title: Immunoscreening of Plasmodium falciparum proteins expressed in a wheat germ cell-free system reveals a novel malaria vaccine candidate.
abstract: The number of malaria vaccine candidates in preclinical and clinical development is limited. To identify novel blood-stage malaria vaccine candidates, we constructed a library of 1,827P. falciparum proteins prepared using the wheat germ cell-free system (WGCFS). Also, a high-throughput AlphaScreen procedure was developed to measure antibody reactivity to the recombinant products. Purified IgGs from residents in malaria endemic areas have shown functional activity against blood-stage parasites as judged by an in vitro parasite Growth Inhibition Assay (GIA). Therefore, we evaluated the GIA activity of 51 plasma samples prepared from Malian adults living in a malaria endemic area against the WGCFS library. Using the AlphaScreen-based immunoreactivity measurements, antibody reactivity against 3 proteins was positively associated with GIA activity. Since anti-LSA3-C responses showed the strongest correlation with GIA activity, this protein was investigated further. Anti-LSA3-C-specific antibody purified from Malian adult plasmas showed GIA activity, and expression of LSA3 in blood-stage parasites was confirmed by western blotting. Taken together, we identified LSA3 as a novel blood-stage vaccine candidate, and we propose that this system will be useful for future vaccine candidate discovery.
authors.affiliation: Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Morita
authors.affiliation: Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan.
authors.forename: Eizo
authors.initials: E
authors.lastname: Takashima
authors.affiliation: Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ito
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, Maryland, 20852, USA.
authors.forename: Kazutoyo
authors.initials: K
authors.lastname: Miura
authors.affiliation: Department of Biology, Faculty of Science, Burapha University, Chonburi, 20131, Thailand.
authors.forename: Amporn
authors.initials: A
authors.lastname: Thongkukiatkul
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, Maryland, 20852, USA.
authors.forename: Ababacar
authors.initials: A
authors.lastname: Diouf
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, Maryland, 20852, USA.
authors.forename: Rick M
authors.initials: RM
authors.lastname: Fairhurst
authors.affiliation: Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Sciences, Techniques, and Technologies of Bamako, Point G, BP 1805, Mali.
authors.forename: Mahamadou
authors.initials: M
authors.lastname: Diakite
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, Maryland, 20852, USA.
authors.forename: Carole A
authors.initials: CA
authors.lastname: Long
authors.affiliation: Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Motomi
authors.initials: M
authors.lastname: Torii
authors.affiliation: Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Tsuboi
mesh_terms: D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology; D000917:Antibody Formation / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D002474:Cell-Free System; D004912:Erythrocytes / Q000469:parasitology / Q000648:ultrastructure; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D017780:Malaria Vaccines / Q000276:immunology*; D008302:Mali; D052940:Merozoites / Q000378:metabolism / Q000648:ultrastructure; D010271:Parasites / Q000254:growth & development; D010963:Plasmodium falciparum / Q000254:growth & development / Q000276:immunology* / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000276:immunology*; D011994:Recombinant Proteins / Q000378:metabolism; D014908:Triticum / Q000378:metabolism*
chemical_list: D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D011994:Recombinant Proteins