Fas-mediated cholangiopathy in the murine model of graft versus host disease

Bile-duct injury observed in hepatic graft versus host disease (GVHD) is re garded as an immune-mediated injury, although its precise mechanism is uncl ear. However, recent studies have suggested the involvement of Fas-mediated cell death in this immune-mediated cholangiopathy. In this study, we first showed the constitutive expression of Fas receptor by cholangiocytes in si tu from normal BALB/c mice, which was upregulated in GVHD mice. Also, we co nfirmed the Fas protein expression in the isolated cholangiocytes from norm al BALB/c mice by immunocytochemistry and immunoblotting. Furthermore, the addition of agonistic Fas antibody-(Jo2)-induced cholangiocyte apoptosis co nfirmed by DNA-ladder formation and annexin V staining. Cholangiocytes from Fas-deficient mice (MRL lpr/lpr) did not show Jo2-induced apoptosis. inter feron-gamma augmented Fas expression and Fas-mediated cell death, respectiv ely Following these observations, experimental GVHD was induced by transfer of splenocytes from B10.D2 mice to irradiated (800 rad) BALB/c mice. Liver -infiltrating lymphocytes from the recipient showed dose-dependent cytotoxi city against Cr-51-labeled cholangiocytes isolated from BALB/c mice. Moreov er, the addition of blocking Fas-Fc fusion protein reduced this cytotoxicit y to 44.7%. Finally, administration of this Fas-Fc protein to the BALB/c mi ce,which had been adoptively transferred with splenocytes of B10.D2 mice, p revented the development of hepatic GVHD in vivo. These results showed the involvement of Fas-mediated cell death in cholangiopathy observed in GVHD, and a soluble Fas-Fc protein may have a therapeutic potential for hepatic G VHD.