OSTEOCLASTS & GIANT CELLS--IMPLICATIONS OF CELL FUSION

这项建议的长远目标是：1）阐明 单核细胞融合的机制及调控 吞噬细胞（MNP）导致破骨细胞的形成 (OC)和巨细胞（GC）和2）表征功能 正常和病理性多核化的后果 骨吸收和参与宿主防御机制， 炎症反应和肿瘤。 将使用两种方法：第一种方法侧重于 细胞和分子基础的细胞的特定趋势， 形成多核体。 这种方法将更多 具体涉及质膜蛋白质动力学研究 的MNPs诱导形成多核细胞在体外，寻找 潜在的融合蛋白。 结合具体 质膜蛋白质的碘化， 膜蛋白及其随后的免疫沉淀 用抗小鼠巨噬细胞抗体，我们将比较 MNP和GC的膜蛋白组成，即，之前和 融合后。 第二种方法集中于地方的作用 微环境的诱导和调节 从多核OC和GC的前体形成 MNP血统。 这种方法将更具体地涉及研究 对淋巴细胞产生的可溶性因子的作用- 巨噬细胞融合因子（Macrophage Fusion Factor） 尝试 本文将对这一假定因素进行提纯，并分析 细胞和细胞相互作用导致其在体外分泌， 特异性淋巴细胞单克隆抗体 亚群和巨噬细胞 当地因素的影响，如 酸化、蛋白酶和钙浓度对融合的影响 还将在体外研究MNP。 这两种方法密切相互作用，因为当地的影响 对质膜蛋白质组成的因素也将是 研究了 将对体内诱导的OC和GC进行平行研究， 研究这些细胞形成的动力学以及 用免疫电子显微镜观察细胞膜的分子组成 显微镜技术和已知的表面抗原标记。 从长远来看，这些研究可能对 了解骨融合的功能意义 再吸收和宿主防御机制。

The long term goals of this proposal are: 1) to elucidate the mechanisms and the regulation of the fusion on mononuclear phagocytes (MNP) leading to the formation of both osteoclasts (OC) and giant cells (GC) and 2) to characterize the function consequences of multinucleation in both normal and pathological bone resorption and in the host defense mechanisms involved in inflammatory reactions and tumors. Two approaches will be used: The first approach focuses upon the cellular and molecular basis for the particular tendency of cells of the MNP lineage to form polykaryons. This approach will more specifically involve kinetic studies of plasma membrane proteins of MNPs induced to form multinucleated cells in vitro, looking for a potential fusogenic protein(s). Combining the specific iodination of plasma membrane proteins, the metabolic labeling of membrane proteins and their subsequent immunoprecipitation with anti-mouse macrophage antibodies we will compare the membrane protein composition of MNPs and GCs, i.e., before and after fusion. The second approach concentrates upon the role of the local microenvironment in the induction and regulation of the formation of multinucleated OC and GC from precursors of the MNP lineage. This approach will more specifically involve studies on the role of soluble factor(s) resulting from lymphocyte- macrophage interactions (Macrophage Fusion Factor). Attempts will be made to purify this putative factor and to analyze which cell(s) and cell interaction(s) lead to its secretion in vitro using monoclonal antibodies directed against specific lymphocyte subsets and macrophages. The effects of local factors such as acidification, proteases and calcium concentration on fusion of MNPs will also be studied in vitro. These two approaches closely interact in that the effects of local factors on the plasma membrane protein composition will also be studied. Parallel studies will be made on in vivo induced OCs and GCs, studying the kinetics of the formation of these cells as well as the molecular composition of their membranes using immunoelectron microscopic techniques and known surface antigen markers. In the long run, these studies may be of critical importance in the understanding of the functional implications of fusion in bone resorption and host defense mechanisms.