title: Model structure of the immunodominant surface antigen of Eimeria tenella identified as a target for sporozoite-neutralizing monoclonal antibody.
abstract: Eimeria tenella is a coccidian parasite of great economical importance for poultry industry. The surface of Eimeria invasive agents, sporozoites and merozoites, is coated with a family of developmentally regulated glycosylphosphatidylinositol (GPI)-linked surface antigens (SAGs), some of them involved in the initiation of the infection process. Using 2D gel electrophoresis followed by mass spectrometry, an antigenic surface protein EtSAG1 (TA4) of E. tenella sporozoites has been identified as a target of neutralizing monoclonal antibody 2H10E3. To clarify the mechanism of invasion inhibition caused by the EtSAG1-specific antibodies, a structural model of EtSAG1 was generated. It appears that "EtSAG fold" does not bear an evolutionary relationship to any known protein structure. The intra- and interchain disulfide bonds could be assigned to certain pairs of six conserved cysteines found in members of the EtSAG protein family. The outward-facing surface of the antigen was found to comprise an expanded positively charged patch, thus suggesting that the parasite invasion process may be initiated by sporozoite attachment to negatively charged sulfated proteoglycans on the surface of the host cell.
authors.affiliation: Novoplant GmbH, Am Schwabeplan 1b, 06466, Gatersleben, Germany.
authors.forename: Doreen
authors.initials: D
authors.lastname: Jahn
authors.forename: Andrea
authors.initials: A
authors.lastname: Matros
authors.forename: Anastasia Y
authors.initials: AY
authors.lastname: Bakulina
authors.forename: Jens
authors.initials: J
authors.lastname: Tiedemann
authors.forename: Ulrike
authors.initials: U
authors.lastname: Schubert
authors.forename: Martin
authors.initials: M
authors.lastname: Giersberg
authors.forename: Sigrun
authors.initials: S
authors.lastname: Haehnel
authors.forename: Karen
authors.initials: K
authors.lastname: Zoufal
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Mock
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Kipriyanov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000913:Antibodies, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology* / Q000302:isolation & purification; D016786:Eimeria tenella / Q000737:chemistry / Q000276:immunology*; D015180:Electrophoresis, Gel, Two-Dimensional; D013058:Mass Spectrometry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000276:immunology* / Q000302:isolation & purification; D034101:Sporozoites / Q000737:chemistry / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins