Salmon J E, Brogle N L, Edberg J C, Kimberly R P
Hospital for Special Surgery, Cornell University Medical College, New York, NY 10021.
J Immunol. 1991 Feb 1;146(3):997-1004.
Human polymorphonuclear leukocytes (PMN) express two classes of Fc gamma R: Fc gamma RII the 42-kDa receptor with a traditional membrane spanning domain and cytoplasmic tail and Fc gamma RIIIPMN the 50- to 80-kDa receptor with a glycosyl-phatidylinositol membrane anchor expressed on PMN. To explore the capacity of Fc gamma RIIIPMN to generate intracellular signals, we have analyzed the ability of Fab and F(ab')2 anti-Fc gamma R mAb to induce actin filament assembly, a prerequisite for motile behaviors. Multivalent ligation of Fc gamma RIIIPMN, independent of Fc gamma RII, results in an increase in F-actin content that is [Ca2+]i dependent. Multivalent ligation of Fc gamma RII also initiates actin polymerization but uses a [Ca2+]i-independent initial pathway. In addition to providing a mechanism for Fc gamma RIIIPMN triggered effector functions, the increase in F-actin and [Ca2+]i generated by Fc gamma RIIIPMN ligation also serves as a "priming" signal to modify PMN responses to other stimuli. Experiments using erythrocytes specifically coated with anti-Fc gamma RII Fab demonstrate that cross-linking of Fc gamma RIIIPMN with anti-Fc gamma RIII F(ab')2 enhances phagocytosis mediated by Fc gamma RII. Thus, Fc gamma RIIIPMN, a glycosyl-phosphatidylinositol anchored protein, may contribute directly to an intracellular program of actin assembly that may trigger and prime neutrophil effector functions.
人多形核白细胞（PMN）表达两类FcγR：FcγRII，一种具有传统跨膜结构域和细胞质尾巴的42 kDa受体；以及FcγRIIIPMN，一种50至80 kDa的受体，通过糖基磷脂酰肌醇膜锚定在PMN上表达。为了探索FcγRIIIPMN产生细胞内信号的能力，我们分析了Fab和F(ab')2抗FcγR单克隆抗体诱导肌动蛋白丝组装的能力，这是运动行为的一个先决条件。FcγRIIIPMN的多价连接，独立于FcγRII，导致F-肌动蛋白含量增加，这依赖于细胞内钙离子浓度（[Ca2+]i）。FcγRII的多价连接也启动肌动蛋白聚合，但使用不依赖[Ca2+]i的初始途径。除了为FcγRIIIPMN触发效应器功能提供一种机制外，FcγRIIIPMN连接产生的F-肌动蛋白和[Ca2+]i增加也作为一种“启动”信号来改变PMN对其他刺激的反应。使用特异性包被抗FcγRII Fab的红细胞进行的实验表明，FcγRIIIPMN与抗FcγRIII F(ab')2的交联增强了FcγRII介导的吞噬作用。因此，FcγRIIIPMN，一种糖基磷脂酰肌醇锚定蛋白，可能直接参与肌动蛋白组装的细胞内程序，该程序可能触发并启动中性粒细胞效应器功能。
