Szatkowski N S, Kunicki T J, Aster R H
Blood. 1986 Feb;67(2):310-5.
An antibody (DIL) from a patient with idiopathic thrombocytopenic purpura (ITP) was shown to have autospecificity on the basis of reactions with autologous platelets that were identical to those obtained with platelets from normal subjects. DIL antibody also reacted strongly in an immunofluorescence test with platelets from a patient with Glanzmann's thrombasthenia, but failed to react with platelets from a patient with the Bernard-Soulier syndrome who was known to be deficient in glycoprotein Ib (GPIb). Purified GPIb and control platelets, but not Bernard-Soulier platelets, inhibited the lytic activity of DIL. Using the GPIb-specific monoclonal antibody AP1 and one-dimensional rocket electrophoresis into gels containing rabbit antihuman platelet membrane antibody, it was shown that staphylococcal protein A-Sepharose beads coated with DIL antibody selectively remove GPIb from solubilized platelet preparations. By crossed immunoelectrophoresis it was found that DIL recognizes a determinant on GPIb on the membrane side of the cleavage site of the platelet calcium-activated protease (calpain). These studies provide direct evidence for binding of a platelet autoantibody to a determinant on GPIb relatively close to the site of insertion of this protein into the platelet membrane.
一名特发性血小板减少性紫癜（ITP）患者的抗体（DIL），基于其与自体血小板的反应表现出自身特异性，该反应与正常受试者血小板的反应相同。DIL抗体在免疫荧光试验中也与一名患有Glanzmann血小板无力症患者的血小板强烈反应，但与一名已知缺乏糖蛋白Ib（GPIb）的Bernard-Soulier综合征患者的血小板无反应。纯化的GPIb和对照血小板可抑制DIL的裂解活性，但Bernard-Soulier血小板则不能。使用GPIb特异性单克隆抗体AP1和一维火箭电泳法进入含有兔抗人血小板膜抗体的凝胶中，结果表明，包被有DIL抗体的葡萄球菌蛋白A-琼脂糖珠可从溶解的血小板制剂中选择性去除GPIb。通过交叉免疫电泳发现，DIL识别血小板钙激活蛋白酶（钙蛋白酶）裂解位点膜侧GPIb上的一个决定簇。这些研究为血小板自身抗体与GPIb上一个相对靠近该蛋白插入血小板膜部位的决定簇结合提供了直接证据。
