Abstract: 　Objective To determine the specific recognition of Echinococcus granulosus (E.g.) cyst fluid crude antigen (EgCF) and antigen B (EgB) by serum specific IgG and IgE using Western blotting during anaphylactic shock induced by E. g. in sheep, and to investigate the importance of defined characteristics and molecular weight of the specific antigens. Methods EgCF was obtained through local slaughterhouses in Urumqi from the cysts of infected sheep liver. Western blotting was used to analyze total specific IgG and IgE antibodies in serum from sheep infected with E.g. using either crude antigen of E. g. and EgB, and to understand specific recognition of hydatid cyst antigens by serum total IgG and specific IgE. Results SDS-PAGE and Western blotting showed that there were differences between EgB and EgCF in electrophoresis pattern. EgB was recognized by IgG from sera of infected sheep in a series of bands with molecular weight ranging from 31, 43 to 66.2 kDa. No binding of IgG against EgCF was observed in any serum from the infected sheep during anaphylactic shock. In contrast, specific IgE antibodies in E. g. infected sheep obviously recognized the single 43 kDa subunit of EgCF, but no binding of specific IgE against EgB was observed in sera of the infected sheep. Conclusion EgCF is consisted of antigenic components in which there is a specific antigen against IgE with a molecular weight of over 43 kDa. This component may lead to an anaphylactic shock induced by E. g. . EgB is a specific antigen against the total IgG but not to the specific IgE.

Key words: Echinococcus granulosus cyst fluid crude antigen, E. g antigen B, Western blotting