Trafficking mechanisms of locally generated colon antigen reactive T cells

描述（由申请人提供）：尽管在正常和炎症组织（如皮肤和小肠）中的白细胞运输领域已经做了大量的工作，但结肠相对而言尚未被探索。我们假设粘附分子表达的选择性组合确定了优先返回结肠的T细胞亚群。我们提出T细胞通过特定的归巢分子进入结肠。在局部充氧后，T细胞进入引流淋巴结，然后利用额外的特定运输分子/机制作为效应T细胞重新进入结肠固有层。这一假设得到了一些发现的支持，即淋巴细胞亚群通过表达独特的粘附分子组合，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：目标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模型，在结肠内使用霍乱毒素和卵清蛋白免疫诱导抗原特异性T细胞。我们将使用流式细胞术和免疫组织化学来确定转运受体在T细胞活化过程中的表达动力学，并诱导效应抗原特异性T细胞通过二次结肠免疫有效地进入结肠固有层。目标2。确定抗原特异性T细胞运输到结肠的机制。使用上述类似的技术，我们将确定T细胞激活和进入或离开结肠期间的运输分子表达。然后，我们将确定所鉴定的转运分子是否介导结肠T细胞的募集。将使用粘附阻断抗体和趋化因子受体缺失转基因小鼠来研究运输分子的作用。在结肠淋巴细胞上鉴定独特的转运分子或转运受体的特殊组合将改善我们对免疫细胞转运到结肠的染色不足，并为炎症性肠病（IBD）提供潜在的新治疗靶点。

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.