Nurden A T, Dupuis D, Pidard D, Kieffer N, Kunicki T J, Cartron J P
J Clin Invest. 1982 Dec;70(6):1281-91. doi: 10.1172/jci110727.
The Tn-syndrome is an acquired disorder characterized by the polyagglutination of blood cells and the pathological exposure of alpha-N-acetyl-D-galactosamine residues (Tn-antigen) at the cell surface. We now report studies on the platelet of a patient (Ba.) of which 81% reacted positively with a fluorescein conjugate of Helix pomatia agglutinin (HPA). The surface proteins of Ba. platelets were labeled with 125I by the lactoperoxidase-catalyzed procedure; single and two-dimensional electrophoresis on sodium dodecyl sulfate (SDS)-polyacrylamide gels was followed by autoradiography that revealed normal 125I-labeling of the major membrane glycoproteins (GP) but that GP Ib had a faster than normal migration. the abnormal GP Ib of Ba. platelets was strongly labeled when platelet suspensions were treated sequentially with neuraminidase, galactose oxidase, and sodium [3H]borohydride. Unlike the GP Ib of normal human platelets, it was also strongly labeled when Ba. platelets were treated with galactose oxidase and sodium [3H]borohydride alone. Both the alloantigen, PlA1, and quinidine-dependent antibody receptor activity were normally expressed by Ba. platelets, which also bound a monoclonal antibody (AN51) to GP Ib. Analysis of Ba. platelets by crossed immunoelectrophoresis using a rabbit anti-human platelet antibody preparation revealed the presence of an immunoprecipitate in the GP Ib position that had an abnormal appearance and migration in the second dimension. An altered position of the precipitate given by Factor VIIIR:Ag was also noted. Incorporation of HPA into the agarose gel during the first dimension electrophoresis resulted in the specific precipitation of the abnormal GP Ib of Ba. platelets. Our studies show that circulating Tn-platelets contain GP Ib with a modified oligosaccharide chain structure responsible for the platelet expression of Tn-antigen activity.
Tn综合征是一种获得性疾病，其特征为血细胞的多凝集以及细胞表面α-N-乙酰-D-半乳糖胺残基（Tn抗原）的病理性暴露。我们现在报告对一名患者（Ba.）血小板的研究，其中81%的血小板与马蹄蟹凝集素（HPA）的荧光素缀合物呈阳性反应。通过乳过氧化物酶催化程序用125I标记Ba.血小板的表面蛋白；在十二烷基硫酸钠（SDS）-聚丙烯酰胺凝胶上进行单向和双向电泳，随后进行放射自显影，结果显示主要膜糖蛋白（GP）的125I标记正常，但GP Ib的迁移速度比正常快。当血小板悬液依次用神经氨酸酶、半乳糖氧化酶和[3H]硼氢化钠处理时，Ba.血小板异常的GP Ib被强烈标记。与正常人血小板的GP Ib不同，当单独用半乳糖氧化酶和[3H]硼氢化钠处理Ba.血小板时，它也被强烈标记。Ba.血小板正常表达同种抗原PlA1和奎尼丁依赖性抗体受体活性，并且也与针对GP Ib的单克隆抗体（AN51）结合。使用兔抗人血小板抗体制剂通过交叉免疫电泳分析Ba.血小板，发现在GP Ib位置存在免疫沉淀物，其在第二维中的外观和迁移异常。还注意到因子VIIIR:Ag产生的沉淀物位置改变。在第一维电泳期间将HPA掺入琼脂糖凝胶中导致Ba.血小板异常GP Ib的特异性沉淀。我们的研究表明，循环中的Tn血小板含有具有修饰寡糖链结构的GP Ib，该结构负责血小板Tn抗原活性的表达。
