Application of magnetic particle antibody immunoassay in detection of anti-Schistosoma japonicum egg antibody

Abstract

OBJECTIVE: To establish a magnetic particle antibody immunoassay (MPAIA) for the detection of specific antibody in sera of schistosomiasis patients. METHODS: Fluorescein isothiocyanate (FITC) was used to label Schistosoma japonicum soluble egg antigen (Sj-SEA). Anti-human IgG coated with alkaline phosphatase (ALP) as enzyme-labeled second antibody, and magnetic beads were coupled with sheep anti-FITC antibody as solid phase. Phenolphthale in monophosphate was used as substrate to set up MPAIA for the detection. Serum samples from cases with schistosomiasis or other helminth infections were tested. RESULTS: The positive rate of MPAIA was 96.7% (116/120) with the sera of S. japonicum-infected cases. No cross reaction was observed with sera of trichinellosis, paragonimiasis or cysticercosis cases. The positive titer with reference sample was 1: 1,600. The precision was lower than 10%. The MPAIA tips can be stored at 4 degrees C for 12 months. CONCLUSION: MPAIA shows a high sensitivity, proper specificity and long-term validity for schistosomiasis detection.