Miyake T, Nomura S, Komiyama Y, Miyazaki Y, Kagawa H, Masuda M, Takahashi H, Fujimura Y, Ikeda Y, Fukuhara S
First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Thromb Haemost. 1997 Aug;78(2):902-9.
Human platelet glycoprotein Ib/IX complex acts as a receptor for von Willebrand factor. It is widely accepted that glycoprotein Ib is the essential receptor component, but the role of glycoprotein IX is still unclear. We produced a new monoclonal anti-glycoprotein IX antibody (KMP-9) by the hybridoma technique using platelets from a patient with Glanzmann's thrombasthenia. The epitope of KMP-9 was localized to the C-terminal 8 kD fragment of glycoprotein IX using ELISA analysis of polyethylene-pin-synthesized peptides, as well as Western blot analysis of platelets after digestion with N-glycosidase and Staphylococcus aureus V8 protease. KMP-9 partially inhibited high shear stress-induced platelet aggregation, but had no effect on aggregation induced by ristocetin or low shear stress. Its inhibitory effect on high shear stress-induced aggregation was weaker than that of anti-glycoprotein Ib or anti-glycoprotein IIb/IIIa monoclonal antibodies. A 21-mer synthetic peptide (glycoprotein IX L110-G130) inhibited the binding of KMP-9 to platelets. It also competively inhibited the suppression of high shear stress-induced platelet aggregation by KMP-9, but had no direct effect on this aggregation. KMP-9 may be useful to clarify the physiological role of GPIX.
人血小板糖蛋白Ib/IX复合物作为血管性血友病因子的受体。人们普遍认为糖蛋白Ib是关键的受体成分，但糖蛋白IX的作用仍不清楚。我们利用来自一名血小板无力症患者的血小板，通过杂交瘤技术制备了一种新的抗糖蛋白IX单克隆抗体（KMP-9）。使用聚乙烯针合成肽的ELISA分析以及用N-糖苷酶和金黄色葡萄球菌V8蛋白酶消化后的血小板的蛋白质印迹分析，将KMP-9的表位定位到糖蛋白IX的C末端8 kD片段。KMP-9部分抑制高剪切应力诱导的血小板聚集，但对瑞斯托霉素或低剪切应力诱导的聚集没有影响。其对高剪切应力诱导聚集的抑制作用比抗糖蛋白Ib或抗糖蛋白IIb/IIIa单克隆抗体弱。一种21聚体合成肽（糖蛋白IX L110-G130）抑制KMP-9与血小板的结合。它还竞争性抑制KMP-9对高剪切应力诱导的血小板聚集的抑制作用，但对这种聚集没有直接影响。KMP-9可能有助于阐明GPIX的生理作用。
