Human cystic echinococcosis is a zoonosis occurring due to dogs handling and exposure to Echinococcus granulosus ova in their stools being an accidental intermediate host. Serology remains the only sure and important tool to diagnose this disease. We aimed to improve the detection of circulating antigen by sandwich ELISA through its binding to gold nanoparticle and proving the role of minute nanoparticles in serodiagnosis. Gold nanoparticles (AuNPs) were employed for the capture of the antigens of protoscolices (pAg) in the patient’s serum by sandwich ELISA. Cross-reactivity for antigens from Hymenolepis nana, Entrobius vermicularis, and Fasciola gigantica was ruled out by using anti-protoscolices polyclonal IgG antibodies (ppAb). Antigen of sonicated protoscolices which were removed from camel lung cysts, was purified and injected to a New-zealand white rabbit giving ppAb which then loaded on AuNPs being used as a diagnostic indicator for circulating pAg by both sandwich ELISA and nanogold sandwich ELISA techniques. Nanogold sandwich ELISA was able to give positive results with 96.3% of hydatid patients and 5% of non-hydatid patients while sandwich ELISA showed 81.4% and 20% positive cases of the same groups respectively. The sensitivity and specificity of nanogold sandwich ELISA were 96.3% & 95% against 81.5% & 80% for those of sandwich ELISA respectively. The conjugation of AuNPs to anti-Echinococcus IgG antibodies seems to be beneficial to increase PPV, NPV, and efficiency and reduce the overall cost of the assay as less antibody was needed. |
