INTEGRIN LIGAND IN GUT LAMINA PROPRIA

粘膜T细胞亚群有不同的定位模式，如CD8+ 占肠道上皮内T淋巴细胞的90%以上 固有层内以CD4+T细胞为主。小才是 已知该子集特定的解释机制 本地化。整合素αEbeta7在大于90的细胞上表达 CD8+淋巴细胞百分比和40-50%的CD4+细胞弥漫性 与肠粘膜一起分布，但不到3% 外周血淋巴细胞，并与E-钙粘附素结合在 上皮细胞。因此，它是在T中起作用的候选者 细胞/上皮细胞相互作用可能改变T细胞的定位。 评价整合素αE的体内功能(S) 产生缺陷小鼠。对这些动物的研究表明， 肠上皮和肠上皮内T细胞的数量 E-钙粘素不表达的固有层。此外，新鲜的 分离的肠上皮内淋巴细胞(IIEL)，表达 αEbeta7，更有效地附着在固有层组织切片上 而不是从AlphaE缺陷小鼠中分离的iIEL。这些观察结果导致了 美国假设αEbeta7介导粘附性相互作用 在固有层内表达的配体。在此应用程序中， 有人建议进行研究，以证明额外的字母Ebeta7 配体在固有层内表达，并定义该配体 在分子水平上。在目标1中，αEbeta7转染体将被 经检测证实，αEbeta7的表达赋予了 将细胞转染至固有层并确定人类 AlphaEbeta7具有类似的黏附功能。此外，研究还包括 将被执行以鉴定表达该基因的培养细胞系 假定附加的αEbeta7配体，使用粘附性试验 识别支持α-Ebeta7依赖黏附的细胞系。在AIM 2、抗配基单抗或可溶性重组形式的 将产生与该配体结合的αEbeta7并用于 测定αEbeta7配体的生化结构。在AIM 3，编码这种固有层配体的基因将被克隆 表达克隆或配基纯化，然后氨基酸 序列确定。这些研究将使识别 和第二个αEbeta7拮抗受体和Will的鉴定 深入了解粘膜淋巴细胞定位的机制。 作为一种抗αE的单抗，显著减少了肠道 在小鼠炎症性肠病模型中的炎症，这些研究 可能对炎症性肠病的治疗有重要意义 疾病。

Mucosal T cells subsets have distinct localization patterns, as CD8+ comprise over 90 percent of the intestinal intraepithelial T lymphocytes while CD4+ T cells predominate within the lamina propria. Little is known about the mechanisms which account for this subset specific localization. The integrin alphaEbeta7 expressed on greater than 90 percent of CD8+ lymphocytes and on 40-50 percent of CD4+ cells diffusely distributed with the intestinal mucosa but on less than 3 percent of peripheral blood lymphocytes, and binds to E-cadherin expressed on epithelial cells. Thus, it is a candidate to function in T cell/epithelial cell interactions which may modify T cell localization. To evaluate the in vivo function(s) of alphaEbeta7, integrin alphaE deficient mice were generated. Study of these animals revealed reduced numbers of T cells within intestinal epithelium and also within the lamina propria where E-cadherin is not expressed. Furthermore, freshly isolated intestinal intraepithelial lymphocytes (iIEL), which express alphaEbeta7, adhered more efficiently to lamina propria tissue sections than iIEL isolated from alphaE deficient mice. These observations led us to hypothesize that alphaEbeta7 mediates an adhesive interaction to a ligand expressed within the lamina propria. In this application, studies are proposed to demonstrate that an additional alphaEbeta7 ligand is expressed within the lamina propria and to define this ligand at the molecular level. In aim 1, alphaEbeta7 transfectants will be tested to confirm that alphaEbeta7 expression confers adhesion of transfected cells to the lamina propria and to determine if human alphaEbeta7 mediates a similar adhesive function. In addition, studies will be performed to identify a cultured cells line which expresses the putative additional alphaEbeta7 ligand, using adhesion assays to identify cell lines which support alphaEbeta7 dependent adhesion. In aim 2, anti-ligand monoclonal antibodies or a soluble recombinant form of alphaEbeta7 which binds to this ligand will be generated and used to determine the biochemical structure of the alphaEbeta7 ligand. In aim 3, the gene encoding this lamina propria ligand will be cloned using either expression cloning or ligand purification followed by amino acid sequence determination. These studies will enable the identification and characterization of a second alphaEbeta7 counter-receptor and will provide insight into the mechanisms of mucosal lymphocytes localization. As an anti-alphaE monoclonal antibody dramatically reduced intestinal inflammation in a murine inflammatory bowel disease model, these studies may have important implications in the treatment of inflammatory bowel disease.