Elicitation of strong immune responses by a DNA vaccine expressing a secreted form of hepatitis C virus envelope protein E2 in murine and porcine animal models.
OBJECTIVE
To characterize the immunogenicity of a hepatitis C virus (HCV) E2 DNA vaccine alone or with a protein vaccine boost in murine and porcine animal models.


METHODS
A DNA vaccine expressing a secreted form of HCV E2 protein was constructed and used to vaccinate mice and piglets with or without boosting with a recombinant E2 protein vaccine formulated with CpG ODN and 10% Emulsigen. The immunogenicity of HCV E2 vaccines was analyzed by ELISA for antibody responses, MTT assay for lymphocyte proliferation, ELISPOT for the number of interferon-gamma secreting cells, and cytotoxic T lymphocyte assays.


RESULTS
Intradermal injection of E2 DNA vaccine induced strong Th1-like immune responses in mice. In piglets, E2 DNA vaccine elicited moderate and more balanced immune responses. A DNA vaccine prime and protein boost vaccination strategy induced significantly higher E2-specific antibody levels and shifted the immune response towards Th2-like ones in piglets.


CONCLUSIONS
A DNA vaccine expressing a secreted form of HCV E2 protein elicited E2-specific immune responses in mice and piglets. Recombinant E2 protein vaccination following DNA immunization significantly increased the antibody response in piglets. These HCV E2 vaccines may represent promising hepatitis C vaccine candidates for further investigations.
Li
Yi-Ping
YP
Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N 5E3, Canada.
Kang
Hye-Na
HN
Babiuk
Lorne-A
LA
Liu
Qiang
Q
D000818:Animals; D000917:Antibody Formation; D005260:Female; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000517:prevention & control*; D007111:Immunity, Cellular; D051379:Mice; D010957:Plasmids; D013552:Swine; D019444:Vaccines, DNA / Q000302:isolation & purification / Q000627:therapeutic use*; D014759:Viral Envelope Proteins / Q000276:immunology* / Q000378:metabolism
D019444:Vaccines, DNA; D014759:Viral Envelope Proteins