Insulin Specific T and B cells in Type 1 Diabetes

项目摘要 对胰岛抗原的获得性免疫反应，尤其是胰岛素原，在1型糖尿病中起着核心作用。 (T1D)发育和病理，T细胞和B细胞都对疾病有贡献。无数次大规模的 预防试验，主要使用胰岛素制剂(皮下、口服和鼻腔)诱导耐受 而延缓临床症状的出现，均未获成功。有必要(1)研究 人T1D靶器官内自身免疫发病机制及(2)翻译免疫表型 从胰岛到高危人群的血液。我们最近从小鼠体内鉴定出胰岛素原反应性T细胞。 T1D器官供者的胰岛具有与胰岛素B链氨基酸9反应的特异性T细胞受体(TCR)。 23经HLADQ8基因转染TCR缺失细胞系后呈阳性。这种T细胞也对分散的 从而将胰岛素B：9-23 T细胞的反应性与人类疾病的发病机制联系起来。胰岛素B：9-23 新发病的T1D患者外周血中存在特定的CD4T细胞。高亲和力胰岛素- 在健康受试者的外周血中发现反应性B细胞，这些细胞仅限于 无能B细胞室(BND)，因此是抗原不反应的。重要的是，在新发的T1D患者中 以及一些携带高危HLA等位基因的一级亲属(FDR)，这些B细胞失去了无能。这些 这些发现导致我们假设胰岛素特异性T细胞和B细胞在 显性疾病的发展，并集中在它们传播的胰岛和淋巴结 疾病。这一假设将在两个具体目标上得到检验。利用网络为胰腺器官捐赠者 (NPOD)，目标1侧重于确定胰岛反应性免疫细胞的抗原特异性、表型和功能 来自新近发病T1D的器官捐赠者的脾和胰岛。目标2是对高危人群的纵向研究。 与HLA2胰岛自身抗体和≥-DQ-DR匹配的自身抗体阴性的一级亲属来自 TrialNet预防路径(PTP)活生物库(以前称为自然历史研究) 测量功能性胰岛素特异性T细胞反应，计数与胰岛素结合的B细胞，并表征 胰岛素自身抗体的抗原亲和力和亚型。建议的研究将会推进我们的长远目标。 弥合靶器官和血液之间关于疾病进展生物标志物的知识差距 最终通过加强对疾病发病机制的了解来预防T1D。

Project Summary The adaptive immune response to islet antigens, especially proinsulin, plays a central role in type 1 diabetes (T1D) development and pathology, with both T and B cells contributing to disease. Numerous large-scale prevention trials, mainly using preparations of insulin (subcutaneous, oral, and intranasal) to induce tolerance and delay the onset of clinical symptoms, have been unsuccessful. There exists the need to (1) study the autoimmune pathogenesis within the target organ of human T1D and (2) translate immunologic phenotypes from the islets to the blood of at risk subjects. We have recently identified proinsulin-reactive T cells from the islets of a T1D organ donor with a specific T cell receptor (TCR) responding to insulin B chain amino acids 9- 23 presented by HLA-DQ8 when transfected into a TCR null cell line. This T cell also responds to dispersed whole human islets, thus linking insulin B:9-23 T cell reactivity to human disease pathogenesis. Insulin B:9-23 specific CD4 T cells are present in the peripheral blood of new-onset T1D subjects. High affinity insulin- reactive B cells are found in the peripheral blood of healthy subjects, and these cells are restricted to the anergic B cell compartment (BND) and thus are antigen unresponsive. Importantly, in new-onset T1D patients and some first-degree relatives (FDRs) carrying high-risk HLA alleles, these B cells lose anergy. These findings lead us to hypothesize that insulin specific T and B cells undergo cognate interactions prior to the development of overt disease and concentrate in the pancreatic islets and lymph nodes where they propagate disease. This hypothesis will be tested in two specific aims. Utilizing the network for pancreatic organ donors (nPOD), Aim 1 focuses on defining antigen specificity, phenotypes and function of islet reactive immune cells from spleen and islets of organ donors with recent onset T1D. Aim 2 is a longitudinal study of at risk subjects with ≥2 islet autoantibodies and HLA-DQ-DR matched autoantibody negative first degree relatives from the TrialNet Pathway to Prevention (PTP) Living Biobank (previously referred to as the Natural History Study) measuring functional insulin specific T cell responses, enumerating insulin binding B cells, and characterizing insulin autoantibodies for antigen affinity and subtypes. The proposed studies will advance our long-term goal of bridging the gap of knowledge between the target organ and blood for biomarkers of disease progression and ultimately T1D prevention with enhanced understanding of disease pathogenesis.