The cellular immune response plays a central role in virus clearance and pathogenesis of liver disease in hepatitis C. The study of hepatitis C virus (HCV)-specific immune responses is limited by currently available cell-culture systems. Here, the establishment and characterization of stable human HLA-A2-positive B-lymphoblastoid x T hybrid cell lines constitutively expressing either the NS3-4A complex or the entire HCV polyprotein are reported. These cell lines, termed T1/NS3-4A and T1/HCVcon, respectively, were maintained in continuous culture for more than 1 year with stable characteristics. HCV structural and non-structural proteins were processed accurately, indicating that the cellular and viral proteolytic machineries are functional in these cell lines. Viral proteins were found in the cytoplasm in dot-like structures when expressed in the context of the HCV polyprotein or in a perinuclear fringe when the NS3-4A complex was expressed alone. T1/NS3-4A and T1/HCVcon cells were lysed efficiently by HCV-specific cytotoxic T lymphocytes from patients with hepatitis C and from human HLA-A2.1 transgenic mice immunized with a liposomal HCV vaccine, indicating that viral proteins are processed endogenously and presented efficiently via the major histocompatibility complex class I pathway. In conclusion, these cell lines represent a unique tool to study the cellular immune response, as well as to evaluate novel vaccine and immunotherapeutic strategies against HCV.