Monoclonal antibodies directed against rat liver epithelial cell lines selectively recognize bile duct epithelium in livers of adult rats.

Monoclonal antibodies directed against antigens on rat liver epithelial cell lines were prepared. Three antibodies, 4C3, 19C6, and 3C2, recognized surface antigens present (although in different quantities) on eight epithelial cell lines tested, irrespective of whether they were normal or transformed. For MAb 3C2, the primary antigen common to all but one cell line showed a Mr of 135 kD. In paraffin sections of liver tissue, two antibodies, 4C3 and 19C6, reacted exclusively with bile duct epithelium, whereas the MAb 3C2 additionally reacted with sinusoidal endothelium and the endothelium of the portal venules. In sections of livers from rats exposed to diethylnitrosamine, the MAb 19C6 selectively stained bile duct-like structures in cholangiomas, while other preneoplastic and neoplastic lesions were not stained. These results demonstrate that the monoclonal antibodies obtained may prove useful for investigating cell lineages related to propagable liver epithelial cell lines and suggest that these cells may be derived from terminal bile ductular cells.