T cell responses in hepatitis C: the good, the bad and the unconventional.

Over recent years, it has become increasingly accepted that virus-specific CD4+ and CD8+ T cell responses play a major role in outcome and pathogenesis of hepatitis C virus (HCV) infection. Indeed, while the emergence of strong and multispecific T cell responses may correlate with spontaneous viral clearance, the virus has developed several mechanisms to avoid T cell control in the majority of acutely HCV-infected patients that subsequently develop persistent HCV infection. In this review, we will discuss the current knowledge about the role of cellular immune responses in HCV infection. Specifically, we will emphasise recent new insights into the effector functions of T cells, possible mechanisms of their failure and the host-virus interactions occurring at the site of the disease, the liver.