穿孔素与颗粒酶B在乙型肝炎不同免疫状态中的作用

Role of perforin and granzyme B in different immune status of hepatitis B

穿孔素(perforin,PFN)是存在于细胞毒性细胞[又称杀伤细胞,包括自然杀伤(natural killer,NK)细胞、细胞毒性T细胞(cytotoxic T cells,CTL)等]的糖蛋白,颗粒酶(granzyme,Gzm)B是表达于杀伤细胞的小分子蛋白质。PFN和Gzm B贮存在细胞毒性细胞的胞浆颗粒中,在与靶细胞接触后通过胞吐而释放。作为细胞毒性细胞所具有的2类重要效应分子,PFN和Gzm B在各种类型肝损伤免疫反应中发挥重要作用。在造成肝损伤的众多原因中,对乙型肝炎所致肝损伤研究较多。HBV复制与宿主抗病毒免疫的相互作用决定了HBV感染的最终结果,PFN和Gzm B是病毒感染的病原清除和靶细胞凋亡重要的介导物质,在HBV感染的不同阶段,PFN和Gzm B表达水平呈现不同特点:在急性HBV感染期,CTL高表达PFN、Gzm B;在慢性HBV感染期,NK细胞、CTL表达PFN、Gzm B呈下调趋势;在重症乙型肝炎阶段,CTL表达PFN、Gzm B的上调可能参与HBV感染重症化。本文主要对HBV感染免疫阶段PFN和Gzm B在不同免疫状态中具体作用特点作一介绍。

Perforin(PFN)is a glycoprotein that present in cytotoxic cells(also known as killer cells,including natural killer cells,cytotoxic T cells and so on),and granzyme B(Gzm B)is a small molecular protein that expressed in cytotoxic cells.PFN and Gzm B reserves in cytoplasmic particles of cytotoxic cells and released by exocytosis after contact with target cells.As two important effector molecules of cytotoxic cells,PFN and Gzm B play important roles in the various types of liver injury against immune response.Among various of liver injury,the liver injury caused by hepatitis B is studied well.The interaction between hepatitis B virus(HBV)replication and host antiviral immunity determines the outcome of HBV infection,PFN and Gzm B are the important mediators of pathogen clearance and apoptosis of target cells in viral infection.The expression levels of PFN and Gzm B are showed different characteristics in different stages of hepatitis B virus infection:In acute HBV infection,cytotoxic T cells(CTL)highly express PFN and Gzm B;In chronic HBV infection,natural killer cells(NK cells),CTL expression of PFN and Gzm B were down-regulated;In the stage of severe hepatitis B,the up-regulation of PFN and Gzm B that expressed by CTL may aggravate the HBV infection.This article mainly introduces the specific functions of PFN and Gzm B in different immune status during the immune stage of HBV infection.