Characterization of Different Types of Human Mast Cells

描述（申请人提供）：肥大细胞是速发型超敏反应的主要效应细胞，可能参与宿主防御、组织稳态和其他形式的超敏反应。目前的建议扩展了工作，起源于两种类型的人肥大细胞的基础上，他们的蛋白酶表型和干细胞因子，使人肥大细胞在体外从造血祖细胞发展的发现鉴定。目的1研究区分MCT（类胰蛋白酶？）来自MCTC（类胰蛋白酶？）人类肥大细胞的类型。其中包括：对于MCTC细胞-仅在MCTC细胞中细胞表面CD 88的功能性表达、IL-6介导的糜酶蛋白/mRNA的上调，以及仅MCTC细胞在无血清培养基中的增殖;对于MCT细胞-IL-6使MCT细胞抵抗IL-4凋亡的机制，肺MCT细胞不能转化为MCTC细胞，以及评价仅在MCT细胞中表达的新基因（包括它们在特应性鼻炎和哮喘受试者的鼻和支气管粘膜中的表达）。目的2通过Fc γ RIIA以及FceRI检查皮肤来源的MCTC细胞的活化。将在体外研究由相同MCTC细胞释放的蛋白酶对细胞因子的降解，并考虑体内结果。将在体外确定IgG免疫复合物是否激活人MCTC细胞。最后，将在体外以及体内评估IgE引起的FceRI水平增加对成熟MCTC细胞的功能影响。目的3将检测Th 1和Th 2型细胞因子是否调节人肥大细胞的介质产生。将检查Th 1和/或Th 2细胞因子诱导LTC 4和增强活化的皮肤MCTC细胞产生PGD 2的机制。将确定IFN-γ致敏的MCTC细胞的Fc γ RI表达是否增强对IgG免疫复合物或对CRP的应答。最后，将评估上调细胞因子受体如IL-4 R对皮肤MCTC细胞的功能影响。这些研究将扩大已知的不同类型的人肥大细胞之间的表型差异的重要功能特征，揭示肥大细胞活化的新范式，并导致更好地了解他们的作用（S）在人类疾病。

DESCRIPTION (provided by applicant): Mast cells are primary effector cells of immediate hypersensitivity, and may be involved in host defense, tissue homeostasis and other forms of hypersensitivity. The current proposal extends work that originated with the identification of two types of human mast cells based on their protease phenotypes and the finding that stem cell factor enables human mast cells to develop in vitro from hematopoietic progenitors. Aim 1 examines new functional and phenotypic characteristics that distinguish MCT (tryptase???) from MCTC (tryptase???) types of human mast cells. These include: for MCTC cells- functional expression of cell-surface CD88, IL-6-mediated upregulation of chymase protein/mRNA in only MCTC cells, and proliferation of only MCTC cells in serum-free media; for MCT cells- mechanism by which IL-6 makes MCT cells resist apoptosis to IL-4, failure of lung MCT cells to convert to MCTC cells, and evaluation of new genes expressed in only MCT cells (including their expression in nasal and bronchial mucosa of atopic rhinitis and asthma subjects). Aim 2 examines the activation of skin-derived MCTC cells through FcyRIIA as well as FceRI. Degradation of cytokines by proteases released from the same MCTC cells will be studied in vitro, and the in vivo consequences considered. Whether IgG immune-complexes activate human MCTC cells will be determined in vitro. Finally, the functional impact of increased FceRI levels on mature MCTC cells caused by IgE will be assessed in vitro as well as in vivo. Aim 3 will test whether Th1 and Th2 type cytokines modulate mediator production by human mast cells. The mechanisms by which Th1 and/or Th2 cytokines induce LTC4 and enhance PGD2 production by activated skin MCTC cells will be examined. Whether FcyRI expression by IFN-y-primed MCTC cells enhances the response to IgG immune complexes or to CRP will be determined. Finally, the functional impact of upregulating cytokine receptors such as IL-4R on skin MCTC cells will be assessed. These studies will extend known phenotypic differences between different types of human mast cells to important functional features, reveal new paradigms for mast cell activation, and lead to a better understanding of their role(s) in human disease.