title: Identification of a specific antigenic region of the P82 protein of Babesia equi and its potential use in serodiagnosis.
abstract: The efficacy of the Be82 gene product fused with glutathione S-transferase (GST/Be82) in an enzyme-linked immunosorbent assay (ELISA) for the diagnosis of Babesia equi infection was reported previously (H. Hirata et al., J. Clin. Microbiol. 40:1470-1474, 2002). However, the ELISA with the GST/Be82 antigen cross-reacted with Babesia caballi-infected horse sera, despite the high rate of detection of B. equi. These results suggested that GST/Be82 has an antigen in common with B. caballi or antigenicity similar to that of B. caballi. In the present study, we constructed a series of five clones with deletions in the Be82 gene product, each of which was fused with GST, and used them in ELISAs in order to overcome the cross-reactivity seen with B. caballi. One of the deletion clones, a clone with a deletion of the Be82 gene from positions 236 to 381 (Be82/236-381), specifically and sensitively detected B. equi-infected horse sera without cross-reactivity with B. caballi-infected horse sera. Assays with clones from which other gene products were deleted showed decreased sensitivities or remained nonspecific for the detection of B. equi-infected horse sera. These results suggest that the Be82/236-381 gene product is a novel antigen for the diagnosis of B. equi infection in horses.
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Hirata
authors.forename: Xuenan
authors.initials: X
authors.lastname: Xuan
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yokoyama
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Nishikawa
authors.forename: Kozo
authors.initials: K
authors.lastname: Fujisaki
authors.forename: Naoyoshi
authors.initials: N
authors.lastname: Suzuki
authors.forename: Ikuo
authors.initials: I
authors.lastname: Igarashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis; D001403:Babesia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay; D017353:Gene Deletion; D005982:Glutathione Transferase / Q000235:genetics; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D012698:Serologic Tests
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase