Purification of a 28 kDa Babesia (Theileria) equi antigen and a 29 kDa spurious erythrocyte antigen from in vitro culture through ion exchange chromatography

An extract of in vitro cultivated Babesia equi was fractionated using a Mon oQ anion exchange column. Separation of a 28 kDa B. equi antigen from a 29 kDa spurious erythrocyte antigen, both of which were intensely immunoreacti ve, was achieved by chromatography of the infected erythrocyte proteins. Us ing tricine-SDS-PAGE, the 28 kDa antigen of B. equi showed multiple band re solution, while the 29 kDa antigen was consistently resolved as a single ba nd. The 29 kDa antigen was identified in both infected and non-infected ery throcyte extracts. Moreover, B. equi antiserum recognised this antigen in t he non-infected erythrocyte extract, and conversely serum from horses not i nfected with babesia detected the antigen in infected erythrocyte extract. This 29 kDa antigen could represent a horse erythrocyte isoantigen. The pur ified 28 kDa antigen is specifically recognised by B. equi antisera and the refore could be useful for the production of the recombinant replica and to employ these in further test systems. (C) 1999 Elsevier Science B.V. All r ights reserved.