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Angage D, Chmielewski J, Maddumage JC, Hesping E, Caiazzo S, Lai KH, Yeoh LM, Menassa J, Opi DH, Cairns C, Puthalakath H, Beeson JG, Kvansakul M, Boddey JA, Wilson DW, Anders RF, Foley M. A broadly cross-reactive i-body to AMA1 potently inhibits blood and liver stages of Plasmodium parasites. Nat Commun 2024; 15:7206. [PMID: 39174515 PMCID: PMC11341838 DOI: 10.1038/s41467-024-50770-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 07/19/2024] [Indexed: 08/24/2024] Open
Abstract
Apical membrane antigen-1 (AMA1) is a conserved malarial vaccine candidate essential for the formation of tight junctions with the rhoptry neck protein (RON) complex, enabling Plasmodium parasites to invade human erythrocytes, hepatocytes, and mosquito salivary glands. Despite its critical role, extensive surface polymorphisms in AMA1 have led to strain-specific protection, limiting the success of AMA1-based interventions beyond initial clinical trials. Here, we identify an i-body, a humanised single-domain antibody-like molecule that recognises a conserved pan-species conformational epitope in AMA1 with low nanomolar affinity and inhibits the binding of the RON2 ligand to AMA1. Structural characterisation indicates that the WD34 i-body epitope spans the centre of the conserved hydrophobic cleft in AMA1, where interacting residues are highly conserved among all Plasmodium species. Furthermore, we show that WD34 inhibits merozoite invasion of erythrocytes by multiple Plasmodium species and hepatocyte invasion by P. falciparum sporozoites. Despite a short half-life in mouse serum, we demonstrate that WD34 transiently suppressed P. berghei infections in female BALB/c mice. Our work describes the first pan-species AMA1 biologic with inhibitory activity against multiple life-cycle stages of Plasmodium. With improved pharmacokinetic characteristics, WD34 could be a potential immunotherapy against multiple species of Plasmodium.
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Affiliation(s)
- Dimuthu Angage
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - Jill Chmielewski
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Janesha C Maddumage
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - Eva Hesping
- Infectious Diseases & Immune Defense Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Sabrina Caiazzo
- Infectious Diseases & Immune Defense Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Keng Heng Lai
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Lee Ming Yeoh
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Department of Medicine, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Joseph Menassa
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - D Herbert Opi
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Department of Medicine, The University of Melbourne, Parkville, Victoria, 3052, Australia
- Central Clinical School and Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia
| | - Callum Cairns
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - Hamsa Puthalakath
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Central Clinical School and Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia
- Department of Infectious Diseases, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Marc Kvansakul
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - Justin A Boddey
- Infectious Diseases & Immune Defense Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Robin F Anders
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia
| | - Michael Foley
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria, 3086, Australia.
- AdAlta, Science Drive, Bundoora, Victoria, 3083, Australia.
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2
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Ciubotariu II, Broyles BK, Xie S, Thimmapuram J, Mwenda MC, Mambwe B, Mulube C, Matoba J, Schue JL, Moss WJ, Bridges DJ, He Q, Carpi G. Diversity and selection analyses identify transmission-blocking antigens as the optimal vaccine candidates in Plasmodium falciparum. EBioMedicine 2024; 106:105227. [PMID: 39018754 DOI: 10.1016/j.ebiom.2024.105227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 07/19/2024] Open
Abstract
BACKGROUND A highly effective vaccine for malaria remains an elusive target, at least in part due to the under-appreciated natural parasite variation. This study aimed to investigate genetic and structural variation, and immune selection of leading malaria vaccine candidates across the Plasmodium falciparum's life cycle. METHODS We analysed 325 P. falciparum whole genome sequences from Zambia, in addition to 791 genomes from five other African countries available in the MalariaGEN Pf3k Database. Ten vaccine antigens spanning three life-history stages were examined for genetic and structural variations, using population genetics measures, haplotype network analysis, and 3D structure selection analysis. FINDINGS Among the ten antigens analysed, only three in the transmission-blocking vaccine category display P. falciparum 3D7 as the dominant haplotype. The antigens AMA1, CSP, MSP119 and CelTOS, are much more diverse than the other antigens, and their epitope regions are under moderate to strong balancing selection. In contrast, Rh5, a blood stage antigen, displays low diversity yet slightly stronger immune selection in the merozoite-blocking epitope region. Except for CelTOS, the transmission-blocking antigens Pfs25, Pfs48/45, Pfs230, Pfs47, and Pfs28 exhibit minimal diversity and no immune selection in epitopes that induce strain-transcending antibodies, suggesting potential effectiveness of 3D7-based vaccines in blocking transmission. INTERPRETATION These findings offer valuable insights into the selection of optimal vaccine candidates against P. falciparum. Based on our results, we recommend prioritising conserved merozoite antigens and transmission-blocking antigens. Combining these antigens in multi-stage approaches may be particularly promising for malaria vaccine development initiatives. FUNDING Purdue Department of Biological Sciences; Puskas Memorial Fellowship; National Institute of Allergy and Infectious Diseases (U19AI089680).
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Affiliation(s)
- Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Bradley K Broyles
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Shaojun Xie
- Bioinformatics Core, Purdue University, West Lafayette, IN, USA
| | | | - Mulenga C Mwenda
- PATH-Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Lusaka, Zambia
| | - Brenda Mambwe
- PATH-Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Lusaka, Zambia
| | - Conceptor Mulube
- PATH-Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Lusaka, Zambia
| | | | - Jessica L Schue
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - William J Moss
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - Qixin He
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA; Purdue Institute of Inflammation, Immunology and Infectious Disease, West Lafayette, IN, USA.
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3
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Ciubotariu II, Broyles BK, Xie S, Thimmapuram J, Mwenda MC, Mambwe B, Mulube C, Matoba J, Schue JL, Moss WJ, Bridges DJ, He Q, Carpi G. Diversity and selection analyses identify transmission-blocking antigens as the optimal vaccine candidates in Plasmodium falciparum. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.11.24307175. [PMID: 38766239 PMCID: PMC11100930 DOI: 10.1101/2024.05.11.24307175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Background A highly effective vaccine for malaria remains an elusive target, at least in part due to the under-appreciated natural parasite variation. This study aimed to investigate genetic and structural variation, and immune selection of leading malaria vaccine candidates across the Plasmodium falciparum's life cycle. Methods We analyzed 325 P. falciparum whole genome sequences from Zambia, in addition to 791 genomes from five other African countries available in the MalariaGEN Pf3k Rdatabase. Ten vaccine antigens spanning three life-history stages were examined for genetic and structural variations, using population genetics measures, haplotype network analysis, and 3D structure selection analysis. Findings Among the ten antigens analyzed, only three in the transmission-blocking vaccine category display P. falciparum 3D7 as the dominant haplotype. The antigens AMA1, CSP, MSP119 and CelTOS, are much more diverse than the other antigens, and their epitope regions are under moderate to strong balancing selection. In contrast, Rh5, a blood stage antigen, displays low diversity yet slightly stronger immune selection in the merozoite-blocking epitope region. Except for CelTOS, the transmission-blocking antigens Pfs25, Pfs48/45, Pfs230, Pfs47, and Pfs28 exhibit minimal diversity and no immune selection in epitopes that induce strain-transcending antibodies, suggesting potential effectiveness of 3D7-based vaccines in blocking transmission. Interpretations These findings offer valuable insights into the selection of optimal vaccine candidates against P. falciparum. Based on our results, we recommend prioritizing conserved merozoite antigens and transmission-blocking antigens. Combining these antigens in multi-stage approaches may be particularly promising for malaria vaccine development initiatives. Funding Purdue Department of Biological Sciences; Puskas Memorial Fellowship; National Institute of Allergy and Infectious Diseases (U19AI089680).
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Affiliation(s)
- Ilinca I. Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Bradley K. Broyles
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Shaojun Xie
- Bioinformatics Core, Purdue University, West Lafayette, Indiana, USA
| | | | - Mulenga C. Mwenda
- PATH-Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Lusaka, Zambia
| | - Brenda Mambwe
- PATH-Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Lusaka, Zambia
| | - Conceptor Mulube
- PATH-Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Lusaka, Zambia
| | | | - Jessica L. Schue
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - William J. Moss
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | - Qixin He
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
- Purdue Institute of Inflammation, Immunology and Infectious Disease, West Lafayette, Indiana, USA
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Winnicki AC, Dietrich MH, Yeoh LM, Carias LL, Roobsoong W, Drago CL, Malachin AN, Redinger KR, Feufack-Donfack LB, Baldor L, Jung NC, McLaine OS, Skomorovska-Prokvolit Y, Orban A, Opi DH, Sattabongkot J, Tham WH, Popovici J, Beeson JG, Bosch J, King CL. Potent AMA1-specific human monoclonal antibody against P. vivax Pre-erythrocytic and Blood Stages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.07.579302. [PMID: 38370683 PMCID: PMC10871283 DOI: 10.1101/2024.02.07.579302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
New therapeutics are a priority for preventing and eliminating Plasmodium vivax (Pv) malaria because of its easy transmissibility and dormant stages in the liver. Relapses due to the dormant liver stages are the major contributor to reoccurring Pv. Therefore, therapies that reduce the establishment of dormant parasites and blood-stage infection are important for controlling this geographically widespread parasite. Here, we isolated 12 human monoclonal antibodies (humAbs) from the plasma of a Pv-exposed individual that recognized Pv apical membrane antigen 1 (PvAMA1). PvAMA1 is important for both sporozoite invasion of hepatocytes and merozoite invasion of reticulocytes. We identified one humAb, 826827, that blocked invasion of human erythrocytes using a transgenic P. falciparum line expressing PvAMA1 (IC 50 = 3 µg/mL) and all Pv clinical isolates in vitro . This humAb also inhibited sporozoite invasion of a human hepatocyte cell line and primary human hepatocytes (IC 50 of 0.3 - 3.7 µg/mL). The crystal structure of recombinant PvAMA1 with the antigen-binding fragment of 826827 at 2.4 Å resolution shows that the humAb partially occupies the highly conserved hydrophobic groove in PvAMA1 that binds its known receptor, RON2. HumAb 826827 binds to PvAMA1 with higher affinity than RON2, accounting for its potency. To our knowledge, this is the first reported humAb specific to PvAMA1, and the PvAMA1 residues it binds to are highly conserved across different isolates, explaining its strain-transcendent properties.
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5
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Hawadak J, Kojom Foko LP, Dongang Nana RR, Yadav K, Pande V, Das A, Singh V. Genetic diversity and natural selection of apical membrane antigen-1 (ama-1) in Cameroonian Plasmodium falciparum isolates. Gene 2024; 894:147956. [PMID: 37925116 DOI: 10.1016/j.gene.2023.147956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/16/2023] [Accepted: 10/31/2023] [Indexed: 11/06/2023]
Abstract
Antigenic variation associated with genetic diversity in global Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a major impediment to designing an effective malaria vaccine. Here, we report the first study on genetic diversity and natural selection of the Pfama-1 gene in P. falciparum isolates from Cameroon. A total of 328 P. falciparum positive samples collected during 2016 and 2019 from five localities of Cameroon were analysed. The ectodomain coding fragment of Pfama-1 gene was amplified for polymorphism profiling and natural selection analysis. A total of 108 distinct haplotypes were found in 203 P. falciparum isolates with considerable nucleotide diversity (π = 0.016) and haplotype diversity (Hd = 0.976). Most amino acid substitutions detected were scattered in ectodomain-I and few specific mutations viz P145L, K148Q, K462I, L463F, N471K, S482L, E537G, K546R and I547F were seen only in Cameroonian isolates. A tendency of natural selection towards positive diversifying selection was observed (Taj-D = 2.058). Five positively selected codon sites (P145L, S283L, Q308E/K, P330S and I547F) were identified, which overlapped with predicted B-cell epitopes and red blood cell (RBC) binding sites, suggesting their potential implication in host immune pressure and parasite-RBC binding complex modulation. The Cameroonian P. falciparum populations indicated a moderate level of genetic differentiation when compared with global sequences, with few exceptions from Vietnam and Venezuela. Our findings provide baseline data on existing Pfama-1 gene polymorphisms in Cameroonian field isolates, which will be useful information for malaria vaccine design.
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Affiliation(s)
- Joseph Hawadak
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Loick Pradel Kojom Foko
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Rodrigue Roman Dongang Nana
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India; Institut de Recherches Médicales et D'Etudes des Plantes Médicinales (IMPM), Yaoundé, Cameroon
| | - Karmveer Yadav
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Bhimtal, Uttarakhand, India
| | - Aparup Das
- ICMR-National Institute for Research in Tribal Health (NIRTH), Jabalpur, India.
| | - Vineeta Singh
- ICMR-National Institute of Malaria Research (NIMR), Delhi, India.
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6
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Patel PN, Dickey TH, Diouf A, Salinas ND, McAleese H, Ouahes T, Long CA, Miura K, Lambert LE, Tolia NH. Structure-based design of a strain transcending AMA1-RON2L malaria vaccine. Nat Commun 2023; 14:5345. [PMID: 37660103 PMCID: PMC10475129 DOI: 10.1038/s41467-023-40878-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/14/2023] [Indexed: 09/04/2023] Open
Abstract
Apical membrane antigen 1 (AMA1) is a key malaria vaccine candidate and target of neutralizing antibodies. AMA1 binds to a loop in rhoptry neck protein 2 (RON2L) to form the moving junction during parasite invasion of host cells, and this complex is conserved among apicomplexan parasites. AMA1-RON2L complex immunization achieves higher growth inhibitory activity than AMA1 alone and protects mice against Plasmodium yoelii challenge. Here, three single-component AMA1-RON2L immunogens were designed that retain the structure of the two-component AMA1-RON2L complex: one structure-based design (SBD1) and two insertion fusions. All immunogens elicited high antibody titers with potent growth inhibitory activity, yet these antibodies did not block RON2L binding to AMA1. The SBD1 immunogen induced significantly more potent strain-transcending neutralizing antibody responses against diverse strains of Plasmodium falciparum than AMA1 or AMA1-RON2L complex vaccination. This indicates that SBD1 directs neutralizing antibody responses to strain-transcending epitopes in AMA1 that are independent of RON2L binding. This work underscores the importance of neutralization mechanisms that are distinct from RON2 blockade. The stable single-component SBD1 immunogen elicits potent strain-transcending protection that may drive the development of next-generation vaccines for improved malaria and apicomplexan parasite control.
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Affiliation(s)
- Palak N Patel
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thayne H Dickey
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Nichole D Salinas
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Holly McAleese
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tarik Ouahes
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Lynn E Lambert
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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7
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Guarra F, Colombo G. Computational Methods in Immunology and Vaccinology: Design and Development of Antibodies and Immunogens. J Chem Theory Comput 2023; 19:5315-5333. [PMID: 37527403 PMCID: PMC10448727 DOI: 10.1021/acs.jctc.3c00513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Indexed: 08/03/2023]
Abstract
The design of new biomolecules able to harness immune mechanisms for the treatment of diseases is a prime challenge for computational and simulative approaches. For instance, in recent years, antibodies have emerged as an important class of therapeutics against a spectrum of pathologies. In cancer, immune-inspired approaches are witnessing a surge thanks to a better understanding of tumor-associated antigens and the mechanisms of their engagement or evasion from the human immune system. Here, we provide a summary of the main state-of-the-art computational approaches that are used to design antibodies and antigens, and in parallel, we review key methodologies for epitope identification for both B- and T-cell mediated responses. A special focus is devoted to the description of structure- and physics-based models, privileged over purely sequence-based approaches. We discuss the implications of novel methods in engineering biomolecules with tailored immunological properties for possible therapeutic uses. Finally, we highlight the extraordinary challenges and opportunities presented by the possible integration of structure- and physics-based methods with emerging Artificial Intelligence technologies for the prediction and design of novel antigens, epitopes, and antibodies.
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Affiliation(s)
- Federica Guarra
- Department of Chemistry, University
of Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Giorgio Colombo
- Department of Chemistry, University
of Pavia, Via Taramelli 12, 27100 Pavia, Italy
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8
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Duffy FJ, Hertoghs N, Du Y, Neal ML, Oyong D, McDermott S, Minkah N, Carnes J, Schwedhelm KV, McElrath MJ, De Rosa SC, Newell E, Aitchison JD, Stuart K. Longitudinal immune profiling after radiation-attenuated sporozoite vaccination reveals coordinated immune processes correlated with malaria protection. Front Immunol 2022; 13:1042741. [PMID: 36591224 PMCID: PMC9798120 DOI: 10.3389/fimmu.2022.1042741] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
Background Identifying immune processes required for liver-stage sterilizing immunity to malaria remains an open problem. The IMRAS trial comprised 5x immunizations with radiation-attenuated sporozoites resulting in 55% protection from subsequent challenge. Methods To identify correlates of vaccination and protection, we performed detailed systems immunology longitudinal profiling of the entire trial time course including whole blood transcriptomics, detailed PBMC cell phenotyping and serum antigen array profiling of 11 IMRAS radiation-attenuated sporozoite (RAS) vaccinees at up to 21 timepoints each. Results RAS vaccination induced serum antibody responses to CSP, TRAP, and AMA1 in all vaccinees. We observed large numbers of differentially expressed genes associated with vaccination response and protection, with distinctly differing transcriptome responses elicited after each immunization. These included inflammatory and proliferative responses, as well as increased abundance of monocyte and DC subsets after each immunization. Increases in Vδ2 γδ; T cells and MAIT cells were observed in response to immunization over the course of study, and CD1c+ CD40+ DC abundance was significantly associated with protection. Interferon responses strongly differed between protected and non-protected individuals with high interferon responses after the 1st immunization, but not the 2nd-5th. Blood transcriptional interferon responses were correlated with abundances of different circulating classical and non-classical monocyte populations. Conclusions This study has revealed multiple coordinated immunological processes induced by vaccination and associated with protection. Our work represents the most detailed immunological profiling of a RAS vaccine trial performed to date and will guide the design and interpretation of future malaria vaccine trials.
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Affiliation(s)
- Fergal J. Duffy
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States,*Correspondence: Fergal J. Duffy, ; Ken Stuart,
| | - Nina Hertoghs
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Ying Du
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Maxwell L. Neal
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Damian Oyong
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Suzanne McDermott
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Nana Minkah
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Jason Carnes
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Katharine V. Schwedhelm
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - M. Juliana McElrath
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - Stephen C. De Rosa
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - Evan Newell
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, United States
| | - John D. Aitchison
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States
| | - Ken Stuart
- Center for Global Infectious Disease Research, Seattle Children’s Hospital, Seattle, WA, United States,*Correspondence: Fergal J. Duffy, ; Ken Stuart,
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9
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Rittipornlertrak A, Nambooppha B, Muenthaisong A, Apinda N, Koonyosying P, Srisawat W, Chomjit P, Sangkakam K, Punyapornwithaya V, Tiwananthagorn S, Yokoyama N, Sthitmatee N. Immunization of Cattle With Recombinant Structural Ectodomains I and II of Babesia bovis Apical Membrane Antigen 1 [BbAMA-1(I/II)] Induces Strong Th1 Immune Response. Front Vet Sci 2022; 9:917389. [PMID: 35812841 PMCID: PMC9260583 DOI: 10.3389/fvets.2022.917389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/23/2022] [Indexed: 12/04/2022] Open
Abstract
Both strong innate and adaptive immune responses are an important component of protection against intraerythrocytic protozoan parasites. Resistance to bovine babesiosis is associated with interferon (IFN)-γ mediated responses. CD4+ T cells and macrophages have been identified as major effector cells mediating the clearance of pathogens. Previously, the apical membrane antigen 1 (AMA-1) was found to significantly induce the immune response inhibiting B. bovis merozoite growth and invasion. However, a detailed characterization of both humoral and cellular immune responses against the structure of B. bovis AMA-1 (BbAMA-1) has not yet been established. Herein, the present study aimed to express the recombinant BbAMA-1 domain I+II protein [rBbAMA-1(I/II)], which is the most predominant immune response region, and to characterize its immune response. As a result, cattle vaccinated with BbAMA-1(I/II) significantly developed high titters of total immunoglobulin (Ig) G antibodies and a high ratio of IgG2/IgG1 when compared to control groups. Interestingly, the BbAMA-1(I/II)-based formulations produced in our study could elicit CD4+ T cells and CD8+ T cells producing IFN-γ and tumor necrosis factor (TNF)-α. Collectively, the results indicate that immunization of cattle with BbAMA-1(I/II) could induce strong Th1 cell responses. In support of this, we observed the up-regulation of Th1 cytokine mRNA transcripts, including IFN-γ, TNF-α, Interleukin (IL)-2 and IL-12, in contrast to down regulation of IL-4, IL-6 and IL-10, which would be indicative of a Th2 cytokine response. Moreover, the up-regulation of inducible nitric oxide synthase (iNOS) was observed. In conclusion, this is the first report on the in-depth immunological characterization of the response to BbAMA-1. According to our results, BbAMA-1 is recognized as a potential candidate vaccine against B. bovis infection. As evidenced by the Th1 cell response, it could potentially provide protective immunity. However, further challenge-exposure with virulent B. bovis strain in immunized cattle would be needed to determine its protective efficacy.
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Affiliation(s)
- Amarin Rittipornlertrak
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Ruminant Clinic, Department of Food Animal Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Boondarika Nambooppha
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Anucha Muenthaisong
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nisachon Apinda
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pongpisid Koonyosying
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Wanwisa Srisawat
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Paweena Chomjit
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Kanokwan Sangkakam
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Veerasak Punyapornwithaya
- Ruminant Clinic, Department of Food Animal Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Saruda Tiwananthagorn
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Nattawooti Sthitmatee
- Laboratory of Veterinary Vaccine and Biological Products, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
- Excellent Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai, Thailand
- *Correspondence: Nattawooti Sthitmatee ;
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10
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Cui YB, Shen HM, Chen SB, Kassegne K, Shi TQ, Xu B, Chen JH, Wu JH, Wang Y. Genetic Diversity and Selection of Plasmodium vivax Apical Membrane Antigen-1 in China-Myanmar Border of Yunnan Province, China, 2009-2016. Front Cell Infect Microbiol 2022; 11:742189. [PMID: 35071030 PMCID: PMC8766981 DOI: 10.3389/fcimb.2021.742189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/09/2021] [Indexed: 11/26/2022] Open
Abstract
Plasmodium vivax apical membrane antigen-1 (PvAMA-1) is an important vaccine candidate for vivax malaria. However, antigenic variation within PvAMA-1 is a major obstacle to the design of a global protective malaria vaccine. In this study, we analyzed the genetic polymorphism and selection of the PvAMA-1 gene from 152 P. vivax isolates from imported cases to China, collected in the China–Myanmar border (CMB) area in Yunnan Province (YP) during 2009–2011 (n = 71) and 2014–2016 (n = 81), in comparison with PvAMA-1 gene information from Myanmar (n = 73), collected from public data. The overall nucleotide diversity of the PvAMA-1 gene from the 152 YP isolates was 0.007 with 76 haplotypes identified (Hd = 0.958). Results from the population structure suggested three groups among the YP and Myanmar isolates with optimized clusters value of K = 7. In addition, YP (2014–2016) isolates generally lacked some K components that were commonly found in YP (2009–2011) and Myanmar. Meanwhile, PvAMA-1 domain I is found to be the dominant target of positive diversifying selection and most mutation loci were found in this domain. The mutation frequencies of D107N/A, R112K/T, K120R, E145A, E277K, and R438H in PvAMA-1 were more than 70% in the YP isolates. In conclusion, high genetic diversity and positive selection were found in the PvAMA-1 gene from YP isolates, which are significant findings for the design and development of PvAMA-1-based malaria vaccine.
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Affiliation(s)
- Yan-Bing Cui
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Hai-Mo Shen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Shen-Bo Chen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Kokouvi Kassegne
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tian-Qi Shi
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Bin Xu
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China.,School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Hong Wu
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, China.,Department of Parasitology, Provincial Key Laboratory of Modern Pathogen Biology, Guizhou Medical University, Guiyang, China
| | - Yue Wang
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
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11
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Genetic Polymorphism and Natural Selection of Apical Membrane Antigen-1 in Plasmodium falciparum Isolates from Vietnam. Genes (Basel) 2021; 12:genes12121903. [PMID: 34946853 PMCID: PMC8701107 DOI: 10.3390/genes12121903] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/22/2021] [Accepted: 11/26/2021] [Indexed: 11/17/2022] Open
Abstract
Apical membrane antigen-1 of Plasmodium falciparum (PfAMA-1) is a leading malaria vaccine candidate antigen. However, the genetic diversity of pfama-1 and associated antigenic variation in global P. falciparum field isolates are major hurdles to the design of an efficacious vaccine formulated with this antigen. Here, we analyzed the genetic structure and the natural selection of pfama-1 in the P. falciparum population of Vietnam. A total of 37 distinct haplotypes were found in 131 P. falciparum Vietnamese isolates. Most amino acid changes detected in Vietnamese pfama-1 were localized in the ectodomain, domains I, II, and III. Overall patterns of major amino acid changes in Vietnamese pfama-1 were similar to those of global pfama-1, but the frequencies of the amino acid changes slightly differed by country. Novel amino acid changes were also identified in Vietnamese pfama-1. Vietnamese pfama-1 revealed relatively lower genetic diversity than currently analyzed pfama-1 in other geographical regions, and suggested a distinct genetic differentiation pattern. Evidence for natural selection was detected in Vietnamese pfama-1, but it showed purifying selection unlike the global pfama-1 analyzed so far. Recombination events were also found in Vietnamese pfama-1. Major amino acid changes that were commonly identified in global pfama-1 were mainly localized to predicted B-cell epitopes, RBC-binding sites, and IUR regions. These results provide important information for understanding the genetic nature of the Vietnamese pfama-1 population, and have significant implications for the design of a vaccine based on PfAMA-1.
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12
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Nasr A, Aljada A, Hamid O, Elsheikh HA, Masuadi E, Al-Bawab A, Alenazi TH, Abushouk A, Salah AM. Significant differences in FcγRIIa, FcγRIIIa and FcγRIIIb genes polymorphism and anti-malarial IgG subclass pattern are associated with severe Plasmodium falciparum malaria in Saudi children. Malar J 2021; 20:376. [PMID: 34551786 PMCID: PMC8459561 DOI: 10.1186/s12936-021-03901-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 09/01/2021] [Indexed: 11/10/2022] Open
Abstract
Background The FcγRs genotypes have been reported to play a key role in the defence against malaria parasites through both cellular and humoral immunity. This study aimed to investigate the possible correlation between FcγR (IIa, IIIa, and IIIb) genes polymorphism and the clinical outcome for anti‐malarial antibody response of Plasmodium falciparum infection among Saudi children. Methods A total of 600 volunteers were enrolled in this study, including 200 malaria-free control (MFC) subjects, 218 patients with uncomplicated malaria (UM) and 182 patients with severe malaria (SM). The FcγR genotypes were analysed using PCR amplification methods, and measurements of immunoglobulin were determined using enzyme-linked immunosorbent assay (ELISA) technique. Results The data revealed that the FcγRIIa-R/R131 showed a statistically significant association with SM patients when compared to UM patients. Furthermore, higher levels of IgG1, IgG2, and IgG4 were associated with the FcγRIIa-H/H131 genotype among UM patients. Although the FcγRIIa-F/V176 genotype was not associated with UM, it showed a significant association with severe malaria. Interestingly, the FcγRIIIa-V/V176 genotype offered protection against SM. Moreover, SM patients carrying the FcγRIIIa-F/F genotype showed higher levels of AMA-1-specific IgG2 and IgG4 antibodies. The FcγRIIIb-NA1/NA1 and FcγRIIIb-NA2/NA2 genotypes did not show significant differences between the UM and the MFC groups. However, the genotype FcγRIIIb-NA2/NA2 was statistically significantly associated with SM patients. Conclusions The data presented in this study suggest that the influence of the FcγRIIa-R/R131, FcγRIIIa-F/F176 and FcγRIIIb-NA2/NA2 genotypes are statistically significantly associated with SM patients. However, the FcγRIIa-H/H13 and FcγRIIIa-V/V176 genotypes have demonstrated a protective effect against SM when compared to UM patients. The impact of the FcyR (IIa, IIIa and IIIb) gene variants and anti-malaria IgG subclasses play an important role in susceptibility to malaria infection and disease outcome in Saudi children.
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Affiliation(s)
- Amre Nasr
- Department of Basic Medical Sciences, College of Medicine, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Kingdom of Saudi Arabia. .,Department of Immunology, King Abdullah International Medical Research Centre (KAIMRC), Ministry of National Guard- Health Affairs, Riyadh, Kingdom of Saudi Arabia.
| | - Ahmad Aljada
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Osama Hamid
- Department of Public Health, Jazan Health Affairs- District Ministry of Health, Jazan, Saudi Arabia
| | - Hatim A Elsheikh
- Department of Pharmacology, College of Medicine, Taif University, POBox 888, Taif, 21944, Saudi Arabia
| | - Emad Masuadi
- Department of Immunology, King Abdullah International Medical Research Centre (KAIMRC), Ministry of National Guard- Health Affairs, Riyadh, Kingdom of Saudi Arabia.,Department of Medical Education, College of Medicine-Riyadh, King Saud Bin Abdul-Aziz University for Health Sciences, (KSAU-HS), Riyadh, Kingdom of Saudi Arabia
| | - Ahmad Al-Bawab
- Department of Basic Medical Sciences, College of Medicine, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Kingdom of Saudi Arabia
| | - Themer H Alenazi
- Infectious Disease Division, Department of Medicine, King Abdulaziz Medical City, National Guard Health Affairs, RiyadhRiyadh, Saudi Arabia.,Department of Medicine, College of Medicine, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Kingdom of Saudi Arabia
| | - Amir Abushouk
- Department of Basic Medical Sciences, College of Medicine, King Saud Bin Abdul-Aziz University for Health Sciences, Jeddah, Kingdom of Saudi Arabia.,King Abdullah International Medical Research Centre (KAIMRC), National Guard Health Affairs, Jeddah, Kingdom of Saudi Arabia
| | - Ayman M Salah
- King Abdullah International Medical Research Centre (KAIMRC), National Guard Health Affairs, Jeddah, Kingdom of Saudi Arabia.,Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Jeddah, Kingdom of Saudi Arabia
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13
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Kale S, Pande V, Singh OP, Carlton JM, Mallick PK. Genetic diversity in two leading Plasmodium vivax malaria vaccine candidates AMA1 and MSP119 at three sites in India. PLoS Negl Trop Dis 2021; 15:e0009652. [PMID: 34370745 PMCID: PMC8376102 DOI: 10.1371/journal.pntd.0009652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/19/2021] [Accepted: 07/15/2021] [Indexed: 11/18/2022] Open
Abstract
Plasmodium vivax, a major contributor to the malaria burden in India, has the broadest geographic distribution and shows higher genetic diversity than P. falciparum. Here, we investigated the genetic diversity of two leading P. vivax vaccine candidate antigens, at three geographically diverse malaria-endemic regions in India. Pvama1 and Pvmsp119 partial coding sequences were generated from one hundred P. vivax isolates in India (Chennai n = 28, Nadiad n = 50 and Rourkela n = 22) and ~1100 published sequences from Asia, South America, North America, and Oceania regions included. These data were used to assess the genetic diversity and potential for vaccine candidacy of both antigens on a global scale. A total of 44 single nucleotide polymorphism (SNPs) were identified among 100 Indian Pvama1 sequences, including 10 synonymous and 34 nonsynonymous mutations. Nucleotide diversity was higher in Rourkela and Nadiad as compared to Chennai. Nucleotide diversity measures showed a strong balancing selection in Indian and global population for domain I of Pvama1, which suggests that it is a dominant target of the protective immune response. In contrast, the Pvmsp119 region showed highly conserved sequences in India and across the Oceania, South America, North America and Asia, demonstrating low genetic diversity in the global population when compared to Pvama1. Results suggest the possibility of including Pvmsp119 in a multivalent vaccine formulation against P. vivax infections. However, the high genetic diversity seen in Pvama1 would be more challenging for vaccine development.
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Affiliation(s)
- Sonal Kale
- Parasite-Host Biology Group, National Institute of Malaria Research, Indian Council of Medical Research, New Delhi, India.,Department of Biotechnology, Kumaun University, Nainital, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Nainital, India
| | - Om P Singh
- Parasite-Host Biology Group, National Institute of Malaria Research, Indian Council of Medical Research, New Delhi, India
| | - Jane M Carlton
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York city, New York, United States of America.,Department of Epidemiology, School of Global Public Health, New York University, New York city, New York, United States of America
| | - Prashant K Mallick
- Parasite-Host Biology Group, National Institute of Malaria Research, Indian Council of Medical Research, New Delhi, India
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14
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Rittipornlertrak A, Nambooppha B, Muenthaisong A, Punyapornwithaya V, Tiwananthagorn S, Chung YT, Tuvshintulga B, Sivakumar T, Yokoyama N, Sthitmatee N. Structural and immunological characterization of an epitope within the PAN motif of ectodomain I in Babesia bovis apical membrane antigen 1 for vaccine development. PeerJ 2021; 9:e11765. [PMID: 34316404 PMCID: PMC8288113 DOI: 10.7717/peerj.11765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/22/2021] [Indexed: 11/25/2022] Open
Abstract
Background Bovine babesiosis caused by Babesia bovis (B. bovis) has had a significant effect on the mobility and mortality rates of the cattle industry worldwide. Live-attenuated vaccines are currently being used in many endemic countries, but their wide use has been limited for a number of reasons. Although recombinant vaccines have been proposed as an alternative to live vaccines, such vaccines are not commercially available to date. Apical membrane antigen-1 (AMA-1) is one of the leading candidates in the development of a vaccine against diseases caused by apicomplexan parasite species. In Plasmodium falciparum (P. falciparum) AMA-1 (PfAMA-1), several antibodies against epitopes in the plasminogen, apple, and nematode (PAN) motif of PfAMA-1 domain I significantly inhibited parasite growth. Therefore, the purpose of this study was to predict an epitope from the PAN motif of domain I in the B. bovis AMA-1 (BbAMA-1) using a combination of linear and conformational B-cell epitope prediction software. The selected epitope was then bioinformatically analyzed, synthesized as a peptide (sBbAMA-1), and then used to immunize a rabbit. Subsequently, in vitro growth- and the invasion-inhibitory effects of the rabbit antiserum were immunologically characterized. Results Our results demonstrated that the predicted BbAMA-1 epitope was located on the surface-exposed α-helix of the PAN motif in domain I at the apex area between residues 181 and 230 with six polymorphic sites. Subsequently, sBbAMA-1 elicited antibodies capable of recognizing the native BbAMA-1 in immunoassays. Furthermore, anti-serum against sBbAMA-1 was immunologically evaluated for its growth- and invasion-inhibitory effects on B. bovis merozoites in vitro. Our results demonstrated that the rabbit anti-sBbAMA-1 serum at a dilution of 1:5 significantly inhibited (p < 0.05) the growth of B. bovis merozoites by approximately 50–70% on days 3 and 4 of cultivation, along with the invasion of merozoites by approximately 60% within 4 h of incubation when compared to the control groups. Conclusion Our results indicate that the epitope predicted from the PAN motif of BbAMA-1 domain I is neutralization-sensitive and may serve as a target antigen for vaccine development against bovine babesiosis caused by B. bovis.
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Affiliation(s)
| | - Boondarika Nambooppha
- Graduate School of Veterinary Sciences, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Anucha Muenthaisong
- Graduate School of Veterinary Sciences, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Veerasak Punyapornwithaya
- Department of Food Animal Clinic, Faculty of Veterinary Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Saruda Tiwananthagorn
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
| | - Yang-Tsung Chung
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taichung, Taiwan
| | - Bumduuren Tuvshintulga
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Thillaiampalam Sivakumar
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Nattawooti Sthitmatee
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand
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15
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Roy K, Roy S, Roy S. A mimotope attached to an ITIM-SHP-1 interaction inhibitory peptide boosts immune response and efficacy. RSC Med Chem 2021; 12:994-999. [PMID: 34223164 PMCID: PMC8221254 DOI: 10.1039/d1md00099c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 04/26/2021] [Indexed: 11/21/2022] Open
Abstract
Antigen binding to the B-cell receptor initiates a downstream signalling pathway that contains both stimulatory and damping components. A malarial parasite-derived conformation-constrained peptide was conjugated to a signal-damping pathway inhibitor. Mice immunized with this antigen produced higher antibody levels which delayed parasitemia. This represents a new approach to antigen design.
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Affiliation(s)
- Koushik Roy
- Division of Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology 4, Raja S.C.Mullick Road Kolkata 700032 India
| | - Syamal Roy
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology 4, Raja S.C. Mullick Road Kolkata 700032 India
| | - Siddhartha Roy
- Department of Biophysics, Bose Institute P1/12, CIT Scheme VII M Kolkata 700054 India
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16
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Zhu J, Wang Y, Cao Y, Shen J, Yu L. Diverse Roles of TgMIC1/4/6 in the Toxoplasma Infection. Front Microbiol 2021; 12:666506. [PMID: 34220751 PMCID: PMC8247436 DOI: 10.3389/fmicb.2021.666506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/25/2021] [Indexed: 11/23/2022] Open
Abstract
Toxoplasma gondii microneme is a specialized secretory organelle that discharges its contents at the apical tip of this apicomplexan parasite in a sequential and regulated manner. Increasing number of studies on microneme proteins (MICs) have shown them as a predominant and important role in host cell attachment, invasion, motility and pathogenesis. In this review, we summarize the research advances in one of the most important MICs complexes, TgMIC1/4/6, which will contribute to improve the understanding of the molecular mechanism of T. gondii infection and provide a theoretical basis for the effective control against T. gondii.
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Affiliation(s)
- Jinjin Zhu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yang Wang
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yuanyuan Cao
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Jilong Shen
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Li Yu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
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17
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De SL, Ntumngia FB, Nicholas J, Adams JH. Progress towards the development of a P. vivax vaccine. Expert Rev Vaccines 2021; 20:97-112. [PMID: 33481638 PMCID: PMC7994195 DOI: 10.1080/14760584.2021.1880898] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Plasmodium vivax causes significant public health problems in endemic regions. A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the development of hypnozoites in the liver with potential for relapse. A minimally effective vaccine should prevent disease and transmission while an ideal vaccine provides sterile immunity. AREAS COVERED Despite decades of research, the complex life cycle, technical challenges and a lack of funding have hampered progress of P. vivax vaccine development. Here, we review the progress of potential P. vivax vaccine candidates from different stages of the parasite life cycle. We also highlight the challenges and important strategies for rational vaccine design. These factors can significantly increase immune effector mechanisms and improve the protective efficacy of these candidates in clinical trials to generate sustained protection over longer periods of time. EXPERT OPINION A vaccine that presents functionally-conserved epitopes from multiple antigens from various stages of the parasite life cycle is key to induce broadly neutralizing strain-transcending protective immunity to effectively disrupt parasite development and transmission.
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Affiliation(s)
- Sai Lata De
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Justin Nicholas
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
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Bailey JA, Berry AA, Travassos MA, Ouattara A, Boudova S, Dotsey EY, Pike A, Jacob CG, Adams M, Tan JC, Bannen RM, Patel JJ, Pablo J, Nakajima R, Jasinskas A, Dutta S, Takala-Harrison S, Lyke KE, Laurens MB, Niangaly A, Coulibaly D, Kouriba B, Doumbo OK, Thera MA, Felgner PL, Plowe CV. Microarray analyses reveal strain-specific antibody responses to Plasmodium falciparum apical membrane antigen 1 variants following natural infection and vaccination. Sci Rep 2020; 10:3952. [PMID: 32127565 PMCID: PMC7054363 DOI: 10.1038/s41598-020-60551-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 02/13/2020] [Indexed: 11/30/2022] Open
Abstract
Vaccines based on Plasmodium falciparum apical membrane antigen 1 (AMA1) have failed due to extensive polymorphism in AMA1. To assess the strain-specificity of antibody responses to malaria infection and AMA1 vaccination, we designed protein and peptide microarrays representing hundreds of unique AMA1 variants. Following clinical malaria episodes, children had short-lived, sequence-independent increases in average whole-protein seroreactivity, as well as strain-specific responses to peptides representing diverse epitopes. Vaccination resulted in dramatically increased seroreactivity to all 263 AMA1 whole-protein variants. High-density peptide analysis revealed that vaccinated children had increases in seroreactivity to four distinct epitopes that exceeded responses to natural infection. A single amino acid change was critical to seroreactivity to peptides in a region of AMA1 associated with strain-specific vaccine efficacy. Antibody measurements using whole antigens may be biased towards conserved, immunodominant epitopes. Peptide microarrays may help to identify immunogenic epitopes, define correlates of vaccine protection, and measure strain-specific vaccine-induced antibodies.
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Affiliation(s)
- Jason A Bailey
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrea A Berry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mark A Travassos
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Amed Ouattara
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sarah Boudova
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Emmanuel Y Dotsey
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Andrew Pike
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Matthew Adams
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - John C Tan
- Previous address: Roche Sequencing Solutions, Madison, WI, USA
- Nimble Therapeutics, Madison, WI, USA
| | - Ryan M Bannen
- Previous address: Roche Sequencing Solutions, Madison, WI, USA
- Nimble Therapeutics, Madison, WI, USA
| | - Jigar J Patel
- Previous address: Roche Sequencing Solutions, Madison, WI, USA
- Nimble Therapeutics, Madison, WI, USA
| | - Jozelyn Pablo
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Rie Nakajima
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Algis Jasinskas
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Sheetij Dutta
- U.S. Military Malaria Vaccine Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kirsten E Lyke
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew B Laurens
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Amadou Niangaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Drissa Coulibaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Bourema Kouriba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ogobara K Doumbo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamadou A Thera
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Philip L Felgner
- Department of Physiology & Biophysics, University of California, Irvine, CA, USA
| | - Christopher V Plowe
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
- Duke Global Health Institute, Duke University, Durham, NC, USA.
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19
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Wang YN, Lin M, Liang XY, Chen JT, Xie DD, Wang YL, Ehapo CS, Eyi UM, Huang HY, Wu JL, Xu DY, Chen ZM, Cao YL, Chen HB. Natural selection and genetic diversity of domain I of Plasmodium falciparum apical membrane antigen-1 on Bioko Island. Malar J 2019; 18:317. [PMID: 31533747 PMCID: PMC6751645 DOI: 10.1186/s12936-019-2948-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/06/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a promising candidate antigen for a blood-stage malaria vaccine. However, antigenic variation and diversity of PfAMA-1 are still major problems to design a universal malaria vaccine based on this antigen, especially against domain I (DI). Detail understanding of the PfAMA-1 gene polymorphism can provide useful information on this potential vaccine component. Here, general characteristics of genetic structure and the effect of natural selection of DIs among Bioko P. falciparum isolates were analysed. METHODS 214 blood samples were collected from Bioko Island patients with P. falciparum malaria between 2011 and 2017. A fragment spanning DI of PfAMA-1 was amplified by nested polymerase chain reaction and sequenced. Polymorphic characteristics and the effect of natural selection were analysed using MEGA 5.0, DnaSP 6.0 and Popart programs. Genetic diversity in 576 global PfAMA-1 DIs were also analysed. Protein function prediction of new amino acid mutation sites was performed using PolyPhen-2 program. RESULTS 131 different haplotypes of PfAMA-1 were identified in 214 Bioko Island P. falciparum isolates. Most amino acid changes identified on Bioko Island were found in C1L. 32 amino acid changes identified in PfAMA-1 sequences from Bioko Island were found in predicted RBC-binding sites, B cell epitopes or IUR regions. Overall patterns of amino acid changes of Bioko PfAMA-1 DIs were similar to those in global PfAMA-1 isolates. Differential amino acid substitution frequencies were observed for samples from different geographical regions. Eight new amino acid changes of Bioko island isolates were also identified and their three-dimensional protein structural consequences were predicted. Evidence for natural selection and recombination event were observed in global isolates. CONCLUSIONS Patterns of nucleotide diversity and amino acid polymorphisms of Bioko Island isolates were similar to those of global PfAMA-1 DIs. Balancing natural selection across DIs might play a major role in generating genetic diversity in global isolates. Most amino acid changes in DIs occurred in predicted B-cell epitopes. Novel sites mapped on a three dimensional structure of PfAMA-1 showed that these regions were located at the corner. These results may provide significant value in the design of a malaria vaccine based on this antigen.
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Affiliation(s)
- Ya-Nan Wang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Min Lin
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Xue-Yan Liang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Jiang-Tao Chen
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou, Guangdong, People's Republic of China
| | - Dong-De Xie
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
| | - Yu-Ling Wang
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
| | - Carlos Salas Ehapo
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Urbano Monsuy Eyi
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Hui-Ying Huang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Jing-Li Wu
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Dan-Yan Xu
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Zhi-Mao Chen
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Yi-Long Cao
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Hai-Bin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China.
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20
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Julien JP, Wardemann H. Antibodies against Plasmodium falciparum malaria at the molecular level. Nat Rev Immunol 2019; 19:761-775. [DOI: 10.1038/s41577-019-0209-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2019] [Indexed: 12/11/2022]
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21
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Moderately Neutralizing Epitopes in Nonfunctional Regions Dominate the Antibody Response to Plasmodium falciparum EBA-140. Infect Immun 2019; 87:IAI.00716-18. [PMID: 30642904 DOI: 10.1128/iai.00716-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/04/2019] [Indexed: 02/08/2023] Open
Abstract
Plasmodium falciparum erythrocyte-binding antigen 140 (EBA-140) plays a role in tight junction formation during parasite invasion of red blood cells and is a potential vaccine candidate for malaria. Individuals in areas where malaria is endemic possess EBA-140-specific antibodies, and individuals with high antibody titers to this protein have a lower rate of reinfection by parasites. The red blood cell binding segment of EBA-140 is comprised of two Duffy-binding-like domains, called F1 and F2, that together create region II. The sialic acid-binding pocket of F1 is essential for binding, whereas the sialic acid-binding pocket in F2 appears dispensable. Here, we show that immunization of mice with the complete region II results in poorly neutralizing antibodies. In contrast, immunization of mice with the functionally relevant F1 domain of region II results in antibodies that confer a 2-fold increase in parasite neutralization compared to that of the F2 domain. Epitope mapping of diverse F1 and F2 monoclonal antibodies revealed that the functionally relevant F1 sialic acid-binding pocket is a privileged site inaccessible to antibodies, that the F2 sialic acid-binding pocket contains a nonneutralizing epitope, and that two additional epitopes reside in F1 on the opposite face from the sialic acid-binding pocket. These studies indicate that focusing the immune response to the functionally important F1 sialic acid binding pocket improves the protective immune response of EBA-140. These results have implications for improving future vaccine designs and emphasize the importance of structural vaccinology for malaria.
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22
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Heide J, Vaughan KC, Sette A, Jacobs T, Schulze Zur Wiesch J. Comprehensive Review of Human Plasmodium falciparum-Specific CD8+ T Cell Epitopes. Front Immunol 2019; 10:397. [PMID: 30949162 PMCID: PMC6438266 DOI: 10.3389/fimmu.2019.00397] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/15/2019] [Indexed: 12/16/2022] Open
Abstract
Control of malaria is an important global health issue and there is still an urgent need for the development of an effective prophylactic vaccine. Multiple studies have provided strong evidence that Plasmodium falciparum-specific MHC class I-restricted CD8+ T cells are important for sterile protection against Plasmodium falciparum infection. Here, we present an interactive epitope map of all P. falciparum-specific CD8+ T cell epitopes published to date, based on a comprehensive data base (IEDB), and literature search. The majority of the described P. falciparum-specific CD8+ T cells were directed against the antigens CSP, TRAP, AMA1, and LSA1. Notably, most of the epitopes were discovered in vaccine trials conducted with malaria-naïve volunteers. Only few immunological studies of P. falciparum-specific CD8+ T cell epitopes detected in patients suffering from acute malaria or in people living in malaria endemic areas have been published. Further detailed immunological mappings of P. falciparum-specific epitopes of a broader range of P. falciparum proteins in different settings and with different disease status are needed to gain a more comprehensive understanding of the role of CD8+ T cell responses for protection, and to better guide vaccine design and to study their efficacy.
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Affiliation(s)
- Janna Heide
- Infectious Diseases Unit, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Kerrie C Vaughan
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States
| | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States.,Department of Medicine, Division of Infectious Diseases, University of California, San Diego (UCSD), La Jolla, CA, United States
| | - Thomas Jacobs
- Protozoa Immunology, Bernhard-Nocht-Institute of Tropical Medicine, Hamburg, Germany
| | - Julian Schulze Zur Wiesch
- Infectious Diseases Unit, I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
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23
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Kang JM, Lee J, Moe M, Jun H, Lê HG, Kim TI, Thái TL, Sohn WM, Myint MK, Lin K, Shin HJ, Kim TS, Na BK. Population genetic structure and natural selection of Plasmodium falciparum apical membrane antigen-1 in Myanmar isolates. Malar J 2018; 17:71. [PMID: 29415731 PMCID: PMC5804060 DOI: 10.1186/s12936-018-2215-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 01/30/2018] [Indexed: 12/16/2022] Open
Abstract
Background Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is one of leading blood stage malaria vaccine candidates. However, genetic variation and antigenic diversity identified in global PfAMA-1 are major hurdles in the development of an effective vaccine based on this antigen. In this study, genetic structure and the effect of natural selection of PfAMA-1 among Myanmar P. falciparum isolates were analysed. Methods Blood samples were collected from 58 Myanmar patients with falciparum malaria. Full-length PfAMA-1 gene was amplified by polymerase chain reaction and cloned into a TA cloning vector. PfAMA-1 sequence of each isolate was sequenced. Polymorphic characteristics and effect of natural selection were analysed with using DNASTAR, MEGA4, and DnaSP programs. Polymorphic nature and natural selection in 459 global PfAMA-1 were also analysed. Results Thirty-seven different haplotypes of PfAMA-1 were identified in 58 Myanmar P. falciparum isolates. Most amino acid changes identified in Myanmar PfAMA-1 were found in domains I and III. Overall patterns of amino acid changes in Myanmar PfAMA-1 were similar to those in global PfAMA-1. However, frequencies of amino acid changes differed by country. Novel amino acid changes in Myanmar PfAMA-1 were also identified. Evidences for natural selection and recombination event were observed in global PfAMA-1. Among 51 commonly identified amino acid changes in global PfAMA-1 sequences, 43 were found in predicted RBC-binding sites, B-cell epitopes, or IUR regions. Conclusions Myanmar PfAMA-1 showed similar patterns of nucleotide diversity and amino acid polymorphisms compared to those of global PfAMA-1. Balancing natural selection and intragenic recombination across PfAMA-1 are likely to play major roles in generating genetic diversity in global PfAMA-1. Most common amino acid changes in global PfAMA-1 were located in predicted B-cell epitopes where high levels of nucleotide diversity and balancing natural selection were found. These results highlight the strong selective pressure of host immunity on the PfAMA-1 gene. These results have significant implications in understanding the nature of Myanmar PfAMA-1 along with global PfAMA-1. They also provide useful information for the development of effective malaria vaccine based on this antigen.
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Affiliation(s)
- Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jinyoung Lee
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,Department of Infection Biology, Zoonosis Research Center, School of Medicine, Wonkwang University, Iksan, 54538, Republic of Korea
| | - Mya Moe
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Hojong Jun
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Tae Im Kim
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,Planning and Management Division, Nakdonggang National Institute of Biological Resources, Sangju, 37242, Republic of Korea
| | - Thị Lam Thái
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Khin Lin
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University College of Medicine, Suwon, 16499, Republic of Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
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24
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Devine SM, MacRaild CA, Norton RS, Scammells PJ. Antimalarial drug discovery targeting apical membrane antigen 1. MEDCHEMCOMM 2017; 8:13-20. [PMID: 30108688 PMCID: PMC6072474 DOI: 10.1039/c6md00495d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/27/2016] [Indexed: 01/06/2023]
Abstract
Malaria continues to frustrate humanity's attempts to eradicate this deadly disease. Although gains have been made over the last 15 years, drug resistance to malaria continues to be a major concern. The lack of new antimalarials with novel mechanisms of action continues to challenge the scientific community to find innovative targets to combat this persistent disease. One such target, apical membrane antigen 1 (AMA1), is an essential protein that helps the parasite invade host erythrocytes. Recently, a number of efforts have focused on the druggability of this target, aiming to block the interactions of AMA1 that mediate invasion of host cells. This review covers recent progress in drug discovery targeting this crucial protein-protein interaction in malaria.
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Affiliation(s)
- Shane M Devine
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Christopher A MacRaild
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Raymond S Norton
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Peter J Scammells
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
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25
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Maskus DJ, Królik M, Bethke S, Spiegel H, Kapelski S, Seidel M, Addai-Mensah O, Reimann A, Klockenbring T, Barth S, Fischer R, Fendel R. Characterization of a novel inhibitory human monoclonal antibody directed against Plasmodium falciparum Apical Membrane Antigen 1. Sci Rep 2016; 6:39462. [PMID: 28000709 PMCID: PMC5175200 DOI: 10.1038/srep39462] [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: 08/25/2016] [Accepted: 11/22/2016] [Indexed: 01/07/2023] Open
Abstract
Malaria remains a major challenge to global health causing extensive morbidity and mortality. Yet, there is no efficient vaccine and the immune response remains incompletely understood. Apical Membrane Antigen 1 (AMA1), a leading vaccine candidate, plays a key role during merozoite invasion into erythrocytes by interacting with Rhoptry Neck Protein 2 (RON2). We generated a human anti-AMA1-antibody (humAbAMA1) by EBV-transformation of sorted B-lymphocytes from a Ghanaian donor and subsequent rescue of antibody variable regions. The antibody was expressed in Nicotiana benthamiana and in HEK239-6E, characterized for binding specificity and epitope, and analyzed for its inhibitory effect on Plasmodium falciparum. The generated humAbAMA1 shows an affinity of 106-135 pM. It inhibits the parasite strain 3D7A growth in vitro with an expression system-independent IC50-value of 35 μg/ml (95% confidence interval: 33 μg/ml-37 μg/ml), which is three to eight times lower than the IC50-values of inhibitory antibodies 4G2 and 1F9. The epitope was mapped to the close proximity of the RON2-peptide binding groove. Competition for binding between the RON2-peptide and humAbAMA1 was confirmed by surface plasmon resonance spectroscopy measurements. The particularly advantageous inhibitory activity of this fully human antibody might provide a basis for future therapeutic applications.
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Affiliation(s)
- Dominika J. Maskus
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Michał Królik
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Susanne Bethke
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Stephanie Kapelski
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Melanie Seidel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Otchere Addai-Mensah
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Torsten Klockenbring
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Stefan Barth
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute for Applied Medical Engineering at RWTH Aachen University and Hospital, Department of Experimental Medicine and Immunotherapy, Aachen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
- Institute for Applied Medical Engineering at RWTH Aachen University and Hospital, Department of Experimental Medicine and Immunotherapy, Aachen, Germany
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26
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Norton RS, Leung EWW, Chandrashekaran IR, MacRaild CA. Applications of (19)F-NMR in Fragment-Based Drug Discovery. Molecules 2016; 21:molecules21070860. [PMID: 27438818 PMCID: PMC6273323 DOI: 10.3390/molecules21070860] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 06/21/2016] [Indexed: 11/16/2022] Open
Abstract
(19)F-NMR has proved to be a valuable tool in fragment-based drug discovery. Its applications include screening libraries of fluorinated fragments, assessing competition among elaborated fragments and identifying the binding poses of promising hits. By observing fluorine in both the ligand and the target protein, useful information can be obtained on not only the binding pose but also the dynamics of ligand-protein interactions. These applications of (19)F-NMR will be illustrated in this review with studies from our fragment-based drug discovery campaigns against protein targets in parasitic and infectious diseases.
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Affiliation(s)
- Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
| | - Eleanor W W Leung
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
| | - Indu R Chandrashekaran
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
| | - Christopher A MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Australia.
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27
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Krishnarjuna B, Lim SS, Devine SM, Debono CO, Lam R, Chandrashekaran IR, Jaipuria G, Yagi H, Atreya HS, Scanlon MJ, MacRaild CA, Scammells PJ, Norton RS. Solution NMR characterization of apical membrane antigen 1 and small molecule interactions as a basis for designing new antimalarials. J Mol Recognit 2016; 29:281-91. [DOI: 10.1002/jmr.2529] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/28/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Bankala Krishnarjuna
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - San Sui Lim
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Shane M. Devine
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Cael O. Debono
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Raymond Lam
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Indu R. Chandrashekaran
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Garima Jaipuria
- NMR Research Centre; Indian Institute of Science; Bangalore 560012 India
| | - Hiromasa Yagi
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | | | - Martin J. Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Christopher A. MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Peter J. Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
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Delgadillo RF, Parker ML, Lebrun M, Boulanger MJ, Douguet D. Stability of the Plasmodium falciparum AMA1-RON2 Complex Is Governed by the Domain II (DII) Loop. PLoS One 2016; 11:e0144764. [PMID: 26731670 PMCID: PMC4701444 DOI: 10.1371/journal.pone.0144764] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/22/2015] [Indexed: 12/20/2022] Open
Abstract
Plasmodium falciparum is an obligate intracellular protozoan parasite that employs a highly sophisticated mechanism to access the protective environment of the host cells. Key to this mechanism is the formation of an electron dense ring at the parasite-host cell interface called the Moving Junction (MJ) through which the parasite invades. The MJ incorporates two key parasite components: the surface protein Apical Membrane Antigen 1 (AMA1) and its receptor, the Rhoptry Neck Protein (RON) complex, the latter one being targeted to the host cell membrane during invasion. Crystal structures of AMA1 have shown that a partially mobile loop, termed the DII loop, forms part of a deep groove in domain I and overlaps with the RON2 binding site. To investigate the mechanism by which the DII loop influences RON2 binding, we measured the kinetics of association and dissociation and binding equilibria of a PfRON2sp1 peptide with both PfAMA1 and an engineered form of PfAMA1 where the flexible region of the DII loop was replaced by a short Gly-Ser linker (ΔDII-PfAMA1). The reactions were tracked by fluorescence anisotropy as a function of temperature and concentration and globally fitted to acquire the rate constants and corresponding thermodynamic profiles. Our results indicate that both PfAMA1 constructs bound to the PfRON2sp1 peptide with the formation of one intermediate in a sequential reversible reaction: A↔B↔C. Consistent with Isothermal Titration Calorimetry measurements, final complex formation was enthalpically driven and slightly entropically unfavorable. Importantly, our experimental data shows that the DII loop lengthened the complex half-life time by 18-fold (900 s and 48 s at 25°C for Pf and ΔDII-Pf complex, respectively). The longer half-life of the Pf complex appeared to be driven by a slower dissociation process. These data highlight a new influential role for the DII loop in kinetically locking the functional binary complex to enable host cell invasion.
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Affiliation(s)
- Roberto F. Delgadillo
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis, CNRS, UMR 7275, 660, route des Lucioles, Sophia Antipolis, 06560, Valbonne, France
| | - Michelle L. Parker
- Department of Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
| | - Maryse Lebrun
- UMR 5235 CNRS, Université de Montpellier, 34095, Montpellier, France
| | - Martin J. Boulanger
- Department of Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
| | - Dominique Douguet
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis, CNRS, UMR 7275, 660, route des Lucioles, Sophia Antipolis, 06560, Valbonne, France
- * E-mail:
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29
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Riglar DT, Whitehead L, Cowman AF, Rogers KL, Baum J. Localisation-based imaging of malarial antigens during erythrocyte entry reaffirms a role for AMA1 but not MTRAP in invasion. J Cell Sci 2015; 129:228-42. [PMID: 26604223 PMCID: PMC4732298 DOI: 10.1242/jcs.177741] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/16/2015] [Indexed: 01/17/2023] Open
Abstract
Microscopy-based localisation of proteins during malaria parasite (Plasmodium) invasion of the erythrocyte is widely used for tentative assignment of protein function. To date, however, imaging has been limited by the rarity of invasion events and the poor resolution available, given the micron size of the parasite, which leads to a lack of quantitative measures for definitive localisation. Here, using computational image analysis we have attempted to assign relative protein localisation during invasion using wide-field deconvolution microscopy. By incorporating three-dimensional information we present a detailed assessment of known parasite effectors predicted to function during entry but as yet untested or for which data are equivocal. Our method, termed longitudinal intensity profiling, resolves confusion surrounding the localisation of apical membrane antigen 1 (AMA1) at the merozoite–erythrocyte junction and predicts that the merozoite thrombospondin-related anonymous protein (MTRAP) is unlikely to play a direct role in the mechanics of entry, an observation supported with additional biochemical evidence. This approach sets a benchmark for imaging of complex micron-scale events and cautions against simplistic interpretations of small numbers of representative images for the assignment of protein function or prioritisation of candidates as therapeutic targets. Highlighted Article: Here we develop a high-definition imaging approach to dissect and assign function to proteins involved in the rapid process of malaria parasite invasion of the human erythrocyte.
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Affiliation(s)
- David T Riglar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia Department of Medical Biology, University of Melbourne, Victoria, 3050, Melbourne, Australia
| | - Lachlan Whitehead
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia Department of Medical Biology, University of Melbourne, Victoria, 3050, Melbourne, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia Department of Medical Biology, University of Melbourne, Victoria, 3050, Melbourne, Australia
| | - Kelly L Rogers
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3052, Australia Department of Medical Biology, University of Melbourne, Victoria, 3050, Melbourne, Australia
| | - Jake Baum
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
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Draper SJ, Angov E, Horii T, Miller LH, Srinivasan P, Theisen M, Biswas S. Recent advances in recombinant protein-based malaria vaccines. Vaccine 2015; 33:7433-43. [PMID: 26458807 PMCID: PMC4687528 DOI: 10.1016/j.vaccine.2015.09.093] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 09/05/2015] [Accepted: 09/28/2015] [Indexed: 01/03/2023]
Abstract
Protein-based vaccines remain the cornerstone approach for B cell and antibody induction against leading target malaria antigens. Advances in antigen selection, immunogen design and epitope-focusing are advancing the field. New heterologous expression platforms are enabling cGMP production of next-generation protein vaccines. Next-generation antigens, protein-based immunogens and virus-like particle (VLP) delivery platforms are in clinical development. Protein-based vaccines will form part of a highly effective multi-component/multi-stage/multi-antigen subunit formulation against malaria.
Plasmodium parasites are the causative agent of human malaria, and the development of a highly effective vaccine against infection, disease and transmission remains a key priority. It is widely established that multiple stages of the parasite's complex lifecycle within the human host and mosquito vector are susceptible to vaccine-induced antibodies. The mainstay approach to antibody induction by subunit vaccination has been the delivery of protein antigen formulated in adjuvant. Extensive efforts have been made in this endeavor with respect to malaria vaccine development, especially with regard to target antigen discovery, protein expression platforms, adjuvant testing, and development of soluble and virus-like particle (VLP) delivery platforms. The breadth of approaches to protein-based vaccines is continuing to expand as innovative new concepts in next-generation subunit design are explored, with the prospects for the development of a highly effective multi-component/multi-stage/multi-antigen formulation seeming ever more likely. This review will focus on recent progress in protein vaccine design, development and/or clinical testing for a number of leading malaria antigens from the sporozoite-, merozoite- and sexual-stages of the parasite's lifecycle–including PfCelTOS, PfMSP1, PfAMA1, PfRH5, PfSERA5, PfGLURP, PfMSP3, Pfs48/45 and Pfs25. Future prospects and challenges for the development, production, human delivery and assessment of protein-based malaria vaccines are discussed.
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Affiliation(s)
- Simon J Draper
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK.
| | - Evelina Angov
- Walter Reed Army Institute of Research, U. S. Military Malaria Research Program, Malaria Vaccine Branch, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 561-873, Japan
| | - Louis H Miller
- Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Prakash Srinivasan
- Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark; Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology and Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sumi Biswas
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK
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Maindola P, Jamal S, Grover A. Cheminformatics Based Machine Learning Models for AMA1-RON2 Abrogators for Inhibiting Plasmodium falciparum Erythrocyte Invasion. Mol Inform 2015; 34:655-64. [PMID: 27490966 DOI: 10.1002/minf.201400139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/21/2015] [Indexed: 01/15/2023]
Abstract
Malaria remains a dreadful disease by putting every year about 3.4 billion people at risk and resulting into mortality of 627 thousand people worldwide. Existing therapies based upon Quinines and Artemisinin-based combination therapies have started showing resistance, pressing the need for search of anti-malarials with different mechanisms of action. In this respect erythrocyte invasion by Plasmodium is immensely crucial, as being obligate intracellular parasite it must invade host cells. This process is mediated by interaction between conserved Apical Membrane Antigen (AMA1) and Rhoptry Neck (RON2) protein, which is compulsory for successful invasion of erythrocyte by Plasmodium and manifestation of the disease Malaria. Here, using the physicochemical properties of the compounds available from a confirmatory high throughput screening, which were tested for their disruption capability of this crucial molecular interaction, we trained supervised classifiers and validated their robustness by various statistical parameters. Best model was used for screening new compounds from Traditional Chinese Medicine Database. Some of the best hits already find their use as anti-malarials and the model predicts that an essential part of their effectiveness is likely due to inhibition of AMA1-RON2 interaction. Pharmacophoric features have also been identified to ease further designing of possible leads in an effective way.
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Affiliation(s)
- Priyank Maindola
- School of Biotechnology, Jawaharlal Nehru University, New Delhi-110067, India phone/fax: +91-11-26738728; fax: +91-11-26702040
| | - Salma Jamal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi-110067, India phone/fax: +91-11-26738728; fax: +91-11-26702040
| | - Abhinav Grover
- School of Biotechnology, Jawaharlal Nehru University, New Delhi-110067, India phone/fax: +91-11-26738728; fax: +91-11-26702040.
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32
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Crossey E, Frietze K, Narum DL, Peabody DS, Chackerian B. Identification of an Immunogenic Mimic of a Conserved Epitope on the Plasmodium falciparum Blood Stage Antigen AMA1 Using Virus-Like Particle (VLP) Peptide Display. PLoS One 2015; 10:e0132560. [PMID: 26147502 PMCID: PMC4493041 DOI: 10.1371/journal.pone.0132560] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 06/16/2015] [Indexed: 12/22/2022] Open
Abstract
We have developed a peptide display platform based on VLPs of the RNA bacteriophage MS2 that combines the high immunogenicity of VLP display with affinity selection capabilities. Random peptides can be displayed on the VLP surface by genetically inserting sequences into a surface-exposed loop of the viral coat protein. VLP-displayed peptides can then be isolated by selection using antibodies, and the VLP selectants can then be used directly as immunogens. Here, we investigated the ability of this platform to identify mimotopes of a highly conserved conformational epitope present on the Plasmodium falciparum blood-stage protein AMA1. Using 4G2, a monoclonal antibody that binds to this epitope and is a potent inhibitor of erythrocyte invasion, we screened three different VLP-peptide libraries and identified specific VLPs that bound strongly to the selecting mAb. We then tested the ability of a handful of selected VLPs to elicit anti-AMA1 antibody responses in mice. Most of the selected VLPs failed to reliably elicit AMA1 specific antibodies. However, one VLP consistently induced antibodies that cross-reacted with AMA1. Surprisingly, this VLP bound to 4G2 more weakly than the other selectants we identified. Taken together, these data demonstrate that VLP-peptide display can identify immunogenic mimics of a complex conformational epitope and illustrate the promise and challenges of this approach.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Protozoan/immunology
- Antibody Affinity
- Antigen-Antibody Reactions
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/immunology
- Antigens, Surface/chemistry
- Antigens, Surface/immunology
- Chromatography, Gel
- Cross Reactions
- Dimerization
- Enzyme-Linked Immunosorbent Assay
- Epitopes/chemistry
- Epitopes/immunology
- Levivirus
- Malaria Vaccines/immunology
- Membrane Proteins/chemistry
- Membrane Proteins/immunology
- Mice
- Mice, Inbred BALB C
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Peptide Library
- Peptides/chemistry
- Peptides/immunology
- Plasmodium falciparum/immunology
- Protein Conformation
- Protozoan Proteins/chemistry
- Protozoan Proteins/immunology
- Sequence Analysis, Protein
- Vaccines, Virus-Like Particle/immunology
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Affiliation(s)
- Erin Crossey
- Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM 87131, United States of America
| | - Kathryn Frietze
- Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM 87131, United States of America
| | - David L. Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, United States of America
| | - David S. Peabody
- Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM 87131, United States of America
| | - Bryce Chackerian
- Department of Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM 87131, United States of America
- * E-mail:
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Reddy SB, Anders RF, Cross N, Mueller I, Senn N, Stanisic DI, Siba PM, Wahlgren M, Kironde F, Beeson JG, Persson KEM. Differences in affinity of monoclonal and naturally acquired polyclonal antibodies against Plasmodium falciparum merozoite antigens. BMC Microbiol 2015; 15:133. [PMID: 26149471 PMCID: PMC4491891 DOI: 10.1186/s12866-015-0461-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 06/03/2015] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major global cause of deaths and a vaccine is urgently needed. Results We have employed the P. falciparum merozoite antigens MSP2-3D7/FC27 and AMA1, used them in ELISA, and coupled them in different ways using surface plasmon resonance (SPR) and estimated affinity (measured as kd) of monoclonal as well as naturally-acquired polyclonal antibodies in human plasma. There were major differences in kd depending on how the antigens were immobilized and where the His-tag was placed. For AMA1 we could see correlations with invasion inhibition. Using different immobilizations of proteins in SPR, we could see only moderate correlations with levels of antibodies in ELISA, indicating that in ELISA the proteins were not uniformly bound and that antibodies with many specificities exist in natural immunisation. The correlations between ELISA and SPR were enhanced when only parasite positive samples were included, which may indicate that high affinity antibodies are difficult to maintain over long periods of time. We found higher kd values for MSP2 (indicating lower affinity) compared to AMA1, which might be partly explained by MSP2 being an intrinsically disordered protein, while AMA1 is globular. Conclusions For future vaccine studies and for understanding immunity, it is important to consider how to present proteins to the immune system to achieve highest antibody affinities. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0461-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sreenivasulu B Reddy
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Robin F Anders
- Department of Biochemistry, La Trobe University, Vic, 3086, Australia
| | - Nadia Cross
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Ivo Mueller
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea
| | - Nicolas Senn
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Danielle I Stanisic
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea.,Institute for Glycomics, Griffith University, Queensland, Australia
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka, 441, Papua New Guinea
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Fred Kironde
- Department of Biochemistry, Makerere University, Kampala, Uganda.,Habib Medical School, IUIU, Kampala, Uganda
| | - James G Beeson
- The Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia.,The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Kristina E M Persson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden. .,Department of Laboratory Medicine, Lund University, 22185, Lund, Sweden.
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34
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Parker ML, Boulanger MJ. An Extended Surface Loop on Toxoplasma gondii Apical Membrane Antigen 1 (AMA1) Governs Ligand Binding Selectivity. PLoS One 2015; 10:e0126206. [PMID: 25955165 PMCID: PMC4425356 DOI: 10.1371/journal.pone.0126206] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/31/2015] [Indexed: 11/18/2022] Open
Abstract
Apicomplexan parasites are the causative agents of globally prevalent diseases including malaria and toxoplasmosis. These obligate intracellular pathogens have evolved a sophisticated host cell invasion strategy that relies on a parasite-host cell junction anchored by interactions between apical membrane antigens (AMAs) on the parasite surface and rhoptry neck 2 (RON2) proteins discharged from the parasite and embedded in the host cell membrane. Key to formation of the AMA1-RON2 complex is displacement of an extended surface loop on AMA1 called the DII loop. While conformational flexibility of the DII loop is required to expose the mature RON2 binding groove, a definitive role of this substructure has not been elucidated. To establish a role of the DII loop in Toxoplasma gondii AMA1, we engineered a form of the protein where the mobile portion of the loop was replaced with a short Gly-Ser linker (TgAMA1ΔDIIloop). Isothermal titration calorimetry measurements with a panel of RON2 peptides revealed an influential role for the DII loop in governing selectivity. Most notably, an Eimeria tenella RON2 (EtRON2) peptide that showed only weak binding to TgAMA1 bound with high affinity to TgAMA1ΔDIIloop. To define the molecular basis for the differential binding, we determined the crystal structure of TgAMA1ΔDIIloop in complex with the EtRON2 peptide. When analyzed in the context of existing AMA1-RON2 structures, spatially distinct anchor points in the AMA1 groove were identified that, when engaged, appear to provide the necessary traction to outcompete the DII loop. Collectively, these data support a model where the AMA1 DII loop serves as a structural gatekeeper to selectively filter out ligands otherwise capable of binding with high affinity in the AMA1 apical groove. These data also highlight the importance of considering the functional implications of the DII loop in the ongoing development of therapeutic intervention strategies targeting the AMA1-RON2 invasion complex.
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Affiliation(s)
- Michelle L. Parker
- Department of Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
| | - Martin J. Boulanger
- Department of Biochemistry & Microbiology, University of Victoria, PO Box 3055 STN CSC, Victoria, BC, V8W 3P6, Canada
- * E-mail:
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35
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Boucher LE, Bosch J. The apicomplexan glideosome and adhesins - Structures and function. J Struct Biol 2015; 190:93-114. [PMID: 25764948 PMCID: PMC4417069 DOI: 10.1016/j.jsb.2015.02.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 02/20/2015] [Accepted: 02/26/2015] [Indexed: 01/10/2023]
Abstract
The apicomplexan family of pathogens, which includes Plasmodium spp. and Toxoplasma gondii, are primarily obligate intracellular parasites and invade multiple cell types. These parasites express extracellular membrane protein receptors, adhesins, to form specific pathogen-host cell interaction complexes. Various adhesins are used to invade a variety of cell types. The receptors are linked to an actomyosin motor, which is part of a complex comprised of many proteins known as the invasion machinery or glideosome. To date, reviews on invasion have focused primarily on the molecular pathways and signals of invasion, with little or no structural information presented. Over 75 structures of parasite receptors and glideosome proteins have been deposited with the Protein Data Bank. These structures include adhesins, motor proteins, bridging proteins, inner membrane complex and cytoskeletal proteins, as well as co-crystal structures with peptides and antibodies. These structures provide information regarding key interactions necessary for target receptor engagement, machinery complex formation, how force is transmitted, and the basis of inhibitory antibodies. Additionally, these structures can provide starting points for the development of antibodies and inhibitory molecules targeting protein-protein interactions, with the aim to inhibit invasion. This review provides an overview of the parasite adhesin protein families, the glideosome components, glideosome architecture, and discuss recent work regarding alternative models.
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Affiliation(s)
- Lauren E Boucher
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA.
| | - Jürgen Bosch
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA.
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36
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Crystal structure of Plasmodium knowlesi apical membrane antigen 1 and its complex with an invasion-inhibitory monoclonal antibody. PLoS One 2015; 10:e0123567. [PMID: 25886591 PMCID: PMC4401722 DOI: 10.1371/journal.pone.0123567] [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: 12/15/2014] [Accepted: 03/05/2015] [Indexed: 11/30/2022] Open
Abstract
The malaria parasite Plasmodium knowlesi, previously associated only with infection of macaques, is now known to infect humans as well and has become a significant public health problem in Southeast Asia. This species should therefore be targeted in vaccine and therapeutic strategies against human malaria. Apical Membrane Antigen 1 (AMA1), which plays a role in Plasmodium merozoite invasion of the erythrocyte, is currently being pursued in human vaccine trials against P. falciparum. Recent vaccine trials in macaques using the P. knowlesi orthologue PkAMA1 have shown that it protects against infection by this parasite species and thus should be developed for human vaccination as well. Here, we present the crystal structure of Domains 1 and 2 of the PkAMA1 ectodomain, and of its complex with the invasion-inhibitory monoclonal antibody R31C2. The Domain 2 (D2) loop, which is displaced upon binding the Rhoptry Neck Protein 2 (RON2) receptor, makes significant contacts with the antibody. R31C2 inhibits binding of the Rhoptry Neck Protein 2 (RON2) receptor by steric blocking of the hydrophobic groove and by preventing the displacement of the D2 loop which is essential for exposing the complete binding site on AMA1. R31C2 recognizes a non-polymorphic epitope and should thus be cross-strain reactive. PkAMA1 is much less polymorphic than the P. falciparum and P. vivax orthologues. Unlike these two latter species, there are no polymorphic sites close to the RON2-binding site of PkAMA1, suggesting that P. knowlesi has not developed a mechanism of immune escape from the host’s humoral response to AMA1.
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37
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Pihan E, Delgadillo RF, Tonkin ML, Pugnière M, Lebrun M, Boulanger MJ, Douguet D. Computational and biophysical approaches to protein-protein interaction inhibition of Plasmodium falciparum AMA1/RON2 complex. J Comput Aided Mol Des 2015; 29:525-39. [PMID: 25822046 DOI: 10.1007/s10822-015-9842-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 03/25/2015] [Indexed: 11/30/2022]
Abstract
Invasion of the red blood cell by Plasmodium falciparum parasites requires formation of an electron dense circumferential ring called the Moving Junction (MJ). The MJ is anchored by a high affinity complex of two parasite proteins: Apical Membrane Antigen 1 (PfAMA1) displayed on the surface of the parasite and Rhoptry Neck Protein 2 that is discharged from the parasite and imbedded in the membrane of the host cell. Structural studies of PfAMA1 revealed a conserved hydrophobic groove localized to the apical surface that coordinates RON2 and invasion inhibitory peptides. In the present work, we employed computational and biophysical methods to identify competitive P. falciparum AMA1-RON2 inhibitors with the goal of exploring the 'druggability' of this attractive antimalarial target. A virtual screen followed by molecular docking with the PfAMA1 crystal structure was performed using an eight million compound collection that included commercial molecules, the ChEMBL malaria library and approved drugs. The consensus approach resulted in the selection of inhibitor candidates. We also developed a fluorescence anisotropy assay using a modified inhibitory peptide to experimentally validate the ability of the selected compounds to inhibit the AMA1-RON2 interaction. Among those, we identified one compound that displayed significant inhibition. This study offers interesting clues to improve the throughput and reliability of screening for new drug leads.
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Affiliation(s)
- Emilie Pihan
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis, CNRS, UMR 7275, 660, Route des Lucioles, Sophia Antipolis, 06560, Valbonne, France
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38
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Arévalo-Pinzón G, Bermúdez M, Curtidor H, Patarroyo MA. The Plasmodium vivax rhoptry neck protein 5 is expressed in the apical pole of Plasmodium vivax VCG-1 strain schizonts and binds to human reticulocytes. Malar J 2015; 14:106. [PMID: 25888962 PMCID: PMC4359499 DOI: 10.1186/s12936-015-0619-1] [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: 11/18/2014] [Accepted: 02/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Different proteins derived from the membrane or the apical organelles become involved in malarial parasite invasion of host cells. Among these, the rhoptry neck proteins (RONs) interact with a protein component of the micronemes to enable the formation of a strong bond which is crucial for the parasite's successful invasion. The present study was aimed at identifying and characterizing the RON5 protein in Plasmodium vivax and evaluating its ability to bind to reticulocytes. METHODS Taking the Plasmodium falciparum and Plasmodium knowlesi RON5 amino acid sequences as template, an in-silico search was made in the P. vivax genome for identifying the orthologous gene. Different molecular tools were used for experimentally ascertaining pvron5 gene presence and transcription in P. vivax VCG-1 strain schizonts. Polyclonal antibodies against PvRON5 peptides were used for evaluating protein expression (by Western blot) and sub-cellular localization (by immunofluorescence). A 33 kDa PvRON5 fragment was expressed in Escherichia coli and used for evaluating the reactivity of sera from patients infected by P. vivax. Two assays were made for determining the RON5 recombinant fragment's ability to bind to reticulocyte-enriched human umbilical cord samples. RESULTS The pvron5 gene (3,477 bp) was transcribed in VCG-1 strain schizonts and encoded a ~133 kDa protein which was expressed in the rhoptry neck of VCG-1 strain late schizonts, together with PvRON2 and PvRON4. Polyclonal sera against PvRON5 peptides specifically detected ~85 and ~30 kDa fragments in parasite lysate, thereby suggesting proteolytic processing in this protein. Comparative analysis of VCG-1 strain PvRON5 with other P. vivax strains having different geographic localizations suggested its low polymorphism regarding other malarial antigens. A recombinant fragment of the PvRON5 protein (rPvRON5) was recognized by sera from P. vivax-infected patients and bound to red blood cells, having a marked preference for human reticulocytes. CONCLUSIONS The pvron5 gene is transcribed in the VCG-1 strain, the encoded protein is expressed at the parasite's apical pole and might be participating in merozoite invasion of host cells, taking into account its marked binding preference for human reticulocytes.
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Affiliation(s)
- Gabriela Arévalo-Pinzón
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
| | - Maritza Bermúdez
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
| | - Manuel A Patarroyo
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
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Molecular insights into the interaction between Plasmodium falciparum apical membrane antigen 1 and an invasion-inhibitory peptide. PLoS One 2014; 9:e109674. [PMID: 25343578 PMCID: PMC4208761 DOI: 10.1371/journal.pone.0109674] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 09/03/2014] [Indexed: 11/28/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) of the human malaria parasite Plasmodium falciparum has been implicated in invasion of the host erythrocyte. It interacts with malarial rhoptry neck (RON) proteins in the moving junction that forms between the host cell and the invading parasite. Agents that block this interaction inhibit invasion and may serve as promising leads for anti-malarial drug development. The invasion-inhibitory peptide R1 binds to a hydrophobic cleft on AMA1, which is an attractive target site for small molecules that block parasite invasion. In this work, truncation and mutational analyses show that Phe5-Phe9, Phe12 and Arg15 in R1 are the most important residues for high affinity binding to AMA1. These residues interact with two well-defined binding hot spots on AMA1. Computational solvent mapping reveals that one of these hot spots is suitable for small molecule targeting. We also confirm that R1 in solution binds to AMA1 with 1∶1 stoichiometry and adopts a secondary structure consistent with the major form of R1 observed in the crystal structure of the complex. Our results provide a basis for designing high affinity inhibitors of the AMA1-RON2 interaction.
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40
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Tonkin ML, Crawford J, Lebrun ML, Boulanger MJ. Babesia divergens and Neospora caninum apical membrane antigen 1 structures reveal selectivity and plasticity in apicomplexan parasite host cell invasion. Protein Sci 2014; 22:114-27. [PMID: 23169033 DOI: 10.1002/pro.2193] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 10/02/2012] [Accepted: 10/05/2012] [Indexed: 11/09/2022]
Abstract
Host cell invasion by the obligate intracellular apicomplexan parasites, including Plasmodium (malaria) and Toxoplasma (toxoplasmosis), requires a step-wise mechanism unique among known host-pathogen interactions. A key step is the formation of the moving junction (MJ) complex, a circumferential constriction between the apical tip of the parasite and the host cell membrane that traverses in a posterior direction to enclose the parasite in a protective vacuole essential for intracellular survival. The leading model of MJ assembly proposes that Rhoptry Neck Protein 2 (RON2) is secreted into the host cell and integrated into the membrane where it serves as the receptor for apical membrane antigen 1 (AMA1) on the parasite surface. We have previously demonstrated that the AMA1-RON2 interaction is an effective target for inhibiting apicomplexan invasion. To better understand the AMA1-dependant molecular recognition events that promote invasion, including the significant AMA1-RON2 interaction, we present the structural characterization of AMA1 from the apicomplexan parasites Babesia divergens (BdAMA1) and Neospora caninum (NcAMA1) by X-ray crystallography. These studies offer intriguing structural insight into the RON2-binding surface groove in the AMA1 apical domain, which shows clear evidence for receptor-ligand co-evolution, and the hyper variability of the membrane proximal domain, which in Plasmodium is responsible for direct binding to erythrocytes. By incorporating the structural analysis of BdAMA1 and NcAMA1 with existing AMA1 structures and complexes we were able to define conserved pockets in the AMA1 apical groove that could be targeted for the design of broadly reactive therapeutics.
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Affiliation(s)
- Michelle L Tonkin
- Department of Biochemistry & Microbiology, University of Victoria, Victoria, British Columbia, V8W 3P6, Canada
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Use of immunodampening to overcome diversity in the malarial vaccine candidate apical membrane antigen 1. Infect Immun 2014; 82:4707-17. [PMID: 25156737 DOI: 10.1128/iai.02061-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) is a leading malarial vaccine candidate; however, its polymorphic nature may limit its success in the field. This study aimed to circumvent AMA1 diversity by dampening the antibody response to the highly polymorphic loop Id, previously identified as a major target of strain-specific, invasion-inhibitory antibodies. To achieve this, five polymorphic residues within this loop were mutated to alanine, glycine, or serine in AMA1 of the 3D7 and FVO Plasmodium falciparum strains. Initially, the corresponding antigens were displayed on the surface of bacteriophage, where the alanine and serine but not glycine mutants folded correctly. The alanine and serine AMA1 mutants were expressed in Escherichia coli, refolded in vitro, and used to immunize rabbits. Serological analyses indicated that immunization with a single mutated form of 3D7 AMA1 was sufficient to increase the cross-reactive antibody response. Targeting the corresponding residues in an FVO backbone did not achieve this outcome. The inclusion of at least one engineered form of AMA1 in a biallelic formulation resulted in an antibody response with broader reactivity against different AMA1 alleles than combining the wild-type forms of 3D7 and FVO AMA1 alleles. For one combination, this extended to an enhanced relative growth inhibition of a heterologous parasite line, although this was at the cost of reduced overall inhibitory activity. These results suggest that targeted mutagenesis of AMA1 is a promising strategy for overcoming antigenic diversity in AMA1 and reducing the number of variants required to induce an antibody response that protects against a broad range of Plasmodium falciparum AMA1 genotypes. However, optimization of the immunization regime and mutation strategy will be required for this potential to be realized.
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Amarasinghe S, Kathriarachchi H, Udagama P. Conserved regions of Plasmodium vivax potential vaccine candidate antigens in Sri Lanka: conscious in silico analysis of prospective conformational epitope regions. ASIAN PAC J TROP MED 2014; 7:832-40. [PMID: 25129470 DOI: 10.1016/s1995-7645(14)60146-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/20/2014] [Accepted: 08/22/2014] [Indexed: 10/24/2022] Open
Abstract
OBJECTIVES To do mapping and modeling of conformational B cell epitope regions of highly conserved and protective regions of three merozoitecandidate vaccine proteins of Plasmodium vivax (P. vivax), ie. merozoite purface protein-1 (PvMSP-1), apical membrane antigen -1 domain ∏ (PvAMA1-D∏) and region ∏ of the Duffy binding protein (PvDBP∏), and to analyze the immunogenic properties of these predicted epitopes. METHODS 3-D structures of amino acid haplotypes from Sri Lanka (available in GeneBank) of PvMSP-119 (n=27), PvAMA1-D∏ (n=21) and PvDBP∏ (n=33) were modeled. SEPPA, selected as the best online server was used for conformational epitope predictions, while prediction and modeling of protein structure and properties related to immunogenicity was carried out with Geno3D server, SCRATCH Protein Server, NetSurfP Server and standalonesoftware, Genious 5.4.4. RESULTS SEPPA revealed that regions of predicted conformational epitopes formed 4 clusters in PvMSP-I19, and 3 clusters each in PvAMA1-D∏ and PvDBP∏, all of which displayed a high degree of hydrophilicity, contained solvent exposed residues, displayed high probability of antigenicity and showed positive antigenic propensity values, that indicated high degree of immunogenicity. CONCLUSIONS Findings of this study revealed and confirmed that different parts of the sequences of each of the conserved regions of the three selected potential vaccine candidate antigens of P. vivax are important with regard to conformational epitope prediction that warrants further laboratory experimental investigations in in vivo animal models.
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Affiliation(s)
- Shanika Amarasinghe
- Department of Plant Sciences, Faculty of Science, University of Colombo, CumarathungaMunidasaMawatha, Colombo 03, Sri Lanka
| | - Hashendra Kathriarachchi
- Department of Plant Sciences, Faculty of Science, University of Colombo, CumarathungaMunidasaMawatha, Colombo 03, Sri Lanka
| | - Preethi Udagama
- Department of Zoology, Faculty of Science, University of Colombo, CumarathungaMunidasaMawatha, Colombo 03, Sri Lanka.
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Chaudhury S, Reifman J, Wallqvist A. Simulation of B cell affinity maturation explains enhanced antibody cross-reactivity induced by the polyvalent malaria vaccine AMA1. THE JOURNAL OF IMMUNOLOGY 2014; 193:2073-86. [PMID: 25080483 DOI: 10.4049/jimmunol.1401054] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Polyvalent vaccines use a mixture of Ags representing distinct pathogen strains to induce an immune response that is cross-reactive and protective. However, such approaches often have mixed results, and it is unclear how polyvalency alters the fine specificity of the Ab response and what those consequences might be for protection. In this article, we present a coarse-grain theoretical model of B cell affinity maturation during monovalent and polyvalent vaccinations that predicts the fine specificity and cross-reactivity of the Ab response. We stochastically simulate affinity maturation using a population dynamics approach in which the host B cell repertoire is represented explicitly, and individual B cell subpopulations undergo rounds of stimulation, mutation, and differentiation. Ags contain multiple epitopes and are present in subpopulations of distinct pathogen strains, each with varying degrees of cross-reactivity at the epitope level. This epitope- and strain-specific model of affinity maturation enables us to study the composition of the polyclonal response in granular detail and identify the mechanisms driving serum specificity and cross-reactivity. We applied this approach to predict the Ab response to a polyvalent vaccine based on the highly polymorphic malaria Ag apical membrane antigen-1. Our simulations show how polyvalent apical membrane Ag-1 vaccination alters the selection pressure during affinity maturation to favor cross-reactive B cells to both conserved and strain-specific epitopes and demonstrate how a polyvalent vaccine with a small number of strains and only moderate allelic coverage may be broadly neutralizing. Our findings suggest that altered fine specificity and enhanced cross-reactivity may be a universal feature of polyvalent vaccines.
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Affiliation(s)
- Sidhartha Chaudhury
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, Frederick, MD 21702
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, Frederick, MD 21702
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, Frederick, MD 21702
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44
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Arnott A, Wapling J, Mueller I, Ramsland PA, Siba PM, Reeder JC, Barry AE. Distinct patterns of diversity, population structure and evolution in the AMA1 genes of sympatric Plasmodium falciparum and Plasmodium vivax populations of Papua New Guinea from an area of similarly high transmission. Malar J 2014; 13:233. [PMID: 24930015 PMCID: PMC4085730 DOI: 10.1186/1475-2875-13-233] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/22/2014] [Indexed: 12/19/2022] Open
Abstract
Background As Plasmodium falciparum and Plasmodium vivax co-exist in most malaria-endemic regions outside sub-Saharan Africa, malaria control strategies in these areas must target both species in order to succeed. Population genetic analyses can predict the effectiveness of interventions including vaccines, by providing insight into patterns of diversity and evolution. The aim of this study was to investigate the population genetics of leading malaria vaccine candidate AMA1 in sympatric P. falciparum and P. vivax populations of Papua New Guinea (PNG), an area of similarly high prevalence (Pf = 22.3 to 38.8%, Pv = 15.3 to 31.8%). Methods A total of 72 Pfama1 and 102 Pvama1 sequences were collected from two distinct areas, Madang and Wosera, on the highly endemic PNG north coast. Results Despite a greater number of polymorphic sites in the AMA1 genes of P. falciparum (Madang = 52; Wosera = 56) compared to P. vivax (Madang = 36, Wosera = 34), the number of AMA1 haplotypes, haplotype diversity (Hd) and recombination (R) was far lower for P. falciparum (Madang = 12, Wosera = 20; Hd ≤0.92, R ≤45.8) than for P. vivax (Madang = 50, Wosera = 38; Hd = 0.99, R = ≤70.9). Balancing selection was detected only within domain I of AMA1 for P. vivax, and in both domains I and III for P. falciparum. Conclusions Higher diversity in the genes encoding P. vivax AMA1 than in P. falciparum AMA1 in this highly endemic area has important implications for development of AMA1-based vaccines in PNG and beyond. These results also suggest a smaller effective population size of P. falciparum compared to P. vivax, a finding that warrants further investigation. Differing patterns of selection on the AMA1 genes indicate that critical antigenic sites may differ between the species, highlighting the need for independent investigations of these two leading vaccine candidates.
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Affiliation(s)
| | | | | | | | | | | | - Alyssa E Barry
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
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Sharon J, Rynkiewicz MJ, Lu Z, Yang CY. Discovery of protective B-cell epitopes for development of antimicrobial vaccines and antibody therapeutics. Immunology 2014; 142:1-23. [PMID: 24219801 PMCID: PMC3992043 DOI: 10.1111/imm.12213] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 11/05/2013] [Accepted: 11/08/2013] [Indexed: 01/07/2023] Open
Abstract
Protective antibodies play an essential role in immunity to infection by neutralizing microbes or their toxins and recruiting microbicidal effector functions. Identification of the protective B-cell epitopes, those parts of microbial antigens that contact the variable regions of the protective antibodies, can lead to development of antibody therapeutics, guide vaccine design, enable assessment of protective antibody responses in infected or vaccinated individuals, and uncover or localize pathogenic microbial functions that could be targeted by novel antimicrobials. Monoclonal antibodies are required to link in vivo or in vitro protective effects to specific epitopes and may be obtained from experimental animals or from humans, and their binding can be localized to specific regions of antigens by immunochemical assays. The epitopes are then identified with mapping methods such as X-ray crystallography of antigen-antibody complexes, antibody inhibition of hydrogen-deuterium exchange in the antigen, antibody-induced alteration of the nuclear magnetic resonance spectrum of the antigen, and experimentally validated computational docking of antigen-antibody complexes. The diversity in shape, size and structure of protective B-cell epitopes, and the increasing importance of protective B-cell epitope discovery to development of vaccines and antibody therapeutics are illustrated through examples from different microbe categories, with emphasis on epitopes targeted by broadly neutralizing antibodies to pathogens of high antigenic variation. Examples include the V-shaped Ab52 glycan epitope in the O-antigen of Francisella tularensis, the concave CR6261 peptidic epitope in the haemagglutinin stem of influenza virus H1N1, and the convex/concave PG16 glycopeptidic epitope in the gp120 V1/V2 loop of HIV type 1.
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MESH Headings
- Animals
- Antibodies, Bacterial/immunology
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/therapeutic use
- Antibodies, Viral/immunology
- Antigen-Antibody Reactions
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Viral/chemistry
- Antigens, Viral/immunology
- Bacterial Vaccines/immunology
- Bacterial Vaccines/therapeutic use
- Epitope Mapping
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/immunology
- Humans
- Models, Molecular
- Protein Conformation
- Viral Vaccines/immunology
- Viral Vaccines/therapeutic use
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Affiliation(s)
- Jacqueline Sharon
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of MedicineBoston, MA, USA
| | - Zhaohua Lu
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| | - Chiou-Ying Yang
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
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Dutta S, Dlugosz LS, Drew DR, Ge X, Ababacar D, Rovira YI, Moch JK, Shi M, Long CA, Foley M, Beeson JG, Anders RF, Miura K, Haynes JD, Batchelor AH. Overcoming antigenic diversity by enhancing the immunogenicity of conserved epitopes on the malaria vaccine candidate apical membrane antigen-1. PLoS Pathog 2013; 9:e1003840. [PMID: 24385910 PMCID: PMC3873463 DOI: 10.1371/journal.ppat.1003840] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 11/04/2013] [Indexed: 12/16/2022] Open
Abstract
Malaria vaccine candidate Apical Membrane Antigen-1 (AMA1) induces protection, but only against parasite strains that are closely related to the vaccine. Overcoming the AMA1 diversity problem will require an understanding of the structural basis of cross-strain invasion inhibition. A vaccine containing four diverse allelic proteins 3D7, FVO, HB3 and W2mef (AMA1 Quadvax or QV) elicited polyclonal rabbit antibodies that similarly inhibited the invasion of four vaccine and 22 non-vaccine strains of P. falciparum. Comparing polyclonal anti-QV with antibodies against a strain-specific, monovalent, 3D7 AMA1 vaccine revealed that QV induced higher levels of broadly inhibitory antibodies which were associated with increased conserved face and domain-3 responses and reduced domain-2 response. Inhibitory monoclonal antibodies (mAb) raised against the QV reacted with a novel cross-reactive epitope at the rim of the hydrophobic trough on domain-1; this epitope mapped to the conserved face of AMA1 and it encompassed the 1e-loop. MAbs binding to the 1e-loop region (1B10, 4E8 and 4E11) were ∼10-fold more potent than previously characterized AMA1-inhibitory mAbs and a mode of action of these 1e-loop mAbs was the inhibition of AMA1 binding to its ligand RON2. Unlike the epitope of a previously characterized 3D7-specific mAb, 1F9, the 1e-loop inhibitory epitope was partially conserved across strains. Another novel mAb, 1E10, which bound to domain-3, was broadly inhibitory and it blocked the proteolytic processing of AMA1. By itself mAb 1E10 was weakly inhibitory but it synergized with a previously characterized, strain-transcending mAb, 4G2, which binds close to the hydrophobic trough on the conserved face and inhibits RON2 binding to AMA1. Novel inhibition susceptible regions and epitopes, identified here, can form the basis for improving the antigenic breadth and inhibitory response of AMA1 vaccines. Vaccination with a few diverse antigenic proteins could provide universal coverage by redirecting the immune response towards conserved epitopes. Numerous reports of vaccine failure are attributed to a mismatch between the genotype of the vaccine and the circulating target strains. This observation is congruent to the view that polyvalent vaccines protect broadly by inducing a multitude of type-specific antibodies. Polyvalent vaccines that can overcome antigenic diversity by refocusing antibody responses towards conserved functional epitopes are highly desirable. Development of an Apical Membrane Antigen-1 (AMA1) malaria vaccine has been impeded by extreme antigenic diversity in the field. We present here a solution to the AMA1 diversity problem. Antibodies against a mixture of only four naturally occurring AMA1 allelic proteins “Quadvax” inhibited invasion of red blood cells by a diverse panel of malaria parasites that represented the global diversity of AMA1 in the field. Competition experiments suggested that in addition to improving the diversity of strain-specific antibodies, the mechanism of broadened inhibition involved an increase in responses against conserved inhibitory epitopes. Monoclonal antibodies against the Quadvax inhibited invasion either by blocking the binding of AMA1 to its receptor RON2 or by blocking a crucial proteolytic processing event. Some mixtures of these antibodies were much more effective than expected and were shown to act synergistically. Together these two classes of functional invasion inhibitory epitopes can be targeted to engineer a more potent AMA1 vaccine.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antigenic Variation/genetics
- Antigenic Variation/immunology
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Cells, Cultured
- Conserved Sequence/immunology
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Immunity, Humoral
- Malaria Vaccines/chemistry
- Malaria Vaccines/immunology
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/immunology
- Mice
- Mice, Nude
- Models, Molecular
- Plasmodium berghei/genetics
- Plasmodium berghei/immunology
- Plasmodium falciparum/immunology
- Protein Structure, Tertiary
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Rabbits
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/immunology
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Affiliation(s)
- Sheetij Dutta
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
- * E-mail:
| | - Lisa S. Dlugosz
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | | | - Xiopeng Ge
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Diouf Ababacar
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yazmin I. Rovira
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - J. Kathleen Moch
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Meng Shi
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Carole A. Long
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - Michael Foley
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | | | - Robin F. Anders
- Department of Biochemistry, La Trobe University, Victoria, Australia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institutes of Health, Rockville, Maryland, United States of America
| | - J. David Haynes
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Adrian H. Batchelor
- Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
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Arnott A, Mueller I, Ramsland PA, Siba PM, Reeder JC, Barry AE. Global Population Structure of the Genes Encoding the Malaria Vaccine Candidate, Plasmodium vivax Apical Membrane Antigen 1 (PvAMA1). PLoS Negl Trop Dis 2013; 7:e2506. [PMID: 24205419 PMCID: PMC3814406 DOI: 10.1371/journal.pntd.0002506] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/16/2013] [Indexed: 12/22/2022] Open
Abstract
Background The Plasmodium vivax Apical Membrane Antigen 1 (PvAMA1) is a promising malaria vaccine candidate, however it remains unclear which regions are naturally targeted by host immunity and whether its high genetic diversity will preclude coverage by a monovalent vaccine. To assess its feasibility as a vaccine candidate, we investigated the global population structure of PvAMA1. Methodology and Principal Findings New sequences from Papua New Guinea (PNG, n = 102) were analysed together with published sequences from Thailand (n = 158), India (n = 8), Sri Lanka (n = 23), Venezuela (n = 74) and a collection of isolates from disparate geographic locations (n = 8). A total of 92 single nucleotide polymorphisms (SNPs) were identified including 22 synonymous SNPs and 70 non-synonymous (NS) SNPs. Polymorphisms and signatures of balancing (positive Tajima's D and low FST values) selection were predominantly clustered in domain I, suggesting it is a dominant target of protective immune responses. To estimate global antigenic diversity, haplotypes comprised of (i) non-singleton (n = 40) and (ii) common (≥10% minor allele frequency, n = 23) polymorphic amino acid sites were then analysed revealing a total of 219 and 210 distinct haplotypes, respectively. Although highly diverse, the 210 haplotypes comprised of only common polymorphisms were grouped into eleven clusters, however substantial geographic differentiation was observed, and this may have implications for the efficacy of PvAMA1 vaccines in different malaria-endemic areas. The PNG haplotypes form a distinct group of clusters not found in any other geographic region. Vaccine haplotypes were rare and geographically restricted, suggesting potentially poor efficacy of candidate PvAMA1 vaccines. Conclusions It may be possible to cover the existing global PvAMA1 diversity by selection of diverse alleles based on these analyses however it will be important to first define the relationships between the genetic and antigenic diversity of this molecule. Traditionally misclassified as benign and neglected as a research priority, it is now understood that P. vivax is an increasingly important cause of human malaria. This important human pathogen poses an enormous obstacle to malaria control and elimination efforts due its broad geographic distribution, ability to cause recurring episodes of malaria after long periods of inactivity and extreme biodiversity. Vaccines are an essential component of global malaria control and elimination campaigns but the diversity of malaria antigens is thought to be a major cause of vaccine failure. Furthermore, at present the majority of current vaccine research is directed toward P. falciparum. The aims of this study were to investigate the global diversity of the P. vivax vaccine candidate, Apical Membrane Antigen 1 (PvAMA1), to determine the feasibility of designing a globally effective PvAMA1 vaccine and to determine which region of PvAMA1 is targeted by host immune responses, in order to identify the most promising vaccine candidates. We report that PvAMA1 diversity is extremely high, and that PvAMA1 domain I is a dominant target of host immune responses. These analyses of PvAMA1 diversity from several geographic regions provide a framework to guide development of a broadly efficacious P. vivax vaccine.
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Affiliation(s)
- Alicia Arnott
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
| | - Ivo Mueller
- Barcelona Centre for International Health Research, Barcelona, Spain
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Paul A. Ramsland
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Immunology, Monash University, Melbourne, Australia
- Department of Surgery Austin Health, University of Melbourne, Heidelberg, Australia
- School of Biomedical Sciences, CHIRI Biosciences, Faculty of Health Sciences, Curtin University, Perth, Australia
| | - Peter M. Siba
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - John C. Reeder
- Centre for Population Health, Burnet Institute, Melbourne, Australia
- Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia
| | - Alyssa E. Barry
- Division of Infection and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- * E-mail:
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Mugyenyi CK, Elliott SR, McCallum FJ, Anders RF, Marsh K, Beeson JG. Antibodies to polymorphic invasion-inhibitory and non-Inhibitory epitopes of Plasmodium falciparum apical membrane antigen 1 in human malaria. PLoS One 2013; 8:e68304. [PMID: 23861883 PMCID: PMC3702562 DOI: 10.1371/journal.pone.0068304] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 06/04/2013] [Indexed: 11/18/2022] Open
Abstract
Background Antibodies to P. falciparum apical membrane protein 1 (AMA1) may contribute to protective immunity against clinical malaria by inhibiting blood stage growth of P. falciparum, and AMA1 is a leading malaria vaccine candidate. Currently, there is limited knowledge of the acquisition of strain-specific and cross-reactive antibodies to AMA1 in humans, or the acquisition of invasion-inhibitory antibodies to AMA1. Methodology/Findings We examined the acquisition of human antibodies to specific polymorphic invasion-inhibitory and non-inhibitory AMA1 epitopes, defined by the monoclonal antibodies 1F9 and 2C5, respectively. Naturally acquired antibodies were measured in cohorts of Kenyan children and adults. Antibodies to the invasion-inhibitory 1F9 epitope and non-inhibitory 2C5 epitope were measured indirectly by competition ELISA. Antibodies to the 1F9 and 2C5 epitopes were acquired by children and correlated with exposure, and higher antibody levels and prevalence were observed with increasing age and with active P. falciparum infection. Of note, the prevalence of antibodies to the inhibitory 1F9 epitope was lower than antibodies to AMA1 or the 2C5 epitope. Antibodies to AMA1 ectodomain, the 1F9 or 2C5 epitopes, or a combination of responses, showed some association with protection from P. falciparum malaria in a prospective longitudinal study. Furthermore, antibodies to the invasion-inhibitory 1F9 epitope were positively correlated with parasite growth-inhibitory activity of serum antibodies. Conclusions/Significance Individuals acquire antibodies to functional, polymorphic epitopes of AMA1 that may contribute to protective immunity, and these findings have implications for AMA1 vaccine development. Measuring antibodies to the 1F9 epitope by competition ELISA may be a valuable approach to assessing human antibodies with invasion-inhibitory activity in studies of acquired immunity and vaccine trials of AMA1.
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Affiliation(s)
- Cleopatra K. Mugyenyi
- Kenya Medical Research Institute, Centre for Geographic Medicine, Coast, Kilifi, Kenya
| | | | - Fiona J. McCallum
- The Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
| | | | - Kevin Marsh
- Kenya Medical Research Institute, Centre for Geographic Medicine, Coast, Kilifi, Kenya
| | - James G. Beeson
- Burnet Institute, Melbourne, Victoria, Australia
- The Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
- Monash University, Victoria, Australia
- * E-mail:
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49
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Overcoming allelic specificity by immunization with five allelic forms of Plasmodium falciparum apical membrane antigen 1. Infect Immun 2013; 81:1491-501. [PMID: 23429537 DOI: 10.1128/iai.01414-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apical membrane antigen 1 (AMA1) is a leading vaccine candidate, but the allelic polymorphism is a stumbling block for vaccine development. We previously showed that a global set of AMA1 haplotypes could be grouped into six genetic populations. Using this information, six recombinant AMA1 proteins representing each population were produced. Rabbits were immunized with either a single recombinant AMA1 protein or mixtures of recombinant AMA1 proteins (mixtures of 4, 5, or 6 AMA1 proteins). Antibody levels were measured by enzyme-linked immunosorbent assay (ELISA), and purified IgG from each rabbit was used for growth inhibition assay (GIA) with 12 different clones of parasites (a total of 108 immunogen-parasite combinations). Levels of antibodies to all six AMA1 proteins were similar when the antibodies were tested against homologous antigens. When the percent inhibitions in GIA were plotted against the number of ELISA units measured with homologous AMA1, all data points followed a sigmoid curve, regardless of the immunogen. In homologous combinations, there were no differences in the percent inhibition between the single-allele and allele mixture groups. However, all allele mixture groups showed significantly higher percent inhibition than the single-allele groups in heterologous combinations. The 5-allele-mixture group showed significantly higher inhibition to heterologous parasites than the 4-allele-mixture group. On the other hand, there was no difference between the 5- and 6-allele-mixture groups. These data indicate that mixtures with a limited number of alleles may cover a majority of the parasite population. In addition, using the data from 72 immunogen-parasite combinations, we mathematically identified 13 amino acid polymorphic sites which significantly impact GIA activities. These results could be a foundation for the rational design of a future AMA1 vaccine.
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Lim SS, Debono CO, MacRaild CA, Chandrashekaran IR, Dolezal O, Anders RF, Simpson JS, Scanlon MJ, Devine SM, Scammells PJ, Norton RS. Development of Inhibitors of Plasmodium falciparum Apical Membrane Antigen 1 Based on Fragment Screening. Aust J Chem 2013. [DOI: 10.1071/ch13266] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Apical membrane antigen 1 (AMA1) is an essential component of the moving junction complex used by Plasmodium falciparum to invade human red blood cells. AMA1 has a conserved hydrophobic cleft that is the site of key interactions with the rhoptry neck protein complex. Our goal is to develop small molecule inhibitors of AMA1 with broad strain specificity, which we are pursuing using a fragment-based approach. In our screening campaign, we identified fragments that bind to the hydrophobic cleft with a hit rate of 5 %. The high hit rate observed strongly suggests that a druggable pocket is present within the cleft.
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