Resta R, Yamashita Y, Thompson L F
Department of Medicine, University of Oklahoma, Oklahoma City, USA.
Immunol Rev. 1998 Feb;161:95-109. doi: 10.1111/j.1600-065x.1998.tb01574.x.
CD73 or ecto-5'-nucleotidase (5'-NT) is a widely expressed ecto-enzyme which catalyzes the dephosphorylation of AMP and other nucleoside monophosphates. CD73 participates in purine salvage through this enzymatic activity, supplying cells with precursors for energy metabolism and nucleic acid biosynthesis. As an enzyme that produces adenosine, CD73 can also regulate adenosine receptor engagement in many tissues. However, CD73 also has functions independent of its enzyme activity. Like many glycosyl phosphatidylinositol (GPI)-anchored molecules, it transmits potent activation signals in T cells when ligated by antibodies. Less compelling evidence suggests that CD73 may function as a cell adhesion molecule. In the human immune system, CD73 is expressed on subsets of T and B cells, on germinal center follicular dendritic cells, and on thymic medullary reticular fibroblasts and epithelial cells. Many challenging areas remain to be explored before the role of CD73 in the immune system will be fully understood. These include an evaluation of the role of adenosine receptors in lymphoid development, the identification of physiological CD73 ligands, a functional assessment of the GPI anchor, and an analysis of the intricate cell-type-specific and developmental regulation of CD73 expression.
CD73即胞外5'-核苷酸酶（5'-NT），是一种广泛表达的胞外酶，可催化AMP及其他核苷单磷酸的去磷酸化反应。CD73通过这种酶活性参与嘌呤补救途径，为细胞提供能量代谢和核酸生物合成的前体物质。作为一种产生腺苷的酶，CD73还可在许多组织中调节腺苷受体的结合。然而，CD73也具有与其酶活性无关的功能。与许多糖基磷脂酰肌醇（GPI）锚定分子一样，当被抗体连接时，它会在T细胞中传递强大的激活信号。不太有说服力的证据表明，CD73可能作为一种细胞粘附分子发挥作用。在人类免疫系统中，CD73表达于T细胞和B细胞亚群、生发中心滤泡树突状细胞、胸腺髓质网状成纤维细胞和上皮细胞上。在全面了解CD73在免疫系统中的作用之前，仍有许多具有挑战性的领域有待探索。这些领域包括评估腺苷受体在淋巴细胞发育中的作用、鉴定生理性CD73配体、对GPI锚进行功能评估以及分析CD73表达复杂的细胞类型特异性和发育调控。
