Chicken egg yolk antibodies (IgY) for detecting circulating antigens of Schistosoma japonicum.

BACKGROUND: IgY isolated from egg yolk has been widely used in immunodiagnostic tests, including tests to detect circulating antigen (soluble egg antigen or SEA) of Schistosoma japonicum.

RESULTS: A sandwich ELISA was established using a combination of anti-S. japonicum SEA-IgY polyclonal antibodies and IgM monoclonal antibodies. To explore sensitivity and specificity of the sandwich ELISA, serum samples from 43 patients infected with S. japonicum were tested. All acute cases and 91.3% of the chronic cases showed a positive reaction. Only 5% of the control sera from healthy persons gave a positive response. Cross-reactions with antibodies to nine other parasites were rare.

CONCLUSION: The developed immunoassay is reasonably sensitive and specific. It could be used for field research and treatment efficacy assessments.