Lymphocyte Homing Mechanisms in Normal & Inflamed Colon

描述(由申请人提供)： 尽管在白细胞在正常组织和炎症组织(如皮肤和小肠)中的运输方面已经进行了广泛的研究，但对结肠的研究相对较少。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。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，这一发现支持了这一假说。此外，我们推测黏附分子表达的改变在一定程度上解释了结肠炎期间T细胞的大量涌入。基于这些假设，我的建议的具体目标是： 目的1.研究慢性自发性结肠炎模型--角蛋白-8缺陷(K8-/-)小鼠的炎症反应。在这个目标中，我们将描述与K8-/-结肠炎相关的免疫反应。虽然K8是小肠和大肠中的主要角蛋白，但在K8-/-小鼠中，结肠是炎症的主要目标。我们发现K8-/-结肠炎与Th2细胞因子的产生有关，Th2细胞因子的产生适合于抗生素治疗。 目的：比较正常和炎症状态下K8+/+和K8-/-小鼠结肠和小肠固有层T细胞和内皮细胞黏附和运输分子的表达。在这里，我们将使用流式细胞术和免疫组织化学来确定与包括小肠在内的其他组织相比，结肠内皮细胞和T细胞表达的黏附和运输分子的差异。 目的3.确定AIM 2中确定的分子是否介导正常和炎症结肠中结肠固有层淋巴细胞在体内的重新募集。在这里，我们将通过实施过继细胞转移和在短期归巢试验中使用封闭抗体来研究各种黏附分子的作用。 K8-/-小鼠是炎症性肠病(IBD)的独特模型，因为它代表了初级上皮细胞缺陷，并为研究炎症和归巢到结肠提供了大量的细胞。这项拟议的研究将提高我们对免疫细胞转运到结肠的理解，为IBD可能的致病机制提供见解，并可能为IBD开辟新的治疗靶点。

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. This hypothesis is supported by findings that subsets of lymphocytes, via their expression of unique combination of adhesion molecules, manifest differential tissue localization. Furthermore, we postulate that altered adhesion molecule expression, in part, explains the massive influx of T cells seen during colonic inflammation. Based on these hypotheses, the specific aims of my proposal are: Aim 1. Characterize the inflammation in a chronic spontaneous mouse colitis model, the keratin-8 deficient (K8 -/-) mice. In this aim we will characterize the immune response associated with the K8 -/- colitis. Although K8 is a major keratin in the small and large intestine, the colon is the primary target of inflammation in K8 -/- mice. We find that K8 -/- colitis is associated with Th2 cytokine production which is amenable to antibiotic treatment. Aim 2. Compare adhesion and trafficking molecule expression in T and endothelial cells within lamina propria of the colon and small intestine, under normal and inflammatory conditions, using K8 +/+ and K8 -/- mice. Here we will use flow cytometry and immunohistochemistry to determine differential adhesion and trafficking molecule expression by colon endothelial and T cells as compared with other tissues, including the small intestine. Aim 3. Determine whether molecules identified in aim 2 mediate recruitment of colon lamina propria lymphocytes in vivo in normal and inflamed colons. Here we will study the role of various adhesion molecules, by perfoming adoptive cell transfers and using blocking antibodies in short-term homing assays. The K8 -/- mouse is a unique model of inflammatory bowel disease (IBD) in that it represents a primary epithelial cell defect, and provides significant cell number to study inflammation and homing to the colon. The proposed study should improve our understanding of immune cell trafficking to the colon, offer insights into possible IBD pathogenic mechanisms, and potentially unfold new therapeutic targets to consider for IBD