Leon M P, Kirby J A, Gibbs P, Burt A D, Bassendine M F
Department of Medicine, Medical School, University of Newcastle upon Tyne, UK.
J Hepatol. 1995 May;22(5):591-5. doi: 10.1016/0168-8278(95)80456-0.
Efficient antigen presentation requires the provision of a co-stimulatory signal, the best characterized of which is provided by the B7 molecules. It is unclear whether biliary epithelial cells expressing Class II major histocompatibility complex molecules can function as antigen presenting cells, although this has been suggested as an important mechanism in the initiation and/or perpetuation of some immune-mediated liver diseases, including primary biliary cirrhosis and liver allograft rejection. We have found that human intrahepatic biliary epithelial cells do not express B7-1 (CD80) or B7-2 in vitro, even after activation with high doses of interferon-gamma, tumour necrosis factor-alpha or phorbol myristate acetate, or in vivo. However, they express similar levels of class II major histocompatibility complex antigens to those expressed by professional antigen presenting cells (Epstein-Barr virus transformed B cells). It is therefore unlikely that biliary epithelial cells stimulate efficient primary T cell activation. It may be possible that these non co-stimulatory class II major histocompatibility complex positive cells play a role in modulating immune responses in the liver.
有效的抗原呈递需要提供共刺激信号，其中最具特征的是由B7分子提供的信号。表达II类主要组织相容性复合体分子的胆管上皮细胞是否能作为抗原呈递细胞发挥作用尚不清楚，尽管这已被认为是包括原发性胆汁性肝硬化和肝移植排斥反应在内的一些免疫介导性肝病的起始和/或持续存在的重要机制。我们发现，人肝内胆管上皮细胞在体外即使经高剂量干扰素-γ、肿瘤坏死因子-α或佛波酯肉豆蔻酸酯激活后，或在体内，均不表达B7-1（CD80）或B7-2。然而，它们表达的II类主要组织相容性复合体抗原水平与专业抗原呈递细胞（爱泼斯坦-巴尔病毒转化的B细胞）表达的水平相似。因此，胆管上皮细胞不太可能刺激有效的初始T细胞活化。这些非共刺激的II类主要组织相容性复合体阳性细胞可能在调节肝脏免疫反应中发挥作用。
