Serological Evaluation of EgAgB16 kDa, a Recombinant Antigen from Echinococcus granulosus for Diagnosis of Human Hydatidosis

BACKGROUND Regarding that accurate diagnosis of human hydatidosis still needs more investigations, the present study was conducted to clone, express, and evaluate the gene encoding AgB subunits (EgAgB16 kDa) from Echinococcus granulosus (Iranian G1 strain) and its evaluation by ELISA test. METHODS DNA was extracted from protoscoleces and was utilized by PCR for strain identification. Total RNA was prepared with RNeasy protect mini kit from E. granulosus (Iranian G1 strain) protoscoleces collected from naturally infected sheep with hydatid cyst. Recombinant AgB16 kDa was produced using pETDuet as vector and evaluated by ELISA method. A panel of sera including hydatid cyst-infected individuals (n=72), healthy individual (n=48), toxoplasmosis (n=4), strongyloidosis (n=4), kala-azar (n=5) and tuberculosis (n=5) were examined using this recombinant antigen. RESULTS Recombinant protein was purified by affinity chromatography using His-Tag column. After purification, recombinant protein was confirmed by western blot analysis using His Tag monoclonal antibody or hydatid positive human serum. The sensitivity, specificity; positive and negative predictive values were calculated as 93.5%, 95.6%, 96% and 92.9%, in that order. The cut-off point was detected 0.3 for rAgB16. CONCLUSION While the produced recombinant AgB16 kDa showed promising results in diagnosing human hydatidosis, but more investigations should be implemented to reach an accurate gold standard.