Project 1: Augmenting Regulatory Mechanisms in Protocols of Transient Mixed Chimerism

项目摘要/摘要 诱导免疫耐受是器官移植领域的最终目标。达到一种状态 如果没有慢性免疫抑制，耐受性将导致移植物无限期存活及其相关 发病率/死亡率，并有望防止/减少慢性排斥反应。同种异体肾移植耐受性 在非人类灵长类动物(NHP)和人类身上通过使用非清髓剂的组合实现 条件调节和供者骨髓移植导致短暂的混合造血嵌合体。 然而，完全相同的混合嵌合体方案未能在NHP同种异体心脏移植受者中诱导耐受。 这反映了这样一个事实，即肾脏(和肝脏)在诱导耐受方面存在器官特异性差异。 同种异体移植物是“易耐受的”，而心脏(和肺)移植物是“耐受的”。尽管有免疫力 对于心脏移植造成的障碍，我们的实验室最近开发了一种新的方案，这是第一次 时间，在食蟹猴身上实现了对完全MHC不匹配的同种异体心脏移植的长期、稳定的耐受性。 在心脏受者中，通过将瞬时混合嵌合体方案与 供肾共移植，增强宿主调节性T细胞(Tregs)的贡献。基于 我们的初步数据，我们假设促进调节性T细胞和/或 接受短暂混合嵌合方案的受者的巨噬细胞将诱导长期和 单独移植同种异体心脏的耐受性稳定。我们将通过1)早期扩充来检验这一假设 用体外扩增的供体特异性MHC反应性CAR树代替供体的宿主调控机制 肾脏，2)靶向增强传统宿主树和输液车树的功能和稳定性 DEPTOR和IL-2途径，以及3)使用下一代mTORi特异性纳米疗法来缓解早期 先天炎症和促进调节巨噬细胞。这些研究将得到项目2的补充， 这将检验一种推论，即条件化疗法的发展能够诱导 持久的混合嵌合体将在心脏接受者中诱导强大的耐受性，项目3将研究一种 新的共刺激阻断策略促进Tregs，同时抑制混合嵌合体后的记忆T细胞 条件反射。通过阐明和区分细胞和分子机制，有效与 对于无效的方案，核心A将通知并改进每个项目中提出的治疗策略。我们 预计，这些高度互动的项目将共同产生一个或多个安全有效的混合 嵌合耐受方案将在年底前准备好在心脏移植受者中进行临床试验 资助期。

PROJECT SUMMARY / ABSTRACT Induction of immune tolerance is the ultimate goal in the field of organ transplantation. Achieving a state of tolerance would lead to indefinite graft survival without chronic immunosuppression and its associated morbidity/mortality and is expected to prevent/reduce of chronic rejection. Tolerance of kidney allografts has been achieved in non-human primates (NHPs) and in humans by using a combination of nonmyeloablative conditioning and donor bone marrow transplantation that results in transient mixed hematopoietic chimerism. However, identical mixed chimerism protocols have failed to induce tolerance in NHP heart allograft recipients. This reflects the fact that there are organ-specific differences in tolerance induction with kidney (and liver) allografts being “tolerance-prone” and heart (and lung) grafts being “tolerance-resistant.” Despite the immune barriers posed by heart allografts, our laboratory has recently developed a novel protocol that has, for the first time, achieved long-term, stable tolerance of fully MHC mismatched heart allografts in cynomolgus monkeys. This remarkable result was attained in heart recipients by combining a transient mixed chimerism protocol with donor kidney cotransplantation which enhanced the contributions of host regulatory T cells (Tregs). Based on our preliminary data, we hypothesize that promoting the contributions of regulatory T cells and/or macrophages in recipients undergoing a transient mixed chimerism regimen will induce long-term and stable tolerance of heart allografts transplanted alone. We will test this hypothesis by 1) augmenting early host regulatory mechanisms using ex vivo expanded donor-specific MHC-reactive CAR Tregs in lieu of donor kidneys, 2) enhancing the function and stability of conventional host Tregs and infused CAR Tregs by targeting the DEPTOR and IL-2 pathways, and 3) using next-generation mTORi-specific nanotherapy to mitigate early innate inflammation and promote regulatory macrophages. These studies will be complemented by Project 2, which will test the corollary hypothesis that the development of conditioning regimens capable of inducing durable mixed chimerism will induce robust tolerance in heart recipients, and Project 3, that will investigate a novel costimulation blockade strategy to promote Tregs while constraining memory T cells after mixed chimerism conditioning. By elucidating and differentiating cellular and molecular mechanisms underlying effective versus ineffective protocols, Core A will inform and refine the treatment strategies proposed in each Project. We anticipate that together, these highly interactive projects will generate one or more safe and effective mixed chimerism tolerance protocols that will be ready for clinical trial in heart allograft recipients by the end of the funding period.