Genetic Modification of Mouse Islets for Transplantation

描述（由申请人提供）：胰岛移植治疗I型糖尿病（T1 DM）的成功取决于其控制T细胞介导的同种异体反应性和T细胞自身免疫性的能力。诱导型共刺激分子（ICOS）/B7相关蛋白1（B7 RP-1）信号传导对于调节效应Th 1和Th 2细胞功能至关重要。ICOS拮抗剂治疗可抑制Th 1和Th 2介导的炎症、EAE、过敏性气道疾病和粘膜炎性疾病，并保护同种异体心脏移植物免受免疫排斥。我们推测，遗传修饰的胰岛局部表达可溶性ICOS-Ig可能会保护胰岛移植免疫排斥反应。这种保护的机制可能涉及通过促进效应T细胞的凋亡和/或无反应性来灭活效应T细胞。我们将使用重组腺相关病毒（rAAV）将ICOS-Ig或其他控制基因递送到胰岛细胞。AAV是一种非致病性病毒，免疫原性小，临床应用可能是安全的。最近的研究表明，通过rAV转导对胰岛进行遗传修饰会导致报告基因在体内长期表达，而不会干扰胰岛素的产生。最后，ICOS-Ig的局部表达可能不影响全身免疫功能，为延长移植胰岛存活提供了一种安全的手段。因此，基于用表达ICOS-Ig的胰岛移植以抑制效应T细胞的免疫疗法可能对于维持同基因和同种异体胰岛移植物耐受特别有效。优化用于产生表达共刺激抑制剂ICOS-Ig的遗传修饰的小鼠胰岛的条件; 2）.检查表达同基因和异基因胰岛的ICOS-Ig的移植是否防止糖尿病复发;和3）.确定ICOS-Ig在移植胰岛功能维持中的作用。 这些研究将解决有关ICOS/B7 RP-1信号对同种异体反应性和自身免疫性T细胞应答的调节功能的基本问题。我们的研究结果可能为预防和抑制人类胰岛移植物免疫排斥的新型免疫疗法提供基础。

DESCRIPTION (provided by applicant): The success of islet transplantation therapy for Type I diabetes mellitus (T1DM) depends on its ability to control both T cell-mediated alloreactivity and the ¿-cell autoimmunity. Inducible costimulator (ICOS)/B7-related protein 1(B7RP-1) signaling is crucial for regulation of effector Th1 and Th2 cell function. Treatment with ICOS antagonist inhibits Th1 and Th2 mediated inflammation, EAE, allergic airway disease, and mucosal inflammatory disease, and protects allogeneic heart grafts from immunorejection. We hypothesize that genetic modification of the islets to locally express soluble ICOS-Ig may protect the islet-grafts from immunorejection. The mechanism(s) underlying this protection may involve the inactivation of effector T cells by promoting their apoptosis and/or anergy. We will use recombinant adeno-associated virus (rAAV) to deliver the ICOS-Ig or other control genes to the islet cells. AAV is a non-pathogenic virus and has little immunogenicity, may therefore be safe in clinical applications. Recent studies have demonstrated that genetic modification of the islets by rAAV transduction results in the long-term expression of reporter genes in vivo, which does not interfere with insulin production. Finally, the local expression of ICOS-Ig may not affect systemic immunological function, providing a safe means to prolong transplanted islet survival. Therefore, immunotherapy based on transplantation with ICOS-Ig expressing islets to inhibit effector T cells may be especially effective for maintaining syngeneic and allogeneic islet-graft tolerance.In this application, we will: 1). optimize conditions for generation of genetically modified mouse islets which express costimulation inhibitor ICOS-Ig; 2). examine whether transplantation of ICOS-Ig expressing syngeneic and allogeneic islets prevents the recurrence of diabetes; and 3). determine the action of ICOS-Ig in the functional maintenance of transplanted islets. These studies will address fundamental questions concerning the regulatory function of ICOS/B7RP-1 signaling on alloreactive and autoimmune T cell responses. Our findings may provide the basis for novel immunotherapies for the prevention and inhibition of immunorejection of islet grafts in man.