MAST CELL MEMBRANE GLYCOLIPID EXPRESSION AND FUNCTION

这项建议的总体目标是发展基础研究 通过调查掌握免疫学和生化方面的技能 肥大细胞膜糖鞘糖脂。拟议的研究是 旨在通过以下途径更多地了解肥大细胞分化 霍乱毒素结合蛋白的表达及功能研究 神经节苷脂GM1在小鼠肥大细胞上的表达 不同的发展阶段。霍乱毒素与病毒的结合 白介素3-质膜上神经节苷脂GM1的表达 依赖小鼠骨髓培养来源的肥大细胞诱导 组胺含量和DNA合成均增加 这些细胞。第一个具体目标是量化表面 神经节苷脂GM1在培养细胞中的表达和生物合成 在白细胞介素3中维持的肥大细胞，有或没有 在培养中来自白介素4的额外的增殖信号- 共培养法进一步分化来源的肥大细胞 成纤维细胞和体外培养的腹膜肥大细胞； 确定霍乱毒素对组胺和 这些人群的环磷酸腺苷含量 与神经节苷脂GM1表达相关。第二个具体问题 目的是确定霍乱毒素是否会增加组胺 通过增加培养来源的肥大细胞的含量来增加其含量 组氨酸摄取和/或组氨酸脱羧化，如果是， 确定这种效应是否与神经节苷脂GM1相关 在分化程度较高的肥大细胞群中表达。这个 第三个具体目标是确定霍乱毒素是否促进 肥大细胞群体中作为细胞的DNA合成 周期进展因子和毒素的作用是否 与白介素4相似或不同。建议的 研究将产生关于第一个的新的基本信息 糖鞘磷脂依赖的功能反应将在 肥大细胞。这些应对措施涉及以下两个重要方面 肥大细胞生物学，即细胞组胺含量的控制 以及肥大细胞复制的调控。虽然这些研究 将重点放在小鼠肥大细胞上，所获得的知识和技能 应该直接适用于未来对 人肥大细胞的免疫生物学和生物化学，包括 参与眼部即刻超敏反应的患者。

The overall objective of this proposal is to develop basic research skills in immunology and biochemistry through the investigation of mast cell membrane glycosphingolipids. The proposed research is designed to learn more about mast cell differentiation through studies of the expression and function of a cholera toxin-binding glycosphingolipid, ganglisoside GM1, on mouse mast cells at different stages of development. The binding of cholera toxin to ganglioside GM1 on the plasma membranes of interleukin 3- dependent, mouse bone marrow culture-derived mast cells induces an increase in both the histamine content and the DNA synthesis of these cells. The first specific aim is to quantify the surface expression and biosynthesis of ganglioside GM1 in culture-derived mast cells maintained in interleukin 3 with or without an additional proliferative signal from interleukin 4, in culture- derived mast cells further differentiated in vitro by co-culture with fibroblasts, and in peritoneal mast cells ex vivo; and to determine if the effects of cholera toxin on the histamine and cyclic adenosine monophosphate contents of these populations correlate with ganglioside GM1 expression. The second specific aim is to determine whether cholera toxin increases the histamine content of culture-derived mast cells by augmenting their histidine uptake and/or decarboxylation of histidine, and if so, to determine whether this effect correlates with ganglioside GM1 expression in the more differentiated mast cell populations. The third specific aim is to determine whether cholera toxin promotes DNA synthesis in the mast cell populations by acting as a cell cycle progression factor and whether the effect of the toxin is similar or different than that of interleukin 4. The proposed research will yield new basic information about the first glycosphingolipid-dependent functional response to be described in mast cells. These responses involve two important aspects of mast cell biology, namely, control of cellular histamine content and the regulation of mast cell replication. While these studies will focus on mouse mast cells, the knowledge and skills obtained should be directly applicable to future studies of the immunobiology and biochemistry of human mast cells, including those involved in ocular immediate hypersensitivity reactions.