ANTIGEN PRESENTING CELL DEFECTS IN AUTOIMMUNE DIABETES

描述(改编自调查者摘要)：本项目建议 研究抗原提呈细胞中调节性缺陷的作用 在NOD小鼠体内发生IDD的过程中。初步数据显示， NOD中介导IDD易感性的一些多基因交互作用 小鼠可能会限制血源性抗原的呈递能力 细胞(APC)，如B淋巴细胞、巨噬细胞和树突状细胞 激活各种免疫调节通路。不寻常的H2 g7 MHC单倍型 已被证明对免疫耐受原性受损有明显的作用 节点APC容量。然而，APC的特定人群(S) 这些MHC控制的免疫耐受缺陷在NOD小鼠身上的表现是 未知。有三个具体目标：1.确定 基因消除B细胞对NOD小鼠APC和APC能力的影响 相关股票选择和激活或呈现致糖尿病T细胞 非致病的。这些研究将利用培育的Ig-Mu-Null突变 转化成表达不同H2基因的标准NOD和修饰的NOD菌种 评估B细胞在介导糖尿病T细胞活化中的作用。 除了直接评估基因敲除的影响外，实验 涉及一系列骨髓和白细胞移植研究 描述必须表达H2 g7单倍型的APC群体 介导糖尿病T细胞的选择和激活将是 已执行。2.探讨自身免疫性IDDM的发病机制 携带损害Th1或Th2的基因操作的NOD小鼠发生改变 回应。这些研究将涉及培育IL-2空基因、IFN空基因和 白介素4缺失等位基因与结节的关系及其对遗传效应的影响 致糖尿病的T细胞。3.确定T细胞减少的基础 NOD巨噬细胞产生IL-1的共刺激活性 这通过抑制Th2反应的激活而导致IDDM β细胞自身抗原。这些研究的重点是确定 遗传机制和可能的基因产物对这种影响负责 含Idd10基因片段对结节巨噬细胞分化的影响 老鼠。以前的研究表明，NOD的巨噬细胞不会 在髓系生长因子存在的情况下完全分化，这 限制他们合成和分泌IL-1的能力。这种表型可能 导致巨噬细胞功能缺陷，这可能会损害 免疫调节通路的激活，包括Th2的激活 对IDDM有潜在保护作用的途径。Idd10在以下方面的作用 这一过程得到了这样一种观察的支持，即这一缺陷已得到纠正 在3号染色体上，携带源自C57BL/6的Idd10区域的同源基因。 IL-1表达降低的生化基础将被评估 Idd10候选基因的潜在作用将被确定。

DESCRIPTION (Adapted from Investigator's abstract): This project proposes to characterize the role of regulatory defects in antigen presenting cells in the development of IDD in the NOD mouse. Preliminary data indicate that some of the polygenic interactions that mediate susceptibility to IDD in NOD mice may limit the ability of hematopoietically derived antigen presenting cells (APC) such as B-lymphocytes, macrophages, and dendritic cells to activate various immunoregulatory pathways. The unusual H2g7 MHC haplotype has been shown to clearly contribute to the impaired immunotolerogenic capacity of NOD APC. However, the specific population(s) of APC that manifest these MHC controlled immunotolerogenic defects in NOD mice is unknown. There are 3 specific aims: 1. To determine the effect of genetically eliminating B-cells on the ability of APC from NOD mice and related stocks to select and activate diabetogenic T-cells or render them non-pathogenic. These studies will utilize the Ig-mu-null mutation bred onto standard NOD and modified NOD stocks expressing various H2 genes to assess the role of B-cells in mediating activation of diabetogenic T-cells. In addition to assessing the effects of knockouts directly, experiments involving a series of bone marrow and leukocyte transfer studies to delineate the populations of APC that must express the H2g7 haplotype to mediate the selection and activation of diabetogenic T-cells will be performed. 2. To determine the etiopathogenesis of autoimmune IDDM is altered in NOD mice carrying genetic manipulations which impair Th1 or Th2 responses. These studies will involve breeding the IL-2null, IFNnull, and IL-4null alleles onto NOD and assessing their effects on the generation of diabetogenic T-cells. 3. To identify the basis for the diminished T-cell co-stimulatory activity of IL-1 produced by NOD macrophages and determine if this contributes to IDDM by inhibiting the activation of Th2 responses to beta cell autoantigens. These studies are focused on identifying the genetic mechanisms and possibly the gene product responsible for the effects of the genomic segment containing Idd10 on macrophage differentiation in NOD mice. Previous studies have demonstrated that macrophages from NOD do not fully differentiate in the presence of myeloid growth factors and that this limits their ability to synthesize and secrete IL-1. This phenotype could result in a deficiency in macrophage function which may impair the activation of immunoregulatory pathways including the activation of Th2 pathways that are potentially protective against IDDM. The role of Idd10 in this process is supported by the observation that this defect is corrected in chromosome 3 congenics carrying the Idd10 region derived from C57BL/6. The biochemical basis for this decreased expression of IL-1 will be assessed and the potential role of the candidate gene for Idd10 will be determined.