Study on the Application of Clonorchis sinensis Recombinant Antigen to the Detection of Specific Circulatory Antibody by ABC ELISA

Objective Evaluating the value of recombinant proteins for the diagnosis of clonorchiasis and exploring the possibility that recombinant proteins, substituting the natural antigen, are used to the serological diagnosis of Clonorchis sinensis infection.Methods Recombinant C.sinensis cysteine proteinase(CysB) and C.sinensis adultworm antigen (CAA) were used to detect clonorchiasis by ABC ELISA. Serum samples from other parasitic infections and healthy individuals were used as control. The sensitivity and specificity of the two kinds of antigens used for the detection were compared. Results 112 cases of C.sinensis infected sera were analyzed, with a positive detection rate of 92.9% (104/112) for the recombinant antigen (CysB) and 94.6% (106/112) for CAA; 56 cases of healthy individual sera, 20 cases of schistosomiasis sera and 10 cases of paragonimiasis sera were also analyzed. All these three kinds of sera showed negative results in the detection using either CysB or CAA. The negative rates for the healthy sera, schistosomiasis sera, and paragonimiasis sera were 96.5% (54/56), 95% (19/20) and 90% (9/10), respectively. Conclusion Recombinant C.sinensis protein CysB has high sensitivity and specificity for the detection of serum specific antibody, that are comparable to CAA for diagnosis. The recombinant protein CysB is a promising alternative antigen useful for the diagnosis of clonorchiasis.