Intrahepatic bile ducts transport bile between bile canaliculi and the extrahepatic bile duct. The luminal surface of this tract is lined by a layer of biliary epithelial cells, or cholangiocytes, which secrete mucins consisting of scaffold proteins and O-glycosidically linked carbohydrate side chains. Although mucin core proteins have been extensively investigated, the structure and function of carbohydrate side chains have not. Here, we demonstrate that distinct sulfated glycans positive for MECA-79, R-10G, and 297-11A, but not 5D4, monoclonal antibodies are expressed in the cytoplasm of cells of large-sized ducts and in the apical membrane of cells in ductules, and that R-10G immunolabeling is partially eliminated by endo-β-galactosidase digestion, supporting the presence of N-acetylglucosamine-6-O-sulfated N-acetyllactosamine structures. We observed comparable apical membrane-predominant staining in ductular reactions seen during regeneration that occurs in various liver diseases and in cholangiolocarcinoma, a subtype of small duct-type intrahepatic cholangiocarcinoma (iCCA). Apical membrane expression of distinct sulfated glycans in large duct-type iCCA was negligible. Intriguingly, under pathological conditions, endo-β-galactosidase digestion almost completely eliminated R-10G immunoreactivity. These findings suggest that apical membrane expression of distinct sulfated glycans is a characteristic feature of ductules and their reactive and neoplastic counterparts

肝内胆管在胆小管和肝外胆管之间运输胆汁。该管道的管腔表面衬有一层胆管上皮细胞或胆管细胞，它们分泌由支架蛋白和O-糖苷连接的碳水化合物侧链组成的粘蛋白。尽管粘蛋白核心蛋白已被广泛研究，但碳水化合物侧链的结构和功能尚未被广泛研究。在这里，我们证明了对 MECA-79、R-10G 和 297-11A（但不是 5D4）呈阳性的不同硫酸化聚糖单克隆抗体在大型导管细胞的细胞质和导管细胞的顶膜中表达，并且 R-10G 免疫标记被内切-β-半乳糖苷酶消化部分消除，支持N-乙酰氨基葡萄糖-6- O-硫酸化的N-乙酰乳糖胺结构。我们观察到在再生过程中发生的各种肝病和胆管癌（小管型肝内胆管癌 (iCCA) 的一种亚型）中所见的导管反应中可比较的顶端膜为主染色。大导管型 iCCA 中不同硫酸化聚糖的顶膜表达可以忽略不计。有趣的是，在病理条件下，内切-β-半乳糖苷酶消化几乎完全消除了 R-10G 的免疫反应性。这些发现表明，不同硫酸化聚糖的顶膜表达是导管及其反应性和肿瘤性对应物的特征。