Viral epitope-specific T cell responses induced in chronic, hepatitis C virus-infected patients

Abstract Background Approximate 180 million people worldwide are infected with hepatitis C virus (HCV). Historically, vaccination has been the most effective strategy for controlling infections of such major health concern. Therapeutic vaccine strategies for HCV, however, have demonstrated negligible success. Aim Demonstrate the ability of highly-conserved viral epitopes to overcome the immune dysfunction often associated with chronic HCV infections. Methods T cells from five chronic, HCV-infected patients were immunophenotyped by flow cytometry. The ex vivo T cell responses to highly-conserved viral epitopes were assessed by ELISpot assay and cytokine bead array analysis. Results Both HLA-DRB-1- and HLA-A2-restricted viral epitopes induced specific, T H 1-type cytokine production by T cells derived from the patients. Induction occurred despite expression of cell-surface inhibitory molecules and the presence of regulatory T cells. Conclusion These findings support the potential ability of a broad, multi-epitope-based therapeutic vaccine to elicit virus-specific immune responses in chronic hepatitis C virus-infected patients.