Magnetic microbead-based enzyme-linked immunoassay for detection of Schistosoma japonicum antibody in human serum

A specific and sensitive immunoassay based on magnetic microbead separation for schistosomiasis japonica screening is presented in this article. So far as we know, this is the first time that magnetic microbead-based enzyme-linked immunoassay (MEIA) has been used for the determination of Schistosoma japonicum (Sj) antibody in human serum. Fluorescein isothiocyanate (FITC)-labeled soluble egg antigen (SEA) and polymer-coated magnetic beads, to which anti-FITC monoclonal antibodies were immobilized, were used as separation support in MEIA. Immunoassay parameters were optimized based on a direct immunoreaction of SEA on the magnetic microbead and Sj antibody in serum samples. The laboratory experimental results showed that the MEIA method was more sensitive and more precise than traditional SEA–ELISA (enzyme-linked immunosorbent assay). In the field test, human sera collected from 513 infected humans and 2260 uninfected humans were tested with indirect hemagglutination assay (IHA), dipstick dye immunoassay (DDIA), and MEIA. IHA and DDIA were then compared with MEIA, and a lower false negative rate (0.97%) was obtained.