Isolation and purification of Echinococcus granulosus antigen B from hydatid cyst fluid using three different methods

Hydatid cyst, the larval stage of cestodes Echinococcus spp., is recognized as a zoonotic infection in the world. The World Health Organization (WHO) has recently classified echinococcosis in a group of neglected tropical diseases.The prevalence of Echinococcus granulosus infection is high in Iran due to the presence of various intermediate hosts in this country. Considering the rising trend of this zoonotic parasitic disease based on national epidemiological studies, diagnosis is of great significance. WHO has suggested the use of specific antigens, especially antigen B (AgB) for serological diagnostic tests. In general, AgB is a polymeric lipoprotein, which disintegrates into 8.12, 16, and 20.24 kDa subunits. In the present study, we applied three different methods for AgB isolation from hydatid cyst fluid (HCF) and compared their efficacy in AgB isolation. Finally, the protein concentration of this antigen was measured by Bradford assay and confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that the application of polyethylene glycol (PEG 4000) as a thickener agent beside purification of HCF in dialysis bag and filtering and also dialysis against acetate buffer leading to the best quantity in purified antigen B.