Regulation of Immune Responses in Humans and Non-Human Primates

人类和非人类灵长类动物免疫反应的调节

• 批准号: 6098937
• 负责人: WARREN STROBER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6098937
• 关键词: B lymphocyte; CD2 molecule; CD3 molecule; CD95 molecule; T cell receptor; T lymphocyte; animal tissue; apoptosis; autoimmunity; biological signal transduction; cell cell interaction; cytokine; cytotoxic T lymphocyte; helper T lymphocyte; human tissue; immunoregulation; interferon gamma; interleukin 2; laboratory mouse; leukocyte activation /transformation; lymphocyte proliferation; tissue /cell culture

Project I: Normal human lamina propria lymphocyte manifest increased unstimulated apoptosis (when compared to peripheral lymphocytes) as well as enhanced apoptosis following stimulation via the CD2-activation pathway. This CD2 pathway-induced apoptosis downregulates cell expansion and cytokine production and thus protects the organisms from potentially harmful responses. In previous studies we demonstrated that lamina propria T cells from patients with Crohn's disease and ulcerative colitis manifest abnormal proliferation and cytokine production. It was therefore of interest to determine if such cells also exhibited abnormal patterns of apoptosis. We found that lamina propria lymphocytes of Crohn's disease patients showed defective CD2-pathway induced apoptosis. In addition, we showed that Crohn's disease lamina propria T cells although expressing comparable amount of cell surface Fas, are less sensitive to Fas-mediated apoptosis as compared to control cells. Finally, we demonstrated that Crohn?s disease lamina propria lymphocytes manifest increased expression of Bcl-2 following CD2-pathway stimulation and elevated Bcl-2 levels in cultures of unstimulated T cells. These studies thus establish that T cells in the inflamed lamina propria of Crohn's disease patients manifest decreased CD2-pathway-induced apoptosis and elevated Bcl-2 levels. These changes are likely to be secondary to the chronic inflammation and may aggravate disease in patients with IBD. Project II: Chronic intestinal inflammation in several animal models has been shown to be mediated by IL-12-driven Th1 T cells. These findings led us to evaluate IL-12 function and signaling in patients with inflammatory bowel diseases. In initial studies we showed that CD40L plus IFN-gamma-stimulated lamina propria (LP) macrophages from patients with Crohn's disease (CD) but not from patients with ulcerative colitis (UC) produce significantly higher levels of IL-12 p70 as compared to control macrophages. In further studies we demonstrated that CD4+ T cells from CD but not UC patients exhibit high levels of IL-12R Beta-2 chain and intranuclear STAT-4 expression. Finally, we showed that down-regulation of STAT-4 by an antisense oligonucleotide strikingly reduced CD4+ T cell IFN- gamma production in CD. In summary, the data suggest a critical role for IL-12 in the differential immunopathogenesis of CD and UC: whereas high levels of IL-12 in CD lead to generation of IFN-gamma-producing Th1 cells, low IL-12 levels in UC favors production of T cells producing Th2 type cytokines. Thus, activation of the IL-12/STAT-4 pathway emerges as a central mechanism in the pathogenesis of Crohn's disease that could be an attractive target for therapeutic intervention.

项目一：正常人固有层淋巴细胞 表现出增加的未受刺激的细胞凋亡（当与 外周淋巴细胞）以及增强的凋亡后， 通过CD 2激活途径刺激。这个CD 2 途径诱导的凋亡下调细胞扩增， 细胞因子的产生，从而保护生物体免受 可能有害的反应。在以前的研究中，我们证明了 克罗恩病患者的固有层T细胞， 溃疡性结肠炎表现为异常增殖和细胞因子 生产因此，确定这些细胞是否 也表现出异常的凋亡模式。我们发现了那层 克罗恩病患者的固有淋巴细胞表现出缺陷 CD 2通路诱导细胞凋亡。此外，我们还表明， 克罗恩病固有层T细胞虽然表达 相当数量的细胞表面Fas，对 Fas介导的凋亡相比，控制细胞。最后我们 证明了克罗恩？s病固有层淋巴细胞 表现出CD 2途径后Bcl-2表达增加 刺激和未刺激T细胞培养物中Bcl-2水平升高 细胞因此，这些研究确定了炎症板层中的T细胞 克罗恩病患者的固有细胞减少 CD 2途径诱导的细胞凋亡和Bcl-2水平升高。这些 变化可能是继发于慢性炎症， 可能加重IBD患者的疾病。项目二：慢性 在几种动物模型中的肠道炎症已经显示， 由IL-12驱动的Th 1 T细胞介导。这些发现使我们 评估炎症性肠病患者中IL-12的功能和信号传导 肠道疾病在最初的研究中，我们发现CD 40 L + IFN-γ刺激的固有层（LP）巨噬细胞来自 克罗恩病（CD）患者，但非克罗恩病患者 溃疡性结肠炎（UC）产生显著更高水平的IL-12 p70与对照巨噬细胞相比。在进一步的研究中，我们 表明CD患者的CD 4 + T细胞而不是UC患者的CD 4 + T细胞 表现出高水平的IL-12 R β-2链和核内STAT-4 表情最后，我们发现，STAT-4的下调， 反义寡核苷酸显著降低CD 4 + T细胞IFN-γ， CD中的伽马生产。总之，数据表明， IL-12在CD的不同免疫发病机制中的作用， UC：而CD中高水平的IL-12可导致 产生IFN-γ的Th 1细胞，UC中低IL-12水平有利于 产生产生Th 2型细胞因子的T细胞。因此，在本发明中， IL-12/STAT-4通路的激活作为一种中枢信号通路， 克罗恩病的发病机制，可能是一个 治疗干预的有吸引力的目标。