Submitted to: Veterinary Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/7/2005
Publication Date: 4/15/2006
Citation: Boonchit, S., Alhassan, A., Chan, B., Xuan, X., Yokoyama, N., Ooshiro, M., Goff, W.L., Waghela, S.D., Wagner, G., Igarashi, I. 2006. Expression of C-terminal truncated and full-length Babesia bigemina rhoptry-associated protein 1 and their potential use in enzyme-linked immunosorbent assay.Veterinary Parasitology. 137(1-2):28-35. Interpretive Summary: Babesia bigemina is a tick-transmitted microorganism, causing disease in cattle throughout much of the tropical and subtropical world. Other related species of Babesia also cause disease, but each in a slightly different way. In addition, more than one species occurs many areas. Thus, assays for differentiating between different babesial species are very important. However, these specific assays are not available in formats that allow for easy and quick diagnosis. In this study, we describe a protein associated with B. bigemina with diagnostic characteristics. A genetic engineered replica of the protein was constructed and portions of it tested to define the site recognized by specific antibody.
Technical Abstract: In order to develop a recombinant antigen-based enzyme-linked immunosorbent assay (ELISA) for the serological diagnosis of B. bigemina infection, the genes encoding the full-length Babesia bigemina rhoptry-associated protein-1 (RAP-1) and truncated C-terminal RAP-1 (RAP-1/CT) were cloned into the plasmid pGEX-4T and expressed in Escherichia coli as a glutathion-S-transferase (GST) fusion protein. These recombinant proteins were purified and used as antigens in the ELISA. The ELISA using rRAP-1 could not differentiate clearly between B. bigemina and B. bovis-infected bovine sera due to cross-reactivity. By contrast, the ELISA using the rRAP-1/CT was found to be highly specific with B. bigemina-infected sera without cross-reactivity with B. bovis-infected bovine sera. The results suggest that the rRAP-1/CT is a candidate for a diagnostic antigen that might be useful for the diagnosis and epidemiological investigation of B. bigemina infections.