SEROLOGIC RECOGNITION OF HYDATID CYST ANTIGENS USING DIFFERENT PURIFICATION METHODS

The specificity and sensitivity of enzyme-2-linked immunosorbent assay s (ELISA) and Western immunoblot assays in detecting antibodies in ser um from patients suffering cystic hydatid disease (Echinococcus granul osus) are compared using either crude antigen preparations (total shee p hydatid fluid and homogenates of protoscoleces), purified fractions enriched in Antigens 5 and B, and glycoproteins from hydatid fluid. Po lyprotein bands of 12-14, 20, and 34 kDn, when purified from hydatid f luid by applying changes in the ionic strength, yielded a sensitive (9 5%) immunodiagnostic test that was also extremely specific (100%) when assayed with sera from noninfected humans and from patients suffering from other parasitic disease. However, subjecting hydatid fluid to ch romatography through a concanavilin A column rendered a 42 kDa band th at was sensitive (95%) was well as highly specific (100%) for hydatido sis. Therefore, purification procedures can strongly affect the diagno stic value of antigens with identical electrophoretic behavior in sodi um dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).