Abstract: The secondary cyst tissues derived from mice infected with protoscoleces of Echinococcus granulosus for 8-10 months were digested with 0.25% trypsin at 37℃ for 30 min.The separation of different cells in the remaining suspension was achieved by discontinuous gradient centrifugation.The germinal cells were washed 3 times with ice-cold HBSS,and then cultivated in the medium of RPMI 1640 supplemented with 20% calf serum.The cells were kept in an incubator at 37℃ in an atmosphere of 95% air-5% CO2.After incubation for 5-7 days,the germinal cells began to multiply accompanied by the enlargement of cells as compared with those before incubation.The surface of both isolated and/or cultured cells showed smooth appearance examined by scanning electron microscopy Immunofluorescence assay and enzyme-linked immunosorbent assay had been used for examining the specific antigenicity of the cells.The results showed that antigen components of E.granulosus were detected either on cell surface or in soluble proteins of the cells.Furthermore,120 NIH female mice were inoculated intraperitoneally with 1-5×107 cultured germinal cells and sacrificed 1-3 months after inoculation.Only 2 cystic materials had been detected in two mice.Of which,one located in the liver and the other in peritoneal cavity of the animals.Histological examination noted that the cystic materials consisted of germinal layer and cyst fluid,but no laminated layer was observed.The above mentioned evidence demonstrated that the cells isolated from the cysts of E.granulosus were germinal cells.Since the cultured germinal cell can be kept in liquid nitrogen,it would be useful for further study on the biology,immunology and biochemistry of the cells as well as for establishing an in vitro system to screen drugs against hydatid disease.(Figs.1-9)