The production and comparative evaluation of native and recombinant antigens for the fast serodiagnosis of cystic echinococcosis with dot immunogold filtration assay.

Clinical diagnosis and post-surgery assessment of cystic echinococcosis depend on laboratory serodiagnosis and ultrasound examinations. This study aims to produce the recombinant antigen (rAgB) and compare its diagnostic effect with natural antigens (crude fluid antigen, protoscolex antigen). After rAgB, crude fluid antigen, protoscolex antigen were produced, and the diagnostic accuracy was evaluated with dot immunogold filtration assay (DIGFA) by the sera from the following groups: surgically confirmed cystic echinococcosis patients (n = 113), alveolar echinococcosis patients (n = 46), other parasitic diseases (n = 49), nonparasitic hepatic diseases (n = 63) and healthy people (n = 121). In diagnosing cystic echinococcosis, the sensitivity of recombinant AgB was 77.9% and the specificity was 98.3%. The crude fluid antigen B showed a sensitivity of 92.9% and specificity of 81.0%. The protoscolex antigen had sensitivity of 87.6% and specificity of 90.9%. The recombinant AgB indicates the advantage of no cross-reaction with other parasite diseases or nonparasite hepatic diseases. Recombinant antigen B can improve the specificity but decrease the sensitivity. The combination of native and recombinant antigens will improve the overall performance of serodiagnosis of cystic echinococcosis.