Mechanism of GP120 cleaving antibodies in lupus

狼疮中 GP120 裂解抗体的机制

• 批准号: 6348918
• 负责人: ALFONSO TRAMONTANO
• 金额: $ 13.42万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6348918
• 关键词: HIV envelope protein gp120; abzyme; active sites; antiAIDS agent; antigen antibody reaction; autoimmunity; clinical research; enzyme activity; genetic library; human subject; laboratory mouse; neutralizing antibody; protein structure function; serine proteinases; systemic lupus erythematosus

Antibodies (Abs) with innate proteolytic activity are detected in the mouse and human autoimmune repertoires. Antibodies in human SLE and in a murine lupus model (MRL/lpr) have also been shown to bind HIV-1 antigens with high affinity. The central hypothesis of this proposal is that specific catalytic Abs against HIV-1 gp120 could be expressed in subjects with autoimmune disease. Such antibodies may have therapeutic potential for inactivation of HIV-1 infectivity through specific proteolysis at viral capsid sites. Molecular studies suggest that a serine protease-like active site at or near the antigen binding site of peptidase Abs is encoded by a germline VL gene. Our proposal will explore the occurrence, molecular specificity and biological activity of HIV- 1 gp120-specific Ab proteases that arise in autoimmunity. A variable domain (Fv)-phage library, constructed from antibody genes found in human SLE is expected to comprise both catalytic and gp120-specific antibodies. Proteolytic Ab fragments from the phage display libraries will be obtained by chemical selection, using active site-modifying reagents for specific covalent labeling and affinity capture of Abs with serine protease-like reactivity. A series of reagents having a common reactive group and differing degrees of analogy with the target substrate (gp120) will be compared for their relative efficacy in capturing specific and catalytically efficient Abs from the library. These studies will also examine if proteolytic degradation at specific gp120 sites, including a neutralizing epitope for conventional antibodies leads to more effective inactivation of the virus. The range of binding specificities in the lupus repertoire suggests that broadly inactivating catalytic Abs are likely to be identified. Insights from the mechanistic studies shall be integrated into the studies of the comparison proposals of the program project application. The overall Program Project has significant implications for development of a new therapeutic modality for treatment or prevention of HIV infection.

在小鼠和人类自身免疫组库中检测到具有先天蛋白水解活性的抗体 (Abs)。 人类 SLE 和小鼠狼疮模型 (MRL/lpr) 中的抗体也已被证明能够以高亲和力结合 HIV-1 抗原。 该提案的中心假设是，针对 HIV-1 gp120 的特异性催化抗体可以在患有自身免疫性疾病的受试者中表达。此类抗体可能具有通过病毒衣壳位点的特异性蛋白水解灭活 HIV-1 感染性的治疗潜力。 分子研究表明，肽酶抗体抗原结合位点处或附近的丝氨酸蛋白酶样活性位点由种系 VL 基因编码。 我们的提案将探讨自身免疫中产生的 HIV-1 gp120 特异性 Ab 蛋白酶的发生、分子特异性和生物活性。 由人类 SLE 中发现的抗体基因构建的可变域 (Fv) 噬菌体文库预计将包含催化抗体和 gp120 特异性抗体。 来自噬菌体展示文库的蛋白水解抗体片段将通过化学选择获得，使用活性位点修饰试剂进行特异性共价标记和亲和捕获具有丝氨酸蛋白酶样反应性的抗体。 将比较具有共同反应基团和与目标底物 (gp120) 不同程度相似性的一系列试剂在从文库中捕获特异性和催化有效抗体的相对功效。 这些研究还将检查特定 gp120 位点（包括常规抗体的中和表位）的蛋白水解降解是否会导致更有效的病毒灭活。狼疮谱系中的结合特异性范围表明，可能会鉴定出广泛失活的催化抗体。 机理研究的见解应纳入计划项目申请的比较方案的研究中。 整个计划项目对于开发治疗或预防艾滋病毒感染的新治疗方式具有重大意义。