title: Characterisation and expression of pbs25, a sexual and sporogonic stage specific protein of Plasmodium berghei.
abstract: Following gametogenesis and fertilisation in the bloodmeal within the mosquito midgut, the newly formed zygotes of the malaria parasite develop into motile invasive ookinetes. During this development, surface molecules are synthesised de novo including molecules of 21-28 kDa from the zygote-ookinete stages. An antiserum recognising a 26 kDa protein of Plasmodium berghei was used to clone the corresponding gene from a cDNA library, which was shown to be identical to the reported Pbs25 gene sequence. We show here that Pbs25 was detectable in preparations of gametes 30 min post-gametocyte activation, expression continued on zygotes, ookinetes and oocysts indicating there is a significant overlap of expression of the two immunogenic zygote-ookinete proteins belonging to the P25/28 protein family of sexual stage antigens. Biochemical analysis of Pbs25 demonstrates the presence of a malaria-specific glycosylphosphatidylinositol (GPI) anchor. Antibodies recognising Pbs25 impaired parasite development in the mosquito.
authors.affiliation: Department of Biology, Infection and Immunity Section, Imperial College of Science Technology and Medicine, Sir Alexander Fleming Building, Imperial College Road, SW7 2AZ, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: del Carmen Rodriguez
authors.forename: P
authors.initials: P
authors.lastname: Gerold
authors.forename: J
authors.initials: J
authors.lastname: Dessens
authors.forename: K
authors.initials: K
authors.lastname: Kurtenbach
authors.forename: R T
authors.initials: RT
authors.lastname: Schwartz
authors.forename: R E
authors.initials: RE
authors.lastname: Sinden
authors.forename: G
authors.initials: G
authors.lastname: Margos
mesh_terms: D000818:Animals; D000852:Anopheles / Q000469:parasitology; D000913:Antibodies, Protozoan / Q000097:blood; D000918:Antibody Specificity; D015153:Blotting, Western; D005260:Female; D005786:Gene Expression Regulation; D007114:Immunization; D008288:Malaria / Q000276:immunology / Q000469:parasitology / Q000635:transmission*; D051379:Mice; D008807:Mice, Inbred BALB C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010962:Plasmodium berghei / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D000913:Antibodies, Protozoan; D015800:Protozoan Proteins; C084246:ookinete surface antigen Pbs21, Plasmodium; D010738:Type C Phospholipases; D043265:Phosphatidylinositol Diacylglycerol-Lyase