In this study, the immunogenicity of three types of antigens (hydatid fluid, protoscolices and whole body of E. granulosus ) was investigated in lambs by ELISA. Sixteen 4 – 6 months old lambs of mixed sexs, were divided into 4 groups of 4 lambs (three immunized and one control group). Twelve lambs as immunized groups received 2 mg of hydatid fluid, protoscolices and whole body of E. granulosus antigens dissolved in 1 ml of PBS per immunization for each lamb, respectively. As an adjuvant, Freund,s complete adjuvant (FCA ) was mixed with antigens to form a water-in-oil emulsion giving a dose of 2 ml which was inoculated subcutaneously on day 1 of the trial. Each control lamb was inoculated with a total of 2 ml of PBS emulsified in equal volumes of FCA. Lambs were boosted on day 28 with the same preparation as described above except that FCA was replaced by Freund,s incomplete adjuvant (FIA). Three weeks after second immunization, each lamb received a challenge infection with 2000 protoscolices intraperitoneally and also10 gravid proglotid of E. granulosus orally. Sera were collected before and after immunization and serum antibodies were tested by ELISA. The results showed that the production of antibody was significant between test groups and control. Lambs immunized with whole body of E. granulosus showed the highest of antibody production. Level of antibody production between lambs immunized with hydatid fluid and protoscolices was not significant, whereas, the level of antibody production between lambs immunized with hydatid fluid and whole body of E. granulosus was significant. The results of this study showed that the antigens of whole body of E. granulosus might be a good candidate for immunization and diagnosis of hydatid cyst in of intermediated host of E. granulosus.

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