Related Experiment Videos
Characterization of the humoral and cellular immune responses against hepatitis C virus core induced by DNA-based
1Department of Transfusion Medicine, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892-1184, USA.
Insights
DNA-based immunization shows promise for Hepatitis C Virus (HCV) infection. Vaccination with HCV-core DNA sequences effectively induced humoral and cellular immune responses, suggesting a potential new vaccine strategy.
Area of Science:
- Immunology
- Virology
- Vaccine Development
Background:
- Hepatitis C Virus (HCV) is a major cause of posttransfusion hepatitis, leading to chronic liver disease, cirrhosis, and hepatocellular carcinoma.
- Current therapies for HCV are minimally effective, and no vaccine is currently available.
- DNA-based immunization presents a potential prophylactic and therapeutic strategy for HCV infection.
Purpose of the Study:
- To evaluate the efficacy of DNA-based immunization with a Hepatitis C Virus (HCV) recombinant plasmid in inducing humoral and cellular immune responses.
- To investigate the potential of boosting with recombinant HCV-core protein to enhance immune responses.
- To characterize the nature of the immune response, including T helper cell priming and cytotoxic T lymphocyte (CTL) activity.
Main Methods:
- BALB/c mice were intramuscularly inoculated with an HCV recombinant plasmid (pCI-HCV-C).
- Mice were boosted with recombinant HCV-core protein (cp1-10).
- Humoral responses (IgM, IgG), spleen cell proliferation, T cell phenotypes (CD4+, CD8+), and cytotoxic T lymphocyte (CTL) activity were assessed using methods including Western-blotting, proliferation blocking assays, and 51Cr-release assays.
Main Results:
- pCI-HCV-C immunization induced significant IgM but not IgG antibodies.
- Boosting with cp1-10 rapidly increased anticore IgG levels and spleen cell proliferation.
- Specific T helper cell priming (CD4+ CD8-) and MHC class I-restricted CTL responses (CD4- CD8+) against HCV-core were demonstrated, with three CTL epitopes identified.
Conclusions:
- DNA-based vaccination with HCV-core derived DNA sequences is effective in inducing both humoral and cellular immune responses.
- This approach holds potential as a vaccination strategy for Hepatitis C Virus infection.
- The study highlights the importance of boosting with core protein to achieve robust IgG responses and CTL activity.
Abstract:
Hepatitis C Virus (HCV) causes most cases of posttransfusion hepatitis. Chronic HCV infection is highly related to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Current therapies are only minimally effective and no vaccine has been developed. DNA-based immunization could be of prophylactic and therapeutic value for HCV infection. By intramuscular inoculation in BALB/c mice with an HCV recombinant plasmid pCI-HCV-C, we found significant levels of IgM antibody, but no significant IgG rise. After boost the immunized mice with recombinant HCV-core protein (cp1-10; 1-164aa), the anticore IgG, verified by Western-blotting, rose rapidly, which was two weeks earlier than that with control plasmid. Spleen cells from pCI-HCV-C immunized mice gave higher proliferation index (PI) than control (P < 0.05). The PI of cp1-10 boosted mice was even higher. Proliferation blocking assay with mAb proved the responding cell to be of CD4+ CD8- phenotype, supporting specific priming of T helper cells. A 51Cr-releasing CTL assay specific for HCV-core was developed, and a specific CTL response against HCV-core was demonstrated in both pCI-HCV-C immunized mice and mice boosted with cp1-10. Strong cytotoxic activity against peptide-pulsed p815 cells (H-2d), but not EL-4 cells (H-2b), suggested MHC class I restriction of the CTL activity. Blocking of CTL with mAb proved the effector cells to be of CD4- CD8+. Three CTL epitopes in HCV-core protein were demonstrated. We failed to detect CTL when immunized only with core protein. The results suggested that vaccination with HCV-core derived DNA sequences could be an effective method to induce humoral and cellular immune responses to HCV.