近日，意大利科学家在著名国际学术期刊cell在线发表了他们关于CD8+效应T细胞在肝脏内执行免疫监视功能的最新研究进展，他们发现循环系统中的CD8+效应T细胞能够通过肝脏血管壁上的血小板停留在肝脏，并穿过血管壁进入到肝脏组织中执行免疫功能。

　　CD8+效应T细胞能够通过抗原递呈细胞向病原体感染组织器官迁移，识别被感染细胞表面的抗原，执行效应细胞功能，因此在抗肝脏病毒感染过程中具有重要作用。但CD8+T细胞如何进入肝脏执行功能一直未有深入研究。

　　在该项研究中，研究人员利用一种先进的成像技术对乙型肝炎病毒（HBV）小鼠模型发病机制进行了相关研究，以了解效应T细胞在肝脏中贮存、识别抗原并发挥效应细胞功能的具体机制。他们发现循环系统中的CD8+效应T细胞能够通过以CD44附着在肝脏窦状小管透明质酸上的血小板停留在肝脏，随后CD8+效应T细胞沿肝脏窦状小管活跃爬行，通过内皮细胞间缝隙利用延伸的胞质突起检测肝脏细胞抗原，对肝细胞抗原的识别能够触发效应T细胞功能。

　　这些研究结果揭示了CD8+效应T细胞控制肝炎病原体的动态行为，并提示了肝纤维化如何抑制CD8+效应T细胞对受到感染或发生转化的肝细胞进行免疫监视,具有重要意义。

　　DOI: http://dx.doi.org/10.1016/j.cell.2015.03.005

　　Immunosurveillance of the Liver by Intravascular Effector CD8+ T Cells

　　Luca G. Guidotti9correspondenceemail, Donato Inverso9, Laura Sironi, Pietro Di Lucia, Jessica Fioravanti, Lucia Ganzer, Amleto Fiocchi, Maurizio Vacca, Roberto Aiolfi, Stefano Sammicheli, Marta Mainetti, Tiziana Cataudella, Andrea Raimondi, Gloria Gonzalez-Aseguinolaza, Ulrike Protzer, Zaverio M. Ruggeri, Francis V. Chisari, Masanori Isogawa, Giovanni Sitia, Matteo Iannacone

　　Effector CD8+ T cells (CD8 TE) play a key role during hepatotropic viral infections. Here, we used advanced imaging in mouse models of hepatitis B virus (HBV) pathogenesis to understand the mechanisms whereby these cells home to the liver, recognize antigens, and deploy effector functions. We show that circulating CD8 TE arrest within liver sinusoids by docking onto platelets previously adhered to sinusoidal hyaluronan via CD44. After the initial arrest, CD8 TE actively crawl along liver sinusoids and probe sub-sinusoidal hepatocytes for the presence of antigens by extending cytoplasmic protrusions through endothelial fenestrae. Hepatocellular antigen recognition triggers effector functions in a diapedesis-independent manner and is inhibited by the processes of sinusoidal defenestration and capillarization that characterize liver fibrosis. These findings reveal the dynamic behavior whereby CD8 TE control hepatotropic pathogens and suggest how liver fibrosis might reduce CD8 TE immune surveillance toward infected or transformed hepatocytes.