Dear Editor: Cholangiocytes have been thought. to play a role db antigen pre—senting cells or target cells in immune—mediated eholangitis. The aberrant expression of VlHC class It proteins on cholangioeytes in primary biliary cirrhosis raisen the possihility that cholangioey tes can function as antigen presenting cells and, in immune—mediated chol—angitis, cholangiocyies appeared to he targeted liy lymphocytes (8). To explore the immune mechanisms underlying cholangitis, a culture of mouse cholangioeytes is essential. because, the mouse is indig—pensahle for immunological study. Cholangiocytes are, a minor component of liver cells. comprising only 3—49? of the rodent liver cells. Most extensively studied cultured