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

BACKGROUND/AIMS: Intra-hepatic bile ducts are the primary site of damage in several immunologically mediated liver diseases. 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-gamma 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-alpha2, VLA-alpha3, VLA-alpha6, VLA-beta1, but not VLA-alpha1, VLA-alpha4 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-gamma treatment of HuGB cell line.

CONCLUSIONS

Both phenotypic and morphological characteristics of HuGB cells suggested their biliary origin. Sensitivity of HuGB cells to interferon-gamma 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.