Introduction and objective: Dicrocoelium dendriticum is a worldwide spread parasite of liver, bile ducts and gallbladder of especially ruminants and humans as well. Identification of specific antigens is useful for early diagnosis of the infection. The goal of this study was the isolation and identification of excretory-secretory and somatic antigens from D. dendriticum by sodium dodecyl sulphate (SDS)-PAGE and evaluation of humoral immune response against these antigens.

  Methods: The parasites were collected and washed by phosphate buffered saline (PBS) and supplemented by antibiotic for several times. For preparing somatic antigens, parasites were sonicated and centrifuged prior to collect supernatant. For preparing excretory-secretory antigens the viable parasites were transferred to the sterile medium. The samples were centrifuged and supernatants were collected. The sera of infected sheep with different infection degrees were collected too. Somatic and excretory-secretory proteins were isolated with SDS PAGE and stained with coomassie blue. Immunogenicity properties of the resulting proteins were determined using western blot analysis.

  Results: The total extract of somatic antigens analyzed by SDS-PAGE revealed 21 proteins. In mild infection, bands of 130 KDa were immune dominant. In moderate infections 48, 80 and 130 KDa and in heavy infections 48, 60, 80, 130 KDa were detected as immune dominant bands. In excretory- secretory antigens seven bands of protein were detected. In mild infection 130 KDa, in moderate infection 100, 120 and 130 KDa and in heavy infection 45, 80, 85, 100, 120 and 130 KDa were immune dominant bands.

  Conclusion: Probably the most immunogenic protein band during different degrees of infection was 130KDa that can be used for vaccination and inducing immunity.