Tolerance induction by gene therapy in organ transplantation

在这个项目中，我们的目标是开发一种策略，以实现有效的免疫抑制，并通过应用基因治疗诱导器官移植耐受。我们通过使用腺病毒载体编码CTLA4Ig和CD40Ig基因，检测了B7-CD28和CD40-CD154共刺激信号阻断的作用，发现单基因治疗足以在大鼠肝移植模型中诱导抗原特异性耐受。尽管这种基因疗法也允许大鼠长期接受心脏和小肠同种异体移植物，但在这些移植中，慢性排斥反应的进展并没有完全消除。利用CD40Ig基因治疗诱导耐受性的机制，我们发现CD40Ig增强CD4^+ T细胞中IL-2的产生，并产生CD4^+CD25^+调节性T细胞。同时使用钙调神经磷酸酶抑制剂并不能消除CD40Ig基因治疗诱导的耐受，而一些治疗策略与钙调神经磷酸酶抑制剂联合使用会加速啮齿动物心脏移植模型中的慢性同种异体移植排斥反应。为了寻找合适的基因治疗辅助疗法，本研究进一步研究了SDF-1/CXCR4信号阻断剂、新型嘧啶合成抑制剂丙二氮酰胺和NF-κB抑制剂DHMEQ的作用。由于在临床试验中注意到病毒介导基因治疗的严重副作用，我们开发了几种减少病毒载体使用量的方法，并应用了cre/loxP系统。我们还尝试了利用电穿孔法进行非病毒基因转导；然而，我们发现这是不实际的。因此，我们研究了一种新的人CD40单克隆抗体4D11在亚人灵长类动物肾移植中的作用。4D11 （10- 40mg /kg）治疗1个月或2.5个月可使同种异体肾移植长期存活，没有出现血栓栓塞或感染等不良反应，这表明4D11是阻断CD40-CD154相互作用的有希望的临床候选药物。少

In this project, we aimed to develop a strategy to achieve potent immunosuppression and to induce tolerance in organ transplantation by applying a gene therapy. We examined the effect of B7-CD28 and CD40-CD154 costimulatory signaling blockades by using adenoviral vectors coding such as CTLA4Ig and CD40Ig genes, and found that a single gene therapy is potent enough to induce antigen specific tolerance in liver transplantation using a rat model. Although such gene therapies also allowed long-term acceptance of heart and small intestinal allografts in rats, progression of chronic rejection was not fully abrogated in these transplants. The mechanism of tolerance induction by CD40Ig gene therapy was exploited, and we found that CD40Ig enhances IL-2 production in CD4^+ T cells and generates CD4^+CD25^+ regulatory T cells. Concomitant use of calcineurin inhibitors did not abolish tolerance induction by the CD40Ig gene therapy, while some treatment strategy together with calcineurin inhibition … More have accelerated chronic allograft rejection in rodent heart transplantation models. To develop a suitable adjunct therapy for the gene therapy, effects of SDF-1/CXCR4 signaling blockade, a new pirimidine synthesis inhibitor Malononitrilamides and NF-κB inhibitor DHMEQ was further examined in this study. Due to the severe side-effects of viral mediated gene therapy noted in clinical trials, we developed several ways to reduce the amount of viral vector use and also applied cre/loxP system. We also tried non-viral gene transduction by utilizing an electroporation method; however, we found that it is not practical. We therefore examined the effect of a new human CD40 monoclonal antibody, 4D11 in sub-human primate kidney transplantation. Treatment with 4D11 (10-40 mg/kg) for one or 2.5 months allowed long-term renal allograft survival, without showing adverse effects such as thromboembolism or infection, which indicating 4D11 as a promising candidate for clinical use to block CD40-CD154 interactions. Less