Chiang T M, Beachey E H, Kang A H
J Clin Invest. 1977 Mar;59(3):405-11. doi: 10.1172/JCI108653.
We previously reported that purified alpha1 chains of type 1 chick skin collagen induce platelet aggregation. We now describe immunological and biochemical evidence that the peptide binds to intact platelets as an early event in the induction of platelet aggregation and the release reaction. Antibody against alpha1 (I) was obtained by immunizing rabbits with complete Freund's adjuvant mixed with purified alpha1. Immunofluorescence studies showed that alpha1(I)-treated platelets exhibited strong immunofluorescence. The intensity of fluorescence was markedly decreased by the pretreatment of platelets with alpha1-CB5 and glucosylgalactosylhydroxylysine. Dose-response curves of platelet aggregation induced by alpha1 and the binding of alpha1 by washed intact platelets are correlated. The biochemical studies showed that the binding of the alpha1 chain to washed intact platelets was platelet concentration and temperature dependent, and that it reached a maximum in 10 min. The process was reversible and specific, with an association constant of 1.7 muM. The inhibitor of alpha1-induced platelet aggregation, glucosylgalactosyl hydroxylysine, inhibited the alpha1 binding. These results suggest that alpha1(I) chains bind to specific receptor site(s) on platelet membranes to trigger aggregation and the release reaction.
我们之前报道过，纯化的1型鸡皮肤胶原蛋白α1链可诱导血小板聚集。我们现在描述免疫学和生化证据，表明该肽作为诱导血小板聚集和释放反应的早期事件与完整血小板结合。用与纯化的α1混合的完全弗氏佐剂免疫兔子，获得了抗α1（I）抗体。免疫荧光研究表明，经α1处理的血小板呈现强烈的免疫荧光。用α1-CB5和葡萄糖基半乳糖基羟赖氨酸预处理血小板后，荧光强度明显降低。α1诱导的血小板聚集剂量反应曲线与洗涤后的完整血小板对α1的结合相关。生化研究表明，α1链与洗涤后的完整血小板的结合依赖于血小板浓度和温度，且在10分钟内达到最大值。该过程是可逆且特异的，缔合常数为1.7 μM。α1诱导的血小板聚集抑制剂葡萄糖基半乳糖基羟赖氨酸抑制了α1的结合。这些结果表明，α1（I）链与血小板膜上的特定受体位点结合，从而触发聚集和释放反应。
