Enhancement
of Immune Responses of Hepatitis B Virus Core DNA Vaccine by a Signal Peptide
and a Universal Helper T Lymphocyte Epitope
ZHAO Ping,ZHAO Lan-Juan,CAO Jie,HONG
Hai-Yan,
QI Zhong-Tian*
（ Department of Microbiology,Second Military Medical
University,Shanghai 200433,China ）
Abstract The human
interleukin-2 signal peptide and a potent universal helper T lymphocyte epitope
PADRE were spliced to the 5′ terminus of hepatitis B viru score（HBcAg）gene.The modified HBcAg gene
was used to construct a DNA vaccine. After the resulted DNA vaccine construct
was transfected into COS7 cells,secreted HBcAg was detected in the supernatant
by ELISA.BALB/c mice were vaccinated intramuscularly with the modified HBcAg
DNA vaccine and the wild-type one.Serum antibodies,T lymphocyte proliferative
response and cytotoxic T lymphocyte response of the immunized mice were
measured.The results showed that the modified DNA construct induced cellular
and humoral immune responses much stronger in vivo than the natural one
did,indicating the potential value as a therapeutic vaccine for treatment of
chronic hepatitis B.
Key words hepatitis B virus;DNA vaccine;signal
peptide;helper T lymphocyte epitope; immune responses
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