Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 9 2 2014 06 15 218 225 EN Zahra Jahani Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Behnam Meshgi Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Masomeh Rajabi-Bzl Dept. of Medical Biochemistry, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Fatemeh Jalousian Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Sajad Hasheminasab Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. 2015 10 14 Background: Cystic echinococcosis caused by the metacestode of Echinococcus granulosus is a major problem in both humans and domestic animals health. There-fore, a standardized and approachable diagnostic tool (rapid tests) for the serodiag-nosis of cystic echinococcosis (CE) is still needed. Methods: In the present work, antigen B labeled with gold nanoparticles was used to detect antibodies against hydatid cyst disease. The prepared antigen B was ana-lyzed by SDS-PAGE. Tetra chloroauric acid (HAuCl4) was used to produce colloi-dal 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. Results: 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. Conclusion: 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. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/410 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/410/334