Mucosal Immunity in Integrin Alpha-E Deficient Mice

整合素α E β 7在T细胞、肥大细胞和树突状细胞（DC）上表达，并与E-钙粘蛋白结合以介导T细胞/上皮细胞特异性粘附。 此外，与alphaE+/+小鼠相比，alphaE-/-小鼠的肠上皮内T细胞数量减少，表明这种相互作用在体内的重要性。 此外，在肠源性内皮细胞上存在另一种α E β 7配体，其分布未知。 为了评估α E β 7在体内的作用，将CD 4 + CD 45 RBhi T细胞转移到scid/scid小鼠中以产生Th 1偏向的肠道炎症。 通过给予抗α E β 7单克隆抗体消除了该综合征。 相比之下，当alphaE+/+受体小鼠用alphaE-/-与alphaE+/+供体T细胞重建时，限制了alphaE缺乏对T细胞的影响，疾病严重程度仅得到适度改善。 最后，在IL-10-/-小鼠中发生的Th 1偏向性肠道炎症中，与alphaE-/-小鼠相比，alphaE-/-小鼠中肠道炎症的临床体征加速，这是一种所有细胞都缺乏alphaE的情况。 总的来说，这些研究表明，除了T细胞之外，还有另一种细胞类型调节肠道炎症，并且当这些非T细胞缺乏α E β 7时，基于Th 1细胞因子的肠道炎症恶化。 重要的是，在体外研究中，当在源自alphaE-/-与alphaE+/+小鼠的DC存在下刺激时，初始CD 4 + T细胞产生更多的Th 1和更少的Th 2细胞因子。这一发现表明，当DC是alphaE缺陷，Th 1偏向肠道炎症更糟，可能通过改变DC的定位，功能或与T细胞的相互作用。 在AIM 1中，将通过流式细胞术、ELISA和免疫组织化学确定α E β 7 + DC的表型、细胞因子表达和分布。 在AIM 2中，通过临床和显微镜评价，当α E β 7缺乏局限于受体小鼠中的非T细胞时，将确定α E β 7缺乏对肠道炎症的CD 4 + CD 45 RBhi T细胞转移模型的过程的影响。 在AIM 3中，在直接刺激后，在有或没有α Ebeta 7交联的情况下，或在T细胞/DC共培养物中刺激后，使用ELISA和流式细胞术评估α Ebeta 7在调节DC细胞因子表达或表面表型中的作用。 在AIM 4中，将通过FACS或北方印迹评估E-钙粘蛋白或其它α E β 7配体在初始或最近活化的T细胞上的可能表达。 此外，将使用粘附和共刺激测定来确定alphaEbeta 7在DC/T细胞相互作用中的作用。 这些实验将提供对整合素α E β 7在DC定位和与Th淋巴细胞分化相关的功能中的影响的深入了解，这与细胞因子失调导致炎症的肠特别相关。

The integrin alphaEbeta7 is expressed on T cells, mast cells and dendritic cells (DCs) and binds to the E-cadherin to mediate T cell/epithelial cell specific adhesion. Furthermore, alphaE-/- mice have reduced numbers of intestinal intraepithelial T cells versus alphaE+/+ mice, indicating the importance of this interaction in vivo. In addition, there is another alphaEbeta7 ligand on intestine derived endothelial cells, whose distribution is not known. To evaluate the role of alphaEbeta7 in vivo, CD4+CD45RBhi T cells were transferred into scid/scid mice to generate Th1 biased intestinal inflammation. This syndrome was abrogated by administration of an anti-alphaEbeta7 monoclonal antibody. In contrast, when the alphaE+/+ recipient mice were reconstituted with alphaE-/- versus alphaE+/+ donor T cells, limiting the impact of alphaE deficiency to the T cell, disease severity was only modestly ameliorated. Finally, in the Th1 biased intestinal inflammation that develops in IL-10-/- mice, clinical signs of intestinal inflammation were accelerated in alphaE-/- versus alphaE-/- mice, a condition in which all cells are alphaE deficient. Overall, these studies suggest that there is another cell type, in addition to T cells, that modulates intestinal inflammation, and that when these non-T cells are alphaEbeta7 deficient, Th1 cytokine based intestinal inflammation is worsened. Importantly, in in vitro studies, naive CD4+ T cells produced more Th1 and less Th2 cytokines when stimulated in the presence of DCs derived from alphaE-/- versus alphaE+/+ mice. This finding suggests that when DCs are alphaE deficient, Th1 biased intestinal inflammation is worse, possibly through altered DC localization, function or interactions with T cells. In AIM 1, the phenotype, cytokine expression and distribution of alphaEbeta7+ DCs will be determined by flow cytometry, ELISA and immunohistochemistry. In AIM 2, the impact of alphaEbeta7 deficiency upon the course of the CD4+CD45RBhi T cell transfer model of intestinal inflammation will be determined when alphaEbeta7 deficiency is restricted to non-T cells in recipient mice, by clinical and microscopic evaluation. In AIM 3, the role of alphaEbeta7 in regulating DC cytokine expression or surface phenotype will be evaluated following direct stimulation, with or without alphaEbeta7 crosslinking, or after stimulation in T cell/DC co-cultures, using ELISA and flow cytometry. In AIM 4, the possible expression of E-cadherin or of other alphaEbeta7 ligands on naive or recently activated T cells will be assessed, by FACS or Northern blot. In addition, the roll of alphaEbeta7 in DC/T cell interactions will be determined using adhesion and co-stimulation assays. These experiments will provide insight into the impact of integrin alphaEbeta7 in DC localization and function relevant to Th lymphocyte differentiation, which have particular relevance to the intestine where cytokine dysregulation leads to inflammation.