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

白细胞粘附蛋白Mac-1（CD 11b/CD 18）的生物学重要性， LFA-1（CD 11 a/CD 18）和p150，95（CD 11 c/CD 18）的研究已经被强调， 发现和表征遗传缺陷的患者， 这些蛋白质的表达（白细胞粘附缺陷或LAD）， 认识到这些蛋白质与其他整合素相关， 细胞外基质（ECM）蛋白，并鉴定 细胞间粘附分子-1（ICAM-1）及其作为一种 LFA-1的配体。 本提案中的研究将解决三个一般性问题， 问题：1）Mac-1依赖性粘附细胞的主要配体 表面和细胞外基质蛋白还没有被定义。 而 最近的证据表明ICAM-1可能是Mac-1的配体，Mac-1 似乎能够与各种其他结构相互作用。 一 一种假设是，一个共同的分子机制，这些 交互. 除了特异性结合位点，定量 和/或中性粒细胞表面Mac-1的质的变化似乎 伴随着趋化刺激，并且可能必然先于相互作用 Mac-1与其配体 努力鉴定可能的配体， 结合位点，并评估定量和定性的作用 Mac-1表面的变化将涉及单克隆抗体的生产和使用， 抗体和合成肽在同型聚集的研究中， 中性粒细胞与内皮细胞的粘附，ECM蛋白（纤连蛋白，l 层粘连蛋白、I型和IV型胶原蛋白）和蛋白质包被的表面（纤维原 和匙孔血蓝蛋白）。 2)Mac-1对某些人的贡献 特异性中性粒细胞功能（同型聚集，粘附白蛋白， 涂覆的玻璃和塑料，iC 3b涂覆的颗粒的结合）已经被 演示。 其在附着内皮细胞和ECM蛋白中的作用， 跨内皮迁移和分泌颗粒内容物具有反应性 氧气，以及Mac-1和其他粘合剂分子的可能合作 这些功能尚未定义。 努力评价其他 Mac-1的功能性作用将利用特异性单克隆抗体 与CD 18家族的每个亚基反应， 中性粒细胞纤连蛋白受体（白细胞反应整联蛋白）在 粘附、迁移、分泌和细胞毒性功能。 3)的作用 急性炎症中的ICAM-1尚未确定。 最近的证据 表明中性粒细胞与内皮细胞的CD 18依赖性粘附 涉及ICAM-1。 评价ICAM-1的这种作用的工作将利用一个 兔急性炎症模型。 这将需要克隆和 对兔ICAM进行测序并开发确定的单克隆抗体 与兔ICAM反应的抗体。 信息来源于这些 调查应提供分子决定因素的定义， 调节机制的白细胞粘附，并应直接导致 评价炎症调节中的抗粘附策略。

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.