BACKGROUND: DNA immunization provides a promising approach to elicit protective humoral and cellular immune responses against HBV. This study was to construct an eukaryotic expression plasmid containing helper T lymphocyte epitope, which will enhance the immunogenicity of a novel hepatitis B virus (HBV) fusion protein DNA vaccine.
METHODS: The target gene containing pan-DR helper T cell epitopes (PADRE) and HBsAg was amplified by polymerase chain reaction (PCR). The PCR products were linked with PMD-18T vector. Plasmid DNA was purified from transformed E.coli competent cell JM109 and digested with Hind III and EcoR I. Then, the target gene was cloned in pcDNA3.1(+) digested by Hind III and EcoR I. Finally, the identity of DNA was verified by digestion and DNA sequencing.
RESULTS: The recombinant expression vectors of pcDNA3.1(+)-PADRE/HBs were identified by restriction enzyme digestion and DNA sequencing. The insert DNA fragment was consistent with the expected sequence.
CONCLUSIONS: The constructed eukaryotic expression plasmid of pcDNA3.1(+)-PADRE/HBs is convenient for further study of eukaryotic transfection and response for cellular and humoral immunity against HBV.