Anticardiolipin Antibodies in Antiphospholipid Syndrome

描述（由申请人提供）：该项目的长期目标是鉴定和表征抗磷脂综合征（APS）中的致病性抗心磷脂抗体（aCL）。最近，我们发现4/5的患者源性，血栓原，单克隆IgG aCL与纤溶酶，凝血酶和活化蛋白C （APC）结合。在这4种纤溶酶反应性aCL中，CL15抑制纤溶酶介导的纤维蛋白溶解和APC的抗凝血活性，并在注射给妊娠小鼠后导致胎儿丢失。它与纤溶蛋白结合的相对Kd值为7 × 10/-10，比IgG抗β - 2gpi抗体（Ab）对β - 2gpi （APS的主要自身抗原）的亲和力高3-4倍。这些数据使我们假设纤溶酶是一种重要的自身抗原，在一些APS患者中驱动某些IgG aCL，并且一些纤溶酶驱动的IgG aCL是血栓原（如CL15）。为了验证这些假设，具体目标是：

DESCRIPTION (provided by applicant): The long-term objectives of this project are to identify and characterize pathogenic anticardiolipin antibodies (aCL) in the antiphospholipid syndrome (APS). Recently, we found 4/5 patient-derived, prothrombotic, monoclonal IgG aCL bind to plasmin, thrombin and activated protein C (APC). Of these 4 plasmin-reactive aCL, CL15 inhibits plasmin-mediated fibrinolysis and anticoagulant activity of APC, and causes fetal loss when injected into pregnant mice. It binds to plasmin with a relative Kd value of 7 x 10/-10 that is 3-4 logs higher than the affinity of IgG anti-beta2GPI antibodies (Ab) toward beta2GPI, the major autoantigen in APS. These data lead us to hypothesize that plasmin is an important autoantigen that drives certain IgG aCL in some APS patients, and that some of the plasmin-driven IgG aCL are prothrombotic (like CL15). To test these hypotheses, the specific aims are: 1. To study the prevalence, characteristics and pathogenic significance of the plasmin-reactive IgG aCL in APS patients. IgG will be purified and analyzed for Ab against CL and plasmin, and by cross inhibition to determine the presence of plasmin-reactive IgG aCL. The plasmin-reactive IgG aCL will be affinity purified and analyzed for binding affinity to plasmin, reactivity with thrombin an APC, and for lupus anticoagulant activity and pathogenicity. 2. To immunize mice with human plasmin and study the induced Ab and the pregnancy outcomes. Blood samples will be analyzed for IgG Ab against human plasmin and CL, and by cross inhibition to determine the presence of plasmin-reactive IgG aCL. Female mice with high titers of plasmin-reactive IgG aCL will be mated and the pregnancy outcomes will be examined to assess the pathogenicity of the plasmin-reactive IgG aCL. 3. To generate and study monoclonal plasmin-reactive aCL from immunized mice. The monoclonal Ab will be injected (individually or in pairs) into pregnant mice to study their pathogenic potentials, and be analyzed for reactivity with murine plasmin, and human thrombin and APC, and for relevant functional activity.