Exposure of platelet fibrinogen-binding sites by collagen, arachidonic acid, and ADP: inhibition by a monoclonal antibody to the glycoprotein IIb-IIIa complex.
Exposure of platelet fibrinogen-binding sites by collagen, arachidonic acid, and ADP: inhibition by a monoclonal antibody to the glycoprotein IIb-IIIa complex.
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DOI：
10.1182/blood.v61.1.140.140
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发表时间：
1983
期刊：
影响因子：
20.3
通讯作者：
G. Minno;P. Thiagarajan;B. Perussia;J. Martínez;S. Shapiro;G. Trinchieri;S. Murphy
中科院分区：
文献类型：
--
作者：
G. Minno;P. Thiagarajan;B. Perussia;J. Martínez;S. Shapiro;G. Trinchieri;S. Murphy
在用二磷酸腺苷 (ADP)、胶原蛋白或花生四烯酸刺激后，未搅拌的人血小板悬浮液会在 30 分钟内完成的反应中结合 125I-纤维蛋白原。 Scatchard 对这些结合数据的分析揭示了所有 3 种试剂的两组结合位点：高亲和力位点 (Kd 0.029-0.045 microM) 结合每个血小板 1000-1600 个纤维蛋白原分子，以及较低亲和力位点 (Kd 1.2-2.0 microM) 结合每个血小板 46,000-76,000 个纤维蛋白原分子。当腺苷三磷酸双磷酸酶的浓度抑制ADP诱导的纤维蛋白原结合大于85%时，胶原蛋白和花生四烯酸诱导的纤维蛋白原结合仅部分受到影响。这表明胶原蛋白或花生四烯酸诱导的纤维蛋白原结合不需要释放的 ADP。我们分离出一种单克隆抗体 B59.2，它可以从溶解的血小板膜中沉淀出糖蛋白 IIb-IIIa 复合物。在暴露于 ADP、胶原蛋白或花生四烯酸之前或之后，标记抗体与血小板的结合显示出单一类别的约 22,000 个结合位点，Kd 为 0.019 microM。 B59.2 的结合在 1 分钟内完成，并且不受 EDTA 抑制。血小板悬浮液与 2.1 µM 浓度的 B59.2 预温育引起分泌和聚集的抑制，但不抑制血栓素-B2 的合成，响应 1 µg/ml 胶原蛋白、40 µM 花生四烯酸或 4 µM ADP，这些聚集剂浓度在不存在 B59.2 的情况下产生完全聚集和分泌。在B59.2的该浓度下，纤维蛋白原与刺激的血小板的结合被抑制约45%-55%。这些数据表明胶原蛋白和花生四烯酸可以独立于释放的 ADP 暴露纤维蛋白原结合位点；糖蛋白 IIb-IIIa 复合物参与分泌、聚集和纤维蛋白原结合，但不参与响应胶原蛋白、花生四烯酸或 ADP 而发生的血栓素合成。
Following stimulation with adenosine diphosphate (ADP), collagen, or arachidonic acid, unstirred human platelet suspensions bind 125I-fibrinogen in a reaction that reaches completion within 30 min. Scatchard analysis of these binding data reveals two sets of binding sites with all 3 agents: a high affinity site (Kd 0.029-0.045 microM) binding 1000-1600 fibrinogen molecules per platelet, and a lower affinity site (Kd 1.2-2.0 microM) binding 46,000-76,000 fibrinogen molecules per platelet. At a concentration of apyrase that inhibited ADP-induced fibrinogen binding by greater than 85%, fibrinogen binding induced by collagen and arachidonic acid was only partially affected. This suggests that fibrinogen binding induced by collagen or arachidonic acid does not require released ADP. We isolated a monoclonal antibody, B59.2, which precipitated the glycoprotein IIb-IIIa complex from solubilized platelet membranes. Binding of labeled antibody to platelets before or after exposure to ADP, collagen, or arachidonic acid showed a single class of approximately 22,000 binding sites with Kd 0.019 microM. Binding of B59.2 was complete within 1 min and was not inhibited by EDTA. Preincubation of platelet suspensions with a 2.1 microM concentration of B59.2 caused inhibition of secretion and aggregation, but not of thromboxane-B2 synthesis, in response to 1 microgram/ml collagen, 40 microM arachidonic acid, or 4 microM ADP, concentrations of aggregating agents that produced complete aggregation and secretion in the absence of B59.2. At this concentration of B59.2, fibrinogen binding to stimulated platelets was inhibited by approximately 45%-55%. These data demonstrate that collagen and arachidonic acid can expose fibrinogen binding sites independently of released ADP; and that the glycoprotein IIb-IIIa complex is involved in secretion, aggregation, and fibrinogen binding, but not in thromboxane synthesis occurring in response to collagen, arachidonic acid, or ADP.