Kouts S, Wang M X, Adelstein S, Krilis S A
Department of Immunology, Allergy and Infectious Disease, University of New South Wales, St. George Hospital, Kogarah, Australia.
J Immunol. 1995 Jul 15;155(2):958-66.
A rabbit immunized with beta 2-glycoprotein I (beta 2-GPI) produced Abs that bind to negatively charged phospholipids and to beta 2-GPI. After affinity purification of the Abs to beta 2-GPI, the dual reactivity could still be detected. Adsorption studies with a phosphatidylserine affinity column depleted phospholipid-reactive Abs, but beta 2-GPI reactivity was retained. The same pattern of reactivity was found with culture supernatants from rabbit anti-beta 2-GPI splenocytes fused with an immortalized rabbit cell line. The reactivity to negatively charged phospholipids is likely to involve ionic interactions, as high ionic strength buffers eliminated binding to anionic phospholipids, but not to beta 2-GPI. Affinity-purified anti-phospholipid (aPL) Abs from four of seven autoimmune patients bound anionic phospholipids in the absence of beta 2-GPI. However, in high ionic strength buffer, this binding was abolished in three patients and significantly reduced in the fourth. In contrast, affinity-purified aPL Abs from seven autoimmune patients bound to beta 2-GPI-coated plates, and binding in high ionic strength buffer was reduced only moderately in three patients. Therefore, autoimmune-type aPL Abs display anti-beta 2-GPI reactivity and charge-dependent binding to anionic phospholipids similar to affinity-purified rabbit anti-beta 2-GPI Abs.
用β2-糖蛋白I（β2-GPI）免疫的兔子产生了与带负电荷的磷脂和β2-GPI结合的抗体。对β2-GPI抗体进行亲和纯化后，仍可检测到双重反应性。用磷脂酰丝氨酸亲和柱进行吸附研究，耗尽了磷脂反应性抗体，但β2-GPI反应性得以保留。用与永生化兔细胞系融合的兔抗β2-GPI脾细胞的培养上清液也发现了相同的反应模式。对带负电荷的磷脂的反应性可能涉及离子相互作用，因为高离子强度缓冲液消除了与阴离子磷脂的结合，但未消除与β2-GPI的结合。来自7名自身免疫性患者中的4名的亲和纯化抗磷脂（aPL）抗体在没有β2-GPI的情况下与阴离子磷脂结合。然而，在高离子强度缓冲液中，3名患者的这种结合被消除，第4名患者的结合显著减少。相比之下，来自7名自身免疫性患者的亲和纯化aPL抗体与β2-GPI包被的平板结合，在高离子强度缓冲液中，3名患者的结合仅适度减少。因此，自身免疫型aPL抗体表现出抗β2-GPI反应性以及与阴离子磷脂的电荷依赖性结合，这与亲和纯化的兔抗β2-GPI抗体相似。
