ABSTRACT
<p><b>BACKGROUND</b>To construct the pRSETB-HDAg recombinant expression plasmid and to obtain soluble hepatitis D virus antigen with high biological and antigenic activity.</p><p><b>METHODS</b>HDAg gene fragment was inserted into fusion expression pRSET B vector that includes T7 promoter and a polyhistidine tag. The recombinant plasmid was transformed into host bacterium BL21 after induction with IPTG. The expression supernatant was purified by chelating affinity chromatography and the recombinant HDAg antigenic activity was detected by EIA.</p><p><b>RESULTS</b>EIA detection using the recombinant HDAg showed strong positive reaction with hepatitis D patients sera. The positive rates of the EIA, compared with HDAg from USA and Hua Mei EIA kit in detecting 26 cases of anti-HDV positive reference sera, were 100%, 96.15% and 100%, respectively.</p><p><b>CONCLUSION</b>Recombinant plasmid for HDAg with good antigenicity was successfully constructed and could be used as hepatitis D antibody detection reagent.</p>