Wohlleber Dirk, Knolle Percy A
Institute of Molecular Immunology, School of Medicine and Health, Technical University of Munich, Munich, Germany.
Institute of Molecular Immunology, School of Life Science, Technical University of Munich, Munich, Germany.
Z Gastroenterol. 2025 Jan;63(1):65-72. doi: 10.1055/a-2365-3900. Epub 2025 Jan 10.
The liver is an organ bearing important metabolic and immune functions. Hepatocytes are the main metabolically active cells of the liver and are the target of infection by hepatotropic viruses. Virus-specific CD8 T cells are essential for the control of hepatocyte infection with hepatotropic viruses but may be subject to local regulation of their effector function. Here, we review our current knowledge of the tissue determinants of antiviral immunity in the liver. Liver Sinusoidal Endothelial Cells (LSECs) not only allow through their fenestrations the access of circulating virus-specific CD8 T cells to engage in direct contact with infected hepatocytes without the need for extravasation but also cross-present viral antigens released from infected hepatocytes to these CD8 T cells. Two important features of LSECs and hepatocytes contribute to antiviral immune surveillance and liver failure. First, CD8 T cell immunity targeting LSECs leads to widespread endothelial cell death and results in sinusoidal microcirculation failure, causing fulminant viral hepatitis, whereas immune-mediated loss of hepatocytes is rapidly compensated by the regenerative capacity of the liver. Second, virus-infected hepatocytes support clearance of infection by responding to TNF, which is released from virus-specific CD8 T cells, with the selective induction of apoptosis. This increased sensitivity for TNF-induced death is caused by reduced mitochondrial resilience in virus-infected hepatocytes and may assist antiviral immunity in preferential targeting of virus-infected hepatocytes. Thus, hepatocytes and LSECs actively contribute to the outcome of antiviral CD8 T cell immunity in the liver. The knowledge of the mechanisms determining CD8 T cell control of hepatotropic viral infection will help to improve strategies to increase antiviral immune surveillance.
肝脏是一个具有重要代谢和免疫功能的器官。肝细胞是肝脏中主要的代谢活跃细胞,也是嗜肝病毒感染的靶细胞。病毒特异性CD8 T细胞对于控制嗜肝病毒感染肝细胞至关重要,但可能会受到其效应功能的局部调节。在此,我们综述了目前关于肝脏抗病毒免疫组织决定因素的知识。肝窦内皮细胞(LSECs)不仅通过其窗孔允许循环中的病毒特异性CD8 T细胞进入,使其无需外渗就能直接与被感染的肝细胞接触,而且还能将从被感染肝细胞释放的病毒抗原交叉呈递给这些CD8 T细胞。LSECs和肝细胞的两个重要特征有助于抗病毒免疫监视和肝衰竭。首先,靶向LSECs的CD8 T细胞免疫会导致广泛的内皮细胞死亡,并导致肝窦微循环衰竭,引起暴发性病毒性肝炎,而免疫介导的肝细胞损失会迅速被肝脏的再生能力所补偿。其次,病毒感染的肝细胞通过对病毒特异性CD8 T细胞释放的TNF作出反应,选择性地诱导凋亡,从而支持感染的清除。病毒感染的肝细胞中线粒体弹性降低,导致对TNF诱导的死亡敏感性增加,这可能有助于抗病毒免疫优先靶向病毒感染的肝细胞。因此,肝细胞和LSECs积极影响肝脏中抗病毒CD8 T细胞免疫的结果。了解决定CD8 T细胞控制嗜肝病毒感染的机制将有助于改进增强抗病毒免疫监视的策略。