title: Anchoring of an immunogenic Plasmodium falciparum circumsporozoite protein on the surface of Dictyostelium discoideum.
abstract: The circumsporozoite protein (CSP), a major antigen of Plasmodium falciparum, was expressed in the slime mold Dictyostelium discoideum. Fusion of the parasite protein to a leader peptide derived from Dictyostelium contact site A was essential for expression. The natural parasite surface antigen, however, was not detected at the slime mold cell surface as expected but retained intracellularly. Removal of the last 23 amino acids resulted in secretion of CSP, suggesting that the C-terminal segment of the CSP, rather than an ectoplasmic domain, was responsible for retention. Cell surface expression was obtained when the CSP C-terminal segment was replaced by the D. discoideum contact site A glycosyl phosphatidylinositol anchor signal sequence. Mice were immunized with Dictyostelium cells harboring CSP at their surface. The raised antibodies recognized two different regions of the CSP. Anti-sporozoite titers of these sera were equivalent to anti-peptide titers detected by enzyme-linked immunosorbent assay. Thus, cell surface targeting of antigens can be obtained in Dictyostelium, generating sporozoite-like cells having potentials for vaccination, diagnostic tests, or basic studies involving parasite cell surface proteins.
authors.affiliation: Institute of Histology and Embryology, University of Lausanne, Switzerland.
authors.forename: C D
authors.initials: CD
authors.lastname: Reymond
authors.forename: C
authors.initials: C
authors.lastname: Beghdadi-Rais
authors.forename: M
authors.initials: M
authors.lastname: Roggero
authors.forename: E A
authors.initials: EA
authors.lastname: Duarte
authors.forename: C
authors.initials: C
authors.lastname: Desponds
authors.forename: M
authors.initials: M
authors.lastname: Bernard
authors.forename: D
authors.initials: D
authors.lastname: Groux
authors.forename: H
authors.initials: H
authors.lastname: Matile
authors.forename: C
authors.initials: C
authors.lastname: Bron
authors.forename: G
authors.initials: G
authors.lastname: Corradin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D000953:Antigens, Protozoan / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D004023:Dictyostelium / Q000235:genetics; D015870:Gene Expression; D005822:Genetic Vectors; D017261:Glycosylphosphatidylinositols; D007114:Immunization; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D021382:Protein Sorting Signals / Q000235:genetics; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D021382:Protein Sorting Signals; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C041595:circumsporozoite protein, Protozoan