Characterization of a surface antigen of Eimeria nieschulzi (Apicomplexa, Eimeriidae) sporozoites.

A monoclonal antibody (McAb 3C3) reacting with a pellicular antigen of Eimeria nieschulzi sporozoites has been selected among hybridomas produced against this organism by immunofluorescence assay. This antigen has been shown to be located on the zoite surface by immunofluorescence on living organisms. Capping and shedding of antigen-monoclonal antibody immune complexes was observed upon incubation at 37 degrees C. On western immunoblotting, two polypeptides at 22 and 26 kDa were recognized by McAb 3C3, whereas only one polypeptide of 22 kDa was immunoprecipitated by the same antibody after lactoperoxidase surface radio-iodination of sporozoites.