improved serodiagnosis of hydatid cyst disease using gold nanoparticle labeled antigen b in naturally infected sheep.

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.