Characterization of Different Types of Human Mast Cells

描述（由申请人提供）：肥大细胞是直接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。目前的提案扩展了源于基于蛋白酶表型的两种类型的人类肥大细胞的鉴定以及干细胞因子使人类肥大细胞能够从造血祖细胞在体外发育的发现的工作。目的1研究区分MCT（胰蛋白酶？？）和MCTC（胰蛋白酶？？？）型人类肥大细胞的新功能和表型特征。这些包括：MCTC细胞-细胞表面CD88的功能性表达，il -6介导的chymase蛋白/mRNA在MCTC细胞中的上调，以及MCTC细胞在无血清培养基中的增殖；MCT细胞- IL-6使MCT细胞抵抗IL-4凋亡的机制，肺MCT细胞转化为MCTC细胞的失败，以及仅在MCT细胞中表达的新基因的评估（包括其在特应性鼻炎和哮喘患者鼻和支气管粘膜中的表达）。目的2通过FcyRIIA和FceRI检测皮肤源性MCTC细胞的激活。我们将在体外研究MCTC细胞释放的蛋白酶对细胞因子的降解，并考虑其在体内的影响。IgG免疫复合物是否能激活人MCTC细胞将在体外测定。最后，我们将在体外和体内评估IgE引起的FceRI水平升高对成熟MCTC细胞的功能影响。目的3将测试Th1和Th2型细胞因子是否调节人肥大细胞产生介质。Th1和/或Th2细胞因子通过激活皮肤MCTC细胞诱导LTC4和增强PGD2产生的机制将被研究。ifn -y引发的MCTC细胞表达FcyRI是否增强了对IgG免疫复合物或CRP的反应将被确定。最后，将评估上调细胞因子受体（如IL-4R）对皮肤MCTC细胞的功能影响。这些研究将把不同类型的人类肥大细胞之间已知的表型差异扩展到重要的功能特征，揭示肥大细胞活化的新范式，并使人们更好地了解它们在人类疾病中的作用。

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.