[PDF][PDF] Role of the coinhibitory receptor cytotoxic T lymphocyte antigen‐4 on apoptosis‐Prone CD8 T cells in persistent hepatitis B virus infection

A Schurich, P Khanna, AR Lopes, KJ Han… - …, 2011 - Wiley Online Library
A Schurich, P Khanna, AR Lopes, KJ Han, D Peppa, L Micco, G Nebbia, PTF Kennedy…
Hepatology, 2011Wiley Online Library
An excess of coinhibitory signals has been proposed to drive the T‐cell exhaustion
characteristic of persistent viral infections. In this study we examined the contribution of the
coinhibitory receptor cytotoxic T lymphocyte antigen‐4 (CTLA‐4) to CD8 T cell tolerance in
chronic hepatitis B virus (HBV) infection (CHB). CD8 T cells in patients with CHB have an
increased propensity to express the coinhibitory receptor CTLA‐4 and this correlates with
viral load. CTLA‐4 is up‐regulated on those HBV‐specific CD8 T cells with the highest …
Abstract
An excess of coinhibitory signals has been proposed to drive the T‐cell exhaustion characteristic of persistent viral infections. In this study we examined the contribution of the coinhibitory receptor cytotoxic T lymphocyte antigen‐4 (CTLA‐4) to CD8 T cell tolerance in chronic hepatitis B virus (HBV) infection (CHB). CD8 T cells in patients with CHB have an increased propensity to express the coinhibitory receptor CTLA‐4 and this correlates with viral load. CTLA‐4 is up‐regulated on those HBV‐specific CD8 T cells with the highest levels of the proapoptotic protein Bim, which we have previously shown mediates their premature attrition; abrogation of CTLA‐4‐mediated coinhibition can reduce Bim expression. Longitudinal study of CHB patients beginning antiviral therapy reveals that HBV DNA suppression induces transient reconstitution of HBV‐specific CD8 T cells but does not reprogram their CTLA‐4hiBimhi tolerogenic phenotype. Blocking CTLA‐4 is able to increase the expansion of interferon gamma (IFN‐γ)‐producing HBV‐specific CD8 T cells in both the peripheral and intrahepatic compartments. The rescue of anti‐HBV responses by either CTLA‐4 or PD‐L1 blockade is nonredundant. Conclusion: CTLA‐4 is expressed by HBV‐specific CD8 T cells with high levels of Bim and helps to drive this proapoptotic phenotype. CTLA‐4 blockade could form one arm of a therapeutic approach to modulate the diverse patterns of coregulation of T‐cell exhaustion in this heterogeneous disease. (HEPATOLOGY 2011;)
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