ROLE OF LFA-1/MAC-1/P150, 95 IN PMN LEUKOCYTE ADHERENCE

白细胞黏附蛋白Mac-1(CD11b/CD18)的生物学意义 LFA-1(CD11a/CD18)和p150，95(CD11c/CD18)已经被 先天性精神分裂症患者的发现及特征分析 这些蛋白的表达(白细胞黏附缺陷或LAD)， 认识到这些蛋白质与其他整合素识别有关 细胞外基质(ECM)蛋白及其鉴定 细胞间黏附分子-1(ICAM-1)及其生物学特性 LFA-1的配体。这项提案中的研究将涉及三个一般问题 问题：1)Mac-1依赖的细胞黏附的主要配体 表面和细胞外基质蛋白还没有定义。而当 最近的证据表明，ICAM-1可能是Mac-1，Mac-1的配体 似乎能够与各种其他结构相互作用。一 假设是一个共同的分子机制支撑着这些 互动。除了特定的结合部位，定量的 和/或中性粒细胞表面Mac-1的质变 伴随着趋化刺激，并可能必然先于相互作用 Mac-1及其配体的表达。努力确定可能的配体和 结合部位，并评价其定量和定性的作用 表面Mac-1的变化将涉及到单克隆的生产和使用 同型聚集研究中的抗体和合成肽， 中性粒细胞与内皮细胞的黏附，细胞外基质蛋白(纤维连接蛋白，L 层粘连蛋白、I型和IV型胶原蛋白)和蛋白质涂层表面(FibroGen 和锁孔帽状血蓝蛋白)。2)Mac-1对某些应用的贡献 特定的中性粒细胞功能(同型聚集、与白蛋白的黏附- 镀膜玻璃和塑料，结合IC3b涂层颗粒)已经 演示了。它在附着内皮细胞和细胞外基质蛋白中的作用， 跨内皮细胞迁移，并分泌颗粒内容物具有反应性 氧，以及Mac-1和其他黏附分子可能的合作 在这些函数中还没有定义。努力评估其他 Mac-1的功能作用将利用特定的单抗 与CD18家族的每个亚单位反应，以及新描述的 中性粒细胞纤维连接蛋白受体(白细胞反应整合素)在糖尿病研究中的应用 具有黏附、迁移、分泌和细胞毒等功能。3)的角色 ICAM-1在急性炎症中的作用尚未明确。最近的证据 提示CD18依赖的中性粒细胞与内皮细胞的黏附 涉及ICAM-1。评估ICAM-1的这种作用的努力将利用 Lapine急性炎症模型。这将需要克隆和 Lapine ICAM(S)的测序及确定型单抗的研制 与Lapine ICAM反应的抗体。从这些信息派生出来的信息 调查应提供分子决定因素的定义和 白细胞黏附的调节机制，并应直接导致 炎症调节中抗黏附策略的评价。

The biologic importance of leukocyte adherence proteins Mac-1 (CDllb/CD18), LFA-1 (CDlla/CD18) and p150,95 (CDllc/CD18) has been underscored by the discovery and characterization of patients genetically deficient in expression of these proteins (Leukocyte Adhesion Deficiency or LAD), the recognition that these proteins are related to other integrins recognizing extracellular matrix (ECM) proteins, and the identification of intercellular adherence molecule-1 (ICAM-1) and its characterization as a ligand for LFA-1. The studies in this proposal will address three general issues: 1) The major ligands for Mac-1-dependent adhesion to cellular surfaces and extracellular matrix proteins have not been defined. While recent evidence indicates that ICAM-1 may be a ligand for Mac-1, Mac-1 appears to be able to interact with a variety of other structures. One hypothesis is that a common molecular mechanism underlies these interactions. In addition to the specific binding sites, quantitative and/or qualitative changes in Mac-1 on the neutrophil's surface appear to accompany chemotactic stimulation, and may necessarily precede interaction of Mac-1 with its ligand. Efforts to identify the possible ligands and binding sites, and evaluate the role of quantitative and qualitative changes in surface Mac-1 will involve the production and use of monoclonal antibodies and synthetic peptides in studies of homotypic aggregation, adherence of neutrophil to endothelial cells, ECM proteins (fibronectin,l laminin, collagen types I and IV), and protein-coated surfaces (fibrogen and keyhole limpet hemocyanin). 2) The contribution of Mac-1 to some specific neutrophil functions (homotypic aggregation, adherence to albumin- coated glass and plastic, binding of iC3b-coated particles) has been demonstrated. Its role in attachment endothelial cells and ECM proteins, transendothelial migration, and secretion of granule contents have reactive oxygen, and the possible cooperation of Mac-1 and other adhesive molecules in these functions have not been defined. Efforts to evaluate additional functional roles for Mac-1 will utilize specific monoclonal antibodies reactive with each of the subunits of the CD18 family and a newly described neutrophil fibronectin receptor (leukocyte response integrin) in studies of adhesion, migratory, secretory and cytotoxic functions. 3) The role of ICAM-1 in acute inflammation has not been defined. Recent evidence indicates that CD18-dependent adhesion of neutrophils to endothelial cells involves ICAM-1. Efforts to evaluate such a role for ICAM-1 will utilize a lapine model of acute inflammation. This will require cloning and sequencing lapine ICAM(s) and the development of defined monoclonal antibodies reactive with lapine ICAM. Information derived from these investigations should provide definition of molecular determinants and regulatory mechanisms of leukocyte adhesion, and should lead directly to evaluations of anti-adherence strategies in the regulation of inflammation.