In the current study, soluble proteins prepared from two hundred mature Echinococcus granulosus, and protoscolices of sheep hydatid cysts were apllied to immunize sheep and mice, respectively. The samples were mechanically homogenized in a blender, sonicated and the final yield was kept at -20 º C until used. Hydatid fluid was isolated from livers or lungs of sheep under sterile conditions. In the first experiment, fifteen mice were randomly allocated to 3 groups of 5 mice. Each mouse in groups 1 and 2 was immunized with 100 μg of hydatid fluid and protoscolex proteins in 100 μl of PBS and emulsified with an equal volume of Freund,s complete adjuvant (FCA), respectively. The mice of group 3 were immunized with adjuvant in PBS. The mice were boosted four weeks after the first vaccination with the same preparation except that FCA was replaced by Freund,s incomplete adjuvant (FIA). In the second experiment, eight male or female lambs 4– 6 months of age, were allocated to 2 groups of 4 lambs. Each lamb in the test group was vaccinated subcutaneously in the neck with a 2 ml dose of vaccine (1 mg of whole body protein of Echinococcus granulosus dissolved in 1 ml of PBS plus 1 ml of FCA). Control lambs were vaccinated with adjuvant in PBS. Lambs were boosted the same way as in the first experiment. Three weeks after the second vaccination, each mouse and lamb received a challenge infection with 2000 protoscolices intraperitoneally and each lamb additionally received 10 gravid E. granulosus. All mice and sheep were killed after 7 months and examined for hydatid cysts. In these studies protective immunity was induced in mice with protoscolex protein andwith hydatid fluid and in sheep with whole body homogenate of Echinococcus granulosus. The levels of protection were 72.1%, 82.6% and 90.9%, respectively. Key words: Echinococcus granulosus, hydatid fluid, protoscolex, sheep, mouse, vaccination.

Keywords