Islet Cell Membrane Antibodies in Diabetes

修订摘要： 1型糖尿病（T1 D）是一种可预测的疾病，针对GAD 65、IA-2或 胰岛素（IAA）是有效的标记物。在本供资期间，我们取得了相当大的进展 用于鉴定与T1 D相关的GAD 65 Ab表位。我们还确定GAD 65 Ab DR 4-DQ 8与IA-2Ab或IAA相关。IAA是 与11号染色体上的INS VNTR相关。我们现在的目标是揭示这些机制， 自身抗体疾病标志物与向T1 D的进展相关地被触发和成熟。具体 目的是检验这些假设：1）胰岛自身免疫通过向特定同种型的转变而建立， 亚型自身抗体; 2）进展至T1 D与朝向特异性GAD 65 Ab的成熟相关 3）针对特异性自身抗体表位的成熟与单独的HLA相关，或与调节的HLA相关。 通过非HLA遗传因素，如用于IAA的INS VNTR和用于GAD 65 Ab的寡腺苷酸合成酶（OAS）。 这些假设将在对大量新生儿、健康受试者、 以及对学生和一级亲属的研究。我们将剖析早期自身抗体反应 包括IgM、伊加和IgE，与持续性GAD 65-IgG相比，使用新的高通量测定， 用于表位作图的重组生物素化GAD 65和GAD 65特异性Fab。我们将a）检测个体 具有对GAD 65的非常早期的自身抗体应答，和B）鉴定同种型转换和成熟， 疾病相关表位。我们将把针对特异性自身抗体表位的成熟与 HLA，非HLA遗传因子，单独或组合。我们还将澄清为什么一些表位限制 自身抗体与单独的胰岛自身免疫相关，而其它抗体与向T1 D的进展相关。这 这项研究旨在揭示GAD 65的早期免疫应答机制，以及GAD 65与免疫应答之间的关系。 自身抗体反应成熟与进展为T1 D临床发作之间的关系。

REVISED ABSTRACT: Type 1 diabetes (T1D) mellitus is a predictable disease and autoantibodies (Ab) against GAD65, IA-2 or insulin (IAA) are effective markers. During the current funding period we have made considerable progress towards the identification of GAD65Ab epitopes associated with T1D. We also established that GAD65Ab were associated with HLA DR3-DQ2 while DR4-DQ8 was associated with IA-2Ab or IAA. IAA were associated with INS VNTR on chromosome 11. We now aim to uncover the mechanisms by which these autoantibody disease markers are triggered and mature in relation to progression towards T1D. The specific aims test these hypotheses:1) Islet autoimmunity is established by the shift towards specific isotype and subtype autoantibodies; 2) Progression to T1D is associated with maturation towards specific GAD65Ab epitopes; 3) Maturation towards specific autoantibody epitopes is associated with HLA alone, or modulated by non-HLA genetic factors such as INS VNTR for IAA and Oligoadenylate synthetase (OAS) for GAD65Ab. These hypotheses will be tested in prospective studies of large populations of newborns, healthy subjects and studies of school children and first-degree relatives. We will dissect early autoantibody responses including IgM, IgA, and IgE compared to persistent GAD65-lgG using novel high throughput assays with recombinant biotinylated GAD65 and GAD65-specific Fab for epitope mapping. We will a) detect individuals with very early autoantibody response to GAD65, and b) identify isotype switches and maturation to disease-associated epitopes. We will correlate the maturation towards specific autoantibody epitopes with HLA, non-HLA genetic factors, alone or in combination. We will also clarify why some epitope-restricted autoantibodies are associated islet autoimmunity alone and others with progression towards T1D. This research aims to uncover the mechanisms of the early immune response to GAD65 and the relationship between the autoantibody response maturation and progression to clinical onset of T1D.