Structural and Biochemical Characterization of Plasmodium falciparum 12 (Pf12) Reveals a Unique Interdomain Organization and the Potential for an Antiparallel Arrangement with Pf41

Tonkin, Michelle L.; Arredondo, Silvia A.; Loveless, Bianca C.; Serpa, Jason J.; Makepeace, Karl A.T.; Sundar, N.; Petrotchenko, Evgeniy V.; Miller, Louis H.; Grigg, Michael E.; Boulanger, Martin J.

doi:10.1074/jbc.m113.455667

Cited by 59 publications

(103 citation statements)

References 67 publications

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“…Pfs230D1M appeared comparable biochemically and biophysically to Pfs230D1H with the exception of the designed changes. In addition, the two disulfide bonds within Pfs230D1M were mapped and assigned as C1 to C2 and C3 to C4, which was in agreement with the NMR analysis of recombinant Pfs12, another malaria protein with a comparable 6-cysteine-rich motif (29). It is interesting to note that the latter disulfide is homologous to the C3-C6 disulfide pairing observed for Pf12 and Pf41 (29,30).…”

Section: Discussionsupporting

confidence: 62%

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Structural and Immunological Characterization of Recombinant 6-Cysteine Domains of the Plasmodium falciparum Sexual Stage Protein Pfs230

MacDonald

Nguyen

Shimp

et al. 2016

Journal of Biological Chemistry

122

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Development of a Plasmodium falciparum (Pf) transmission blocking vaccine (TBV) has the potential to significantly impact malaria control. Antibodies elicited against sexual stage proteins in the human bloodstream are taken up with the blood meal of the mosquitoes and inactivate parasite development in the mosquito. In a phase 1 trial, a leading TBV identified as Pfs25-EPA/Alhydrogel appeared safe and immunogenic, however, the level of Pfs25-specific antibodies were likely too low for an effective vaccine. Pfs230, a 230-kDa sexual stage protein expressed in gametocytes is an alternative vaccine candidate. A unique 6-cysteine-rich domain structure within Pfs230 have thwarted its recombinant expression and characterization for clinical evaluation for nearly a quarter of a century. Here, we report on the identification, biochemical, biophysical, and immunological characterization of recombinant Pfs230 domains. Rabbit antibodies generated against recombinant Pfs230 domains blocked mosquito transmission of a laboratory strain and two field isolates using an ex vivo assay. A planned clinical trial of the Pfs230 vaccine is a significant step toward the potential development of a transmission blocking vaccine to eliminate malaria.Development of a malaria vaccine that effectively protects against parasite infection of both the natural host, Anopheles mosquitoes, and its secondary host, man, would effectively disrupt transmission and clinical disease. The most well known investigational vaccine against Plasmodium falciparum malaria that recently received a positive scientific opinion from the Committee for Medicinal Products for Human Use of the European Medicines Agency in July 2015, is identified as RTS,S (Mosquirix TM ). This vaccine targets the circumsporozoite protein that is present on the surface of the sporozoite, the parasite stage that infects man (1). RTS,S, a virus like-particle-based vaccine, is protective against clinical disease in about 30% of the young children who participated in a phase 3 trial (1, 2).Efforts toward development of a vaccine to disrupt parasite infection of the mosquito host, also identified as a transmission blocking vaccine have to date only been able to evaluate a sexual stage-specific protein, Pfs25, 2 which is a 25-kDa protein expressed on the zygote and ookinete surfaces. A phase 1 study demonstrated that human antibodies raised against a recombinant Pfs25 (Pfs25H) protein formulated in Montanide ISA 51, a water-in-oil adjuvant formulation, were biologically active in an ex vivo feeding assay (3), however, this formulation was not deemed suitable for a public health vaccine. More recently, in preclinical studies, Pfs25H has been shown to have enhanced immunogenic properties when chemically conjugated to a carrier molecule such as Neisseria meningitis outer membrane protein complex (4), or Pseudomonas aeruginosa ExoProtein A (EPA) (5, 6). In particular, the chemically conjugated Pfs25-EPA has the biophysical features of a nanoparticle with a diameter of about 25 m in solution, simil...

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Section: Discussionsupporting

confidence: 62%

“…Structural Modeling-The comparative model of Pfs230D1M was constructed with Rosetta (44) using the crystal structures of Pf12, PDB code 2YMO (29), and Pf41, PDB code 4YS4 (30), as templates. Secondary structure analysis was performed with STRIDE (45).…”

Section: Methodsmentioning

confidence: 99%

Structural and Immunological Characterization of Recombinant 6-Cysteine Domains of the Plasmodium falciparum Sexual Stage Protein Pfs230

MacDonald

Nguyen

Shimp

et al. 2016

Journal of Biological Chemistry

122

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“…Analysis of Pfs47 in 364 worldwide P. falciparum isolates (Dataset S1) allowed us to identify 47 different DNA haplotypes (Dataset S2) that exhibit a high ratio of nonsynonymous/synonymous (dN/dS = 30) substitutions, in agreement with previous reports (22) and indicative of selection. Pfs47 has three s48/45 domains and most polymorphisms are present in the second domain (D2) (SI Appendix, Fig.…”

Section: Mosquito Antiplasmodial Immunity Mediates the Incompatibilitysupporting

confidence: 65%

Plasmodium evasion of mosquito immunity and global malaria transmission: The lock-and-key theory

Molina-Cruz

Canepa

Kamath

et al. 2015

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

113

167

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Plasmodium falciparum malaria originated in Africa and became global as humans migrated to other continents. During this journey, parasites encountered new mosquito species, some of them evolutionarily distant from African vectors. We have previously shown that the Pfs47 protein allows the parasite to evade the mosquito immune system of Anopheles gambiae mosquitoes. Here, we investigated the role of Pfs47-mediated immune evasion in the adaptation of P. falciparum to evolutionarily distant mosquito species. We found that P. falciparum isolates from Africa, Asia, or the Americas have low compatibility to malaria vectors from a different continent, an effect that is mediated by the mosquito immune system. We identified 42 different haplotypes of Pfs47 that have a strong geographic population structure and much lower haplotype diversity outside Africa. Replacement of the Pfs47 haplotypes in a P. falciparum isolate is sufficient to make it compatible to a different mosquito species. Those parasites that express a Pfs47 haplotype compatible with a given vector evade antiplasmodial immunity and survive. We propose that Pfs47-mediated immune evasion has been critical for the globalization of P. falciparum malaria as parasites adapted to new vector species. Our findings predict that this ongoing selective force by the mosquito immune system could influence the dispersal of Plasmodium genetic traits and point to Pfs47 as a potential target to block malaria transmission. A new model, the "lock-and-key theory" of P. falciparum globalization, is proposed, and its implications are discussed. malaria globalization | immune evasion | anopheles immunity | Plasmodium selection | Pfs47

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“…While epitope analysis of Pfs48/45 has revealed surface targets of transmission blocking monoclonal antibodies [46], lack of any structural information and knowledge of conformational target epitopes has resulted in limited success in the development of recombinant TBV based on Pfs48/45. Computational modeling [6] and experimental structure determination [47, 48] approaches have been used to predict structure of Pfs48/45. However, reproducible production of correctly folded recombinant protein remains a challenge and the immunization studies thus far have revealed efficacies not ideal for vaccine development.…”

Section: Discussionmentioning

confidence: 99%

Immunogenicity and malaria transmission reducing potency of Pfs48/45 and Pfs25 encoded by DNA vaccines administered by intramuscular electroporation

Datta

Bansal

Gerloff

et al. 2017

Vaccine

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Pfs48/45 and Pfs25 are leading candidates for the development of Plasmodium falciparum transmission blocking vaccines (TBV). Expression of Pfs48/45 in the erythrocytic sexual stages and presentation to the immune system during infection in the human host also makes it ideal for natural boosting. However, it has been challenging to produce a fully folded, functionally active Pfs48/45, using various protein expression platforms. In this study, we demonstrate that full-length Pfs48/45 encoded by DNA plasmids is able to induce significant transmission reducing immune responses. DNA plasmids encoding Pfs48/45 based on native (WT), codon optimized (SYN), or codon optimized and mutated (MUT1 and MUT2), to prevent any asparagine (N)-linked glycosylation were compared with or without intramuscular electroporation (EP). EP significantly enhanced antibody titers and transmission blocking activity elicited by immunization with SYN Pfs48/45 DNA vaccine. Mosquito membrane feeding assays also revealed improved functional immunogenicity of SYN Pfs48/45 (N-glycosylation sites intact) as compared to MUT1 or MUT2 Pfs48/45 DNA plasmids (all N-glycosylation sites mutated). Boosting with recombinant Pfs48/45 protein after immunization with each of the different DNA vaccines resulted in significant boosting of antibody response and improved transmission reducing capabilities of all four DNA vaccines. Finally, immunization with a combination of DNA plasmids (SYN Pfs48/45 and SYN Pfs25) also provides support for the possibility of combining antigens targeting different life cycle stages in the parasite during transmission through mosquitoes.

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Structural and Biochemical Characterization of Plasmodium falciparum 12 (Pf12) Reveals a Unique Interdomain Organization and the Potential for an Antiparallel Arrangement with Pf41

Cited by 59 publications

References 67 publications

Structural and Immunological Characterization of Recombinant 6-Cysteine Domains of the Plasmodium falciparum Sexual Stage Protein Pfs230

Structural and Immunological Characterization of Recombinant 6-Cysteine Domains of the Plasmodium falciparum Sexual Stage Protein Pfs230

Plasmodium evasion of mosquito immunity and global malaria transmission: The lock-and-key theory

Immunogenicity and malaria transmission reducing potency of Pfs48/45 and Pfs25 encoded by DNA vaccines administered by intramuscular electroporation

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