title: The glycosylphosphatidylinositol-anchored protein repertoire of Babesia bovis and its significance for erythrocyte invasion.
abstract: Glycosylphosphatidylinositol-anchored proteins are abundant on the surface of pathogenic protozoans and might play an important role for parasite survival. In the present work, the relevance of GPI-anchored proteins for erythrocyte invasion of the cattle hemoparasite Babesia bovis was studied. We show that cleavage of GPI-anchored antigens from the merozoite parasite stage by phosphatidylinositol-specific phospholipase C abolished invasion of erythrocytes demonstrating the importance of this class of molecules for parasite propagation. In addition, the repertoire of GPI-anchored proteins of B. bovis was predicted with high fidelity by searching its genome with available web-based bioinformatic tools. Altogether 17 GPI-anchored proteins were identified, 5 of which represent the already characterized variable merozoite surface antigens (VMSAs). Fifteen of the identified GPI-anchored proteins contain 2-26 amino acid repeats indicating that they are likely involved in functions of recognition, adhesion, or transport. Repeats were found to contain an increased frequency of proline, indicative of unstructured regions; and were estimated to be 3.21 times more hydrophilic than non-repeat regions. This suggests that they might represent eminent antibody epitopes. The majority of the putative GPI-anchored antigens reported in this work have so far remained unnoticed, though they may represent potential candidates for inclusion in a subunit vaccine.
authors.affiliation: Instituto de Patobiología, CICVyA, INTA-Castelar, 1686 Hurlingham, Prov. de Buenos Aires, Argentina.
authors.forename: Anabel Elisa
authors.initials: AE
authors.lastname: Rodriguez
authors.affiliation: Instituto de Patobiología, CICVyA, INTA-Castelar, 1686 Hurlingham, Prov. de Buenos Aires, Argentina; CONICET, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Monica
authors.initials: M
authors.lastname: Florin-Christensen
authors.affiliation: Instituto de Patobiología, CICVyA, INTA-Castelar, 1686 Hurlingham, Prov. de Buenos Aires, Argentina; ANPCyT, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Daniela Agustina
authors.initials: DA
authors.lastname: Flores
authors.affiliation: EEA-Rafaela, INTA, Argentina.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Echaide
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-704, United States.
authors.forename: Carlos Esteban
authors.initials: CE
authors.lastname: Suarez
authors.affiliation: Instituto de Patobiología, CICVyA, INTA-Castelar, 1686 Hurlingham, Prov. de Buenos Aires, Argentina; CONICET, Ciudad Autónoma de Buenos Aires, Argentina. Electronic address: lschnittger@cnia.inta.gov.ar.
authors.forename: Leonhard
authors.initials: L
authors.lastname: Schnittger
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D016793:Babesia bovis / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D001404:Babesiosis / Q000276:immunology / Q000469:parasitology*; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000469:parasitology*; D019295:Computational Biology; D004912:Erythrocytes / Q000469:parasitology; D058851:GPI-Linked Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018503:Genome, Protozoan / Q000235:genetics*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D052940:Merozoites; D005810:Multigene Family; D020543:Proteome; D010738:Type C Phospholipases / Q000494:pharmacology
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D058851:GPI-Linked Proteins; D017261:Glycosylphosphatidylinositols; D020543:Proteome; D010738:Type C Phospholipases
keywords: Babesia bovis; Bovine babesiosis; Erythrocyte invasion; GPI-anchor; Glycosylphosphatidylinositol