Characterization of Epitopes on an 18 kDa Piroplasm Surface Protein of Babesia equi

Abstract

Monoclonal antibodies were produced against Babesia equi piroplasms. Three MoAbs reacting with an 18 kDa surface membrane protein (p18) of B. equi in immunoblot analysis, were used to characterize the epitopes on p18. All the three MoAbs recognized the same epitope on p18 as indicated by competitive ELISA. Negative results in two-site ELISA suggest absence of repetitive epitopes on p18. Triton X-114 phase partitioning confirmed that 18 kDa antigen is an integral membrane protein of B. equi piroplasms. As these MoAbs identified a single protein and showed no crossreaction with B. caballi or equine erythrocyte proteins, these can be a candidate to be used in the differential diagnosis of mixed equine piroplasma infections.