Construction of HCV core and envelope 2 fusion gene DNA vaccine and its immunogenicity in mice
Objective To observe the immunogenicity of a novel hepatitis C virus (HCV)fusion protein DNA vaccine in BALB/c mice and determine its value as an agent against hepatitis C. Methods A DNA fragment encoding signal peptide of murine IgG kappa chain and a universal helper T lymphocyte epitope PADRE were spliced by overlapping PCR. HCV core gene and envelope 2 (E2)gene were amplified by PCR respectively. The three DNA fragments were then inserted into an eukaryotic expression vector pcDNA3.1. The resultant recombinant expression plasmid pST CE2t was transfected into COS7 cells and its expressed product was identified by immunohistochemical staining. BALB/c mice were intramuscularly vaccinated with pST CE2t or pcDNA3.1 core (HCV core DNA vaccine) three times. The serum antibodies, T lymphocyte proliferative response and cytotoxic T lymphocyte response of the mice were examined. Results pST CE2t expressed HCV core and E2 antigens in COS7 cells and induced humoral as well as cellular immune responses in BALB/c mice effectively. The immune responses against HCV core protein elicited by pST CE2t are stronger and more inclined to T H1 type than that of pcDNA3.1 core. Conclusion This optimal HCV core and E2 fusion protein DNA vaccine may be potentially used for prevention and treatment of hepatitis C. [