title: Excystation of Eimeria tenella sporozoites impaired by antibody recognizing gametocyte/oocyst antigens GAM22 and GAM56.
abstract: Eimeria tenella is the causative agent of coccidiosis in poultry. Infection of the chicken intestine begins with ingestion of sporulated oocysts releasing sporocysts, which in turn release invasive sporozoites. The monoclonal antibody E2E5 recognizes wall-forming body type II (WFBII) in gametocytes and the WFBII-derived inner wall of oocysts. Here we describe that this antibody also binds to the stieda body of sporocysts and significantly impairs in vitro excystation of sporozoites. Using affinity chromatography and protein sequence analysis, E2E5 is shown to recognize EtGAM56, the E. tenella ortholog of the Eimeria maxima gametocyte-specific GAM56 protein. In addition, this antibody was used to screen a genomic phage display library presenting E. tenella antigens as fusion proteins with the gene VIII product on the surfaces of phagemid particles and identified the novel 22-kDa histidine- and proline-rich protein EtGAM22. The Etgam22 mRNA is expressed predominantly at the gametocyte stage, as detected by Northern blotting. Southern blot analysis in combination with data from the E. tenella genome project revealed that Etgam22 is an intronless multicopy gene, with approximately 12 to 22 copies in head-to-tail arrangement. Conspicuously, Etgam56 is also intronless and is localized adjacent to another gam56-like gene, Etgam59. Our data suggest that amplification is common for genes encoding oocyst wall proteins.
authors: Division of Molecular Parasitology, Heinrich-Heine-University, Universitätsstr. 1, 40225 Düsseldorf, Germany. kruecken@uni-duesseldorf.de
authors: Jürgen
authors: J
authors: Krücken
authors: Ralf J
authors: RJ
authors: Hosse
authors: Aimdip N
authors: AN
authors: Mouafo
authors: Rolf
authors: R
authors: Entzeroth
authors: Stefan
authors: S
authors: Bierbaum
authors: Predrag
authors: P
authors: Marinovski
authors: Karolina
authors: K
authors: Hain
authors: Gisela
authors: G
authors: Greif
authors: Frank
authors: F
authors: Wunderlich
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology*; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D002645:Chickens; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D003048:Coccidiosis / Q000469:parasitology; D016786:Eimeria tenella / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D008297:Male; D008969:Molecular Sequence Data; D033661:Oocysts / Q000254:growth & development / Q000276:immunology*; D019151:Peptide Library; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D034101:Sporozoites / Q000502:physiology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D019151:Peptide Library; D015800:Protozoan Proteins