Mizutani H, Engelman R W, Kurata Y, Ikehara S, Good R A
Department of Pediatrics, University of South Florida, All Children's Hospital, St Petersburg 33701.
Blood. 1993 Aug 1;82(3):837-44.
Male (NZW x BXSB)F1 (W/BF1) mice develop systemic autoimmunity involving autoantibodies, progressive thrombocytopenia, lupus nephritis, and degenerative coronary vascular disease with myocardial infarction. Platelet-associated IgG (PAIgG) on the platelet surface mediates platelet destruction by the reticuloendothelial system in the autoimmune thrombocytopenic purpura (ATP) of W/BF1 mice. Because the epitopes targeted in ATP by PAIgG have not been identifiable using serum from thrombocytopenic W/BF1 mice, we developed seven hybridomas secreting antiplatelet monoclonal antibodies (MoAbs) using splenocytes of thrombocytopenic W/BF1 mice. Epitopes recognized by three MoAbs were similar to those recognized by PAIgG, because eluted IgG from platelets of thrombocytopenic W/BF1 mice inhibited platelet binding by MoAbs in competitive micro-enzyme-linked immunosorbent assay. Hybridoma cells or purified Ig from the ascites of two clones (2A12 and 6A6), when injected into nude mice produced acute thrombocytopenia, elevated the levels of PAIgG, purpura, and megakaryocytosis. MoAbs of two clones also reacted with single-stranded DNA or double-stranded DNA, and one of these clones (4-13) bound to cardiolipin (CL) but was nonpathogenic in nude mice, suggesting that anti-CL and antiplatelet autoantibodies can be distinct. On immunoblotting analysis, antiplatelet MoAbs frequently bound a 100-Kd platelet protein. These MoAbs contribute to an understanding of the etiopathogenesis of ATP and the several antigens and autoantibodies involved.
雄性（新西兰白兔×BXSB）F1（W/BF1）小鼠会发生全身性自身免疫反应，包括自身抗体、进行性血小板减少、狼疮性肾炎以及伴有心肌梗死的退行性冠状动脉血管疾病。血小板表面的血小板相关IgG（PAIgG）在W/BF1小鼠的自身免疫性血小板减少性紫癜（ATP）中通过网状内皮系统介导血小板破坏。由于使用血小板减少的W/BF1小鼠的血清无法鉴定出PAIgG在ATP中靶向的表位，我们利用血小板减少的W/BF1小鼠的脾细胞制备了7种分泌抗血小板单克隆抗体（MoAb）的杂交瘤。三种MoAb识别的表位与PAIgG识别的表位相似，因为在竞争性微酶联免疫吸附试验中，从血小板减少的W/BF1小鼠的血小板上洗脱的IgG可抑制MoAb与血小板的结合。将两个克隆（2A12和6A6）的杂交瘤细胞或腹水中纯化的Ig注射到裸鼠体内时，会导致急性血小板减少，使PAIgG水平升高、出现紫癜并伴有巨核细胞增多。两个克隆的MoAb也与单链DNA或双链DNA发生反应，其中一个克隆（4-13）与心磷脂（CL）结合，但在裸鼠中无致病性，这表明抗CL和抗血小板自身抗体可能是不同的。在免疫印迹分析中，抗血小板MoAb经常与一种100-Kd的血小板蛋白结合。这些MoAb有助于理解ATP的发病机制以及所涉及的几种抗原和自身抗体。
