Novel DNA vaccine based on hepatitis B virus core gene induces specific immune responses in Balb/c mice.

Aim: To investigate the immunogenicity of a novel DNA vaccine, pSW3891/HBc, based on HBV core gene in Balb/c mice.

Methods: A novel DNA vaccine, pSW3891/HBc, encoding HBV core gene was constructed using a vector plasmid pSW3891. Balb/c mice were immunized with either pSW3891/HBc or empty vector DNA via gene gun. IgG anti-HBc responses in mouse sera were demonstrated by ELISA. Specific cytotoxicity of cytotoxic T lymphocytes (CTLs) of mice was quantitatively measured by lactate dehydrogenase release assay.

Results: HBcAg was expressed effectively in 293T cell line transiently transfected with pSW3891/HBc. Strong IgG anti-HBc responses were elicited in mice immunized with pSW3891/HBc. The end-point titers of anti-HBc reached the highest 1:97,200, 4 wk after the third immunization. The specific CTL killing with the highest specific lysis reached 73.25% at effector:target ratio of 20:1 in mice that received pSW3891/HBc DNA vaccine.

Conclusion: pSW3891/HBc vaccination elicits specific anti-HBc response and induces HBc-specific CTL response in immunized Balb/c mice.