IDENTIFICATION OF B-CELL EPITOPES OF A 30 KDA BABESIA-EQUI MEROZOITE SURFACE PROTEIN

A 30 kDa immunodominant surface antigen (p30) of Babesia equi has been used as a diagnostic antigen. The B cell epitopes on this molecule re cognized by horse sera and monoclonal antibody (MAb) against p30, 36/1 33.97, were determined. A synthetic peptide of p30 with amino acid seq uence of (123)FYQEVLFKGFEAV(135) exhibited strong positive reaction wi th the infected horse sera. In contrast, MAb 36/133.97 recognized diff erent region of p30, as peptide synthesized with amino acid sequence o f (27)ASGAVVDFQLESI(39) reacted strongly. In competitive inhibition EL ISA, the binding of MAb 36/133.97 to recombinant p30 was inhibited by horse antibodies, although they did not recognize same or an overlappi ng epitope. The data on B cell epitopes in this study may be important in improving serodiagnostic methods of B. equi infection.