Defining thymic epithelial heterogeneity

描述（由申请人提供）：尽管胸腺环境对T细胞的产生和自我投射的重要性，有助于定义发展中的T细胞的自我耐受性，但导致胸腺上皮分化的许多程序仍然知之甚少。该领域的一个重要进展是认识到这种上皮具有有丝分裂活性，并且在出生后不断被替换。这意味着胸腺上皮的组成代表了不同分化阶段上皮细胞的混合物。目前，分析这种上皮异质性的手段还不充分，这阻碍了定义上皮分化程序以及将这一过程与影响胸腺上皮细胞呈递耐受原性自身抗原的Aire表达联系起来的努力。我们之前的工作已经证明，Aire-/-胸腺的MTEC隔室表现出与MTEC分化改变程序一致的特征，并且在WT胸腺中罕见的MTEC亚群扩展。我们在此建议从Aire+/+和Aire-/-胸腺中产生针对MTEC富集群体的试剂抗体，作为开发试剂抗体的手段，这将使我们能够更精确地定义MTEC异质性。这些新工具将支持我们长期以来在胸腺上皮间室中建立前体-后代关系的努力，并将有助于了解影响胸腺上皮组织的不同突变如何影响胸腺上皮分化。

DESCRIPTION (provided by applicant): Despite the importance of the thymic environment for the generation of T cells and the projection of self that helps define self-tolerance for developing T cells, much of the differentiation program that gives rise to thymic epithelium remains poorly understood. An important advance in this area has been the appreciation that this epithelium is mitotically active and that it is continually replaced postnatally. This means that the composition of thymic epithelium represents a mixture of epithelial cells at different stages of differentiation. Presently, the means to parse this epithelial heterogeneity is inadequate and this has hampered efforts to define the program of epithelial differentiation and to relate this process to the expression of Aire, which influences the ability of thymic epithelial cells to present tolerogenic self antigens. Our previous work has demonstrated that the MTEC compartment of the Aire-/- thymus exhibits features consistent with an altered program of MTEC differentiation, with expansion of a MTEC subset that is rare in the WT thymus. We propose here to generate reagent antibodies against enriched populations of MTEC from Aire+/+ and Aire-/- thymi as a means to develop reagent antibodies that will allow us to define MTEC heterogeneity with more precision. These new tools will support our long-standing efforts to establish precursor-progeny relationships within the thymic epithelial compartment and will help efforts to understand how different mutations that affect thymic epithelial organization are affecting thymic epithelial differentiation. PUBLIC HEALTH RELEVANCE: Epithelial cells comprising the thymic environment play a critical role in the generation and differentiation of T cells. Lack of knowledge regarding the basis for the observed heterogeneity of thymic epithelium is impeding the development of strategies to retard age-related loss of thymic function or to enhance thymic expression of molecules that could modulate the ability to establish self-tolerance. This project will generate much needed antibody tools to help define thymic epithelial heterogeneity and relate the expression of these molecules to several models of perturbed thymic epithelial differentiation.