STUDIES OF MAST CELL DIFFERENTIATION IN VITRO

肥大细胞是研究细胞的一个很有吸引力的模型系统。 分化是因为表型变化不同于祖代 细胞到肥大细胞是伟大的，需要信号来诱导 与其他细胞相比，分化似乎很少 比如B淋巴细胞。我们已经定义了一个后期的、承诺的阶段 在肥大细胞前体细胞的分化过程中 肉芽组织。这个受控于肥大细胞的祖细胞不 需要IL-3进行区分，但不需要因子或 结缔组织微环境提供的因子，如 小鼠胚胎皮肤。如果肥大细胞承诺的祖细胞 可以成功分离出结缔组织因子 鉴定出来，一个明确的体外分化系统可能是 开发用于单独检查帐户的离散更改 肥大细胞表型。 首先，我们提出了一种新的体外分化系统。 由此可以通过以下方式研究几个肥大单元特征中的任何一个 在晚期祖细胞对已定义的 各种因素。为了实现这一目标，以下战略将 将用于：我们将获得肥大细胞的纯化制剂- 基于对胚胎皮肤亲和力的承诺祖细胞 单层。这些祖细胞的表型将是 下定决心。我们将准确地确定一个或多个因素 小鼠胚胎皮肤的单层，它是 肥大细胞定向祖细胞分化为肥大细胞 细胞。当这项工作完成后，分离的祖细胞将 用所需因子的纯化制剂触发以 检测激活事件、高亲和力表达的变化 免疫球蛋白受体和生长因子受体，以及 去分化。 其次，我们建议使用肥大细胞承诺的祖细胞 在拨款建议中描述的文化系统，以确定是否 是否有任何已知的免疫球蛋白E调节因素也会影响MAST 细胞分化。 第三，我们建议将这种分化系统适应于大鼠 为了检测乳糜酶、羧基肽酶A或 体外培养的肥大细胞肝素蛋白多糖的研究 胚胎皮肤单层。这将使我们能够研究肥大细胞 异质性(体外培养的粘膜与结缔组织类型 系统。

The mast cell is an attractive model system for studies of cellular differentiation because the phenotypic changes from progenitor cell to mast cell are great and the signals required to induce differentiation appear to be few as compared with other cells such as B lymphocytes. We have defined a late, committed stage in the differentiation of the mast cell progenitor just prior to granulation. This mast cell-committed progenitor does not require IL-3 for differentiation but does require a factor or factors provided by a connective tissue microenvironment such as murine embryonic skin. If the mast cell-committed progenitor can be successfully isolated and the connective tissue factors identified, a well-defined in vitro differentiation system could be developed to individually examine discrete changes that account for the mast cell phenotype. First, we propose to develop a new in vitro differentiation system whereby any of several mast cell features can be studied by following the response of late-stage progenitor cells to defined factors. For the goal to be realized, the following strategy will be used: We will obtain a purified preparation of mast cell- committed progenitors based on affinity for embryonic skin monolayers. The phenotype of these progenitors will be determined. We will precisely identify the factor or factors in monolayers of murine embryonic skin which are required for differentiation of the mast cell committed progenitor into mast cells. When this is done, the isolated progenitor cells will be triggered with purified preparations of the required factor to examine changes in activation events, expression of high-affinity IgE receptors and growth factor receptors, and the ability to dedifferentiate. Second, we propose to use the mast cell-committed progenitor culture system described in the grant proposal to determine if there are any known IgE regulatory factors which also affect mast cell differentiation. Third, we propose to adapt this differentiation system for rat studies in order to detect chymase, carboxypeptidase A, or heparin proteoglycan in mast cells derived from culture on embryonic skin monolayers. This will allow us to study mast cell heterogeneity (mucosal vs connective tissue type in an in vitro system.