title: Identification and characterization of an interspersed repeat antigen of Babesia microti (BmIRA).
abstract: In this report, a novel gene encoding an interspersed repeat antigen from Babesia microti (BmIRA) was identified and described. The full-length cDNA containing an open reading frame of 1,947 bp was obtained by immunoscreening a B. microti cDNA expression library. The full-length of BmIRA gene was expressed as a GST fusion recombinant BmIRA (rBmIRA) in Escherichia coli. Sera of mice immunized with the rBmIRA detected a native parasite protein with a molecular mass of 76 kDa on Western blot analysis. The same protein was detected in the parasites by immunofluorescent antibody test (IFAT). An enzyme-linked immunosorbent assay (ELISA) using rBmIRA detected specific antibodies as early as 11 days post-infection in sera from a hamster experimentally infected with B. microti Gray stain (US type). Furthermore, a rapid immunochromatographic test (ICT) using rBmIRA detected specific antibodies in a hamster experimentally infected with B. microti from day 11 to at least day 180 post-infection. The results indicate the antibody response against the rBmIRA was maintained during the chronic stage of infection. On the other hand, an immunoprotective property of rBmIRA as a subunit vaccine was evaluated in hamsters against B. microti challenge, but no significant protection was observed. Our data suggest that the immunodominant antigen BmIRA could be a useful serodiagnostic antigen for screening of B. microti infection.
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Shinuo
authors.initials: S
authors.lastname: Cao
authors.forename: Yuzi
authors.initials: Y
authors.lastname: Luo
authors.forename: Gabriel Oluga
authors.initials: GO
authors.lastname: Aboge
authors.forename: Mohamad Alaa
authors.initials: MA
authors.lastname: Terkawi
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Masatani
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Ikuo
authors.initials: I
authors.lastname: Igarashi
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Nishikawa
authors.forename: Xuenan
authors.initials: X
authors.lastname: Xuan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D041001:Babesia microti / Q000145:classification / Q000235:genetics / Q000276:immunology*; D001404:Babesiosis / Q000517:prevention & control*; D001483:Base Sequence; D015153:Blotting, Western; D002846:Chromatography, Affinity; D006224:Cricetinae; D018076:DNA, Complementary / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006400:Hematocrit; D006801:Humans; D008647:Mesocricetus; D051379:Mice; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D018512:Parasitemia / Q000517:prevention & control; D010802:Phylogeny; D013047:Specific Pathogen-Free Organisms; D014611:Vaccination / Q000592:standards*
chemical_list: D000953:Antigens, Protozoan; D018076:DNA, Complementary; D016054:DNA, Protozoan