PMN MOTILITY AND ADHERENCE IN NEONATES

患有遗传性Mac-1，LFA 1缺乏症的人类新生儿和个体在 感染并发症的发展风险高， 吞噬细胞的组织动员受损。 这些研究将 评估可能导致PMN受损的致病机制，或 单核白细胞动员。 主要重点 将包括确定： 细胞粘附和迁移特性，B）调节细胞粘附和迁移特性的机制， 细胞粘附的诱导、调节和功能活化 炎症刺激，和c）细胞骨架的可能病理影响 蛋白质（微管）对细胞易位。 他们将专注于 一个“粘附性”糖蛋白（GP）家族（Mac-1，LFA 1， p150，95）对白细胞粘附依赖性的影响;比较 使用新生儿和Mac-1缺陷细胞的研究将实现独特的 有机会了解功能和临床后果的异常 表情 Mac-1 GP在趋化因子介导下的表面表达 分泌刺激将使用免疫荧光流定量 流式细胞术和125 I免疫沉淀技术， 抗体（MAb）;它们与其他表面的拓扑关系 将由IIF评价受体（FcR和CR 1）和“粘附部位”的粘附情况 显微镜 针对每个Mac-1亚基的MAb将用于阻断 实验以评估它们对粘附依赖性的功能贡献， 细胞功能包括微管和微丝装配（IIF 微管蛋白和肌动蛋白探针）。 Mac-1 GP的“上调”， 将研究过度粘附和分泌事件， Mac-1 GP诱导受损和新生儿高粘附的决定因素 将对PMN进行评估。 亚细胞分级分离和一种新的伴刀豆球蛋白A 将采用结合测定来确定细胞内的 Mac-1池并评估调节其表面表达的机制， 再分配和/或再循环。 选定致病机制核算 对于新生儿PMN的MT组装紊乱，包括：异常细胞 粘附依赖性细胞骨架激活，异常翻译后 微管蛋白酪氨酸基化，或内源性免疫化学异常或α 或β微管蛋白将用细胞内免疫荧光法进行评价 在促进MT组装或拆卸的条件下使用探针。 这些 研究应提供一个基础，了解功能和 粘附依赖性细胞功能紊乱的临床后果 炎症反应，并可能允许发展 这些和其他高风险儿科模型的治疗策略。

Human neonates and individuals with heritable Mac-1, LFA1 deficiency are at high risk for the development of infectious complications resulting from impaired tissue mobilization of phagocytic cells. These studies will evaluate pathogenic mechanisms that may account for impaired PMN or mononuclear leukocyte mobilization in these populations. Major emphases will include determinations of: a) functional relationships between cellular adherence and migratory properties, b) mechanisms regulatin the induction, modulation and functional activation of cellular adherence by inflammatory stimuli, and c) possible pathologic influences of cytoskeletal proteins (microtubules) on cell translocation. They will focus on the contributions of a family of "adhesive" glycoproteins (GPs) (Mac-1, LFA1, p150,95) to adherence-dependent properties of leukocytes; comparative studies employing neonatal and Mac-1 deficient cells will allow a unique opportunity to understand functional and clinical consequences of abnormal expression. Surface expression of Mac-1 GP when mediated by chemotactic or secretory stimuli will be quantitated using immunofluorescence flow cytometry and 125I immunoprecipitation techniques employing monoclonal antibodies (MAb); their topographical relationships to other surface reptors (FcR and CR1) and to "adhesion sites" will be evaluated by IIF microscopy. MAbs to each Mac-1 subunit will be employed in blocking experiments to assess their functional contributions to adhesion-dependent cell functions including microtubule and microfilament assemblage (IIF tubulin and actin probes). The relationships of Mac-1 GP "up regulation", hyperadherence and secretory events will be studied and possible secretory determinants of impaired Mac-1 GP induction and hyperadherence of neonatal PMNs will be assessed. Subcellular fractionation and a new concanavalin A binding assay will be employed to determine the location of intracellular Mac-1 pools and to evaluate mechanisms regulating their surface expression, redistribution and/or recycling. Selected pathogenic mechanisms accounting for disturbed MT assembly of neonatal PMN including: abnormal cell adherence-dependent cytoskeletal activation, abnormal post-translational tubulin tyrosylation, or intrinsic immunochemical abnormalities of or Alpha or Beta tubulin will be evaluated with intracellular immunofluorescence probes under conditions promoting MT assembly or disassembly. These studies should provide a basis for understanding the functional and clinical consequences of disturbed adhesion-dependent cellular functions in the inflammatory response, and potentially allow the development of therapeutic strategies in these and other high risk pediatric models.