Low dose and gene gun immunization with a hepatitis C virus nonstructural (NS) 3 DNA-based vaccine containing NS4A inhibit NS3/4A-expressing tumors in vivo

• Published in: Gene therapy Vol. 10; no. 8; pp. 686 - 699
• Main Authors: FRELIN, L, ALHEIM, M, CHEN, A, SÖDERHOLM, J, ROZELL, B, BARNFIELD, C, LILJESTRÖM, P, SÄLLBERG, M
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 01.04.2003
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Applied cell therapy and gene therapy; Biolistics; Biological and medical sciences; Cytotoxicity; DNA helicase; DNA vaccines; DNA viruses; Genetic Therapy - methods; Genotypes; Hepacivirus - genetics; Hepatitis; Hepatitis C; Immunization; Immunogenicity; Immunoglobulin G; Immunohistochemistry; Lymphocytes T; Medical sciences; Medicin och hälsovetenskap; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Multiple Myeloma - immunology; Multiple Myeloma - therapy; Multiple Myeloma - virology; NS3 protein; Statistics, Nonparametric; T-Lymphocytes, Cytotoxic - immunology; Th1 Cells - immunology; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Tumor cells; Vaccines; Vaccines, DNA - administration & dosage; Viral Nonstructural Proteins - genetics; DNA vaccine; Microprojectile bombardment; Immunization; Immune response; Vaccination; Genetic vaccine; NS3; Virus; gene gun; Tumor; HCV; Flaviviridae; Hepatitis C virus; Hepacivirus
• ISSN: 0969-7128; 1476-5462
• DOI: 10.1038/sj.gt.3301933

The hepatitis C virus (HCV) protease and helicase encompasses the nonstructural (NS) 3 protein and the cofactor NS4A, which targets the NS3/4A-complex to intracellular membranes. We here evaluate the importance of NS4A in NS3-based genetic immunogens. A full-length genotype 1 NS3/4A gene was cloned into a eucaryotic expression vector in the form of NS3/4A and NS3 alone. Transient transfections revealed that the inclusion of NS4A increased the expression levels of NS3. Subsequently, immunization with the NS3/4A gene primed 10- to 100-fold higher levels of NS3-specific antibodies as compared to immunization with the NS3 gene. Humoral responses primed by the NS3/4A gene had a higher IgG2a/IgG1 ratio (>20) as compared to the NS3 gene (3.0), suggesting a T helper 1-skewed response. Low dose i.m. (10 microg) immunization with the NS3/4A gene inhibited the growth of NS3/4A-expressing tumor cells in vivo, whereas the NS3 gene alone or NS3 protein did not. We then evaluated the efficiency of the NS3/4A gene administered by the gene gun, at the same doses used for humans, in priming cytotoxic T lymphocyte (CTL) responses. Three to four 4 microg doses of the NS3/4A gene primed CTL at a precursor frequency of 2-4%, which inhibited the growth of NS3/4A-expressing tumor cells in vivo. Thus, NS4A enhances the expression levels and immunogenicity of NS3, and an NS3/4A gene delivered transdermally could be a therapeutic vaccine candidate.