title: A novel 57-kDa merozoite protein of Babesia gibsoni is a prospective antigen for diagnosis and serosurvey of canine babesiosis by enzyme-linked immunosorbent assay.
abstract: We isolated a novel single copy gene encoding a 57-kDa merozoite protein of Babesia gibsoni (BgP57). The nucleotide sequence of the cDNA was 2387 bp with an open reading frame (ORF) of 1644 bp encoding a 57-kDa predicted polypeptide having 547 amino acid residues. The recombinant BgP57 (rBgP57) without a predicted signal peptide was expressed in Escherichia coli as a soluble glutathione S-transferase (GST) fusion protein. Western blotting showed that the corresponding native protein was 57-kDa, consistent with molecular weight of predicted mature polypeptide. An indirect enzyme-linked immunosorbent assay (ELISA) using the rBgP57 detected specific antibodies in the sequential sera from a dog experimentally infected with B. gibsoni. Moreover, the antigen did not cross-react with antibodies to B. canis sub-species and closely related apicomplexan parasites indicating that the rBgP57 was a specific antigen for B. gibsoni antibodies. The diagnostic performance of ELISA based on rBgP57 using 107 sera from B. gibsoni-naturally infected dogs was the same as the previously identified rBgP32 but performed better than the previously studied rBgP50. Although, seminested PCR detected higher proportions (82%) of positive samples than the ELISAs, the Mcnemar's chi-square test showed that there was no significant difference in relative effectiveness of rBgP57-ELISA and seminested PCR (chi(2)=2.70; P=0.1003) in identifying positive samples. The rBgP57-ELISA when used in combination with rBgP32-ELISA and rBgP50-ELISA appeared to improve sensitivity of the rBgP57-ELISA for detection of B. gibsoni antibodies. Overall, the rBgP57-ELISA and seminested PCR when used in combination, could improve epidemiological surveys and clinical diagnosis of B. gibsoni infection.
authors: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors: Gabriel Oluga
authors: GO
authors: Aboge
authors: Honglin
authors: H
authors: Jia
authors: Mohamad Alaa
authors: MA
authors: Terkawi
authors: Younkyoung
authors: Y
authors: Goo
authors: Ken
authors: K
authors: Kuriki
authors: Yoshifumi
authors: Y
authors: Nishikawa
authors: Ikuo
authors: I
authors: Igarashi
authors: Hiroshi
authors: H
authors: Suzuki
authors: Xuenan
authors: X
authors: Xuan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000097:blood* / Q000235:genetics / Q000378:metabolism; D001403:Babesia / Q000235:genetics / Q000378:metabolism*; D001404:Babesiosis / Q000175:diagnosis / Q000453:epidemiology / Q000662:veterinary*; D001483:Base Sequence; D003001:Cloning, Molecular; D004283:Dog Diseases / Q000175:diagnosis* / Q000453:epidemiology; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary*; D052940:Merozoites / Q000378:metabolism; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins