Trafficking mechanisms of locally generated colon antigen reactive T cells

描述(申请人提供)：尽管在白细胞在正常组织和炎症组织如皮肤和小肠中的运输方面已经做了广泛的工作，但结肠相对来说还没有被探索。我们假设，黏附分子表达的选择性组合识别出优先定位于结肠的T细胞亚群。我们认为T细胞通过特定的归巢分子进入结肠。在局部刺激后，T细胞进入引流淋巴结，然后作为效应器T细胞通过额外的特定转运分子/机制重新进入结肠固有层。支持这一假说的发现是，淋巴细胞亚群通过其独特的黏附分子组合的表达，表现出不同的组织定位，例如在小肠和皮肤中。基于这些假设，我的建议的具体目标是：目的1.建立体内模型，研究抗原反应性T细胞的结肠特异性靶向。在这里，我们将使用最近描述的使用霍乱毒素和卵清蛋白免疫在结肠内诱导抗原特异性T细胞的模型。我们将使用流式细胞术和免疫组织化学来确定T细胞活化过程中运输受体表达的动力学，并通过二次结肠免疫诱导能够有效进入结肠固有层的效应性抗原特异性T细胞。目的2.确定抗原特异性T细胞转运至结肠的机制。使用上面的类似技术，我们将确定T细胞激活期间以及进入或离开结肠期间的运输分子的表达。然后，我们将确定运输分子是否参与了结肠T细胞的募集。运输分子的作用将使用黏附阻断抗体和可用的趋化因子受体缺失转基因小鼠进行研究。识别独特的转运分子或结肠淋巴细胞上转运受体的特殊组合将改善免疫细胞转运到结肠的底色，并为炎症性肠病(IBD)提供潜在的新治疗靶点。 公共卫生相关性： 这个项目与影响肠道的自身免疫性疾病，如炎症性肠病(IBD)的相关性是巨大的。我的导师和他的团队此前已经确定并表征了针对白细胞交通的黏附分子的生理作用，如(4(7)整合素；[SIC])，这导致了抗(4-整合素(Natalizumab))重组单抗在治疗IBD(如克罗恩病)中的关键应用和临床试验(21)。我的研究结果可能有助于更好地了解优先免疫细胞向结肠的转运，并可能为IBD的治疗靶点和理解IBD的发病机制提供新的见解。

DESCRIPTION (provided by applicant): Although extensive work has been done in the area of leukocyte trafficking in normal and inflamed tissues such as the skin and small intestine, the colon is relatively unexplored. We hypothesize that selective combinations of adhesion molecule expression identifies subsets of T cells that preferentially home to the colon. We propose that T cells enter the colon via specific homing molecules. Following local anitgen [sic] primiming [sic] the T cells exit to draining lymph nodes and later re-enter colon lamina propria as effector T cells using additional specific trafficking molecules/mechanisms. This hypothesis is supported by findings that subsets of lymphocytes, via their expression of unique combination of adhesion molecules, manifest differential tissue localization for e.g. in the small intestine and the skin. Based on these hypotheses, the specific aims of my proposal are: Aim 1. Generate an in vivo model to study colon-specific targeting of antigen-reactive T cells. Here we will use recently described model of inducing antigen specific T cell within the colon using cholera toxin and ovalbumin immunizations. We will use flow cytometry and immunohistochemistry to determine the kinetics of trafficking receptor expression during T cell activation and induce effector antigen specific T cells capable of efficiently entering the colon lamina propria with secondary colon immunizations. Aim 2. Determine mechanisms of antigen specific T cell trafficking to the colon. Using similar techniques above [sic] we will determine trafficking molecule expression during T cell activation and during entry to or exit from the colon. We will then determine whether the trafficking molecules identfied [sic] mediate recruitment of colon T cells. The role of the trafficking molecules will be studied using adhesion blocking antibodies and where available chemokine receptor deletion transgenic mice. Identification of unique trafficking molecules or specialized combination of trafficking receptors on colon lymphocytes will improve our understaining [sic] of immune cell trafficking to the colon and offer potentially new therapeutic targets for inflammatory bowel disease (IBD). PUBLIC HEALTH RELEVANCE: The relevance of this project to autoimmune diseases affecting the intestine, such as inflammatory bowel disease (IBD) is tremendous. My mentor and his group have previously identified and characterized the physiologic roles of adhesion molecules targeting leukocyte traffic such as the (4(7 integrin; [sic] which have led to key application and clinical trials of a recombinant monoclonal antibody against (4-integrin (natalizumab), in the treatment of IBD such as Crohn's disease (21). Findings from my studies could lead to better understanding of preferential immune cell trafficking to the colon and potentially offer new insights into IBD therapeutic targets and understanding the pathogenesis of IBD.