C-terminal region of 48-kDa rhoptry protein for serological detection of Babesia caballi antibodies in horses

A recombinant C-terminal antigen derived from Babesia caballi 48-kDa rhoptry protein (rBc48/CT) was made for the development of a serologically diagnostic test. Antiserum raised against the rBc48/CT reacted specifically with the corresponding native protein by Western blotting and the indirect fluorescent antibody test (IFAT). Next, an indirect enzyme-linked immunosorbent assay (Bc48/CT-ELISA) and an immunochromatographic test based on the Bc48/CT (Bc48/CT-ICT) were constructed and employed for the detection of an antibody to B. caballi in a variety of equine sera. The results of Bc48/CT-ELISA and Bc48/CT-ICT were highly concordant with those of IFAT and ELISA, with full-length protein of Bc48 used as the reference tests. Our results demonstrate the success of Bc48/CT as antigen for the serological diagnosis of B. caballi infection in horses.

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► C-terminal region of Babesia caballi 48-kDa protein was employed for serodetection of the infection in horses.
► Recombinant Bc48/CT showed good diagnostic performance by ELISA and ICT with a variety of equine sera.
► Bc48/CT may replace Bc48 as diagnostic antigen for detection of the B. caballi antibody.