Echinococcus granulosus: Antigenic proteins in oncospheres and on the surface of protoscoleces identified by serum antibodies from infected dogs

Proteins present in oncospheres and on the surface of living protoscoleces of Echinococcus granulosus were radioiodinated by the lodogen technique and immunoprecipitated with sera from dogs with E granulosus infection and several categories of control sera. Analysis of immunoprecipitates was performed using sodium dodecyl-sulphate polyacrylamide gel electrophoresis to identify antigenic protein components specific for E granulosus. Sera from dogs with E granulosus infection identified antigenic proteins of around Mr 37,000, 30,000 or 22,000 in oncospheres, and proteins of around Mr 70,000, 43,000, 36,000, 27,000 (triplet), 20,000 or 14,000 on the surface of protoscoleces. These antigens appear to be both species- and stage-specific and may be useful for serological discrimination between 'current' and 'recent past' prepatent and patent E granulosus infections in dogs.