SjHSP90 recombinant protein and its possible application in the diagnosis of schistosomiasis and treatment efficacy monitoring

Purpose: The fraction antigen of Schistosoma japonicum (107-121 kDa) eggs can be used for treatment efficacy monitoring, but the methods are laborious. This study analyzed the antigen and its feasibility for infection screening and treatment efficacy monitoring, which is the key to schistosomiasis control.Methods: The fraction antigens have been analyzed by shotgun mass spectrometry. The recombinant proteins of candidates from the fraction antigens have been prokaryotic expression and purification in large amounts with high purity. The sera have been collected from rabbits and mice models of schistosomiasis infection and treatment. ELISA evaluated the diagnostic value of the candidate proteins. Results: SJCHGC00820 and SJCHGC06900, with higher credibility, were identified through Shotgun mass spectrometry. ELISA results showed that rSj00820 has a diagnostic value for schistosomiasis (positive OD/ negative OD P/N=3.6), while rSj06900 showed negative (P/N)<2. In rabbits, the specific serum antibodies for SjHSP90(rSj00820) in the infected animals peaked 6 weeks after infection and gradually decreased after treatment, reaching negative levels at 11 weeks. SjHSP90-ELISA was used to test serum samples from infected mice. The sensitivity and specificity reached >90%, similar to the diagnostic value obtained with soluble egg antigen (SEA) (SEA-ELISA). After treatment, the negative conversion rate reached >80%, significantly superior to SEAELISA.Conclusions: The SjHSP90-ELISA can be used for the immunological diagnosis and treatment efficacy monitoring of schistosomiasis. The study lays a foundation for further developing screening and diagnostic kits.