Rao L V, Hoang A D, Rapaport S I
Department of Biochemistry, University of Texas Health Center at Tyler 75710, USA.
Thromb Haemost. 1995 Apr;73(4):668-74.
Lupus anticoagulant (LA) IgGs have been reported to inhibit more effectively and consistently the Xa/Va/phospholipid complex-catalyzed activation of human prothrombin that the Xa/Va/phospholipid complex-catalyzed activation of bovine prothrombin. This led us to carry out studies to determine whether the ability to inhibit the activation of prothrombin of LA IgGs, separated from the plasma of 15 patients by protein A affinity chromatography, could be related to the ability of the LA IgGs to bind to prothrombin under various experimental conditions. Of 14 LA IgG preparations tested all prolonged to a variable but substantial extent the dilute Russell's viper venom time (dRVVT) of human plasma but only minimally prolonged the dRVVT of bovine plasma. In a purified prothrombin activation system with a rate limiting concentration of phospholipid, all 15 LA IgG preparations inhibited the activation of human prothrombin with the majority showing > 50% of inhibition. In contrast, only one LA IgG markedly inhibited (> 50%) the activation of bovine prothrombin and five others moderately inhibited (25-40%) the activation of bovine prothrombin. Nevertheless, the majority of LA IgG preparations bound to immobilized bovine prothrombin on a Western blot and also to immobilized bovine prothrombin on a microtiter well. In an ELISA in which phosphatidylserine (PS) was immobilized on microtiter wells, bovine prothrombin supported the binding of 10 of 15 LA IgG preparations to PS. However, the extent of binding was lower than that observed with human prothrombin.(ABSTRACT TRUNCATED AT 250 WORDS)
据报道，狼疮抗凝物（LA）IgG 能更有效且持续地抑制 Xa/Va/磷脂复合物催化的人凝血酶原激活，相较于其对牛凝血酶原激活的抑制作用。这促使我们开展研究，以确定通过蛋白 A 亲和层析从 15 名患者血浆中分离出的 LA IgG 抑制凝血酶原激活的能力，是否与 LA IgG 在各种实验条件下结合凝血酶原的能力相关。在所测试的 14 种 LA IgG 制剂中，所有制剂都在不同程度上显著延长了人血浆的稀释蝰蛇毒时间（dRVVT），但仅轻微延长了牛血浆的 dRVVT。在磷脂浓度为限速浓度的纯化凝血酶原激活系统中，所有 15 种 LA IgG 制剂均抑制人凝血酶原的激活，大多数制剂的抑制率>50%。相比之下，只有一种 LA IgG 显著抑制（>50%）牛凝血酶原的激活，另外五种则中度抑制（25 - 40%）牛凝血酶原的激活。然而，大多数 LA IgG 制剂在 Western 印迹中能与固定化的牛凝血酶原结合，在微量滴定孔中也能与固定化的牛凝血酶原结合。在将磷脂酰丝氨酸（PS）固定在微量滴定孔上的 ELISA 中，牛凝血酶原支持 15 种 LA IgG 制剂中的 10 种与 PS 结合。然而，结合程度低于用人凝血酶原观察到的结合程度。（摘要截断于 250 字）
