T cell-tissue interaction models

 描述(申请人提供)：本R21提案直接响应PA-13-145，题为“发展动物模型和相关的生物研究材料”。这项提议的目标是开发两种新的动物模型，以满足包括免疫学、病毒学和干细胞医学在内的广泛领域中尚未满足的主要需求。所有有核细胞的表面都覆盖着MHC I类分子，这些分子提供来自细胞内蛋白质的多肽。T细胞扫描细胞表面，只接触它们所在的细胞 T细胞受体与特定的MHC-多肽复合体具有亲和力。一旦T细胞参与，结果高度依赖于呈递抗原的细胞和局部环境。不同的细胞类型可以导致不同的T细胞反应；例如，一些细胞可能会引导CD4T细胞分化为效应器，而其他细胞的呈递可能会指示它们变得调节。T细胞如何与特定类型的细胞相互作用是免疫学中最重要的问题之一。答案可以告诉我们为什么某些类型的细胞更容易产生自身免疫反应，以及为什么其他类型的细胞，如癌细胞，可能不太容易杀死T细胞。虽然我们知道T细胞如何与某些细胞类型反应，但有许多细胞类型与T细胞的相互作用从未被研究过。例如，我们不知道T细胞如何与多种类型的干细胞相互作用。我们假设，如果绿色荧光蛋白(GFP)可以作为模型抗原，那么可以研究T细胞与多种细胞类型的相互作用，这些细胞类型以前没有被研究过，包括许多类型的干细胞。Aim 1的目标是建立T细胞识别以MHC I或II类物质呈现的GFP表位的小鼠。Aim 1的结果将建立一个抗原特异性T细胞模型，该模型以一种常用的、易于监测的荧光报告为靶点。由于绿色荧光蛋白特异的CD8T细胞可以杀伤绿色荧光蛋白表达的细胞，我们假设绿色荧光蛋白特异的CD8T细胞可以用于选择性地清除小鼠体内几乎任何细胞群，如果感兴趣的细胞类型S表达绿色荧光蛋白。我们已经获得了初步数据，表明我们可以使用GFP特异性T细胞来杀伤脾、胰腺、肠道和心脏中表达GFP的细胞。目标2的目的是比较T细胞介导的细胞消融和白喉毒素(DT)介导的耗竭，并确定我们如何有效地使用GFP特异性T细胞来杀伤大脑中的细胞。这些研究的结果将建立一种新的细胞耗竭方法，可以用于已经存在的100只表达GFP的细胞类型特定的小鼠，而且它可能比DT介导的耗竭更少炎症。大量基于GFP的试剂和动物模型使GFP特异性T细胞小鼠与许多实验室相关，这些实验室进行了广泛的研究，包括但不限于：(I)了解特定细胞类型的抗原提呈能力，(Ii)模拟自身免疫破坏，(Iii)病原体-T细胞相互作用的特征，以及(Iv)鉴定特定细胞类型的功能 体内的细胞。

 DESCRIPTION (provided by applicant): This R21 proposal is in direct response to PA-13-145, entitled "Development of Animal Models and Related Biological Materials for Research". The goal of this proposal is to develop two new animal models to fill major unmet needs in a broad array of fields, including immunology, virology, and stem cell medicine. The surface of all nucleated cells are covered in MHC class I molecules that present peptides derived from proteins made in the cell. T cells scan the surface of a cell, and engage only cells in which their T cell receptor has affinity for a specific MHC-peptide complex. Once the T cell engages, the outcome is highly dependent on the cell presenting the antigen and the local context. Different cell types can result in different T cell responses; for example some cells may direct CD4+ T cell to differentiate into an effector, whereas presentation by other cells may direct them to become regulatory. How a T cell interacts with a particular cell type is one of the most important questions in immunology. The answer can tell us why some cell types are more prone to autoimmune responses, and why other cell types, such as cancer cells, may be less prone to T cell killing. While we know how T cells react with some cell types, there are many cell types whose interaction with T cells has never been studied. For example, we do not know how T cells interact with many types of stem cells. We hypothesize that if green florescent protein (GFP) can be utilized as a model antigen, than T cell interactions with numerous cell types, which were not previously studied including many types of stem cells, can be investigated. The objective of Aim 1 is to generate mice in which the T cells recognize an epitope of GFP presented in MHC class I or II. The outcome of Aim 1 would establish an antigen-specific T cell model that targets a commonly used, easily monitored, florescent reporter. Since GFP-specific CD8+ T cells can kill GFP-expressing cells, we hypothesize that GFP-specific CD8+ T cells can be used to selectively deplete almost any cell population in a mouse, if the cell type of interest s expressing GFP. We have already obtained preliminary data showing that we can use GFP-specific T cells to kill GFP expressing cells in the spleen, pancreas, gut, and heart. The objective of Aim 2 is to compare T cell mediated cell ablation to diphtheria toxin (DT)-mediated depletion, and to determine how effectively we can use the GFP-specific T cells to kill cells in the brain. The outcome of these studies will establish a new method of cell depletion that can be used with the 100s of cell type-specific GFP expressing mice that already exist, and it is potentially less inflammatory than DT-mediated depletion. The abundance of GFP-based reagents and animal models makes the GFP-specific T cell mice relevant for numerous labs doing a wide variety of research including, but not limited to: (i) understanding the antigen presenting capacity of specific cell types, (ii) modeling autoimmune destruction, (iii) characterization of pathogen-T cell interactions, and for (iv) identifying the function of specific cells in vivo.