Construction and Evaluation of DNA Vaccine Encoding Fusion Protein of Hepatitis C Virus Core Protein and Hepatitis B Surface Antigen as a Vaccine Candidate

While hepatitis C virus (HCV) is the major cause of acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma worldwide, no vaccine against this infection has been proved to date. Cellular immune responses play an important role for eradicating persistent viral infections. Among different vaccine strategies, the use of DNA vaccine has been shown to be a promising approach for enhancing cellular immune responses. In spite of their advantages, DNA-based vaccines might induce weaker antibody and cytotoxic T-lymphocyte responses compared to protein immunization. To overcome this obstacle, several methods such as different immunization regimens, fusion of particle forming units [like hepatitis B surface antigen (HBsAg)] and co-expressing cytokines have been tested. The aim of this study was to design, construct, and evaluate an HBsAg-fused core-based DNA vaccine against HCV infection. The HCV core gene was amplified by polymerase chain reaction (PCR) and cloned in BamHI/EcoRV sites of pcDNA3.1 containing HBsAg. The constructed plasmid (pCHCORE) was analyzed by restriction enzyme and sequencing analyses and evaluated for the protein expression in HEK293T cell line by western blot analysis with anti-HBsAg polyclonal antibody. The correctness of the constructed DNA vaccine was shown by restriction enzyme analysis and sequencing. Western blotting results confirmed the expression of HBsAg-HCV fusion protein with an expected molecular weight in HEK239T cell line. In accordance with previous studies, the constructed vector (pCHCORE) compromising the fusion of HBsAg to HCV core in pCDNA3 plasmid might be used as a HCV DNA vaccine (due to proper expression in cell lines) to induce augmented cellular immune responses.