Development of novel therapy targeting innate immunity for Crohn's disease

克罗恩病(CD)是一种累及胃肠道的慢性炎症过程，以间歇性和跨壁性炎症为特征。虽然CD的病因尚不完全清楚，但越来越多的证据表明，局部免疫系统的失调在CD的发病机制中起着关键作用。来自人类和实验性小鼠结肠炎模型的研究表明，在CD中，局部免疫反应往往以T辅助细胞1型为主，并通过局部释放细胞因子如肿瘤坏死因子α、白介素12和白介素18来反映。然而，CD中的Th1免疫反应的触发机制尚不清楚。在本研究中，我们试图建立从人肠系膜淋巴结(MLN)中分离纯化树突状细胞的方法，并对CD3^+、CD11b^+和CD16^+细胞进行密度梯度离心法和免疫磁珠法纯化，然后用CD4^+细胞进行阳性分离。从MLN获得的细胞分析显示，CD的MLN中Dc1的比例比溃疡性结肠炎和对照组增加，CD MLN中的CD4+T细胞呈Th1分布。此外，我们试图通过建立IL-10缺陷(IL-10-/-)小鼠结肠炎模型来阐明巨噬细胞在肠道炎症中的作用，并证明了肠道巨噬细胞分化异常的亚群在Th1主导型慢性结肠炎中起关键作用。这些数据为了解肠道巨噬细胞与肠道菌群在IL-10-/-小鼠结肠炎发展中的关系提供了新的见解。

Crohn's disease (CD) is a chronic inflammatory process involving the gastrointestinal tract, characterized by discontinuous and transmural inflammation. Although the etiology of CD is not fully understood, accumulating evidence suggests that dysregulation of the local immune system is pivotal in the pathogenesis of CD. Studies from humans and experimental murine colitis models indicate that in CD, the local immune response tends to be predominantly T helper cell type 1 (Th1) and is reflected by local release of cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-12, and IL-18. However, it has not been elucidated what triggers the Th1 immune response in CD. In the present study, we attempted to establish the purification of dendritic cells from mesenteric lymph nodes (MLN) and to analyze the immune cascade in the mesenteric lymph nodes of human CD.We established the purification of dendritic cells from MLN by density gradient centrifugation and immunomagnetic depletion of CD3^+,CD11b^+ and CD16^+cells followed by positive isolation with CD4^+. The analysis of cells obtained from MLNs revealed that the proportion of DC1 was increased in the MLN of CD compared to ulcerative colitis and control and that CD4+ T lymphocytes from the MLN of CD show a Th1 profile.Furthermore, we tried to elucidate the roles of macrophages in intestinal inflammation by using an IL-10-deficient (IL-10-/-) mouse colitis model, and demonstrated that abnormally differentiated subsets of intestinal macrophage play a key role in Th1-dominant chronic colitis through excess production of IL-12 and IL-23 in response to bacteria. These data provide new insights into the intestinal macrophages to gut flora relationship in the development of colitis in IL-10-/- mice.