REGULATION OF IL 12 IN MUCOSAL IMMUNITY AND IBD

拟议研究的目的是了解 人炎症性肠病(IBD)免疫发病机制研究 白细胞介素12(IL-12)的调控表达特征。IL-12 是一种具有多效性的异二聚体细胞因子，包括 T辅助细胞1(Th1)应答的诱导和维持。在体内，Th1 免疫应答是发展免疫系统的关键。 胞内微生物。在自身免疫性疾病中，Th1细胞可能参与 组织损伤。辅助性T细胞2(Th2)在传染性支气管炎感染中是有害的 细胞内生物，但可能抑制Th1引起的组织损伤 自身免疫性和炎症性疾病的反应。最近描述的 动物模型强调Th1和Th2亚群在慢性粒细胞白血病中的重要性 慢性肠黏膜炎症的发病机制。的分泌物 由抗原提呈细胞(APC)分泌的IL-12是一种专有的信号。 产生稳定的Th1表型。因此，IL-12的调节 基因表达可能是影响Th亚群的主要事件 体内分化和细胞因子的产生。两种IL-2的表达 12个基因将在APC品系中通过定义 潜在的诱导物，并测定mRNA诱导的动力学。5. 将从小鼠基因组DNA中分析每个基因的调节区 转录起始点定位、限制性内切酶定位和DNA克隆 测序。然后将确定IL-12的表达是否 通过调节转录起始、mRNA稳定性、 或转录的衰减。最后，每个LL-1的启动子区域 12基因将通过描述顺式作用来描述其功能特征 参与IL-12转录启动的调控元件 瞬时和稳定转染法。涉及的反式作用因素 IL-12基因的表达将通过电泳迁移率进行分析 移位分析和DNA酶I足迹。一旦这些监管要素 它们对IL-12表达的贡献将在 特定的疾病模型。通过表征IL-2的调控表达 12在APC中，决定Th1反应的分子机制可能是 描述。然后可以利用这些机制来改变宿主免疫力 感染和炎症性疾病，包括IBD。

The objective of the proposed study is to understand the immunopathogenesis of the human inflammatory bowel diseases (IBD) by characterizing the regulated expression of interleukin-12 (IL-12). IL-12 is a heterodimeric cytokine with pleiotropic effects, including the induction and maintenance of T helper 1 (Th1) responses. In vivo, Th1 responses are critical in the development of immunity against intracellular microbes. In autoimmune disorders, Th1 cells may mediate tissue injury. T helper 2 (Th2) cells are deleterious in infections with intracellular organisms, but may inhibit the tissue damage elicited by Th1 responses in autoimmune and inflammatory diseases. Recently described animal models highlight the importance of Th1 and Th2 subsets in the pathogenesis of chronic intestinal mucosal inflammation. The secretion of IL-12 by antigen presenting cells (APCs) is an obligate signal for the generation of a stable Th1 phenotype. Therefore, the regulation of IL-12 gene expression is likely to be a primary event influencing Th subset differentiation and cytokine production Th vivo. Expression of the two IL- 12 genes will be characterized in APC lines by defining the effects of potential inducers, and determining the kinetics of mRNA induction. The 5 regulatory region of each gene will be analyzed from murine genomic DNA clones by transcription start site mapping, restriction mapping, and DNA sequencing. It will then be determined whether IL-12 expression is regulated through modulation of transcription initiation, mRNA stability, or attenuation of transcription. Finally, the promotor region for each lL- 12 gene will be functionally characterized by describing cis-acting control elements involved in initiation of IL-12 transcription in transient and stable transfection assays. Trans-acting factors involved in IL-12 gene-expression will be analyzed by electrophoretic mobility shift assays and DNAse I footprinting. Once these regulatory elements are identified, their contribution to IL-12 expression will be studied in specific disease models. By characterizing the regulated expression of IL- 12 in APC, molecular mechanisms that determine Th1 responses may be described. These mechanisms may then be exploited to alter host immunity in infectious and inflammatory disorders, including IBD.