en Medical Biotechnology Medical Biotechnology مقاله کامل Full Length/Original Article <strong>Background:</strong> Cystic echinococcosis (CE) is a helminthic disease caused by the larval form of <em>Echinococcus granulosus. </em>&nbsp;In the present study, the B8/2 subunit of antigen B (AgB) of <em>E. granulosus</em> was expressed in <em>E. coli</em> host and then applied in a diagnostic ELISA set up. <strong>Methods:</strong> The DNA sequence of AgB8/2 subunit from <em>E. granulosus</em> was extracted from the GenBank and codon-optimized. The target sequence was cloned in an expression vector (pGEX-4T-1)<span dir="RTL">.</span> The produced antigen was used in an ELISA system, and its performance for the diagnosis of human hydatid cyst was evaluated, using sera from CE and non-CE patients, along with the sera from healthy subjects. Moreover, the diagnostic value of the recombinant protein was compared with native AgB, as well as with a commercial kit. <strong>Results:</strong> Antibodies to hydatid cyst were detected in 27 out of 30 patients corresponding to a sensitivity of 90% (95% CI: 73-98%). Cross-reaction with sera of non-CE subjects was seen in two cases resulted in a specificity of 93.5% (95% CI: 82-98%) for the test. A sensitivity of 87% and specificity of 90% were found for the native form of the antigen, while the ELISA commercial kit had a sensitivity of 97% and specificity of 95%. <strong>Conclusion:</strong> Our data show that rEgAgB8/2 is an appropriate source of antigen for the serological diagnosis of human hydatid cyst. Co-expression of the rEgAgB/2 along with other subunits of AgB may enhance the performances of these antigens for the serodiagnosis of human CE. Diagnosis, Echinococcus granulosus, Hydatid cyst 246 252 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-754&slc_lang=en&sid=1 Amir Savardashtaki 0000-0003-1700-9426 No Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran Zohreh Mostafavi-Pour 0000-0002-3779-177X No Recombinant Proteins Laboratory, Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Farzaneh Arianfar No Recombinant Proteins Laboratory, Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Bahador Sarkari 0000-0003-2045-9057 Yes Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran