Sakuraba Atsushi, Sato Toshiro, Kamada Nobuhiko, Kitazume Mina, Sugita Akira, Hibi Toshifumi
Division of Gastroenterology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Gastroenterology. 2009 Nov;137(5):1736-45. doi: 10.1053/j.gastro.2009.07.049. Epub 2009 Jul 24.
BACKGROUND & AIMS: Dendritic cells (DCs) possess the most potent ability to induce acquired immunity. However, their involvement in the pathogenesis of Crohn's disease (CD) has not yet been determined. We aimed to establish the immune status of mesenteric lymph nodes, the major gut-associated lymphoid tissue, and isolated DCs and determine their involvement in the pathogenesis of CD.
CD4(+) T cells and DCs were isolated from mesenteric lymph nodes of CD, ulcerative colitis, and normal control. The immune status of CD4(+) T cells was analyzed by cytokine production and transcriptional profile. Surface phenotype of DCs was analyzed by flow cytometry. Cytokine production by myeloid DCs was analyzed by real-time polymerase chain reaction and exogenous bacterial stimulation. Immune stimulating activity of DCs was determined by mixed lymphocyte reaction.
In CD, mesenteric lymph node CD4(+) T cells produced higher amounts of interferon-gamma and interleukin (IL)-17 compared with ulcerative colitis and normal control, and this was dictated by increased T-bet and retinoic acid-related orphan receptor-gamma expression. Three subtypes of DCs, myeloid DC, plasmacytoid DC, and mature DC, were identified in all groups. When stimulated with exogenous bacterial derivative, myeloid DCs from CD produced a higher amount of IL-23 and a lower amount of IL-10. Myeloid DCs from CD induced stronger T helper cell (Th)1 immune response in mixed lymphocyte reaction compared with those from ulcerative colitis and normal control.
Our findings revealed that mesenteric lymph node is the key pathogenic location of CD elicited by the unique cytokine milieu produced by DCs leading to a dysregulated Th1/Th17 immune response.
树突状细胞（DCs）具有诱导获得性免疫的最强能力。然而，它们在克罗恩病（CD）发病机制中的作用尚未明确。我们旨在确定肠系膜淋巴结（主要的肠道相关淋巴组织）和分离出的DCs的免疫状态，并确定它们在CD发病机制中的作用。
从CD、溃疡性结肠炎和正常对照的肠系膜淋巴结中分离出CD4(+) T细胞和DCs。通过细胞因子产生和转录谱分析CD4(+) T细胞的免疫状态。通过流式细胞术分析DCs的表面表型。通过实时聚合酶链反应和外源性细菌刺激分析髓样DCs产生的细胞因子。通过混合淋巴细胞反应确定DCs的免疫刺激活性。
在CD中，与溃疡性结肠炎和正常对照相比，肠系膜淋巴结CD4(+) T细胞产生更高水平的干扰素-γ和白细胞介素（IL）-17，这是由T-bet和视黄酸相关孤儿受体-γ表达增加所决定的。在所有组中均鉴定出三种DCs亚型，即髓样DC、浆细胞样DC和成熟DC。当用外源性细菌衍生物刺激时，来自CD的髓样DCs产生更高水平的IL-23和更低水平的IL-10。与来自溃疡性结肠炎和正常对照的髓样DCs相比，来自CD 的髓样DCs在混合淋巴细胞反应中诱导更强的辅助性T细胞（Th）1免疫反应。
我们的研究结果表明，肠系膜淋巴结是由DCs产生的独特细胞因子环境引发的CD关键致病部位，导致Th1/Th17免疫反应失调。
