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Cao Y, Hayashi CTH, Kumar N. A Novel Ex Vivo Assay to Evaluate Functional Effectiveness of Plasmodium vivax Transmission-Blocking Vaccine Using Pvs25 Transgenic Plasmodium berghei. J Infect Dis 2024; 229:1894-1903. [PMID: 38408353 PMCID: PMC11175679 DOI: 10.1093/infdis/jiae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/20/2024] [Accepted: 02/22/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Plasmodium falciparum and Plasmodium vivax account for >90% global malaria burden. Transmission intervention strategies encompassing transmission-blocking vaccines (TBV) and drugs represent ideal public health tools to eliminate malaria at the population level. The availability of mature P. falciparum gametocytes through in vitro culture has facilitated development of a standard membrane feeding assay to assess efficacy of transmission interventions against P. falciparum. The lack of in vitro culture for P. vivax has significantly hampered similar progress on P. vivax and limited studies have been possible using blood from infected patients in endemic areas. The ethical and logistical limitations of on-time access to blood from patients have impeded the development of P. vivax TBVs. METHODS Transgenic murine malaria parasites (Plasmodium berghei) expressing TBV candidates offer a promising alternative for evaluation of P. vivax TBVs through in vivo studies in mice, and ex vivo membrane feeding assay (MFA). RESULTS We describe the development of transmission-competent transgenic TgPbvs25 parasites and optimization of parameters to establish an ex vivo MFA to evaluate P. vivax TBV based on Pvs25 antigen. CONCLUSIONS The MFA is expected to expedite Pvs25-based TBV development without dependence on blood from P. vivax-infected patients in endemic areas for evaluation.
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Affiliation(s)
- Yi Cao
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Clifford T H Hayashi
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Nirbhay Kumar
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
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2
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Sassmannshausen J, Bennink S, Distler U, Küchenhoff J, Minns AM, Lindner SE, Burda PC, Tenzer S, Gilberger TW, Pradel G. Comparative proteomics of vesicles essential for the egress of Plasmodium falciparum gametocytes from red blood cells. Mol Microbiol 2024; 121:431-452. [PMID: 37492994 DOI: 10.1111/mmi.15125] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 06/19/2023] [Accepted: 06/27/2023] [Indexed: 07/27/2023]
Abstract
Transmission of malaria parasites to the mosquito is mediated by sexual precursor cells, the gametocytes. Upon entering the mosquito midgut, the gametocytes egress from the enveloping erythrocyte while passing through gametogenesis. Egress follows an inside-out mode during which the membrane of the parasitophorous vacuole (PV) ruptures prior to the erythrocyte membrane. Membrane rupture requires exocytosis of specialized egress vesicles of the parasites; that is, osmiophilic bodies (OBs) involved in rupturing the PV membrane, and vesicles that harbor the perforin-like protein PPLP2 (here termed P-EVs) required for erythrocyte lysis. While some OB proteins have been identified, like G377 and MDV1/Peg3, the majority of egress vesicle-resident proteins is yet unknown. Here, we used high-resolution imaging and BioID methods to study the two egress vesicle types in Plasmodium falciparum gametocytes. We show that OB exocytosis precedes discharge of the P-EVs and that exocytosis of the P-EVs, but not of the OBs, is calcium sensitive. Both vesicle types exhibit distinct proteomes with the majority of proteins located in the OBs. In addition to known egress-related proteins, we identified novel components of OBs and P-EVs, including vesicle-trafficking proteins. Our data provide insight into the immense molecular machinery required for the inside-out egress of P. falciparum gametocytes.
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Affiliation(s)
- Juliane Sassmannshausen
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Sandra Bennink
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Ute Distler
- Core Facility for Mass Spectrometry, Institute of Immunology, University Medical Centre of the Johannes-Gutenberg University, Mainz, Germany
| | - Juliane Küchenhoff
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Allen M Minns
- Department of Biochemistry and Molecular Biology, Huck Center for Malaria Research, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Scott E Lindner
- Department of Biochemistry and Molecular Biology, Huck Center for Malaria Research, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Paul-Christian Burda
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Stefan Tenzer
- Core Facility for Mass Spectrometry, Institute of Immunology, University Medical Centre of the Johannes-Gutenberg University, Mainz, Germany
| | - Tim W Gilberger
- Centre for Structural Systems Biology, Hamburg, Germany
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
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3
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Lyons FMT, Gabriela M, Tham WH, Dietrich MH. Plasmodium 6-Cysteine Proteins: Functional Diversity, Transmission-Blocking Antibodies and Structural Scaffolds. Front Cell Infect Microbiol 2022; 12:945924. [PMID: 35899047 PMCID: PMC9309271 DOI: 10.3389/fcimb.2022.945924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/22/2022] [Indexed: 11/30/2022] Open
Abstract
The 6-cysteine protein family is one of the most abundant surface antigens that are expressed throughout the Plasmodium falciparum life cycle. Many members of the 6-cysteine family have critical roles in parasite development across the life cycle in parasite transmission, evasion of the host immune response and host cell invasion. The common feature of the family is the 6-cysteine domain, also referred to as s48/45 domain, which is conserved across Aconoidasida. This review summarizes the current approaches for recombinant expression for 6-cysteine proteins, monoclonal antibodies against 6-cysteine proteins that block transmission and the growing collection of crystal structures that provide insights into the functional domains of this protein family.
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Affiliation(s)
- Frankie M. T. Lyons
- The Walter and Eliza Hall Institute of Medical Research, Infectious Diseases and Immune Defence Division, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Mikha Gabriela
- The Walter and Eliza Hall Institute of Medical Research, Infectious Diseases and Immune Defence Division, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Infectious Diseases and Immune Defence Division, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Melanie H. Dietrich
- The Walter and Eliza Hall Institute of Medical Research, Infectious Diseases and Immune Defence Division, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
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4
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Wang PP, Jiang X, Zhu L, Zhou D, Hong M, He L, Chen L, Yao S, Zhao Y, Chen G, Wang C, Cui L, Cao Y, Zhu X. A G-Protein-Coupled Receptor Modulates Gametogenesis via PKG-Mediated Signaling Cascade in Plasmodium berghei. Microbiol Spectr 2022; 10:e0015022. [PMID: 35404079 PMCID: PMC9045217 DOI: 10.1128/spectrum.00150-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/20/2022] [Indexed: 12/13/2022] Open
Abstract
Gametogenesis is essential for malaria parasite transmission, but the molecular mechanism of this process remains to be refined. Here, we identified a G-protein-coupled receptor 180 (GPR180) that plays a critical role in signal transduction during gametogenesis in Plasmodium. The P. berghei GPR180 was predominantly expressed in gametocytes and ookinetes and associated with the plasma membrane in female gametes and ookinetes. Knockout of pbgpr180 (Δpbgpr180) had no noticeable effect on blood-stage development but impaired gamete formation and reduced transmission of the parasites to mosquitoes. Transcriptome analysis revealed that a large proportion of the dysregulated genes in the Δpbgpr180 gametocytes had assigned functions in cyclic nucleotide signal transduction. In the Δpbgpr180 gametocytes, the intracellular cGMP level was significantly reduced, and the cytosolic Ca2+ mobilization showed a delay and a reduction in the magnitude during gametocyte activation. These results suggest that PbGPR180 functions upstream of the cGMP-protein kinase G-Ca2+ signaling pathway. In line with this functional prediction, the PbGPR180 protein was found to interact with several transmembrane transporter proteins and the small GTPase Rab6 in activated gametocytes. Allele replacement of pbgpr180 with the P. vivax ortholog pvgpr180 showed equal competence of the transgenic parasite in sexual development, suggesting functional conservation of this gene in Plasmodium spp. Furthermore, an anti-PbGPR180 monoclonal antibody and the anti-PvGPR180 serum possessed robust transmission-blocking activities. These results indicate that GPR180 is involved in signal transduction during gametogenesis in malaria parasites and is a promising target for blocking parasite transmission. IMPORTANCE Environmental changes from humans to mosquitoes activate gametogenesis of the malaria parasite, an obligative process for parasite transmission, but how the signals are relayed remains poorly understood. Here, we show the identification of a Plasmodium G-protein-coupled receptor, GPR180, and the characterization of its function in gametogenesis. In P. berghei, GPR180 is dispensable for asexual development and gametocytogenesis, but its deletion impairs gametogenesis and reduces transmission to mosquitoes. GPR180 appears to function upstream of the cGMP-protein kinase G-Ca2+ signaling pathway and is required for the maximum activity of this pathway. Genetic complementation shows that the GPR180 ortholog from the human malaria parasite P. vivax was fully functional in P. berghei, indicating functional conservation of GPR180 in Plasmodium spp. With predominant expression and membrane association of GPR180 in sexual stages, GPR180 is a promising target for blocking transmission, and antibodies against GPR180 possess robust transmission-blocking activities.
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Affiliation(s)
- Peng-peng Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xuefeng Jiang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Liying Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Dan Zhou
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Mingyang Hong
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lu He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lumeng Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Shijie Yao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Guang Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Basic Medical Sciences, Taizhou University Hospital, Taizhou University, Taizhou, China
| | - Chengqi Wang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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5
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Takashima E, Tachibana M, Morita M, Nagaoka H, Kanoi BN, Tsuboi T. Identification of Novel Malaria Transmission-Blocking Vaccine Candidates. Front Cell Infect Microbiol 2021; 11:805482. [PMID: 34917521 PMCID: PMC8670312 DOI: 10.3389/fcimb.2021.805482] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 11/16/2021] [Indexed: 01/02/2023] Open
Abstract
Control measures have significantly reduced malaria morbidity and mortality in the last two decades; however, the downward trends have stalled and have become complicated by the emergence of COVID-19. Significant efforts have been made to develop malaria vaccines, but currently only the RTS,S/AS01 vaccine against Plasmodium falciparum has been recommended by the WHO, for widespread use among children in sub-Saharan Africa. The efficacy of RTS,S/AS01 is modest, and therefore the development of more efficacious vaccines is still needed. In addition, the development of transmission-blocking vaccines (TBVs) to reduce the parasite transmission from humans to mosquitoes is required toward the goal of malaria elimination. Few TBVs have reached clinical development, and challenges include low immunogenicity or high reactogenicity in humans. Therefore, novel approaches to accelerate TBV research and development are urgently needed, especially novel TBV candidate discovery. In this mini review we summarize the progress in TBV research and development, novel TBV candidate discovery, and discuss how to accelerate novel TBV candidate discovery.
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Affiliation(s)
- Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Bernard N Kanoi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Takafumi Tsuboi
- Division of Cell-Free Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
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6
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PSOP1, putative secreted ookinete protein 1, is localized to the micronemes of Plasmodium yoelii and P. berghei ookinetes. Parasitol Int 2021; 84:102407. [PMID: 34147682 DOI: 10.1016/j.parint.2021.102407] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/01/2021] [Accepted: 06/15/2021] [Indexed: 11/23/2022]
Abstract
Plasmodium parasites cause malaria in mammalian hosts and are transmitted by Anopheles mosquitoes. Activated gametocytes in the mosquito midgut egress from erythrocytes followed by fertilization and zygote formation. Zygotes differentiate into motile invasive ookinetes, which penetrate the midgut epithelium before forming oocysts beneath the basal lamina. Ookinete development and traversal across the mosquito midgut wall are major bottlenecks in the parasite life cycle. In ookinetes, surface proteins and proteins stored in apical organelles have been shown to be involved in parasite-host interactions. A group of ookinete proteins that are predicted to have such functions are named PSOPs (putative secreted ookinete protein). PSOP1 is possibly involved in migration through the midgut wall, and here its subcellular localization was examined in ookinetes by immunoelectron microscopy. PSOP1 localizes to the micronemes of Plasmodium yoelii and Plasmodium berghei ookinetes, indicating that it is stored and possibly apically secreted during ookinete penetration through the mosquito midgut wall.
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7
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Zheng W, Liu F, Du F, Yang F, Kou X, He Y, Feng H, Fan Q, Luo E, Min H, Miao J, Cui L, Cao Y. Characterization of a Sulfhydryl Oxidase From Plasmodium berghei as a Target for Blocking Parasite Transmission. Front Cell Infect Microbiol 2020; 10:311. [PMID: 32670896 PMCID: PMC7332561 DOI: 10.3389/fcimb.2020.00311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/22/2020] [Indexed: 11/13/2022] Open
Abstract
Quiescin sulfhydryl oxidase (QSOX), present in a wide variety of eukaryotic species, catalyzes the insertion of disulfide bonds into unfolded, reduced proteins. Here we characterized the QSOX protein from the rodent malaria parasite Plasmodium berghei (PbQSOX), which is conserved in all sequenced malaria parasite species. The PbQSOX protein was not expressed in asexual erythrocytic stages, but was most abundantly expressed in ookinetes. Indirect immunofluorescence assays revealed PbQSOX was not only localized in cytoplasm of gametocytes, gametes and ookinetes, but also expressed on the surface of gametes and ookinetes. Western blot identified extracellular presence of PbQSOX in the culture medium of ookinetes suggestive of secretion. Pbqsox deletion (Δpbqsox) did not affect asexual intraerythrocytic development, but reduced exflagellation of male gametocytes as well as formation and maturation of ookinetes. Pbqsox deletion also led to a significant increase in the reduced thiol groups of ookinete surface proteins, suggesting that it may play a role in maintaining the integrity of disulfide bonds of surface proteins, which might be needed for ookinete development. Mosquitoes that fed on Δpbqsox-infected mice showed a significant reduction in ookinete and oocyst numbers compared to those fed on wild-type parasite-infected mice. Further, both polyclonal mouse antisera and a monoclonal antibody against the recombinant PbQSOX exhibited substantial transmission-blocking activities in in vitro and mosquito feeding assays, suggesting QSOX is a potential target for blocking parasite transmission.
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Affiliation(s)
- Wenqi Zheng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Clinical Laboratory, Affiliated Hospital of Inner Mongolian Medical University, Hohhot, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Feng Du
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Fan Yang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xu Kou
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Animal Quarantine, College of Animal Husbandry and Veterinary Sciences, Liaoning Medical University, Jinzhou, China
| | - Yiwen He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Hui Feng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Hui Min
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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Plasmodium vivax transcriptional profiling of low input cryopreserved isolates through the intraerythrocytic development cycle. PLoS Negl Trop Dis 2020; 14:e0008104. [PMID: 32119669 PMCID: PMC7067476 DOI: 10.1371/journal.pntd.0008104] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 03/12/2020] [Accepted: 01/30/2020] [Indexed: 11/19/2022] Open
Abstract
Approximately one-third of the global population is at risk of Plasmodium vivax infection, and an estimated 7.51 million cases were reported in 2017. Although, P. vivax research is currently limited by the lack of a robust continuous in vitro culture system for this parasite, recent work optimizing short-term ex vivo culture of P. vivax from cryopreserved isolates has facilitated quantitative assays on synchronous parasites. Pairing this improved culture system with low-input Smart-seq2 RNAseq library preparation, we sought to determine whether transcriptional profiling of P. vivax would provide insight into the differential survival of parasites in different culture media. To this end we probed the transcriptional signature of three different ex vivo P. vivax samples in four different culture media using only 1000 cells for each time point taken during the course of the intraerythrocytic development cycle (IDC). Using this strategy, we achieved similar quality transcriptional data to previously reported P. vivax transcriptomes. We found little effect with varying culture media on parasite transcriptional signatures, identified many novel gametocyte-specific genes from transcriptomes of FACS-isolated gametocytes, and determined invasion ligand expression in schizonts in biological isolates and across the IDC. In total, these data demonstrate the feasibility and utility of P. vivax RNAseq-based transcriptomic studies using minimal biomass input to maximize experimental capacity. Plasmodium vivax is the most prevalent malaria-causing parasite species outside of Sub-Saharan Africa and has many unique and poorly understood biological characteristics that make it particularly challenging to study and combat. Transcriptomic profiling of P. vivax under various conditions has the potential to unlock new experimental abilities and aid in elucidating biology and the development of clinical interventions. However, a lack of a robust in vitro culture system for this parasite has restricted transcriptomic studies to researchers with timely access to fresh human isolates from clinics, which often are in resource-poor settings, as well as nearby, well-equipped laboratories for sample processing. This study aimed to gain insight into the differential survival of P. vivax in various culture media from the parasites transcriptional signature in each media. By implementing low-input RNA library preparation strategies, this study obtains robust transcriptomic data at various parasite development stages and in different culture conditions from just 1000 FACS-purified, P. vivax-infected erythrocytes from viable cryopreserved patient isolates. With these data, we find culture media has little effect on transcriptional profile, we characterize invasion ligand expression across intraerythrocytic development and between clinical isolates, and we define the transcriptome of sexual, transmissible stages of the P. vivax parasite. These results highlight the establishment and utility of a powerful platform for studying the transcriptomic biology of this particularly challenging parasite.
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Tachibana M, Ishino T, Tsuboi T, Torii M. The Plasmodium yoelii microgamete surface antigen (PyMiGS) induces anti-malarial transmission blocking immunity that reduces microgamete motility/release from activated male gametocytes. Vaccine 2018; 36:7463-7471. [DOI: 10.1016/j.vaccine.2018.10.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 02/03/2023]
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10
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Antimalarial Transmission-Blocking Interventions: Past, Present, and Future. Trends Parasitol 2018; 34:735-746. [PMID: 30082147 DOI: 10.1016/j.pt.2018.07.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/14/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022]
Abstract
Malaria remains a major global health challenge. Appropriate use of current antimalarial tools has reduced the disease burden, but morbidity and mortality remain unacceptably high. It is widely accepted that, to achieve long-term control/eradication, it will be necessary to use interventions that inhibit the transmission of parasites to mosquitoes - these tools are termed transmission-blocking interventions (TBIs). This article aims to outline the rationale for the development of TBIs, with a focus on transmission-blocking drugs and (parasite-derived) transmission-blocking vaccines. We describe and summarise the current status of each of these intervention classes and attempt to identify future requirements in development, with a focus on the challenges of establishing each method within an integrated malarial control programme in the future.
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11
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Characterization of Plasmodium berghei Pbg37 as Both a Pre- and Postfertilization Antigen with Transmission-Blocking Potential. Infect Immun 2018; 86:IAI.00785-17. [PMID: 29866905 DOI: 10.1128/iai.00785-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 05/26/2018] [Indexed: 01/29/2023] Open
Abstract
Transmission-blocking vaccines (TBVs) interrupting malaria transmission are an integrated tool for malaria eradication. We characterized a sexual-stage-specific gene (PBANKA_060330) from Plasmodium berghei and studied its potential for use as a TBV. This gene, referred to as pbg37, encodes a protein of 37 kDa with a signal peptide and multiple transmembrane domains and is preferentially expressed in gametocytes. A recombinant Pbg37 (rPbg37) protein targeting the N-terminal 63 amino acids (amino acids 26 to 88) expressed in bacteria elicited strong antibody responses in mice. Western blotting demonstrated Pbg37 expression in gametocytes, zygotes, and, to a lesser extent, ookinetes and its predominant association with the membranes of gametocytes. Indirect immunofluorescence assay showed an abundant surface localization of Pbg37 on gametes and zygotes but reduced amounts on retorts and ookinetes. Knockout of pbg37 (Δpbg37) led to a considerable reduction in gametocytemia, which translated into a ~92.1% decrease in the oocyst number in mosquitoes. Deletion of pbg37 had a more substantial influence on the development and maturation of microgametocytes. As a result, the Δpbg37 lines exhibited a higher female/male gametocyte ratio, fewer mature male gametocytes, and defects in the exflagellation of mature microgametocytes. To test the transmission-blocking potential of Pbg37, an in vitro ookinete assay showed that the major inhibitory effects of anti-Pbg37 antiserum were on the exflagellation and fertilization processes. Direct feeding of mosquitoes on mice immunized with rPbg37 or a control protein showed that rPbg37-immunized and P. berghei-infected mice had a significant reduction (49.1%) in oocyst density compared to the controls. The conservation of this gene in Plasmodium warrants further investigations in human malaria parasites.
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12
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Targeting the Conserved Fusion Loop of HAP2 Inhibits the Transmission of Plasmodium berghei and falciparum. Cell Rep 2018; 21:2868-2878. [PMID: 29212032 PMCID: PMC5732318 DOI: 10.1016/j.celrep.2017.11.024] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/05/2017] [Accepted: 11/02/2017] [Indexed: 01/01/2023] Open
Abstract
Inhibiting transmission of Plasmodium is a central strategy in malarial eradication, and the biological process of gamete fusion during fertilization is a proven target for this approach. The lack of a structure or known molecular function of current anti-malarial vaccine targets has previously been a hindrance in the development of transmission-blocking vaccines. Structure/function studies have indicated that the conserved gamete membrane fusion protein HAP2 is a class II viral fusion protein. Here, we demonstrate that targeting a function-critical site of the fusion/cd loop with species-specific antibodies reduces Plasmodium berghei transmission in vivo by 58.9% and in vitro fertilization by up to 89.9%. A corresponding reduction in P. falciparum transmission (75.5%/36.4% reductions in intensity/prevalence) is observed in complimentary field studies. These results emphasize conserved mechanisms of fusion in Apicomplexa, while highlighting an approach to design future anti-malarial transmission-blocking vaccines. Plasmodium HAP2 is a class II fusion protein Class II proteins are targetable to inhibit fertilization/transmission A short synthetically generated peptide can induce transmission-blocking immunity
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13
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Single-Cell Analysis Reveals Distinct Gene Expression and Heterogeneity in Male and Female Plasmodium falciparum Gametocytes. mSphere 2018; 3:3/2/e00130-18. [PMID: 29643077 PMCID: PMC5909122 DOI: 10.1128/msphere.00130-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 03/22/2018] [Indexed: 01/19/2023] Open
Abstract
Most human deaths that result from malaria are caused by the eukaryotic parasite Plasmodium falciparum. The only form of this parasite that is transmitted to the mosquito is the sexual form, called the gametocyte. The production of mature gametocytes can take up to 2 weeks and results in phenotypically distinct males and females, although what causes this gender-specific differentiation remains largely unknown. Here, we demonstrate the first use of microfluidic technology to capture single gametocytes and determine their temporal sex-specific gene expression in an unbiased manner. We were able to determine male or female identity of single cells based on the upregulation of gender-specific genes as early as mid-stage gametocytes. This analysis has revealed strong markers for male and female gametocyte differentiation that were previously concealed in population analyses. Similar single-cell analyses in eukaryotic pathogens using this method may uncover rare cell types and heterogeneity previously masked in population studies. Sexual reproduction is an obligate step in the Plasmodium falciparum life cycle, with mature gametocytes being the only form of the parasite capable of human-to-mosquito transmission. Development of male and female gametocytes takes 9 to 12 days, and although more than 300 genes are thought to be specific to gametocytes, only a few have been postulated to be male or female specific. Because these genes are often expressed during late gametocyte stages and for some, male- or female-specific transcript expression is debated, the separation of male and female populations is technically challenging. To overcome these challenges, we have developed an unbiased single-cell approach to determine which transcripts are expressed in male versus female gametocytes. Using microfluidic technology, we isolated single mid- to late-stage gametocytes to compare the expression of 91 genes, including 87 gametocyte-specific genes, in 90 cells. Such analysis identified distinct gene clusters whose expression was associated with male, female, or all gametocytes. In addition, a small number of male gametocytes clustered separately from female gametocytes based on sex-specific expression independent of stage. Many female-enriched genes also exhibited stage-specific expression. RNA fluorescent in situ hybridization of male and female markers validated the mutually exclusive expression pattern of male and female transcripts in gametocytes. These analyses uncovered novel male and female markers that are expressed as early as stage III gametocytogenesis, providing further insight into Plasmodium sex-specific differentiation previously masked in population analyses. Our single-cell approach reveals the most robust markers for sex-specific differentiation in Plasmodium gametocytes. Such single-cell expression assays can be generalized to all eukaryotic pathogens. IMPORTANCE Most human deaths that result from malaria are caused by the eukaryotic parasite Plasmodium falciparum. The only form of this parasite that is transmitted to the mosquito is the sexual form, called the gametocyte. The production of mature gametocytes can take up to 2 weeks and results in phenotypically distinct males and females, although what causes this gender-specific differentiation remains largely unknown. Here, we demonstrate the first use of microfluidic technology to capture single gametocytes and determine their temporal sex-specific gene expression in an unbiased manner. We were able to determine male or female identity of single cells based on the upregulation of gender-specific genes as early as mid-stage gametocytes. This analysis has revealed strong markers for male and female gametocyte differentiation that were previously concealed in population analyses. Similar single-cell analyses in eukaryotic pathogens using this method may uncover rare cell types and heterogeneity previously masked in population studies.
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14
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Yoshida K, Iyori M, Blagborough AM, Salman AM, Dulal P, Sala KA, Yamamoto DS, Khan SM, Janse CJ, Biswas S, Yoshii T, Yusuf Y, Tokoro M, Hill AVS, Yoshida S. Adenovirus-prime and baculovirus-boost heterologous immunization achieves sterile protection against malaria sporozoite challenge in a murine model. Sci Rep 2018; 8:3896. [PMID: 29497047 PMCID: PMC5832798 DOI: 10.1038/s41598-018-21369-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/02/2018] [Indexed: 12/16/2022] Open
Abstract
With the increasing prevalence of artemisinin-resistant malaria parasites, a highly efficacious and durable vaccine for malaria is urgently required. We have developed an experimental virus-vectored vaccine platform based on an envelope-modified baculovirus dual-expression system (emBDES). Here, we show a conceptually new vaccine platform based on an adenovirus-prime/emBDES-boost heterologous immunization regimen expressing the Plasmodium falciparum circumsporozoite protein (PfCSP). A human adenovirus 5-prime/emBDES-boost heterologous immunization regimen consistently achieved higher sterile protection against transgenic P. berghei sporozoites expressing PfCSP after a mosquito-bite challenge than reverse-ordered or homologous immunization. This high protective efficacy was also achieved with a chimpanzee adenovirus 63-prime/emBDES-boost heterologous immunization regimen against an intravenous sporozoite challenge. Thus, we show that the adenovirus-prime/emBDES-boost heterologous immunization regimen confers sterile protection against sporozoite challenge by two individual routes, providing a promising new malaria vaccine platform for future clinical use.
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Affiliation(s)
- Kunitaka Yoshida
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kakuma-machi, Kanazawa, 920-1192, Japan.,Kanazawa University Graduate School of Medical Sciences, 13 Takara-machi, Kanazawa, 920-0934, Japan
| | - Mitsuhiro Iyori
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Andrew M Blagborough
- Department of Life Sciences, Sir Alexander Fleming Building, Imperial College London, Imperial College Road, South Kensington, London, SW7 2AZ, UK
| | - Ahmed M Salman
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.,Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, (LUMC, L4-Q), Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Pawan Dulal
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Katarzyna A Sala
- Department of Life Sciences, Sir Alexander Fleming Building, Imperial College London, Imperial College Road, South Kensington, London, SW7 2AZ, UK
| | - Daisuke S Yamamoto
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, 329-0431, Tochigi, Japan
| | - Shahid M Khan
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, (LUMC, L4-Q), Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Chris J Janse
- Leiden Malaria Research Group, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, (LUMC, L4-Q), Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Sumi Biswas
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Tatsuya Yoshii
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Yenni Yusuf
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Masaharu Tokoro
- Kanazawa University Graduate School of Medical Sciences, 13 Takara-machi, Kanazawa, 920-0934, Japan
| | - Adrian V S Hill
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Shigeto Yoshida
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kakuma-machi, Kanazawa, 920-1192, Japan.
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15
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Andreadaki M, Hanssen E, Deligianni E, Claudet C, Wengelnik K, Mollard V, McFadden GI, Abkarian M, Braun-Breton C, Siden-Kiamos I. Sequential Membrane Rupture and Vesiculation during Plasmodium berghei Gametocyte Egress from the Red Blood Cell. Sci Rep 2018; 8:3543. [PMID: 29476099 PMCID: PMC5824807 DOI: 10.1038/s41598-018-21801-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/02/2018] [Indexed: 11/24/2022] Open
Abstract
Malaria parasites alternate between intracellular and extracellular stages and successful egress from the host cell is crucial for continuation of the life cycle. We investigated egress of Plasmodium berghei gametocytes, an essential process taking place within a few minutes after uptake of a blood meal by the mosquito. Egress entails the rupture of two membranes surrounding the parasite: the parasitophorous vacuole membrane (PVM), and the red blood cell membrane (RBCM). High-speed video microscopy of 56 events revealed that egress in both genders comprises four well-defined phases, although each event is slightly different. The first phase is swelling of the host cell, followed by rupture and immediate vesiculation of the PVM. These vesicles are extruded through a single stabilized pore of the RBCM, and the latter is subsequently vesiculated releasing the free gametes. The time from PVM vesiculation to completion of egress varies between events. These observations were supported by immunofluorescence microscopy using antibodies against proteins of the RBCM and PVM. The combined results reveal dynamic re-organization of the membranes and the cortical cytoskeleton of the erythrocyte during egress.
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16
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Iyori M, Blagborough AM, Sala KA, Nishiura H, Takagi K, Yoshida S. Protective efficacy of an IL-12-expressing baculoviral malaria vaccine. Parasite Immunol 2017; 39. [DOI: 10.1111/pim.12498] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/19/2017] [Indexed: 12/13/2022]
Affiliation(s)
- M. Iyori
- Laboratory of Vaccinology and Applied Immunology; Kanazawa University School of Pharmacy; Kanazawa Japan
| | | | - K. A. Sala
- Department of Life Sciences; Imperial College London; London UK
| | - H. Nishiura
- Laboratory of Vaccinology and Applied Immunology; Kanazawa University School of Pharmacy; Kanazawa Japan
| | - K. Takagi
- Laboratory of Vaccinology and Applied Immunology; Kanazawa University School of Pharmacy; Kanazawa Japan
| | - S. Yoshida
- Laboratory of Vaccinology and Applied Immunology; Kanazawa University School of Pharmacy; Kanazawa Japan
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17
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Abstract
Basic science holds enormous power for revealing the biological mechanisms of disease and, in turn, paving the way toward new, effective interventions. Recognizing this power, the 2011 Research Agenda for Malaria Eradication included key priorities in fundamental research that, if attained, could help accelerate progress toward disease elimination and eradication. The Malaria Eradication Research Agenda (malERA) Consultative Panel on Basic Science and Enabling Technologies reviewed the progress, continuing challenges, and major opportunities for future research. The recommendations come from a literature of published and unpublished materials and the deliberations of the malERA Refresh Consultative Panel. These areas span multiple aspects of the Plasmodium life cycle in both the human host and the Anopheles vector and include critical, unanswered questions about parasite transmission, human infection in the liver, asexual-stage biology, and malaria persistence. We believe an integrated approach encompassing human immunology, parasitology, and entomology, and harnessing new and emerging biomedical technologies offers the best path toward addressing these questions and, ultimately, lowering the worldwide burden of malaria.
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18
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Iyori M, Yamamoto DS, Sakaguchi M, Mizutani M, Ogata S, Nishiura H, Tamura T, Matsuoka H, Yoshida S. DAF-shielded baculovirus-vectored vaccine enhances protection against malaria sporozoite challenge in mice. Malar J 2017; 16:390. [PMID: 28962615 PMCID: PMC5622557 DOI: 10.1186/s12936-017-2039-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/21/2017] [Indexed: 01/31/2023] Open
Abstract
Background Previous studies have shown that the baculovirus-vectored vaccine based on the “baculovirus dual expression system (BDES)” is an effective vaccine delivery platform for malaria. However, a point of weakness remaining for use of this vaccine platform in vivo concerns viral inactivation by serum complement. In an effort to achieve complement resistance, the gene encoding the human decay-accelerating factor (hDAF) was incorporated into the BDES malaria vaccine expressing the Plasmodium falciparum circumsporozoite protein (PfCSP). Results The newly-developed BDES vaccine, designated BDES-sPfCSP2-Spider, effectively displayed hDAF and PfCSP on the surface of the viral envelope, resulting in complement resistance both in vitro and in vivo. Importantly, upon intramuscular inoculation into mice, the BDES-sPfCSP2-Spider vaccine had a higher protective efficacy (60%) than that of the control vaccine BDES-sPfCSP2-Spier (30%) against challenge with transgenic Plasmodium berghei sporozoites expressing PfCSP. Conclusion DAF-shielded BDES-vaccines offer great potential for development as a new malaria vaccine platform against the sporozoite challenge. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-2039-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mitsuhiro Iyori
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, First Natural Science Building 1A219, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Daisuke S Yamamoto
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Miako Sakaguchi
- Central Laboratory, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Sakamoto, Nagasaki, Japan
| | - Masanori Mizutani
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, First Natural Science Building 1A219, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Sota Ogata
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, First Natural Science Building 1A219, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Hidesato Nishiura
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, First Natural Science Building 1A219, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Takahiko Tamura
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, First Natural Science Building 1A219, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Hiroyuki Matsuoka
- Division of Medical Zoology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Shigeto Yoshida
- Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, First Natural Science Building 1A219, Kakuma-machi, Kanazawa, 920-1192, Japan.
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19
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Vaughan AM, Kappe SHI. Malaria Parasite Liver Infection and Exoerythrocytic Biology. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025486. [PMID: 28242785 DOI: 10.1101/cshperspect.a025486] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In their infection cycle, malaria parasites undergo replication and population expansions within the vertebrate host and the mosquito vector. Host infection initiates with sporozoite invasion of hepatocytes, followed by a dramatic parasite amplification event during liver stage parasite growth and replication within hepatocytes. Each liver stage forms up to 90,000 exoerythrocytic merozoites, which are in turn capable of initiating a blood stage infection. Liver stages not only exploit host hepatocyte resources for nutritional needs but also endeavor to prevent hepatocyte cell death and detection by the host's immune system. Research over the past decade has identified numerous parasite factors that play a critical role during liver infection and has started to delineate a complex web of parasite-host interactions that sustain successful parasite colonization of the mammalian host. Targeting the parasites' obligatory infection of the liver as a gateway to the blood, with drugs and vaccines, constitutes the most effective strategy for malaria eradication, as it would prevent clinical disease and onward transmission of the parasite.
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Affiliation(s)
- Ashley M Vaughan
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Stefan H I Kappe
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, Washington 98109.,Department of Global Health, University of Washington, Seattle, Washington 98195
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20
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Zheng W, Liu F, He Y, Liu Q, Humphreys GB, Tsuboi T, Fan Q, Luo E, Cao Y, Cui L. Functional characterization of Plasmodium berghei PSOP25 during ookinete development and as a malaria transmission-blocking vaccine candidate. Parasit Vectors 2017; 10:8. [PMID: 28057055 PMCID: PMC5217559 DOI: 10.1186/s13071-016-1932-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/06/2016] [Indexed: 12/23/2022] Open
Abstract
Background Plasmodium ookinete surface proteins as post-fertilization target antigens are potential malaria transmission-blocking vaccine (TBV) candidates. Putative secreted ookinete protein 25 (PSOP25) is a highly conserved ookinete surface protein, and has been shown to be a promising novel TBV target. Here, we further investigated the TBV activities of the full-length recombinant PSOP25 (rPSOP25) protein in Plasmodium berghei, and characterized the potential functions of PSOP25 during the P. berghei life-cycle. Methods We expressed the full-length P. berghei PSOP25 protein in a prokaryotic expression system, and developed polyclonal mouse antisera and a monoclonal antibody (mAb) against the recombinant protein. Indirect immunofluorescence assay (IFA) and Western blot were used to test the specificity of antibodies. The transmission-blocking (TB) activities of antibodies were evaluated by the in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). Finally, the function of PSOP25 during Plasmodium development was studied by deleting the psop25 gene. Results Both polyclonal mouse antisera and anti-rPSOP25 mAb recognized the PSOP25 proteins in the parasites, and IFA showed the preferential expression of PSOP25 on the surface of zygotes, retorts and mature ookinetes. In vitro, these antibodies significantly inhibited ookinetes formation in an antibody concentration-dependent manner. In DFA, mice immunized with the rPSOP25 and those receiving passive transfer of the anti-rPSOP25 mAb reduced the prevalence of mosquito infection by 31.2 and 26.1%, and oocyst density by 66.3 and 63.3%, respectively. Genetic knockout of the psop25 gene did not have a detectable impact on the asexual growth of P. berghei, but significantly affected the maturation of ookinetes and the formation of midgut oocysts. Conclusions The full-length rPSOP25 could elicit strong antibody response in mice. Polyclonal and monoclonal antibodies against PSOP25 could effectively block the formation of ookinetes in vitro and transmission of the parasites to mosquitoes. Genetic manipulation study indicated that PSOP25 is required for ookinete maturation in P. berghei. These results support further testing of the PSOP25 orthologs in human malaria parasites as promising TBV candidates. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1932-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wenqi Zheng
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.,Laboratory of Surgery, The Affiliated Hospital, Inner Mongolia Medical University, Hohhot, 010050, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Yiwen He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Qingyang Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Gregory B Humphreys
- Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Takafumi Tsuboi
- Cell-free Science and Technology Research Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA
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21
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The s48/45 six-cysteine proteins: mediators of interaction throughout the Plasmodium life cycle. Int J Parasitol 2016; 47:409-423. [PMID: 27899328 DOI: 10.1016/j.ijpara.2016.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/01/2016] [Accepted: 10/05/2016] [Indexed: 01/05/2023]
Abstract
During their life cycle Plasmodium parasites rely upon an arsenal of proteins that establish key interactions with the host and vector, and between the parasite sexual stages, with the purpose of ensuring infection, reproduction and proliferation. Among these is a group of secreted or membrane-anchored proteins known as the six-cysteine (6-cys) family. This is a small but important family with only 14 members thus far identified, each stage-specifically expressed during the parasite life cycle. 6-cys proteins often localise at the parasite surface or interface with the host and vector, and are conserved in different Plasmodium species. The unifying feature of the family is the s48/45 domain, presumably involved in adhesion and structurally related to Ephrins, the ligands of Eph receptors. The most prominent s48/45 members are currently under functional investigation and are being pursued as vaccine candidates. In this review, we examine what is known about the 6-cys family, their structure and function, and discuss future research directions.
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22
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Suárez-Cortés P, Sharma V, Bertuccini L, Costa G, Bannerman NL, Sannella AR, Williamson K, Klemba M, Levashina EA, Lasonder E, Alano P. Comparative Proteomics and Functional Analysis Reveal a Role of Plasmodium falciparum Osmiophilic Bodies in Malaria Parasite Transmission. Mol Cell Proteomics 2016; 15:3243-3255. [PMID: 27432909 DOI: 10.1074/mcp.m116.060681] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 11/06/2022] Open
Abstract
An essential step in the transmission of the malaria parasite to the Anopheles vector is the transformation of the mature gametocytes into gametes in the mosquito gut, where they egress from the erythrocytes and mate to produce a zygote, which matures into a motile ookinete. Osmiophilic bodies are electron dense secretory organelles of the female gametocytes which discharge their contents during gamete formation, suggestive of a role in gamete egress. Only one protein with no functional annotation, Pfg377, is described to specifically reside in osmiophilic bodies in Plasmodium falciparum Importantly, Pfg377 defective gametocytes lack osmiophilic bodies and fail to infect mosquitoes, as confirmed here with newly produced pfg377 disrupted parasites. The unique feature of Pfg377 defective gametocytes of lacking osmiophilic bodies was here exploited to perform comparative, label free, global and affinity proteomics analyses of mutant and wild type gametocytes to identify components of these organelles. Subcellular localization studies with fluorescent reporter gene fusions and specific antibodies revealed an osmiophilic body localization for four out of five candidate gene products analyzed: the proteases PfSUB2 (subtilisin 2) and PfDPAP2 (Dipeptidyl aminopeptidase 2), the ortholog of the osmiophilic body component of the rodent malaria gametocytes PbGEST and a previously nonannotated 13 kDa protein. These results establish that osmiophilic bodies and their components are dispensable or marginally contribute (PfDPAP2) to gamete egress. Instead, this work reveals a previously unsuspected role of these organelles in P. falciparum development in the mosquito vector.
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Affiliation(s)
- Pablo Suárez-Cortés
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Vikram Sharma
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Lucia Bertuccini
- ¶Dipartimento Tecnologie e Salute, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Giulia Costa
- ‖Department of Vector Biology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Naa-Lamiley Bannerman
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Anna Rosa Sannella
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Kim Williamson
- **Department of Biology, Loyola University, 1032 West Sheridan Road, Chicago, Illinois 60660
| | - Michael Klemba
- ‡‡Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
| | - Elena A Levashina
- ‖Department of Vector Biology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Edwin Lasonder
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Pietro Alano
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy;
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23
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Zheng W, Kou X, Du Y, Liu F, Yu C, Tsuboi T, Fan Q, Luo E, Cao Y, Cui L. Identification of three ookinete-specific genes and evaluation of their transmission-blocking potentials in Plasmodium berghei. Vaccine 2016; 34:2570-8. [PMID: 27083421 DOI: 10.1016/j.vaccine.2016.04.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/12/2016] [Accepted: 04/05/2016] [Indexed: 12/31/2022]
Abstract
With a renewed hope for malaria elimination, interventions that prevent transmission of parasites from humans to mosquitoes have received elevated attention. Transmission-blocking vaccines (TBVs) targeting the sexual stages are well suited for this task. Here, through bioinformatic analysis, we selected two putative Plasmodium berghei ookinete-stage proteins (PBANKA_111920, and PBANKA_145770) and a previously characterized ookinete protein PBANKA_135340 (PSOP7) for evaluation of their transmission-blocking potentials. Fragments of these predicted proteins were expressed in bacteria and purified recombinant proteins were used to immunize mice. Antisera against these recombinant proteins recognized proteins of predicted sizes from ookinete lysates and localized their expression on the surface of ookinetes. Inclusion of these antisera in in vitro ookinete culture significantly inhibited ookinete formation. Mosquitoes fed on mice immunized with the recombinant proteins also showed significantly reduced oocyst densities (60.0-70.7%) and modest reductions of oocyst prevalence (10.7-37.4%). These data, together with the conservation of these genes in Plasmodium, suggest that these three ookinete proteins could be new promising targets for TBVs and are worth of future investigations in the human malaria parasites.
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Affiliation(s)
- Wenqi Zheng
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China
| | - Xu Kou
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China; College of Animal Husbandry and Veterinary, Liaoning Medical University, Jinzhou, Liaoning 121001, China
| | - Yunting Du
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China
| | - Chunyun Yu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning 110001, China.
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
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Kou X, Zheng W, Du F, Liu F, Wang M, Fan Q, Cui L, Luo E, Cao Y. Characterization of a Plasmodium berghei sexual stage antigen PbPH as a new candidate for malaria transmission-blocking vaccine. Parasit Vectors 2016; 9:190. [PMID: 27038925 PMCID: PMC4818878 DOI: 10.1186/s13071-016-1459-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/15/2016] [Indexed: 12/01/2022] Open
Abstract
Background Transmission-blocking vaccines (TBVs) are a promising strategy for malaria control and elimination. However, candidate TBV antigens are currently limited, highlighting the urgency of identifying new antigens for TBV development. Methods Using a combination of bioinformatic analysis and functional studies in the rodent malaria model Plasmodium berghei, we identified a conserved Plasmodium protein PbPH (PBANKA_041720) containing a pleckstrin homology (PH) domain. The expression of PbPH was detected by Western blot and indirect immunofluorescence assay (IFA). The function of PbPH was tested by genetic knockout. The TB activity was confirmed by in vitro ookinete conversion assay and mosquito feeding. Results PbPH was detected in Western blot as highly expressed in sexual stages (gametocytes and ookinetes). IFA revealed localizations of PbPH on the surface of gametes, zygotes, and ookinetes. Deletion of the pbph gene did not affect asexual growth, but significantly reduced the formation of gametocytes, ookinetes, and oocysts, indicating that PbPH protein is required for parasite sexual development. Recombinant PbPH expressed and purified from bacteria elicited strong antibody responses in mice and the antibodies significantly inhibited exflagellation of male gametocytes and formation of ookinetes in a concentration-dependent manner. Mosquito feeding experiments confirmed that mosquitoes fed on mice immunized with PbPH had 13 % reduction in the prevalence of infection and almost 48 % reduction in oocyst density. Conclusions Pbph is a highly conserved Plasmodium gene and is required for parasite sexual development. PbPH protein is expressed on the surface of gametes and ookinetes. Immunization of mice against the recombinant PbPH protein induced strong antibody responses that effectively reduced the formation of male gametes and ookinetes in vitro and blocked transmission of the parasites to mosquitoes. These results highlight PbPH as a potential TBV candidate that is worth future investigations in human malaria parasites. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1459-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xu Kou
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.,College of Animal Husbandry and Veterinary, Liaoning Medical University, Jinzhou, Liaoning, 121001, China
| | - Wenqi Zheng
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Feng Du
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Meilian Wang
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.
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Beeson JG, Drew DR, Boyle MJ, Feng G, Fowkes FJI, Richards JS. Merozoite surface proteins in red blood cell invasion, immunity and vaccines against malaria. FEMS Microbiol Rev 2016; 40:343-72. [PMID: 26833236 PMCID: PMC4852283 DOI: 10.1093/femsre/fuw001] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2016] [Indexed: 01/11/2023] Open
Abstract
Malaria accounts for an enormous burden of disease globally, with Plasmodium falciparum accounting for the majority of malaria, and P. vivax being a second important cause, especially in Asia, the Americas and the Pacific. During infection with Plasmodium spp., the merozoite form of the parasite invades red blood cells and replicates inside them. It is during the blood-stage of infection that malaria disease occurs and, therefore, understanding merozoite invasion, host immune responses to merozoite surface antigens, and targeting merozoite surface proteins and invasion ligands by novel vaccines and therapeutics have been important areas of research. Merozoite invasion involves multiple interactions and events, and substantial processing of merozoite surface proteins occurs before, during and after invasion. The merozoite surface is highly complex, presenting a multitude of antigens to the immune system. This complexity has proved challenging to our efforts to understand merozoite invasion and malaria immunity, and to developing merozoite antigens as malaria vaccines. In recent years, there has been major progress in this field, and several merozoite surface proteins show strong potential as malaria vaccines. Our current knowledge on this topic is reviewed, highlighting recent advances and research priorities. The authors summarize current knowledge of merozoite surface proteins of malaria parasites; their function in invasion, processing of surface proteins before, during and after invasion, their importance as targets of immunity, and the current status of malaria vaccines that target merozoite surface proteins.
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Affiliation(s)
- James G Beeson
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Michelle J Boyle
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Gaoqian Feng
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Epidemiology and Preventive Medicine, Monash University, Clayton, Victoria, Australia School of Population Health, University of Melbourne, Parkville, Victoria, Australia
| | - Jack S Richards
- Burnet Institute for Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, Australia Department of Microbiology, Monash University, Clayton, Victoria, Australia Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
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Dutta S, DasSarma P, DasSarma S, Jarori GK. Immunogenicity and protective potential of a Plasmodium spp. enolase peptide displayed on archaeal gas vesicle nanoparticles. Malar J 2015; 14:406. [PMID: 26463341 PMCID: PMC4605222 DOI: 10.1186/s12936-015-0914-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/25/2015] [Indexed: 11/15/2022] Open
Abstract
Background Plasmodium falciparum enolase has been shown to localize on the surface of merozoites and ookinetes. Immunization of mice with recombinant Plasmodium enolase (rPfeno) showed partial protection against malaria. Anti-rPfeno antibodies inhibited growth of the parasite in in vitro cultures and blocked ookinete invasion of mosquito midgut epithelium. It is hypothesized that parasite specific moonlighting functions (e.g. host cell invasion) may map on to unique structural elements of Pfeno. Since enolases are highly conserved between the host and the parasite, a parasite-specific epitope of enolase was displayed on novel protein nanoparticles produced by a halophilic Archaeon Halobacterium sp. NRC-1 and tested their ability to protect mice against live challenge. Methods By genetic engineering, a Plasmodium-enolase specific peptide sequence 104EWGWS108 with protective antigenic potential was inserted into the Halobacterium gas vesicle protein GvpC, a protein localized on the surface of immunogenic gas vesicle nanoparticles (GVNPs). Two groups of mice were immunized with the wild type (WT) and the insert containing recombinant (Rec) GVNPs respectively. A third group of mice was kept as un-immunized control. Antibody titres were measured against three antigens (i.e. WT-GVNPs, Rec-GVNPs and rPfeno) using ELISA. The protective potential was determined by measuring percentage parasitaemia and survival after challenge with the lethal strain Plasmodium yoelii 17XL. Results Rec-GVNP-immunized mice showed higher antibody titres against rPfeno and Rec-GVNPs, indicating that the immunized mice had produced antibodies against the parasite enolase-specific insert sequence. Challenging the un-immunized, WT-GVNP and Rec-GVNP-immunized mice with a lethal strain of mice malarial parasite showed significantly lower parasitaemia and longer survival in the Rec-GVNP-immunized group as compared to control groups. The extent of survival advantage in the Rec-GVNP-group showed positive correlation with anti-rPfeno antibody titres while the parasitaemia showed a negative correlation. These results indicate that the parasite enolase peptide insert displayed on Halobacterium GVNPs is a good candidate as a protective antigenic epitope. Conclusion The work reported here showed that the parasite-specific peptide sequence is a protective antigenic epitope. Although antibody response of B-cells to the guest sequence in Rec-GVNPs was mild, significant advantage in the control of parasitaemia and survival was observed. Future efforts are needed to display multiple antigens with protective properties to improve the performance of the GVNP-based approach.
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Affiliation(s)
- Sneha Dutta
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400005, India.
| | - Priya DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, 21202, USA.
| | - Shiladitya DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, 21202, USA.
| | - Gotam K Jarori
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400005, India.
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