Improved serodiagnosis of hydatid cyst disease using gold nanoparticle labeled antigen B in naturally infected sheep

Cystic echinococcosis caused by the metacestode of Echinococcus granulosus is a major problem in both humans and domestic animals health. Therefore, a standardized and approachable diagnostic tool (rapid tests) for the serodiagnosis of cystic echinococcosis (CE) is still needed.

In the present work, antigen B labeled with gold nanoparticles was used to detect antibodies against hydatid cyst disease. The prepared antigen B was analyzed by SDS-PAGE. Tetra chloroauric acid (HAuCl4) was used to produce colloidal gold and antigen B labeled by gold nanoparticles, then it was tested by using rabbits antisera and sera from naturally infected sheep. The labeled antigen B was evaluated using Dot-immunogold staining (Dot-IGS) method.

Electrophoretic pattern of hydatid cyst fluid showed the quality of bands in the condensed fluid is better than crude fluid. SDS-PAGE analysis cyst fluid and antigen B revealed three specific protein bands that were detected at molecular weights of 24, 30 and 40 kDa that all are the subunits of antigen B. Evaluation of antigen B labeled by gold nanoparticles by using Dot-IGS technique showed 1/1 and 1/50 dilutions in comparison with another has the best immunoreaction. In this method, nanoparticles produced a typical purple color, when they binded to the strip at the site of immunoreaction.

Therefore, using gold nanoparticles is a good candidate for detection of helminthiasis, also as selective tools of early detection, simple and cost-effective, regardless of specific skills and equipment with optimal durability.