Gharavi A E
Antiphospholipid Research Laboratory, Hospital for Special Surgery, Cornell University Medical Center, New York, N.Y. 10021.
Stroke. 1992 Feb;23(2 Suppl):I7-10.
A plasma protein is required as a cofactor for the binding of antiphospholipid antibodies to phospholipids. This protein has been identified as beta 2-glycoprotein I, an apolipoprotein that binds to negatively charged phospholipids and is a natural inhibitor of the coagulation cascade. It is not certain whether antiphospholipid antibodies bind to beta 2-glycoprotein I alone, to beta 2-glycoprotein I-phospholipid complex, or to a phospholipid epitope modified by beta 2-glycoprotein I. We used isolated beta 2-glycoprotein I and purified IgG and IgM antiphospholipid antibodies from serum or plasma of patients with the antiphospholipid syndrome to study the relation between antiphospholipid antibodies and beta 2-glycoprotein I in enzyme-linked immunosorbent assays. IgG antiphospholipid antibodies did not bind to beta 2-glycoprotein I when it was used as an antigen on the assay plate. The binding of IgG and IgM antiphospholipid antibodies to phospholipid was enhanced when beta 2-glycoprotein I was added to the phospholipid antigens either before or together with the antiphospholipid antibodies. The degree of enhancement varied across patients. IgM antiphospholipid antibodies required less cofactor for binding to phospholipid antigens. These results confirm the requirement of beta 2-glycoprotein I as a cofactor for the binding of autoimmune antiphospholipid antibodies to phospholipids.
一种血浆蛋白是抗磷脂抗体与磷脂结合所必需的辅助因子。这种蛋白已被鉴定为β2糖蛋白I，一种与带负电荷的磷脂结合的载脂蛋白，是凝血级联反应的天然抑制剂。尚不确定抗磷脂抗体是单独与β2糖蛋白I结合，与β2糖蛋白I - 磷脂复合物结合，还是与由β2糖蛋白I修饰的磷脂表位结合。我们使用从抗磷脂综合征患者的血清或血浆中分离出的β2糖蛋白I以及纯化的IgG和IgM抗磷脂抗体，在酶联免疫吸附试验中研究抗磷脂抗体与β2糖蛋白I之间的关系。当β2糖蛋白I用作检测板上的抗原时，IgG抗磷脂抗体不与β2糖蛋白I结合。当在抗磷脂抗体之前或与抗磷脂抗体一起将β2糖蛋白I添加到磷脂抗原中时，IgG和IgM抗磷脂抗体与磷脂的结合增强。增强程度因患者而异。IgM抗磷脂抗体与磷脂抗原结合所需的辅助因子较少。这些结果证实了β2糖蛋白I作为自身免疫性抗磷脂抗体与磷脂结合的辅助因子的必要性。
