Monoclonal antibodies against Bonamia ostreae (Protozoa: Ascetospora), an intra-haemocytic parasite of flat oyster Ostrea edulis (Mollusca: Bivalvia)

Abstract

The protozoan Bonani~a ostreae (Ascetospora), a parasite of the flat oyster Ostrea edulis, was purlfled bv d~fferential and isopycn~c centrifugations. Mice of the strain Balb/c were immunized with purified parasites and hybridomas were prepared by fusion of ilnmunizcd mouse splenocytes with the mouse myeloma cell line P3-X63-Ag8-653. From the fusion, 12 clones were isolated and saved. The resulting antibodies were characterized with a solid phase radioimmunoassay (RIA). Antibodies from 7 clones reacted only with B. ostreae and not with normal host tissue. Although some of the antibodies appeared to rcact with the same epitopes, at least 4 clcarly different epitope specificitles were identified. Onc of these antibodies (20B2-lB12) had an apparent association constant of ca 3 X 108 h?-' and bound to a number of different sltes on the parasite. These monoclonal antibodies should prove to be of great value as diagnostic and research tools.