title: Identification and molecular characterization of a novel antigen of Eimeria acervulina.
abstract: Eimeria acervulina (E. acervulina) is one of the seven species of Eimeria infected in chicken. Until now, only a few antigen genes of E. acervulina have been reported. In this study, a cDNA expression library of E. acervulina sporozoites was constructed in a eukaryotic expression vector, pVAX1.0. Subsequently, the library was divided into pools and inoculated into chickens to observe the ability of the antigens to induce humoral immune response and cell-mediated immune response. The positive pools that stimulated significant immune responses were fractionated sequentially until a single positive clone was screened. After three rounds of screening, a clone, named as cSZ-JN1, with the ability to stimulate chicken immune response was obtained. The sequence analysis showed that the opening reading fragment (ORF) of cSZ-JN1 was 615 bp in size and encoded a predicted protein of 204 amino acids with 21.8 kDa. BLASTN and other sequence databases searches revealed that the identity of the amino acid sequence of cSZ-JN1 to the complete sequence of Eimeria tenella annotated protein (ETH_00022005.1.pep) was 31.37% and to Toxoplasma gondii ME49 hypothetical protein (gb|EEB00972.1|) 24%, and had no significant homology with the known genes of E. acervulina and other parasites. Immunofluorescence analysis using antibody against recombinant cSZ-JN1 indicated that this protein was expressed in sporozoite and merozoite development stages. Animal challenge experiments demonstrated that the recombinant protein of cSZ-JN1 and DNA vaccine carrying cSZ-JN1 could significantly increase the average body weight gains, decrease the mean lesion scores and the oocyst outputs of the immunized chickens and presented anti-coccidial index more than 160. All the above results suggested that the cSZ-JN1 was a novel E. acervulina antigen and could be an effective candidate for the development of new vaccine against E. acervulina infection.
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, Jiangsu, PR China.
authors.forename: Huili
authors.initials: H
authors.lastname: Zhu
authors.forename: Ruofeng
authors.initials: R
authors.lastname: Yan
authors.forename: Song
authors.initials: S
authors.lastname: Wang
authors.forename: Xiaokai
authors.initials: X
authors.lastname: Song
authors.forename: Lixin
authors.initials: L
authors.lastname: Xu
authors.forename: Xiangrui
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D001835:Body Weight; D002645:Chickens; D003048:Coccidiosis / Q000473:pathology / Q000517:prevention & control; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004539:Eimeria / Q000235:genetics* / Q000276:immunology*; D020869:Gene Expression Profiling; D015723:Gene Library; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016366:Open Reading Frames; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000276:immunology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014122:Toxoplasma / Q000235:genetics
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D016052:Protozoan Vaccines