Purification of Human Biliary Epithelial Antigen and T Cell Autoimmunity in Patients with Primary biliary Cirrchosis

为了确定原发性胆汁性肝硬化（PBC）中参与胆管损伤的自身抗原，我们采用SDS-PAGE和Western blotting （WB）技术从人胆汁液中纯化抗原。在WB中，兔抗人胆道上皮作为监测探针。免疫电镜检查证实兔抗血清的相应抗原存在于微绒毛上，而不存在于胆管上。WB检测到两条主要的蛋白带（B1, B2）。外周血淋巴细胞对B1的选择性增殖在PBC患者中观察到，而在对照疾病中则没有。B1刺激T细胞，不含直接的B细胞有丝分裂原。抗MHC I类单克隆抗体可抑制T细胞增殖。然而，B2对PBC没有刺激作用。B1为唾液蛋白，脂质染色阴性。B1的m.w大于200K。D . .在WB中，抗分泌IgA、抗层粘连蛋白、IV型胶原、抗M2阳性PBC血清、抗MHC类抗原均未检测到B1。其次，PBC患者脾淋巴细胞对自身胆道上皮细胞具有细胞毒性，这些细胞是通过胆总管泵送Disparse溶液获得的。效应细胞表型为CD8阳性T淋巴细胞。抗MHCⅰ类对CTL活性有抑制作用，而抗MHⅱ类对CTL活性无抑制作用。综上所述，针对B1的T细胞自身免疫可能参与了PBC的发病机制。

To determine the autoantigen involved in the bile duct injury in primary biliary cirrhosis (PBC), we purified antigens from human bile juice using SDS-PAGE and Western blotting (WB). In WB, rabbit anti human biliary epithelium was used as a monitoring probe. Corresponding antigen of rabbit antisera was proved to exist on microvilli, but not on the bile canaliculi by immuno-electron microscopic examination. Two major protein bands (B1, B2) were detected in WB. Proliferation of peripheral lymphocytes against B1 was observed selectively in patients of PBC, but not in control diseases. B1 stimulated T cells and was free of direct B cell mitogen. This T cell proliferation was inhibited by anti MHC class I monoclonal antibody. However, B2 was not stimulatory in PBC.B1 was sialic protein and negative for lipid staining. M. W. of B1 was more than 200K. D.. In WB, B1 was not detected by antisecretory IgA, anti laminin, type IV collagen, anti M2 positive PBC sera, or anti MHC class antigen.Secondary, cytotoxicity of spleen lymphocytes from PBC patients was against autologous biliary epithelial cells which were obtained by pumping Disparse solution through common bile ducts. Phenotype of Effector cells was CD8 positive T lymphocytes. CTL activity was inhibited by anti MHC class I, but not by anti MH class II.In conclusion, T cell autoimmunity against B1 may be involved in the pathogenesis of PBC.