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: Gabriel Oluga Aboge, Honglin Jia, Mohamad Alaa Terkawi, Younkyoung Goo, Ken Kuriki, Yoshifumi Nishikawa, Ikuo Igarashi, Hiroshi Suzuki, Xuenan Xuan
• Journal: Veterinary parasitology (Vet Parasitol) Vol. 149 Issue 1-2 Pg. 85-94 (Oct 21 2007) ISSN: 0304-4017 [Print] Netherlands
• PMID: 17706873 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Protozoan
• Protozoan Proteins

Topics

• Amino Acid Sequence
• Animals
• Antigens, Protozoan (blood, genetics, metabolism)
• Babesia (genetics, metabolism)
• Babesiosis (diagnosis, epidemiology, veterinary)
• Base Sequence
• Cloning, Molecular
• Dog Diseases (diagnosis, epidemiology)
• Dogs
• Enzyme-Linked Immunosorbent Assay (veterinary)
• Merozoites (metabolism)
• Molecular Sequence Data
• Protozoan Proteins (chemistry)
• Sensitivity and Specificity