Type 4 chain H expression by bile ductules and hepatocytes in cirrhosis

Abstract The monoclonal antibody MBrl defines the blood group H determinant with β 1 → 3N‐acetylgalactosamine linkage (Fucα 1 → 2Galβ 1 → 3GalNAc → R) carried by type 3 or 4 backbone. The distribution of the antigen detected by this antibody was studied immunohistochemically in liver tissues. Although bile ducts with a diameter of more than about 100 μm normally expressed the MBrl‐reactive antigen supranuclearly, smaller bile ducts and bile ductules did not express the antigen. In cirrhotic liver, proliferated bile ductules extensively expressed the MBrl‐reactive antigen. In spite of the absence in normal liver cells, the antigen was expressed membranously in some cirrhotic liver cells. Under subcellular fractionation, MBrl reactivity was almost exclusively recovered in the microsomal fraction. By HPTLC immunostaining, the major MBrl‐reactive antigen was shown to be carried by type 4 chain H glycolipid (globo‐H, Fuca 1 → 2Galβ 1 → 3GalNAcβ 1 → 3Galα 1 → 4Galβ 1 → 4Glcβ 1 → 1Cer). MBrl reactive glycoprotein was not found. In conclusion, although type 4 chain H glycolipid is not expressed by normal bile ductules and liver cells, it is actively synthesized and expressed by proliferated bile ductules and some of the liver cells in cirrhosis in the absence of any neoplastic change.