Related Experiment Video
Updated: Sep 21, 2026
Two Methods of Heterokaryon Formation to Discover HCV Restriction Factors
Published on: July 16, 2012
Hepatitis C virus (HCV)-specific cytotoxic T lymphocytes recognize epitopes in the core and envelope proteins of HCV
M J Koziel1, D Dudley, N Afdhal
1Infectious Disease Unit, Massachusetts General Hospital, Boston.
Insights
Hepatitis C virus (HCV)-specific cytotoxic T lymphocytes (CTL) were found in the liver but not peripheral blood of patients with chronic HCV hepatitis. These CTL target conserved HCV core and variable E2 proteins, aiding vaccine development.
Area of Science:
- Immunology
- Virology
- Hepatology
Background:
- Hepatitis C virus (HCV) infection frequently leads to chronic hepatitis.
- Understanding the host immune response is crucial for developing vaccines and immunomodulatory therapies.
- Cellular immunity, particularly cytotoxic T lymphocytes (CTL), plays a key role in controlling viral infections.
Purpose of the Study:
- To investigate the presence and characteristics of HCV-specific CTL in individuals with chronic HCV hepatitis.
- To identify specific epitopes targeted by these CTL within HCV proteins.
- To determine the localization of HCV-specific CTL within infected tissues.
Main Methods:
- Liver-infiltrating lymphocytes and peripheral blood CD8+ lymphocytes were isolated from patients with chronic HCV.
- Recombinant vaccinia viruses expressing HCV proteins (core, E1, E2, NS2) were used to stimulate target cells.
- CTL activity was assessed using bulk expansion and limiting dilution cloning.
- Synthetic HCV peptides were used to define recognized epitopes, with HLA class I restriction analyzed.
Main Results:
- HCV-specific CTL activity was detected in bulk-expanded liver-derived CD8+ lymphocytes, but not in peripheral blood counterparts.
- Four distinct HLA class I-restricted CTL epitopes were identified within HCV proteins.
- Two of these epitopes were located in the conserved N-terminal region of the HCV core protein.
- Additional epitopes were identified within the more variable E2 envelope protein.
Conclusions:
- HCV-specific CTL are present and active at the site of liver injury in chronic HCV hepatitis.
- The conserved HCV core protein is a significant target for CTL responses.
- CTL epitopes within the E2 envelope protein were identified, suggesting T-cell recognition of variable regions.
- Identifying these epitopes is vital for understanding HCV pathogenesis and for developing effective vaccines or therapies.
Abstract:
Hepatitis C virus (HCV) is a major cause of posttransfusion and community-acquired hepatitis, and a majority of individuals infected with this virus will subsequently develop chronic hepatitis. Characterization of the host immune response to this infection is an important first step that should facilitate the development of immunomodulatory agents and vaccines. Cellular immune responses, especially those mediated by cytotoxic T lymphocytes (CTL), are important in the control of many viral diseases. In this study, liver-infiltrating lymphocytes from persons with chronic HCV hepatitis were examined for evidence of HCV-specific CTL by using target cells infected with recombinant vaccinia viruses expressing the HCV core, E1, E2, and part of the NS2 proteins. Bulk expansion of liver-derived CD8+ lymphocytes resulted in the detection of HCV-specific CTL activity, whereas activity could not be found in CD8+ lymphocytes expanded from peripheral blood. Epitopes recognized by these CTL were defined by using CTL clones obtained by limiting dilution and target cells sensitized with synthetic HCV peptides. Four distinct HLA class I-restricted epitopes were identified, including two epitopes in the amino-terminal portion of the core protein. These studies provide evidence that the highly conserved core protein is a target for HCV-specific CTL and identify CTL epitopes within the more highly variable E2 envelope protein. Our studies also suggest that HCV-specific CTL are localized at the site of tissue injury in infected persons with chronic hepatitis. Identification of the epitopes recognized by HCV-specific CTL will facilitate exploration of their role in disease pathogenesis and may provide information useful in development of therapeutic interventions or vaccines.
More Related Videos
Related Concept Videos
01:26Antigens Involved in Adaptive Immunity
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
01:22T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...
01:24T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
01:27Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
01:29Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
01:25Hepatitis