Identification of IgE and IgG1 specific antigens in Echinococcus granulosus cyst fluid

Abstract Cystic echinococcosis (CE) is an anthropozoonotic disease with worldwide distribution and is caused by the cestode Echi-nococcus granulosus. Anaphylactic shock induced by CE rupture is a serious complication especially in patients with hydatidinfections, as the resulting leakage of fluid contains highly toxic endogenous antigen. We aimed to isolate and identify theantigens of specific IgE and IgG1 (sIgE and sIgG1) in E. granulosus cyst fluid (EgCF). Crude antigen for EgCF was preparedfrom E. granulosus-infected sheep liver. Antigens were separated and identified by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D SDS-PAGE), two-dimensional gel electrophoresis (2-DE), and immunoblotting. Resultsof 1D SDS-PAGE and immunoblotting showed that 40.5 kDa protein was the major antigen of sIgE, and 35.5 kDa protein wasthe major antigen of sIgG1 in EgCF. Results of 2-DE and immunoblotting showed that main antigens of sIgE in EgCF were fourproteins with pI values ranging from 6.5 to 9.0 and a molecular weight of 40.5 kDa. Main antigens of sIgG1 in EgCF were fiveproteins with pI values ranging from 6.5 to 9.0 and a molecular weight of 35.5 kDa. The antigens identified for sIgE and sIgG1can provide critical insights into cellular and molecular mechanisms underlying anaphylactic shock induced by CE.Key words: Cystic echinococcosis; Anaphylactic shock; Specific antigens; Specific antibody