Exploring the transcriptome of the malaria sporozoite stage

Kappe, Stefan H. I.; Gardner, Malcolm J.; Brown, Stuart M.; Ross, J. Cosbie; Matuschewski, Kai; Ribeiro, José M. C.; Adams, John; Quackenbush, John; Cho, Jennifer; Carucci, Daniel J.; Hoffman, Stephen L.; Nussenzweig, Victor

doi:10.1073/pnas.171185198

Cited by 125 publications

(100 citation statements)

References 45 publications

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“…B, Presence in independent blood stage specific proteomic or transcriptomic data sets: blood stage mass spectrometry, published (4, 7) and unpublished (Leiden Malaria group, www.PlasmoDB.org); blood stage EST (13); and experimentally infected or naturally exposed protein microarray data sets (3,14). and/or liver stage of the Pf parasite lifecycle by multidimensional protein identification technology (17), MS/MS (29,30), or EST expression analysis (31)(32)(33)(34)(35), validating our identification as putative sporozoite and/or liver stage antigens (supplementary Table S1). Likewise, almost all of the bloodstage specific antigens (91%, 21/23 proteins) have been previously identified in MS ((17, 36), Leiden group, unpublished), transcript (37) or protein array data sets (7,18).…”

Section: Discussionsupporting

confidence: 54%

Sterile Protective Immunity to Malaria is Associated with a Panel of Novel P. falciparum Antigens

Trieu

Kayala

Burk

et al. 2011

Molecular & Cellular Proteomics

140

155

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The development of an effective malaria vaccine remains a global public health priority. Less than 0.5% of the Plasmodium falciparum genome has been assessed as potential vaccine targets and candidate vaccines have been based almost exclusively on single antigens. It is possible that the failure to develop a malaria vaccine despite decades of effort might be attributed to this historic focus. To advance malaria vaccine development, we have fabricated protein microarrays representing 23% of the entire P. falciparum proteome and have probed these arrays with plasma from subjects with sterile protection or no protection after experimental immunization with radiation attenuated P. falciparum sporozoites. A panel of 19 pre-erythrocytic stage antigens was identified as strongly associated with sporozoite-induced protective immunity; 16 of these antigens were novel and 85% have been independently identified in sporozoite and/or liver stage proteomic or transcriptomic data sets. Reactivity to any individual antigen did not correlate with protection but there was a highly significant difference in the cumulative signal intensity between protected and not protected individuals. Functional annotation indicates that most of these signature proteins are involved in cell cycle/DNA processing and protein synthesis. In addition, 21 novel blood-stage specific antigens were identified. Our data provide the first evidence that sterile protective immunity against malaria is directed against a panel of novel P. falciparum antigens rather than one antigen in isolation. These results have important implications for vaccine development, suggesting that an efficacious malaria vaccine should be multivalent and targeted at a select panel of key antigens, many of which have not been previously

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Section: Discussionsupporting

confidence: 54%

Sterile Protective Immunity to Malaria is Associated with a Panel of Novel P. falciparum Antigens

Trieu

Kayala

Burk

et al. 2011

Molecular & Cellular Proteomics

140

155

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“…MAEBL was identified in P. yoelii and P. falciparum blood stage parasites as a minor membrane protein with erythrocyte binding activity expressed in the apical organelles and on the surface of invasive merozoites [3][4][5][6]. Expressed abundantly in sporozoites, MAEBL appears to be important for sporozoite invasion into the mosquito salivary glands and in establishing exoerythrocytic schizonts [6][7][8][9][10][11][12]. It has been reported that sera from infected individuals living in a malaria endemic region of western Kenya recognized M2 recombinant antigen and had the ability to inhibit M2-erythrocyte binding [6].…”

Section: Malaria; Plasmodium Falciparum; Maebl; Erythrocyte Binding Pmentioning

confidence: 99%

Targeted disruption of maebl in Plasmodium falciparum

Saénz

Reed

et al. 2005

Molecular and Biochemical Parasitology

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Keywords malaria; Plasmodium falciparum; MAEBL; erythrocyte binding protein; invasion assaysMalaria parasites have a complex life cycle that requires invasion of several different cell types in both vertebrate and mosquito hosts. In Plasmodium falciparum, the merozoite must attach to and invade a new erythrocyte in order to continue parasite development in the blood of an infected host. Merozoite entry into erythrocytes is a multi-step process requiring merozoite adhesion, re-orientation, junction formation, and invasion [1]. Each step is thought to be mediated by the coordinated interactions of numerous specific merozoite ligands and erythrocyte surface receptors [2]. A number of mediators involved in the invasion process are positioned on the merozoite surface and in the organelles of the apical complex. However, the functions of molecules involved in this interaction are still poorly characterized.Understanding the complex process of P. falciparum merozoite invasion requires identification and characterization of numerous potential parasite ligands and their potential interactions. MAEBL is a paralogue of the DBL-EBP family (Duffy binding like-erythrocyte binding protein), but has a chimerical structure and shares similarity with AMA1 [3]. M1 and M2 are tandem cysteine-rich regions with similarity to AMA1 and are present in the N-terminal portion of the MAEBL ectodomain. MAEBL was identified in P. yoelii and P. falciparum blood stage parasites as a minor membrane protein with erythrocyte binding activity expressed in the apical organelles and on the surface of invasive merozoites [3][4][5][6]. Expressed abundantly in sporozoites, MAEBL appears to be important for sporozoite invasion into the mosquito salivary glands and in establishing exoerythrocytic schizonts [6][7][8][9][10][11][12]. It has been reported that sera from infected individuals living in a malaria endemic region of western Kenya recognized M2 recombinant antigen and had the ability to inhibit M2-erythrocyte binding [6]. However, whether MAEBL is essential or even has a significant role for erythrocytic stage growth is unclear.To evaluate MAEBL expression in P. falciparum erythrocyte stages and its potential role in merozoite invasion of erythrocytes, maebl disrupted parasite lines were created and examined for possible importance of MAEBL in erythrocytic invasion pathways (Fig. 1A). Homologous integration into the maebl locus was carried out by using the plasmid pHH1/Δmaebl containing the selection marker hDHFR and targeting sequence that disrupted maebl coding sequence (CDS) after the second ligand domain (M2). A cloned parasite line of the P. falciparum W2mef isolate was transfected with this construct and two independent clones, B7 and D8, were obtained through intermittent selection with WR99210. In order to confirm that pHH1/ hDHFRΔmaebl had integrated through single crossover homologous recombination into the maebl locus, genomic DNA from parental wild-type W2mef and W2mef Δmaebl clones were analyzed by Southern blot hybridization probed ...

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“…Their products exhibit a predicted N-terminal cleavable signal peptide followed by two 6-Cys domains. In addition, P52 exhibits a C-terminal hydrophobic sequence predicted to be a putative GPI anchor attachment signal (15). PfP52 and PfP36 show 40% and 43% amino acid identity to their respective P. yoelii orthologs.…”

mentioning

confidence: 99%

Preerythrocytic, live-attenuated Plasmodium falciparum vaccine candidates by design

VanBuskirk

O'Neill

Vega

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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153

150

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Falciparum malaria is initiated when Anopheles mosquitoes transmit the Plasmodium sporozoite stage during a blood meal. Irradiated sporozoites confer sterile protection against subsequent malaria infection in animal models and humans. This level of protection is unmatched by current recombinant malaria vaccines. However, the live-attenuated vaccine approach faces formidable obstacles, including development of accurate, reproducible attenuation techniques. We tested whether Plasmodium falciparum could be attenuated at the early liver stage by genetic engineering. The P. falciparum genetically attenuated parasites (GAPs) harbor individual deletions or simultaneous deletions of the sporozoiteexpressed genes P52 and P36. Gene deletions were done by double-cross-over recombination to avoid genetic reversion of the knockout parasites. The gene deletions did not affect parasite replication throughout the erythrocytic cycle, gametocyte production, mosquito infections, and sporozoite production rates. However, the deletions caused parasite developmental arrest during hepatocyte infection. The double-gene deletion line exhibited a more severe intrahepatocytic growth defect compared with the single-gene deletion lines, and it did not persist. This defect was assessed in an in vitro liver-stage growth assay and in a chimeric mouse model harboring human hepatocytes. The strong phenotype of the double knockout GAP justifies its human testing as a whole-organism vaccine candidate using the established sporozoite challenge model. GAPs might provide a safe and reproducible platform to develop an efficacious whole-cell malaria vaccine that prevents infection at the preerythrocytic stage.genetically attenuated parasites ͉ malaria vaccine ͉ P36 ͉ P52 ͉ sporozoite M alaria is a formidable global health problem, affecting 300 million to 500 million people worldwide annually (1). The resulting Ϸ1 million deaths per year are mainly caused by Plasmodium falciparum infections. Eradication of malaria will in large part depend on an effective vaccine that prevents infection by Plasmodium, but such a vaccine has remained elusive. The parasites' preerythrocytic stages, encompassing the mosquito-inoculated sporozoites and liver stages that develop from sporozoites after their invasion of hepatocytes, are attractive targets for antiinfection vaccines, because at this stage the number of infected host cells is low, and further transmission of the parasite is not yet possible. Occurrence of blood-stage infection after sporozoite challenge is completely preventable by immunization with radiation-attenuated sporozoites in mouse models of malaria (2). This was a landmark finding that set the standards for malaria preerythrocytic vaccine development. Radiation-attenuated sporozoites arrest in development during hepatocyte infection, but their safety and efficacy are dependent on a precise irradiation dose. Humans immunized with P. falciparum radiation-attenuated sporozoites have been effectively protected from subsequent challenge with homologous an...

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Exploring the transcriptome of the malaria sporozoite stage

Cited by 125 publications

References 45 publications

Sterile Protective Immunity to Malaria is Associated with a Panel of Novel P. falciparum Antigens

Sterile Protective Immunity to Malaria is Associated with a Panel of Novel P. falciparum Antigens

Targeted disruption of maebl in Plasmodium falciparum

Preerythrocytic, live-attenuated Plasmodium falciparum vaccine candidates by design

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