Human platelet-initiated formation and uptake of the C5-9 complex of human complement.
Human platelet-initiated formation and uptake of the C5-9 complex of human complement.
复制标题
人血小板启动人补体 C5-9 复合物的形成和摄取。
DOI：
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发表时间：
1976
影响因子：
15.9
通讯作者：
William P. KoLs
中科院分区：
文献类型：
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作者：
T. S. Zimmerman;William P. KoLs
我们研究了放射性标记的补体成分与正常人血小板、阵发性夜间血红蛋白尿患者血小板和兔血小板在缺乏已知补体激活剂或眼镜蛇毒液因子（CVF）存在时的相互作用。当富血小板血浆中未洗涤的血小板，或悬浮在血清或自体血浆中的洗涤后的血小板孵育30分钟时，发现C3和末端组分（C5、C8和C9）与它们结合。通过从血小板膜上洗脱其末端组分并在超离心下检查其行为，表明其结合为C5-9复合物，而不是单独的蛋白质。它们以稳定的C5-9络合物（22S）的速率共同沉积。据计算，在潜伏期内，多达370-1,380个C5-9配合物/血小板被结合。通过超离心标准，形成的复合物与CVF激活补体后与兔血小板的结合没有区别。虽然C3不包含在复合物中，但它似乎不受非特异性吸收的束缚。它不能通过洗涤去除，而是通过用于洗脱C5-9复合物的冻融技术洗脱。在无血小板血浆中孵育放射性标记成分不会导致C5-9复合物的形成，这表明血小板在该反应中起初始作用。与血小板相反，在类似血浆中培养的红细胞不能诱导可检测到的C5-9形成。EDTA、苯基甲基磺酰氟和epsilon-氨基- n-己酸都不能阻止血小板启动的C5-9的形成，这表明该反应可能涉及补体激活的机制，而不是以前描述的。
We have studied the interaction of radiolabeled complement components with normal human platelets, platelets from a patient with paroxysmal nocturnal hemoglobinuria, and rabbit platelets in the absence of known complement activators or in the presence of cobra venom factor (CVF). When unwashed platelets in platelet-rich plasma, or washed platelets suspended in serum or autologous plasma, were incubated for 30 min, C3 and terminal components (C5, C8, and C9) were found to bind to them. The terminal components were shown to be bound as the C5-9 complex, rather than as individual proteins, by eluting them from the platelet membrane and examining their behavior on ultracentrifugation. They cosedimented at a rate characteristic of the stable C5-9 complex (22S). As many as 370-1,380 C5-9 complexes/platelet were calculated to have been bound during the incubation period. The complex so formed did not differ by ultracentrifugational criteria from that binding to rabbit platelets after CVF activation of complement. Though C3 was not included in the complex, it did not appear to be bound by nonspecific absorption. It could not be removed by washing but rather was eluted by the freeze-thaw technique used to elute the C5-9 complex. Incubation of radiolabeled components in platelet-free plasma did not result in C5-9 complex formation, indicating an initiating role for platelets in this reaction. In contrast to platelets, erythrocytes incubated in analogous plasma did not induce detectable C5-9 formation. Neither EDTA, phenylmethylsulfonylfluoride, nor epsilon-amino-N-caproic acid prevented platelet-initiated formation of C5-9, suggesting that the reaction may involve mechanisms of complement activation not previously described.