Dendritic Cells with Galectin-1 to Enhance Islet Grafts

描述(申请人提供)：胰岛素依赖型糖尿病(IDDM)是一种自身免疫性疾病，选择性地破坏胰腺中产生胰岛素的β细胞。治疗IDDM的唯一可能的方法是替换被破坏的β细胞团。与胰岛分离相关的技术问题不再限制同种异体供体胰岛的治疗用途。然而，用于预防同种异体胰岛排斥反应的免疫抑制药物会导致全身性免疫抑制和不良副作用。同种异体胰岛细胞移植排斥反应的发生主要是因为同种异体抗原(Ag)特异性T细胞对移植组织的反应。树突状细胞(DC)是一种抗原提呈细胞(APC)，能激活受体NA和T细胞，从而触发移植排斥反应。Galectin-1是一种有效的T细胞反刺激剂，在抗原提呈过程中，在DC-T细胞相互作用的早期阶段，它会干扰免疫突触的形成。因此，Galectin-1诱导T细胞凋亡。 在这个方案中，我们假设表达转基因Galectin-1的供者来源的DC可以作为“耐受性DC”，在小鼠胰岛细胞移植模型中诱导抗原特异性T细胞耐受。将编码人Galectin-1和报告基因增强型绿色荧光蛋白(EGFP)的重组腺病毒(Rad)载体(Rad-GAI-1-EGFP)导入DC。本研究的目的如下：目的1和2)研究表达Galectin-1基因的DC在体内外与T细胞的相互作用；目的3)确定转导供者来源的Rad-Gal-1-EGFP的DC能否逆转高血糖并促进胰岛移植物的长期存活。这些研究将探索结合移植领域的两种有前景的工具：耐受性DC和T细胞反刺激因子(即Galectin-1)，产生allo-Ag特异性1细胞耐受的新途径。在同种异体胰岛细胞移植排斥反应中，DC激活受体I细胞的机制将被研究。这种方法可以显著延长同种异体移植物的存活时间，并将对胰岛的副作用和毒性的免疫抑制药物的需求降至最低。这一结果可能会对β细胞自身免疫的调节以及移植的其他领域产生重要影响。

DESCRIPTION (provided by applicant): Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disorder that destroys selectively the insulin-producing beta cells of pancreas. The only possible cure for IDDM is the replacement of the destroyed beta cell mass. Technical problems related to pancreatic islet isolation no longer limit the therapeutic use of pancreatic islets obtained from allogeneic donors. However, the immunosuppressive drugs employed to prevent rejection of allogeneic islets induce generalized immunosuppression and harmful side-effects. Rejection of islet cell allografts occurs mainly because allo-antigen (Ag)-specific T cells react against the transplanted tissue. Dendritic cells (DC) are the Ag-presenting cells (APC) that activate the recipient na¿ve T cells that trigger the transplant rejection. Galectin-1 is a potent T cell counterstimulator that interferes with the formation of the immunological synapse at the early stages of DC-T cell interaction during Ag presentation. As a consequence, galectin-1 induces T cell apoptosis. In this proposal, we hypothesize that donor-derived DC expressing transgenic galectin-1 can be used as "tolerogenic DC" to induce Ag-specific T cell tolerance in a murine model of islet cell transplantation. DC will be transduced with a recombinant adenovirus (rAd) vector encoding human galectin-1 plus the reporter gene enhanced green fluorescent protein (EGFP) (rAd-GaI-1 -EGFP). The aims of this proposal are the following:Aims 1 and 2) to investigate the interaction of DC expressing transgenic galectin-1 with na¿ve T cells in vitro and in vivo; and Aim 3) to determine whether transfer of donor-derived rAd-Gal-1-EGFP-transduced DC can reverse hyperglycemia and promote long-term pancreatic islet allograft survival.These studies will explore novel ways to generate allo-Ag specific 1-cell tolerance combining two promising tools in the transplantation field: tolerogenic DC and T cell counterstimulators (i.e. galectin-1). The mechanisms by which DC activate recipient I cells during rejection of islet cell allografts will be investigated. This approach may achieve significant prolongation of allograft survival and minimize the need for immunosuppressive drugs with side-effects and toxicity against pancreatic islets. The results may have an important impact on regulation of beta-cell autoimmunity and in other areas of transplantation.