Fiber-modified recombinant adenoviral constructs encoding hepatitis C virus proteins induce potent HCV-specific T cell response.

Hepatitis C virus (HCV)-specific cytotoxic T lymphocytes (CTLs) play an important role in HCV clearance. The frequency of HCV-specific T(CD8) in peripheral blood of HCV-infected donors is very low and HCV cannot be cultivated for reinfection of antigen presenting cells, making it difficult to detect T(CD8) of broad HCV specificities from peripheral blood mononuclear cells (PBMCs). We have developed a recombinant adenoviral system that efficiently reactivates and expands HCV-specific CTLs from PBMCs of HCV-infected donors. Replication-incompetent adenoviruses expressing individual HCV proteins (core and NS3) were produced and PBMCs from HCV-infected donors were transduced with these recombinant adeno-HCV constructs to stimulate HCV-specific CTL populations. T cells expanded from adeno-HCV stimulated cultures were potent producers of HCV-specific IFN-gamma and TNF-alpha and efficiently lysed target cells pulsed with HCV peptides. These constructs could stimulate T(CD8) directed towards multiple HCV peptides while preserving the determinant hierarchy. This approach therefore overcomes some of the shortcomings of the selective expansion of CTLs with peptide-based vaccine strategies. These findings provide an effective approach for the expansion of HCV-specific CTLs from PBMCs of HCV-infected patients and have potential for immunotherapeutic/vaccine development.