title: Presence of a circumsporozoite-like protein in micronemes of blood-stage merozoites of malaria parasites.
abstract: We demonstrate for the first time the presence of a circumsporozoite (CS)-like protein in invasive blood stages of malaria parasites. Immunogold electron microscopy using antisporozoite monoclonal antibodies localized these antigens in the micronemes of merozoites. Western immunoblot and two-dimensional gel electrophoresis of mature blood-stage extracts of Plasmodium falciparum, P. berghei, P. cynomolgi, and P. brasilianum identified polypeptides having the same apparent molecular mass and isoelectric points as the corresponding sporozoite (CS) proteins. The CS-like protein of merozoites is present in relatively minor amounts, compared to the CS protein of sporozoites. Mice with long-term P. berghei blood-induced infections develop antibodies which react with sporozoites.
authors.affiliation: Department of Medical and Molecular Parasitology, New York University School of Medicine, New York 10016.
authors.forename: A H
authors.initials: AH
authors.lastname: Cochrane
authors.forename: S
authors.initials: S
authors.lastname: Uni
authors.forename: M
authors.initials: M
authors.lastname: Maracic
authors.forename: L
authors.initials: L
authors.lastname: di Giovanni
authors.forename: M
authors.initials: M
authors.lastname: Aikawa
authors.forename: R S
authors.initials: RS
authors.lastname: Nussenzweig
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000302:isolation & purification*; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D004912:Erythrocytes / Q000469:parasitology; D007525:Isoelectric Focusing; D015388:Organelles / Q000276:immunology*; D010961:Plasmodium / Q000276:immunology* / Q000648:ultrastructure; D015800:Protozoan Proteins
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan