Objective: To study the applicability of soluble egg antigen (SEA) 38 kDa molecule of Schistosoma japonicum in the immunodiagnosis of schistosomiasis.
Methods: The target immunodiagnositic antigen SEA 38 kDa molecule was separated and purified by SDS-PAGE and electroelution technique and evaluated by SDS-PAGE and Western blotting. To compare their immunodiagnostic efficacy, the purified SEA 38 kDa and SEA were used to examine the sera from 182 cases including 31 acute schistosomiasis patients, 31 chronic schistosomiasis patients, 60 normal human controls, 30 paragonimiasis patients and 30 clonorchiasis patients.
Results: The positive rates of purified SEA 38 kDa and SEA for acute schistosomiasis patients, chronic schistosomiasis patients, normal human controls, paragonimiasis patients and clonorchiasis patients were 90.3%, 90.3%, 1.7%, 0, 0 and 90.3%, 83.9%, 3.3%, 0, 0, respectively. The P/N ratio of purified SEA 38 kDa and SEA in immunodiagnosis of schistosomiasis by ELISA had been compared by two-sample t-test. It was demonstrated that there existed significant differences between purified SEA 38 kDa and SEA in the three groups of acute and chronic schistosomiasis patients and normal persons(P < 0.001). The P/N ratio of SEA 38 kDa in detecting the sera from schistosomiasis patients was obviously higher than that of SEA, but when SEA 38 kDa was used to examine normal human sera, the result was converse.
Conclusion: The purified SEA 38 kDa has higher sensitivity and specificity and immunodiagnostic potential.