Alemtuzumab and Regulatory T Cells for Heart Transplant Tolerance in Monkeys

我们建议的研究将探讨调节性T细胞(Treg)在促进食蟹猴异位心脏移植耐受性方面的潜力。基于小型动物研究的有说服力的证据表明，在给予Treg之前清除T效应细胞有利于Treg诱导的免疫调节的结果。我们在印度尼西亚食蟹猴身上开发了一种T细胞去除方案，使用人源化抗CD52单抗(Alemtuzumab)和霉酚酸酯(MMF)相结合。CD3[]T细胞可以在4周内保持在非常低的数量，而CD4[]T细胞可以维持几个月。我们还分离并成功地扩增了猴树突状细胞，并展示了它们的免疫调节特性。我们假设，移植后将自体Treg过继转移到淋巴细胞耗尽的宿主，结合雷帕霉素单一治疗疗程，将提高同种异体心脏移植物的存活率并促进耐受诱导。我们拟议的研究有以下目的：目的I将确定阿伦图珠单抗对食蟹猴心脏移植结局和宿主免疫反应性的影响；目的II将评估多克隆Treg(无论是扩展的自然发生的Treg还是诱导的Treg)对Alemtuzumab治疗的猕猴心脏移植结局和潜在机制的影响，并将结果与Aim I的结果进行比较；Aim III将评估Alemtuzumab治疗猴的同种异体抗原特异性Treg促进同种异体心脏移植结果的能力和潜在机制，并将结果与AIMS I和II中的结果进行比较。在每个Aim中，Treg将在初始T细胞耗尽和心脏移植(第0天)后第21天给予；免疫抑制治疗将逐渐减少，并在3个月后停止。随访时间为移植后6个月。结果将通过(I)移植物存活时间，(Ii)移植物血管病变(慢性排斥)的发生率，(Iii)抗供者T细胞反应的发展，(Iv)抗供者抗体(Abs)的发展，(V)抗波形蛋白和抗肌球蛋白抗体的发展，以及(Vi)对这些自身抗原的T细胞反应的评估来监测。此外，在AIMS II和AIMS III中，我们将确定Treg疗法影响宿主免疫反应性和移植结果的机制基础。这些研究将为过继转移的自体Treg诱导对非人类灵长类同种异体心脏移植的耐受状态或道具耐受的能力提供明确的信息，并可能提供足够的数据来证明临床试验的合理性。

Our proposed studies will investigate the potential of regulatory T cells (Treg) for the promotion of tolerance to heterotopic heart allografts in cynomolgus monkeys. There is persuasive evidence, based on small animal studies, that depletion of T effector cells prior to the administration of Treg is advantageous to the outcome of Treg-induced immunomodulation. We have developed a T cell-depleting regimen in Indonesian cynomolgus monkeys, using humanized anti-CD52 mAb (alemtuzumab) in combination with mycophenolate mofetil (MMF). CD3[+]T cells can be maintained at very low numbers for periods >4 weeks, and CD4[+] T cells for several months. We have also isolated and successfully expanded monkey Treg and demonstrated their immunomodulatory properties. We hypothesize that posttransplant adoptive transfer of autologous Treg to lymphocyte-depleted hosts, in combination with a course of rapamycin monotherapy, will enhance heart allograft survival and promote tolerance induction. Our proposed investigations have the following Aims: Aim I will determine the Influence of alemtuzumab on heart allograft outcome and host immune reactivity in cynomolgus monkeys; Aim II will assess the impact of polyclonal Treg (either expanded naturally-occurring Treg or induced Treg) on heart allograft outcome and underlying mechanisms in alemtuzumab-treated monkeys and will compare the results with those obtained in Aim I; Aim III will assess the ability of alloantigen-specific Treg to promote heart allograft outcome and underlying mechanisms in alemtuzumab-treated monkeys treated as in Aim I and will compare the results with those in Aims I and II. In each Aim, the Treg will be administered on day 21, after the initial T cell depletion and heart transplantation (day 0); immunosuppressive therapy will be tapered and discontinued at 3 months. Follow-up will be for 6 months post transplant. Outcomes will be monitored by (i) length of graft survival, (ii) incidence of graft vasculopathy (chronic rejection), (iii) development of anti-donor T cell responses, (iv) development of anti-donor antibodies (Abs), (v) development of anti-vimentin and anti-myosin Abs, and T cell responses to these autoantigens, and (vi) assessment of memory T cell responses. In addition, in Aims II and III, we will ascertain the mechanistic basis of the influence of the Treg therapy on host immune reactivity and transplant outcome. These studies will provide definitive information on the ability of adoptively-transferred autologous Treg to induce a state of tolerance or prope tolerance to non-human primate heart allografts, and may provide sufficient data to justify a clinical trial.