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

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, T1-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.