Antigenic characterization of Echinococcus granulosus cysts.

Limited numbers of antigens were detected in the structural components of Echinococcus granulosus cysts by double diffusion and immunoelectrophoresis tests using homologous and heterologous antisera without antibody activity to host serum contaminants. Although antigens common to the germinal membranes, laminated layers and protoscoleces were demonstrated, no evidence was found of antigen sharing between the laminated layer and hydatid fluid from fertile and sterile cysts. These fluids, however, had antigenic determinants in common with protoscoleces. Antigens responsible for the formation of a characteristic cathodic are were detected but only in the three structural cyst components. In contrast, E. granulosus arc 5 antigens were found solely in hydatid fluid. These observations suggest that these two antigen groups are of somatic and metabolic origin, respectively. The results are discussed in terms of current knowledge of the immunobiology of hydatid cysts.