 92.6% in Western blots and ELISA, respectively. Levels of cytokine interferon-gamma, interleukin-2, interleukin-4, and interleukin-10 significantly increased in pkMSP-142-immunized mice as compared to the negative control mice. pkMSP-142-raised antibody had high endpoint titres, and the IgG isotype distribution was IgG1 > IgG2b > IgG3 > IgG2a. Conclusions pkMSP-142 was highly immunogenic and able to detect human malaria. Hence, pkMSP-142 would be a useful candidate for malaria vaccine development and seroprevalence studies.
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Affiliation(s)
| | - Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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19
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Warimwe GM, Lorenzo G, Lopez-Gil E, Reyes-Sandoval A, Cottingham MG, Spencer AJ, Collins KA, Dicks MDJ, Milicic A, Lall A, Furze J, Turner AV, Hill AVS, Brun A, Gilbert SC. Immunogenicity and efficacy of a chimpanzee adenovirus-vectored Rift Valley fever vaccine in mice. Virol J 2013; 10:349. [PMID: 24304565 PMCID: PMC4235025 DOI: 10.1186/1743-422x-10-349] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/29/2013] [Indexed: 02/07/2023] Open
Abstract
Background Rift Valley Fever (RVF) is a viral zoonosis that historically affects livestock production and human health in sub-Saharan Africa, though epizootics have also occurred in the Arabian Peninsula. Whilst an effective live-attenuated vaccine is available for livestock, there is currently no licensed human RVF vaccine. Replication-deficient chimpanzee adenovirus (ChAd) vectors are an ideal platform for development of a human RVF vaccine, given the low prevalence of neutralizing antibodies against them in the human population, and their excellent safety and immunogenicity profile in human clinical trials of vaccines against a wide range of pathogens. Methods Here, in BALB/c mice, we evaluated the immunogenicity and efficacy of a replication-deficient chimpanzee adenovirus vector, ChAdOx1, encoding the RVF virus envelope glycoproteins, Gn and Gc, which are targets of virus neutralizing antibodies. The ChAdOx1-GnGc vaccine was assessed in comparison to a replication-deficient human adenovirus type 5 vector encoding Gn and Gc (HAdV5-GnGc), a strategy previously shown to confer protective immunity against RVF in mice. Results A single immunization with either of the vaccines conferred protection against RVF virus challenge eight weeks post-immunization. Both vaccines elicited RVF virus neutralizing antibody and a robust CD8+ T cell response. Conclusions Together the results support further development of RVF vaccines based on replication-deficient adenovirus vectors, with ChAdOx1-GnGc being a potential candidate for use in future human clinical trials.
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Gómez CE, Perdiguero B, García-Arriaza J, Esteban M. Clinical applications of attenuated MVA poxvirus strain. Expert Rev Vaccines 2013; 12:1395-416. [PMID: 24168097 DOI: 10.1586/14760584.2013.845531] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The highly attenuated poxvirus strain modified vaccinia virus Ankara (MVA) has reached maturity as a vector delivery system and as a vaccine candidate against a broad spectrum of diseases. This has been largely recognized from research on virus-host cell interactions and immunological studies in pre-clinical and clinical trials. This review addresses the studies of MVA vectors used in phase I/II clinical trials, with the aim to provide the main findings obtained on their behavior when tested against relevant human diseases and cancer and also highlights the strategies currently implemented to improve the MVA immunogenicity. The authors assess that MVA vectors are progressing as strong vaccine candidates either alone or when administered in combination with other vectors.
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Affiliation(s)
- Carmen Elena Gómez
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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21
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Sheehy SH, Douglas AD, Draper SJ. Challenges of assessing the clinical efficacy of asexual blood-stage Plasmodium falciparum malaria vaccines. Hum Vaccin Immunother 2013; 9:1831-40. [PMID: 23778312 PMCID: PMC3906345 DOI: 10.4161/hv.25383] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In the absence of any highly effective vaccine candidate against Plasmodium falciparum malaria, it remains imperative for the field to pursue all avenues that may lead to the successful development of such a formulation. The development of a subunit vaccine targeting the asexual blood-stage of Plasmodium falciparum malaria infection has proven particularly challenging with only limited success to date in clinical trials. However, only a fraction of potential blood-stage vaccine antigens have been evaluated as targets, and a number of new promising candidate antigen formulations and delivery platforms are approaching clinical development. It is therefore essential that reliable and sensitive methods of detecting, or ruling out, even modest efficacy of blood-stage vaccines in small clinical trials be established. In this article we evaluate the challenges facing blood-stage vaccine developers, assess the appropriateness and limitations of various in vivo approaches for efficacy assessment and suggest future directions for the field.
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22
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Duffy PE, Sahu T, Akue A, Milman N, Anderson C. Pre-erythrocytic malaria vaccines: identifying the targets. Expert Rev Vaccines 2013; 11:1261-80. [PMID: 23176657 DOI: 10.1586/erv.12.92] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pre-erythrocytic malaria vaccines target Plasmodium during its sporozoite and liver stages, and can prevent progression to blood-stage disease, which causes a million deaths each year. Whole organism sporozoite vaccines induce sterile immunity in animals and humans and guide subunit vaccine development. A recombinant protein-in-adjuvant pre-erythrocytic vaccine called RTS,S reduces clinical malaria without preventing infection in field studies and additional antigens may be required to achieve sterile immunity. Although few vaccine antigens have progressed to human testing, new insights into parasite biology, expression profiles and immunobiology have offered new targets for intervention. Future advances require human trials of additional antigens, as well as platforms to induce the durable antibody and cellular responses including CD8(+) T cells that contribute to sterile protection.
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Affiliation(s)
- Patrick E Duffy
- Laboratory of Malaria Immunology & Vaccinology, Division of Intramural Research, NIAID, NIH, Rockville, MD, USA.
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23
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Zong S, Kron MW, Epp C, Engler T, Bujard H, Kochanek S, Kreppel F. ΔE1 and high-capacity adenoviral vectors expressing full-length codon-optimized merozoite surface protein 1 for vaccination against Plasmodium falciparum. J Gene Med 2013; 13:670-9. [PMID: 22095915 DOI: 10.1002/jgm.1627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The merozoite surface protein (MSP)-1 of Plasmodium falciparum, the causative agent of malaria tropica, is considered to be a promising vaccine candidate. Although its stable cloning and expression has been difficult in the past, adenoviral vectors expressing the complex protein are described in the present study. METHODS Codon-optimized msp-1 was used to construct a set of first generation (ΔE1Ad) and high-capacity adenovirus (HC-Ad) vectors, and cellular and humoral immune responses induced by the vectors were characterized in detail in mice. RESULTS Generation of stable ΔE1Ad and HC-Ad vectors expressing full-length MSP-1 and their production to high vector titers was found to be feasible. Epitope identification and analysis of frequencies of specific CD8 T-cells revealed that MSP-1 expressing HC-Ad vectors induced higher frequencies of interferon-γ + CD8 T-cells than ΔE1 vectors. Irrespective of the vector format, higher titers of MSP-1 specific antibodies were generated by Ad vectors expressing MSP-1 from a chicken β-actin (CAG) promoter comprising the cytomegalovirus early enhancer element and the chicken β-actin promoter. CONCLUSIONS The findings of the present study suggest that Ad vectors expressing full-length codon-optimized MSP-1 are promising candidate vaccines against P. falciparum infections. Use of the HC-Ad vector type for delivery, as well as the CAG promoter to control MSP-1 expression, may further increase the efficacy of this vaccine candidate.
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Affiliation(s)
- Shan Zong
- Department of Gene Therapy, University of Ulm, Ulm, Germany
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24
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Cheong FW, Lau YL, Fong MY, Mahmud R. Evaluation of recombinant Plasmodium knowlesi merozoite surface protein-1(33) for detection of human malaria. Am J Trop Med Hyg 2013; 88:835-40. [PMID: 23509118 DOI: 10.4269/ajtmh.12-0250] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Plasmodium knowlesi is now known as the fifth Plasmodium species that can cause human malaria. The Plasmodium merozoite surface protein (MSP) has been reported to be potential target for vaccination and diagnosis of malaria. MSP-1(33) has been shown to be immunogenic and its T cell epitopes could mediate cellular immune protection. However, limited studies have focused on P. knowlesi MSP-133. In this study, an approximately 28-kDa recombinant P. knowlesi MSP-1(33) (pkMSP-1(33)) was expressed by using an Escherichia coli system. The purified pkMSP-1(33) reacted with serum samples of patients infected with P. knowlesi (31 of 31, 100%) and non-P. knowlesi malaria (27 of 28, 96.43%) by Western blotting. The pkMSP-1(33) also reacted with P. knowlesi (25 of 31, 80.65%) and non-P. knowlesi malaria sera (20 of 28, 71.43%) in an enzyme-linked immunosorbent assay (ELISA). Most of the non-malarial infection (49 of 52 in by Western blotting and 46 of 52 in the ELISA) and healthy donor serum samples (65 of 65 by Western blotting and ELISA) did not react with recombinant pkMSP-1(33).
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Affiliation(s)
- Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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25
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Elias SC, Collins KA, Halstead FD, Choudhary P, Bliss CM, Ewer KJ, Sheehy SH, Duncan CJA, Biswas S, Hill AVS, Draper SJ. Assessment of immune interference, antagonism, and diversion following human immunization with biallelic blood-stage malaria viral-vectored vaccines and controlled malaria infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:1135-47. [PMID: 23293353 PMCID: PMC3672846 DOI: 10.4049/jimmunol.1201455] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Overcoming antigenic variation is one of the major challenges in the development of an effective vaccine against Plasmodium falciparum, a causative agent of human malaria. Inclusion of multiple Ag variants in subunit vaccine candidates is one strategy that has aimed to overcome this problem for the leading blood-stage malaria vaccine targets, that is, merozoite surface protein 1 (MSP1) and apical membrane Ag 1 (AMA1). However, previous studies, utilizing malaria Ags, have concluded that inclusion of multiple allelic variants, encoding altered peptide ligands, in such a vaccine may be detrimental to both the priming and in vivo restimulation of Ag-experienced T cells. In this study, we analyze the T cell responses to two alleles of MSP1 and AMA1 induced by vaccination of malaria-naive adult volunteers with bivalent viral-vectored vaccine candidates. We show a significant bias to the 3D7/MAD20 allele compared with the Wellcome allele for the 33 kDa region of MSP1, but not for the 19 kDa fragment or the AMA1 Ag. Although this bias could be caused by "immune interference" at priming, the data do not support a significant role for "immune antagonism" during memory T cell restimulation, despite observation of the latter at a minimal epitope level in vitro. A lack of class I HLA epitopes in the Wellcome allele that are recognized by vaccinated volunteers may in fact contribute to the observed bias. We also show that controlled infection with 3D7 strain P. falciparum parasites neither boosts existing 3D7-specific T cell responses nor appears to "immune divert" cellular responses toward the Wellcome allele.
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Affiliation(s)
- Sean C Elias
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom.
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26
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Goodman AL, Forbes EK, Williams AR, Douglas AD, de Cassan SC, Bauza K, Biswas S, Dicks MDJ, Llewellyn D, Moore AC, Janse CJ, Franke-Fayard BM, Gilbert SC, Hill AVS, Pleass RJ, Draper SJ. The utility of Plasmodium berghei as a rodent model for anti-merozoite malaria vaccine assessment. Sci Rep 2013; 3:1706. [PMID: 23609325 PMCID: PMC3632886 DOI: 10.1038/srep01706] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/08/2013] [Indexed: 12/17/2022] Open
Abstract
Rodent malaria species Plasmodium yoelii and P. chabaudi have been widely used to validate vaccine approaches targeting blood-stage merozoite antigens. However, increasing data suggest the P. berghei rodent malaria may be able to circumvent vaccine-induced anti-merozoite responses. Here we confirm a failure to protect against P. berghei, despite successful antibody induction against leading merozoite antigens using protein-in-adjuvant or viral vectored vaccine delivery. No subunit vaccine approach showed efficacy in mice following immunization and challenge with the wild-type P. berghei strains ANKA or NK65, or against a chimeric parasite line encoding a merozoite antigen from P. falciparum. Protection was not improved in knockout mice lacking the inhibitory Fc receptor CD32b, nor against a Δsmac P. berghei parasite line with a non-sequestering phenotype. An improved understanding of the mechanisms responsible for protection, or failure of protection, against P. berghei merozoites could guide the development of an efficacious vaccine against P. falciparum.
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Affiliation(s)
- Anna L Goodman
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK.
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27
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Affiliation(s)
- Joseph D Smith
- Seattle Biomedical Research Institute, Seattle, WA 98109, USA.
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28
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ChAd63-MVA-vectored blood-stage malaria vaccines targeting MSP1 and AMA1: assessment of efficacy against mosquito bite challenge in humans. Mol Ther 2012; 20:2355-68. [PMID: 23089736 DOI: 10.1038/mt.2012.223] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The induction of cellular immunity, in conjunction with antibodies, may be essential for vaccines to protect against blood-stage infection with the human malaria parasite Plasmodium falciparum. We have shown that prime-boost delivery of P. falciparum blood-stage antigens by chimpanzee adenovirus 63 (ChAd63) followed by the attenuated orthopoxvirus MVA is safe and immunogenic in healthy adults. Here, we report on vaccine efficacy against controlled human malaria infection delivered by mosquito bites. The blood-stage malaria vaccines were administered alone, or together (MSP1+AMA1), or with a pre-erythrocytic malaria vaccine candidate (MSP1+ME-TRAP). In this first human use of coadministered ChAd63-MVA regimes, we demonstrate immune interference whereby responses against merozoite surface protein 1 (MSP1) are dominant over apical membrane antigen 1 (AMA1) and ME-TRAP. We also show that induction of strong cellular immunity against MSP1 and AMA1 is safe, but does not impact on parasite growth rates in the blood. In a subset of vaccinated volunteers, a delay in time to diagnosis was observed and sterilizing protection was observed in one volunteer coimmunized with MSP1+AMA1-results consistent with vaccine-induced pre-erythrocytic, rather than blood-stage, immunity. These data call into question the utility of T cell-inducing blood-stage malaria vaccines and suggest that the focus should remain on high-titer antibody induction against susceptible antigen targets.
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29
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Biswas S, Spencer AJ, Forbes EK, Gilbert SC, Holder AA, Hill AVS, Draper SJ. Recombinant viral-vectored vaccines expressing Plasmodium chabaudi AS apical membrane antigen 1: mechanisms of vaccine-induced blood-stage protection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 188:5041-53. [PMID: 22504652 PMCID: PMC3378655 DOI: 10.4049/jimmunol.1101106] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Apical membrane Ag 1 (AMA1) is one of the leading candidate Ags for inclusion in a subunit vaccine against blood-stage malaria. However, the efficacy of Ab-inducing recombinant AMA1 protein vaccines in phase IIa/b clinical trials remains disappointing. In this article, we describe the development of recombinant human adenovirus serotype 5 and modified vaccinia virus Ankara vectors encoding AMA1 from the Plasmodium chabaudi chabaudi strain AS. These vectors, when used in a heterologous prime-boost regimen in BALB/c mice, are capable of inducing strong transgene-specific humoral and cellular immune responses. We show that this vaccination regimen is protective against a nonlethal P. chabaudi chabaudi strain AS blood-stage challenge, resulting in reduced peak parasitemias. The role of vaccine-induced, AMA1-specific Abs and T cells in mediating the antiparasite effect was investigated by in vivo depletion of CD4(+) T cells and adoptive-transfer studies into naive and immunodeficient mice. Depletion of CD4(+) T cells led to a loss of vaccine-induced protection. Adoptive-transfer studies confirmed that efficacy is mediated by both CD4(+) T cells and Abs functioning in the context of an intact immune system. Unlike previous studies, these results confirm that Ag-specific CD4(+) T cells, induced by a clinically relevant vaccine-delivery platform, can make a significant contribution to vaccine blood-stage efficacy in the P. chabaudi model. Given that cell-mediated immunity may also contribute to parasite control in human malaria, these data support the clinical development of viral-vectored vaccines that induce both T cell and Abs against Plasmodium falciparum blood-stage malaria Ags like AMA1.
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MESH Headings
- Adenoviruses, Human/genetics
- Adenoviruses, Human/immunology
- Animals
- Antibodies, Protozoan/biosynthesis
- Antibodies, Protozoan/blood
- Antibodies, Viral/biosynthesis
- Antibodies, Viral/blood
- Antigens, Protozoan/blood
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Female
- Genetic Vectors/administration & dosage
- Genetic Vectors/immunology
- Humans
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/genetics
- Malaria Vaccines/immunology
- Malaria, Falciparum/blood
- Malaria, Falciparum/immunology
- Malaria, Falciparum/prevention & control
- Membrane Proteins/blood
- Membrane Proteins/genetics
- Membrane Proteins/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Mice, Nude
- Molecular Sequence Data
- Plasmodium chabaudi/genetics
- Plasmodium chabaudi/immunology
- Plasmodium falciparum/genetics
- Plasmodium falciparum/immunology
- Protozoan Proteins/blood
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Vaccines, Subunit/administration & dosage
- Vaccines, Subunit/genetics
- Vaccines, Subunit/immunology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/genetics
- Vaccines, Synthetic/immunology
- Vaccinia virus/genetics
- Vaccinia virus/immunology
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Affiliation(s)
- Sumi Biswas
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom.
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30
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Approaching the target: the path towards an effective malaria vaccine. Mediterr J Hematol Infect Dis 2012; 4:e2012015. [PMID: 22550560 PMCID: PMC3340989 DOI: 10.4084/mjhid.2012.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/07/2012] [Indexed: 11/08/2022] Open
Abstract
Developing an effective malaria vaccine has been the goal of the scientific community for many years. A malaria vaccine, added to existing tools and strategies, would further prevent infection and decrease the unacceptable malaria morbidity and mortality burden. Great progress has been made over the last decade and a number of vaccine candidates are in the clinical phases of development. The RTS,S malaria vaccine candidate, based on a recombinant P. falciparum protein, is the most advanced of such candidates, currently undergoing a large phase III trial. RTS,S has consistently shown around 50% efficacy protecting against the first clinical episode of malaria, in some cases extending up to 4 years. It is hoped that RTS,S will eventually become the first licensed malaria vaccine. This first vaccine against a human parasite is a groundbreaking achievement, but improved malaria vaccines conferring higher protection will be needed if the aspiration of malaria eradication is to be achieved.
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31
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Sheehy SH, Duncan CJA, Elias SC, Biswas S, Collins KA, O'Hara GA, Halstead FD, Ewer KJ, Mahungu T, Spencer AJ, Miura K, Poulton ID, Dicks MDJ, Edwards NJ, Berrie E, Moyle S, Colloca S, Cortese R, Gantlett K, Long CA, Lawrie AM, Gilbert SC, Doherty T, Nicosia A, Hill AVS, Draper SJ. Phase Ia clinical evaluation of the safety and immunogenicity of the Plasmodium falciparum blood-stage antigen AMA1 in ChAd63 and MVA vaccine vectors. PLoS One 2012; 7:e31208. [PMID: 22363582 PMCID: PMC3283618 DOI: 10.1371/journal.pone.0031208] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 01/04/2012] [Indexed: 02/07/2023] Open
Abstract
Background Traditionally, vaccine development against the blood-stage of Plasmodium falciparum infection has focused on recombinant protein-adjuvant formulations in order to induce high-titer growth-inhibitory antibody responses. However, to date no such vaccine encoding a blood-stage antigen(s) alone has induced significant protective efficacy against erythrocytic-stage infection in a pre-specified primary endpoint of a Phase IIa/b clinical trial designed to assess vaccine efficacy. Cell-mediated responses, acting in conjunction with functional antibodies, may be necessary for immunity against blood-stage P. falciparum. The development of a vaccine that could induce both cell-mediated and humoral immune responses would enable important proof-of-concept efficacy studies to be undertaken to address this question. Methodology We conducted a Phase Ia, non-randomized clinical trial in 16 healthy, malaria-naïve adults of the chimpanzee adenovirus 63 (ChAd63) and modified vaccinia virus Ankara (MVA) replication-deficient viral vectored vaccines encoding two alleles (3D7 and FVO) of the P. falciparum blood-stage malaria antigen; apical membrane antigen 1 (AMA1). ChAd63-MVA AMA1 administered in a heterologous prime-boost regime was shown to be safe and immunogenic, inducing high-level T cell responses to both alleles 3D7 (median 2036 SFU/million PBMC) and FVO (median 1539 SFU/million PBMC), with a mixed CD4+/CD8+ phenotype, as well as substantial AMA1-specific serum IgG responses (medians of 49 µg/mL and 41 µg/mL for 3D7 and FVO AMA1 respectively) that demonstrated growth inhibitory activity in vitro. Conclusions ChAd63-MVA is a safe and highly immunogenic delivery platform for both alleles of the AMA1 antigen in humans which warrants further efficacy testing. ChAd63-MVA is a promising heterologous prime-boost vaccine strategy that could be applied to numerous other diseases where strong cellular and humoral immune responses are required for protection. Trial Registration ClinicalTrials.gov NCT01095055
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Affiliation(s)
- Susanne H Sheehy
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom.
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32
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A hybrid multistage protein vaccine induces protective immunity against murine malaria. Infect Immun 2012; 80:1491-501. [PMID: 22252877 DOI: 10.1128/iai.05980-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We have previously reported the design and expression of chimeric recombinant proteins as an effective platform to deliver malaria vaccines. The erythrocytic and exoerythrocytic protein chimeras described included autologous T helper epitopes genetically linked to defined B cell epitopes. Proof-of-principle studies using vaccine constructs based on the Plasmodium yoelii circumsporozoite protein (CSP) and P. yoelii merozoite surface protein-1 (MSP-1) showed encouraging results when tested individually in this mouse malaria model. To evaluate the potential synergistic or additive effect of combining these chimeric antigens, we constructed a synthetic gene encoding a hybrid protein that combined both polypeptides in a single immunogen. The multistage vaccine was expressed in soluble form in Escherichia coli at high yield. Here we report that the multistage protein induced robust immune responses to individual components, with no evidence of vaccine interference. Passive immunization using purified IgG from rabbits immunized with the hybrid protein conferred more robust protection against the experimental challenge with P. yoelii sporozoites than passive immunization with purified IgG from rabbits immunized with the individual proteins. High antibody titers and high frequencies of CD4(+)- and CD8(+)-specific cytokine-secreting T cells were elicited by vaccination. T cells were multifunctional and able to simultaneously produce interleukin-2 (IL-2), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α). The mechanism of vaccine-induced protection involved neutralizing antibodies and effector CD4(+) T cells and resulted in the control of hyperparasitemia and protection against malarial anemia. These data support our strategy of using an array of autologous T helper epitopes to maximize the response to multistage malaria vaccines.
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33
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Staines HM, Croft SL, Horrocks PD. Developing novel strategies to prevent parasitic infections. Expert Rev Anti Infect Ther 2012; 9:783-5. [PMID: 21810050 DOI: 10.1586/eri.11.62] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The 49th Annual Spring Meeting of the British Society of Parasitology was held at Nottingham University, UK, on 11-14 April 2011. Although a meeting of a national parasitological society, the meeting attracted approximately 375 delegates from 30 countries worldwide. Of the various themes at this meeting, two were focused on the biology, etiology and development of therapeutics for the parasitic diseases; malaria and schistosomiasis. Here we report on three aspects of this meeting that are focused on the development of novel therapeutics to address the significant health burden imposed by these tropical diseases.
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Affiliation(s)
- Henry M Staines
- Centre for Infection and Immunology, Division of Clinical Sciences, St George's, University of London, London, SW170RE, UK.
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34
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Goodman AL, Blagborough AM, Biswas S, Wu Y, Hill AV, Sinden RE, Draper SJ. A viral vectored prime-boost immunization regime targeting the malaria Pfs25 antigen induces transmission-blocking activity. PLoS One 2011; 6:e29428. [PMID: 22216279 PMCID: PMC3247263 DOI: 10.1371/journal.pone.0029428] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 11/29/2011] [Indexed: 11/18/2022] Open
Abstract
The ookinete surface protein Pfs25 is a macrogamete-to-ookinete/ookinete stage antigen of Plasmodium falciparum, capable of exerting high-level anti-malarial transmission-blocking activity following immunization with recombinant protein-in-adjuvant formulations. Here, this antigen was expressed in recombinant chimpanzee adenovirus 63 (ChAd63), human adenovirus serotype 5 (AdHu5) and modified vaccinia virus Ankara (MVA) viral vectored vaccines. Two immunizations were administered to mice in a heterologous prime-boost regime. Immunization of mice with AdHu5 Pfs25 at week 0 and MVA Pfs25 at week 10 (Ad-MVA Pfs25) resulted in high anti-Pfs25 IgG titers, consisting of predominantly isotypes IgG1 and IgG2a. A single priming immunization with ChAd63 Pfs25 was as effective as AdHu5 Pfs25 with respect to ELISA titers at 8 weeks post-immunization. Sera from Ad-MVA Pfs25 immunized mice inhibited the transmission of P. falciparum to the mosquito both ex vivo and in vivo. In a standard membrane-feeding assay using NF54 strain P. falciparum, oocyst intensity in Anopheles stephensi mosquitoes was significantly reduced in an IgG concentration-dependent manner when compared to control feeds (96% reduction of intensity, 78% reduction in prevalence at a 1 in 5 dilution of sera). In addition, an in vivo transmission-blocking effect was also demonstrated by direct feeding of immunized mice infected with Pfs25DR3, a chimeric P. berghei line expressing Pfs25 in place of endogenous Pbs25. In this assay the density of Pfs25DR3 oocysts was significantly reduced when mosquitoes were fed on vaccinated as compared to control mice (67% reduction of intensity, 28% reduction in prevalence) and specific IgG titer correlated with efficacy. These data confirm the utility of the adenovirus-MVA vaccine platform for the induction of antibodies with transmission-blocking activity, and support the continued development of this alternative approach to transmission-blocking malaria subunit vaccines.
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Affiliation(s)
- Anna L Goodman
- The Jenner Institute, University of Oxford, Oxford, United Kingdom.
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35
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The blood-stage malaria antigen PfRH5 is susceptible to vaccine-inducible cross-strain neutralizing antibody. Nat Commun 2011; 2:601. [PMID: 22186897 DOI: 10.1038/ncomms1615] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 11/28/2011] [Indexed: 11/08/2022] Open
Abstract
Current vaccine strategies against the asexual blood stage of Plasmodium falciparum are mostly focused on well-studied merozoite antigens that induce immune responses after natural exposure, but have yet to induce robust protection in any clinical trial. Here we compare human-compatible viral-vectored vaccines targeting ten different blood-stage antigens. We show that the full-length P. falciparum reticulocyte-binding protein homologue 5 (PfRH5) is highly susceptible to cross-strain neutralizing vaccine-induced antibodies, out-performing all other antigens delivered by the same vaccine platform. We find that, despite being susceptible to antibody, PfRH5 is unlikely to be under substantial immune selection pressure; there is minimal acquisition of anti-PfRH5 IgG antibodies in malaria-exposed Kenyans. These data challenge the widespread beliefs that any merozoite antigen that is highly susceptible to immune attack would be subject to significant levels of antigenic polymorphism, and that erythrocyte invasion by P. falciparum is a degenerate process involving a series of parallel redundant pathways.
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36
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Sedegah M, Tamminga C, McGrath S, House B, Ganeshan H, Lejano J, Abot E, Banania GJ, Sayo R, Farooq F, Belmonte M, Manohar N, Richie NO, Wood C, Long CA, Regis D, Williams FT, Shi M, Chuang I, Spring M, Epstein JE, Mendoza-Silveiras J, Limbach K, Patterson NB, Bruder JT, Doolan DL, King CR, Soisson L, Diggs C, Carucci D, Dutta S, Hollingdale MR, Ockenhouse CF, Richie TL. Adenovirus 5-vectored P. falciparum vaccine expressing CSP and AMA1. Part A: safety and immunogenicity in seronegative adults. PLoS One 2011; 6:e24586. [PMID: 22003383 PMCID: PMC3189181 DOI: 10.1371/journal.pone.0024586] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 08/15/2011] [Indexed: 11/24/2022] Open
Abstract
Background Models of immunity to malaria indicate the importance of CD8+ T cell responses for targeting intrahepatic stages and antibodies for targeting sporozoite and blood stages. We designed a multistage adenovirus 5 (Ad5)-vectored Plasmodium falciparum malaria vaccine, aiming to induce both types of responses in humans, that was tested for safety and immunogenicity in a Phase 1 dose escalation trial in Ad5-seronegative volunteers. Methodology/Principal Findings The NMRC-M3V-Ad-PfCA vaccine combines two adenovectors encoding circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1). Group 1 (n = 6) healthy volunteers received one intramuscular injection of 2×10∧10 particle units (1×10∧10 each construct) and Group 2 (n = 6) a five-fold higher dose. Transient, mild to moderate adverse events were more pronounced with the higher dose. ELISpot responses to CSP and AMA1 peaked at 1 month, were higher in the low dose (geomean CSP = 422, AMA1 = 862 spot forming cells/million) than in the high dose (CSP = 154, p = 0.049, AMA1 = 423, p = 0.045) group and were still positive at 12 months in a number of volunteers. ELISpot depletion assays identified dependence on CD4+ or on both CD4+ and CD8+ T cells, with few responses dependent only on CD8+ T cells. Intracellular cytokine staining detected stronger CD8+ than CD4+ T cell IFN-γ responses (CSP p = 0.0001, AMA1 p = 0.003), but similar frequencies of multifunctional CD4+ and CD8+ T cells secreting two or more of IFN-γ, TNF-α or IL-2. Median fluorescence intensities were 7–10 fold higher in triple than single secreting cells. Antibody responses were low but trended higher in the high dose group and did not inhibit growth of cultured P. falciparum blood stage parasites. Significance As found in other trials, adenovectored vaccines appeared safe and well-tolerated at doses up to 1×10∧11 particle units. This is the first demonstration in humans of a malaria vaccine eliciting strong CD8+ T cell IFN-γ responses. Trial Registration ClinicalTrials.govNCT00392015
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Affiliation(s)
- Martha Sedegah
- U.S. Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, Maryland, United States of America.
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Butler NS, Schmidt NW, Vaughan AM, Aly AS, Kappe SHI, Harty JT. Superior antimalarial immunity after vaccination with late liver stage-arresting genetically attenuated parasites. Cell Host Microbe 2011; 9:451-62. [PMID: 21669394 DOI: 10.1016/j.chom.2011.05.008] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 04/20/2011] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
Abstract
While subunit vaccines have shown partial efficacy in clinical trials, radiation-attenuated sporozoites (RAS) remain the "gold standard" for sterilizing protection against Plasmodium infection in human vaccinees. The variability in immunogenicity and replication introduced by the extensive, random DNA damage necessary to generate RAS could be overcome by genetically attenuated parasites (GAP) designed via gene deletion to arrest at defined points during liver-stage development. Here, we demonstrate the principle that late liver stage-arresting GAP induce larger and broader CD8 T cell responses that provide superior protection in inbred and outbred mice compared to RAS or early-arresting GAP immunizations. Late liver stage-arresting GAP also engender high levels of cross-stage and cross-species protection and complete protection when administered by translationally relevant intradermal or subcutaneous routes. Collectively, our results underscore the potential utility of late liver stage-arresting GAP as broadly protective next-generation live-attenuated malaria vaccines and support their potential as a powerful model for identifying antigens to generate cross-stage protection.
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Affiliation(s)
- Noah S Butler
- Department of Microbiology, University of Iowa, 3-512 Bowen Science Building, Iowa City, IA 52242, USA
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38
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Pusic KM, Hashimoto CN, Lehrer A, Aniya C, Clements DE, Hui GS. T cell epitope regions of the P. falciparum MSP1-33 critically influence immune responses and in vitro efficacy of MSP1-42 vaccines. PLoS One 2011; 6:e24782. [PMID: 21931852 PMCID: PMC3172285 DOI: 10.1371/journal.pone.0024782] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 08/17/2011] [Indexed: 12/01/2022] Open
Abstract
The C-terminal 42 kDa fragments of the P. falciparum Merozoite Surface Protein 1, MSP1-42 is a leading malaria vaccine candidate. MSP1-33, the N-terminal processed fragment of MSP1-42, is rich in T cell epitopes and it is hypothesized that they enhance antibody response toward MSP1-19. Here, we gave in vivo evidence that T cell epitope regions of MSP1-33 provide functional help in inducing anti-MSP1-19 antibodies. Eleven truncated MSP1-33 segments were expressed in tandem with MSP1-19, and immunogenicity was evaluated in Swiss Webster mice and New Zealand White rabbits. Analyses of anti-MSP1-19 antibody responses revealed striking differences in these segments' helper function despite that they all possess T cell epitopes. Only a few fragments induced a generalized response (100%) in outbred mice. These were comparable to or surpassed the responses observed with the full length MSP1-42. In rabbits, only a subset of truncated antigens induced potent parasite growth inhibitory antibodies. Notably, two constructs were more efficacious than MSP1-42, with one containing only conserved T cell epitopes. Moreover, another T cell epitope region induced high titers of non-inhibitory antibodies and they interfered with the inhibitory activities of anti-MSP1-42 antibodies. In mice, this region also induced a skewed TH2 cellular response. This is the first demonstration that T cell epitope regions of MSP1-33 positively or negatively influenced antibody responses. Differential recognition of these regions by humans may play critical roles in vaccine induced and/or natural immunity to MSP1-42. This study provides the rational basis to re-engineer more efficacious MSP1-42 vaccines by selective inclusion and exclusion of MSP1-33 specific T cell epitopes.
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Affiliation(s)
- Kae M Pusic
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States of America.
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39
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de Cassan SC, Forbes EK, Douglas AD, Milicic A, Singh B, Gupta P, Chauhan VS, Chitnis CE, Gilbert SC, Hill AVS, Draper SJ. The requirement for potent adjuvants to enhance the immunogenicity and protective efficacy of protein vaccines can be overcome by prior immunization with a recombinant adenovirus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2011; 187:2602-16. [PMID: 21813775 PMCID: PMC3160495 DOI: 10.4049/jimmunol.1101004] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A central goal in vaccinology is the induction of high and sustained Ab responses. Protein-in-adjuvant formulations are commonly used to achieve such responses. However, their clinical development can be limited by the reactogenicity of some of the most potent preclinical adjuvants and the cost and complexity of licensing new adjuvants for human use. Also, few adjuvants induce strong cellular immunity, which is important for protection against many diseases, such as malaria. We compared classical adjuvants such as aluminum hydroxide to new preclinical adjuvants and adjuvants in clinical development, such as Abisco 100, CoVaccine HT, Montanide ISA720, and stable emulsion-glucopyranosyl lipid A, for their ability to induce high and sustained Ab responses and T cell responses. These adjuvants induced a broad range of Ab responses when used in a three-shot protein-in-adjuvant regimen using the model Ag OVA and leading blood-stage malaria vaccine candidate Ags. Surprisingly, this range of Ab immunogenicity was greatly reduced when a protein-in-adjuvant vaccine was used to boost Ab responses primed by a human adenovirus serotype 5 vaccine recombinant for the same Ag. This human adenovirus serotype 5-protein regimen also induced a more cytophilic Ab response and demonstrated improved efficacy of merozoite surface protein-1 protein vaccines against a Plasmodium yoelii blood-stage challenge. This indicates that the differential immunogenicity of protein vaccine adjuvants may be largely overcome by prior immunization with recombinant adenovirus, especially for adjuvants that are traditionally considered poorly immunogenic in the context of subunit vaccination and may circumvent the need for more potent chemical adjuvants.
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Affiliation(s)
- Simone C de Cassan
- The Jenner Institute, University of Oxford, Headington, Oxford OX3 7DQ, United Kingdom.
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40
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Forbes EK, Biswas S, Collins KA, Gilbert SC, Hill AVS, Draper SJ. Combining liver- and blood-stage malaria viral-vectored vaccines: investigating mechanisms of CD8+ T cell interference. THE JOURNAL OF IMMUNOLOGY 2011; 187:3738-50. [PMID: 21876036 DOI: 10.4049/jimmunol.1003783] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Replication-deficient adenovirus and modified vaccinia virus Ankara (MVA) vectors expressing single pre-erythrocytic or blood-stage Plasmodium falciparum Ags have entered clinical testing using a heterologous prime-boost immunization approach. In this study, we investigated the utility of the same immunization regimen when combining viral vectored vaccines expressing the 42-kDa C terminus of the blood-stage Ag merozoite surface protein 1 and the pre-erythrocytic Ag circumsporozoite protein in the Plasmodium yoelii mouse model. We find that vaccine coadministration leads to maintained Ab responses and efficacy against blood-stage infection, but reduced secondary CD8(+) T cell responses against both Ags and efficacy against liver-stage infection. CD8(+) T cell interference can be minimized by coadministering the MVA vaccines at separate sites, resulting in enhanced liver-stage efficacy in mice immunized against both Ags compared with just one. CD8(+) T cell interference (following MVA coadministration as a mixture) may be caused partly by a lack of physiologic space for high-magnitude responses against multiple Ags, but is not caused by competition for presentation of Ag on MHC class I molecules, nor is it due to restricted T cell access to APCs presenting both Ags. Instead, enhanced killing of peptide-pulsed cells is observed in mice possessing pre-existing T cells against two Ags compared with just one, suggesting that priming against multiple Ags may in part reduce the potency of multiantigen MVA vectors to stimulate secondary CD8(+) T cell responses. These data have important implications for the development of a multistage or multicomponent viral vectored malaria vaccine for use in humans.
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Affiliation(s)
- Emily K Forbes
- The Jenner Institute, University of Oxford, Oxford, United Kingdom.
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Sheehy SH, Duncan CJA, Elias SC, Collins KA, Ewer KJ, Spencer AJ, Williams AR, Halstead FD, Moretz SE, Miura K, Epp C, Dicks MDJ, Poulton ID, Lawrie AM, Berrie E, Moyle S, Long CA, Colloca S, Cortese R, Gilbert SC, Nicosia A, Hill AVS, Draper SJ. Phase Ia clinical evaluation of the Plasmodium falciparum blood-stage antigen MSP1 in ChAd63 and MVA vaccine vectors. Mol Ther 2011; 19:2269-76. [PMID: 21862998 DOI: 10.1038/mt.2011.176] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Efficacy trials of antibody-inducing protein-in-adjuvant vaccines targeting the blood-stage Plasmodium falciparum malaria parasite have so far shown disappointing results. The induction of cell-mediated responses in conjunction with antibody responses is thought to be one alternative strategy that could achieve protective efficacy in humans. Here, we prepared chimpanzee adenovirus 63 (ChAd63) and modified vaccinia virus Ankara (MVA) replication-deficient vectors encoding the well-studied P. falciparum blood-stage malaria antigen merozoite surface protein 1 (MSP1). A phase Ia clinical trial was conducted in healthy adults of a ChAd63-MVA MSP1 heterologous prime-boost immunization regime. The vaccine was safe and generally well tolerated. Fewer systemic adverse events (AEs) were observed following ChAd63 MSP1 than MVA MSP1 administration. Exceptionally strong T-cell responses were induced, and these displayed a mixed of CD4(+) and CD8(+) phenotype. Substantial MSP1-specific serum immunoglobulin G (IgG) antibody responses were also induced, which were capable of recognizing native parasite antigen, but these did not reach titers sufficient to neutralize P. falciparum parasites in vitro. This viral vectored vaccine regime is thus a leading approach for the induction of strong cellular and humoral immunogenicity against difficult disease targets in humans. Further studies are required to assess whether this strategy can achieve protective efficacy against blood-stage malaria infection.
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Affiliation(s)
- Susanne H Sheehy
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford, Churchill Hospital, Oxford, UK.
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Haussig JM, Matuschewski K, Kooij TWA. Inactivation of a Plasmodium apicoplast protein attenuates formation of liver merozoites. Mol Microbiol 2011; 81:1511-25. [PMID: 21848587 PMCID: PMC3206223 DOI: 10.1111/j.1365-2958.2011.07787.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Malaria parasites undergo a population expansion inside the host liver before disease onset. Developmental arrest inside host hepatocytes elicits protective immune responses. Therefore, elucidation of the molecular mechanisms leading to mature hepatic merozoites, which initiate the pathogenic blood phase, also informs anti-malaria vaccine strategies. Using targeted gene deletion in the rodent model malaria parasite Plasmodium berghei, we show that a Plasmodium-specific Apicoplast protein plays an important role for Liver Merozoite formation (PALM). While the resulting knockout mutants develop normally for most of the life cycle, merozoite release into the blood stream and the ability to establish an infection are severely impaired. Presence of a signature blood-stage antigen, merozoite surface protein 1 and normal apicoplast morphology indicate that the inability to finalize merozoite segregation is a direct consequence of loss of PALM function. Experimental immunization of mice with as few as two doses of palm- sporozoites can elicit sterile protection up to 110 days after final immunization. Our data establish that a tailor-made arrest in the final steps of hepatic merozoite formation can induce strong protective immune responses and that malaria parasites employ a distinct apicoplast protein for efficient formation of pre-erythrocytic merozoites.
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Affiliation(s)
- Joana M Haussig
- Parasitology Unit, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
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43
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Biswas S, Dicks MDJ, Long CA, Remarque EJ, Siani L, Colloca S, Cottingham MG, Holder AA, Gilbert SC, Hill AVS, Draper SJ. Transgene optimization, immunogenicity and in vitro efficacy of viral vectored vaccines expressing two alleles of Plasmodium falciparum AMA1. PLoS One 2011; 6:e20977. [PMID: 21698193 PMCID: PMC3116848 DOI: 10.1371/journal.pone.0020977] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 05/17/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Apical membrane antigen 1 (AMA1) is a leading candidate vaccine antigen against blood-stage malaria, although to date numerous clinical trials using mainly protein-in-adjuvant vaccines have shown limited success. Here we describe the pre-clinical development and optimization of recombinant human and simian adenoviral (AdHu5 and ChAd63) and orthopoxviral (MVA) vectors encoding transgene inserts for Plasmodium falciparum AMA1 (PfAMA1). METHODOLOGY/PRINCIPAL FINDINGS AdHu5-MVA prime-boost vaccination in mice and rabbits using these vectors encoding the 3D7 allele of PfAMA1 induced cellular immune responses as well as high-titer antibodies that showed growth inhibitory activity (GIA) against the homologous but not heterologous parasite strains. In an effort to overcome the issues of PfAMA1 antigenic polymorphism and pre-existing immunity to AdHu5, a simian adenoviral (ChAd63) vector and MVA encoding two alleles of PfAMA1 were developed. This antigen, composed of the 3D7 and FVO alleles of PfAMA1 fused in tandem and with expression driven by a single promoter, was optimized for antigen secretion and transmembrane expression. These bi-allelic PfAMA1 vaccines, when administered to mice and rabbits, demonstrated comparable immunogenicity to the mono-allelic vaccines and purified serum IgG now showed GIA against the two divergent strains of P. falciparum encoded in the vaccine. CD8(+) and CD4(+) T cell responses against epitopes that were both common and unique to the two alleles of PfAMA1 were also measured in mice. CONCLUSIONS/SIGNIFICANCE Optimized transgene inserts encoding two divergent alleles of the same antigen can be successfully inserted into adeno- and pox-viral vaccine vectors. Adenovirus-MVA immunization leads to the induction of T cell responses common to both alleles, as well as functional antibody responses that are effective against both of the encoded strains of P. falciparum in vitro. These data support the further clinical development of these vaccine candidates in Phase I/IIa clinical trials.
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Affiliation(s)
- Sumi Biswas
- The Jenner Institute, University of Oxford, Oxford, Oxfordshire, United Kingdom.
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Shuaibu MN, Cherif MS, Kurosaki T, Helegbe GK, Kikuchi M, Yanagi T, Sasaki H, Hirayama K. Effect of nanoparticle coating on the immunogenicity of plasmid DNA vaccine encoding P. yoelii MSP-1 C-terminal. Vaccine 2011; 29:3239-47. [PMID: 21354479 DOI: 10.1016/j.vaccine.2011.02.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/03/2011] [Accepted: 02/12/2011] [Indexed: 11/30/2022]
Abstract
In order to assess a new strategy for DNA vaccine formulation and delivery, plasmid encoding Plasmodium yoelii MSP-1 C-terminal was formulated with newly designed nanoparticle-an anionic ternary complex of polyethylenimine and γ-polyglutamic acid (pVAX-MSP-1/PEI/γ-PGA), and intravenously administered to C57BL/6 mice in four different doses, three times at 3-week interval. Antibody response as determined by ELISA, IFA and Western blot, was dose-dependent and subsequent challenge with 10(5)P. yoelii-infected red blood cells revealed 33-60% survival in repeated experiments at a dose of 80 μg pDNA/mouse. IgG subtypes and cytokine levels in the serum and culture supernatants of stimulated spleen cells were also measured. Antigen-specific IgG response provoked by the DNA vaccination was dominated by IgG1 and IgG2b. Although the elevation of IL-12p40 and IFN-γ was marginal (P≥0.354) in the coated group, interleukin-4 levels were significantly higher (P≥0.013) in the coated group than in the naked or control group, suggesting a predominant Th2-type CD4(+) T cell response. These results therefore, overall indicate the possibility of selection and optimization of DNA vaccine formulation for intravenous delivery and may be useful in designing a nanoparticle-coated DNA vaccine that could optimally elicit a desired antibody response for various disease conditions.
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Affiliation(s)
- M N Shuaibu
- Department of Immunogenetics, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
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Douglas AD, de Cassan SC, Dicks MDJ, Gilbert SC, Hill AVS, Draper SJ. Tailoring subunit vaccine immunogenicity: maximizing antibody and T cell responses by using combinations of adenovirus, poxvirus and protein-adjuvant vaccines against Plasmodium falciparum MSP1. Vaccine 2011; 28:7167-78. [PMID: 20937436 PMCID: PMC3404461 DOI: 10.1016/j.vaccine.2010.08.068] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 12/15/2022]
Abstract
Subunit vaccination modalities tend to induce particular immune effector responses. Viral vectors are well known for their ability to induce strong T cell responses, while protein-adjuvant vaccines have been used primarily for induction of antibody responses. Here, we demonstrate in mice using a Plasmodium falciparum merozoite surface protein 1 (PfMSP1) antigen that novel regimes combining adenovirus and poxvirus vectored vaccines with protein antigen in Montanide ISA720 adjuvant can achieve simultaneous antibody and T cell responses which equal, or in some cases surpass, the best immune responses achieved by either the viral vectors or the protein vaccine alone. Such broad responses can be achieved either using three-stage vaccination protocols, or with an equally effective two-stage protocol in which viral vectors are admixed with protein and adjuvant, and were apparent despite the use of a protein antigen that represented only a portion of the viral vector antigen. We describe further possible advantages of viral vectors in achieving consistent antibody priming, enhanced antibody avidity, and cytophilic isotype skew. These data strengthen the evidence that tailored combinations of vaccine platforms can achieve desired combinations of immune responses, and further encourage the co-administration of antibody-inducing recombinant protein vaccines with T cell- and antibody-inducing recombinant viral vectors as one strategy that may achieve protective blood-stage malaria immunity in humans.
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Draper SJ, Biswas S, Spencer AJ, Remarque EJ, Capone S, Naddeo M, Dicks MDJ, Faber BW, de Cassan SC, Folgori A, Nicosia A, Gilbert SC, Hill AVS. Enhancing Blood-Stage Malaria Subunit Vaccine Immunogenicity in Rhesus Macaques by Combining Adenovirus, Poxvirus, and Protein-in-Adjuvant Vaccines. THE JOURNAL OF IMMUNOLOGY 2010; 185:7583-95. [DOI: 10.4049/jimmunol.1001760] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
The concept of a malaria vaccine has sparked great interest for decades; however, the challenge is proving to be a difficult one. Immune dysregulation by Plasmodium and the ability of the parasite to mutate critical epitopes in surface antigens have proved to be strong defense weapons. This has led to reconsideration of polyvalent and whole parasite strategies and ways to enhance cellular immunity to malaria that may be more likely to target conserved antigens and an expanded repertoire of antigens. These and other concepts will be discussed in this review.
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Goodman AL, Draper SJ. Blood-stage malaria vaccines - recent progress and future challenges. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2010; 104:189-211. [PMID: 20507694 DOI: 10.1179/136485910x12647085215534] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Plasmodium falciparum malaria is a major global health problem, responsible for up to 1 million deaths each year. Major efforts have been made to develop an effective vaccine against this disease, to reduce the associated morbidity and mortality. There has already been considerable progress, with the first vaccine against the pre-erythrocytic stages of P. falciparum now en route to licensure. There remains, however, a strong scientific rationale for the development of a highly effective additional vaccine component against the blood stages of the parasite, which could be deployed in conjunction with partially effective control measures against the pre-erythrocytic stages. Here, recent progress in the clinical development of blood-stage vaccines is reviewed, including methods of antigen selection, the limitations of in-vitro assays for selecting vaccines for clinical development, and the results of recently published clinical trials. This review seeks to summarize recent developments in our understanding of immunity to blood-stage parasites, as well as the relevant key advances made in vaccine technologies over the last decade. The future challenges that face this field of vaccine research are also described.
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Affiliation(s)
- A L Goodman
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK.
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New candidate vaccines against blood-stage Plasmodium falciparum malaria: prime-boost immunization regimens incorporating human and simian adenoviral vectors and poxviral vectors expressing an optimized antigen based on merozoite surface protein 1. Infect Immun 2010; 78:4601-12. [PMID: 20713623 DOI: 10.1128/iai.00315-10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Although merozoite surface protein 1 (MSP-1) is a leading candidate vaccine antigen for blood-stage malaria, its efficacy in clinical trials has been limited in part by antigenic polymorphism and potentially by the inability of protein-in-adjuvant vaccines to induce strong cellular immunity. Here we report the design of novel vectored Plasmodium falciparum vaccines capable of overcoming such limitations. We optimized an antigenic insert comprising the four conserved blocks of MSP-1 fused to tandemly arranged sequences that represent both allelic forms of the dimorphic 42-kDa C-terminal region. Inserts were expressed by adenoviral and poxviral vectors and employed in heterologous prime-boost regimens. Simian adenoviral vectors were used in an effort to circumvent preexisting immunity to human adenoviruses. In preclinical studies these vaccines induced potent cellular immune responses and high-titer antibodies directed against MSP-1. The antibodies induced were found to have growth-inhibitory activity against dimorphic allelic families of P. falciparum. These vectored vaccines should allow assessment in humans of the safety and efficacy of inducing strong cellular as well as cross-strain humoral immunity to P. falciparum MSP-1.
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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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