Fas Ligand Is Responsible for CXCR3 Chemokine Induction in CD4+ T Cell-Dependent Liver Damage

Abstract

Immune-mediated hepatic damage has been demonstrated in the pathogenesis of hepatitis C virus (HCV) and other hepatotrophic infections. Fas/Fas ligand (FasL) interaction plays a critical role in immune-mediated hepatic damage. To understand the molecular mechanism(s) of FasL-mediated liver inflammation, we examined the effect of CD4+ T cells expressing high levels of FasL on the initiation of hepatic damage through analysis of chemokine and chemokine receptor expression in HCV core × TCR (DO11.10) double-transgenic mice. In vivo antigenic stimulation triggers a marked influx of core-expressing Ag-specific CD4+ T cells into the liver of the immunized core+ TCR mice but not their core− TCR littermates. Strikingly, the inflammatory process in the liver of core+ TCR mice was accompanied by a dramatic increase in IFN-inducible protein 10 and monokine induced by IFN-γ production. The intrahepatic lymphocytes were primarily CXCR3-positive and anti-CXCR3 Ab treatment abrogates migration of CXCR3+ lymphocytes into the liver and hepatic damage. Importantly, the blockade of Fas/FasL interaction reduces the expression of IFN-inducible protein 10 and monokine induced by IFN-γ and cellular infiltration into the liver. These findings suggest that activated CD4+ T cells with elevated FasL expression are involved in promoting liver inflammation and hepatic damage through the induction of chemokines.