Huizinga T W, van der Schoot C E, Jost C, Klaassen R, Kleijer M, von dem Borne A E, Roos D, Tetteroo P A
Central Laboratory, Netherlands Red Cross Blood Transfusion Service, Amsterdam.
Nature. 1988 Jun 16;333(6174):667-9. doi: 10.1038/333667a0.
Human phagocytic cells express receptors for the constant (Fc) region of immunoglobulin G. Neutrophils carry Fc receptor II (FcRII; CDw32) and FcRIII (CD16) which both bind IgG-containing immune complexes, leading to phagocytosis of the complex and activation of the neutrophil. We find that patients with paroxysmal nocturnal haemoglobinuria (PNH) have only about 10% of the normal levels of FcRIII on their neutrophils, whereas the expression of FcRII is unaffected. We show that FcRIII is a phosphatidyl inositol (PI)-anchored protein in neutrophils. Analysis of FcRIII expression in cells of PNH patients, known to be deficient in PI-linked proteins, suggests FcRIII is not PI-linked in monocytes. We find that the synthesis of FcRIII in neutrophils from PNH patients appears normal, indicating that the defect lies in the PI linkage. This lipid linkage of the receptor on neutrophils suggests that its release may be important for its function, and indeed FcRIII release was observed on stimulation of neutrophils by an inflammatory bacterial peptide (f-Met-Leu-Phe), suggesting a role for FcRIII shedding in inflammatory reactions. Activation of the PNH neutrophils with IgG-coated latex beads appeared normal (although binding of dimer IgG complexes was reduced), indicating that FcRII, rather than FcRIII, is involved in neutrophil stimulation.
人类吞噬细胞表达免疫球蛋白G恒定区（Fc）的受体。中性粒细胞携带Fc受体II（FcRII；CDw32）和FcRIII（CD16），二者均可结合含IgG的免疫复合物，从而导致复合物的吞噬作用及中性粒细胞的激活。我们发现，阵发性夜间血红蛋白尿（PNH）患者中性粒细胞上的FcRIII水平仅为正常水平的10%左右，而FcRII的表达未受影响。我们发现FcRIII是中性粒细胞中一种磷脂酰肌醇（PI）锚定蛋白。对已知缺乏PI连接蛋白的PNH患者细胞中的FcRIII表达进行分析，结果表明FcRIII在单核细胞中并非PI连接。我们发现PNH患者中性粒细胞中FcRIII的合成似乎正常，这表明缺陷在于PI连接。中性粒细胞上受体的这种脂质连接表明其释放可能对其功能很重要，事实上，在用炎性细菌肽（f - 甲硫氨酸 - 亮氨酸 - 苯丙氨酸）刺激中性粒细胞时可观察到FcRIII的释放，这表明FcRIII脱落在炎症反应中起作用。用IgG包被的乳胶珠激活PNH中性粒细胞似乎正常（尽管二聚体IgG复合物的结合减少），这表明参与中性粒细胞刺激的是FcRII而非FcRIII。
