Patterns of intermediate filaments, VLA integrins and HLA antigens in a new human biliary epithelial cell line sensitive to interferon-γ

Abstract

Background/Aims: Intra-hepatic bile ducts are the primary site of damage in several immunologically mediated liver diseaes. However, immunological processes underlying biliary epithelial cell recognition by T lymphocytes are poorly understood. Therefore, a convenient in vitro model that could mimic these immunologic disorders would be of great interest. Methods: A human cell line (HuGB) was established from a metastasis of gallbladder adenocarcinoma in the liver. Intermediate filament expression was analysed by immunostaining, and gamma-glutamyl transpeptidase and albumin secretion were measured. VLA integrin expression pattern, expression of HLA class I and II antigens and ICAM-1 protein were analysed by flow cytometry and their modulation by interferon-γ was quantitated using a QIFIKIT commercial kit. Results: Histological analysis showed high similarity between the initial gallbladder adenocarcinoma and the established cell line. Cytokeratins 8 and 19 and vimentin showed strong positive staining in the established cell line. Gamma-glutamyl transpeptidase was secreted by these cells while albumin expression was negative. HuGB cells also expressed VLA-α2, VLA-α3, VLA-α6, VLA-β1, but not VLA-α1, VLA-α4 and NCAM, a pattern of adhesion molecule expression compatible with the biliary epithelium. Also, similar to the biliary epithelium found in normal liver, HuGB cells expressed abundant HLA class I but few HLA class II antigens. We found that the expression of HLA antigens and ICAM-1 protein were increased during interferon-γ treatment of HuGB cell line. Conclusions: Both phenotypic and morphological characteristics of HuGB cells suggested their biliary origin. Sensitivity of HuGB cells to interferon-γ suggests that this new cell line could represent a suitable model to investigate the up-regulation of membrane antigens occurring in immune diseases involving biliary epithelial cells.