Effector Mechanisms in Graft Tolerance

移植物耐受的效应机制

• 批准号: 7922765
• 负责人: RANDOLPH J. NOELLE
• 金额: $ 15.41万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-17 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7922765
• 关键词: Adoptive Transfer; Alleles; Alloantigen; Allogenic; Allografting; Animal Model; Antigens; Apoptosis; Autoimmunity; Behavior; CD4 Positive T Lymphocytes; CD8B1 gene; Cell physiology; Cells; Clonal Anergy; Complex; Data; Development; Differentiation and Growth; Disease; Elements; Environment; Enzymes; Epitopes; Eragrostis; Family member; Funding; Future; Gene Expression; Generations; Genetic; Graft Rejection; Graft Survival; Graft Tolerance; Histocompatibility Antigens; Immune; Immune Tolerance; Immune response; In Vitro; Inflammation; Inflammatory; Infusion procedures; Interleukin-10; Interleukin-9; Intravenous infusion procedures; Ketoglutarate Dehydrogenase Complex; Knock-in Mouse; Knock-out; Leukocytes; Life; Longevity; Measures; Mediating; Mediator of activation protein; Methods; Mission; Modeling; Molecular; Monkeys; Mus; Nature; Organ; Peptides; Peripheral; Phase; Play; Population; Positioning Attribute; Prevention; Production; Progress Reports; Publishing; Resolution; Role; SIYRYYGL; Series; Simplexvirus; Skin; Skin Transplantation; Skin graft; Staging; Study models; System; T memory cell; T-Cell Receptor; T-Lymphocyte; TNF gene; TNFSF5 gene; Tea; Thymidine Kinase; Time; Tissues; Transfusion; Transgenic Organisms; Transplantation; anergy; base; cellular targeting; conditioning; graft vs host disease; granzyme B; in vivo; interest; irradiation; islet; mast cell; prevent; response; tool

DESCRIPTION (provided by applicant): Immunologic tolerance was conceived as an "indifference or non-reactivity" measured by the acceptance of allogeneic skin grafts. While thought to be due to the lack of immune responsiveness, we now know that, in addition to clonal anergy, active suppression is essential for graft persistence. This proposal focuses on the active, effector mechanisms that underlie the longevity of allografts in the tolerant recipient. The cellular complexity of graft tolerance can be reduced by using well-defined, alloantigen-specific, TCR Tg populations of effector T cells (Teff) and regulatory T cells (Treg). We present a TCR Tg system can be used to study the cellular dynamics of graft rejection and tolerance in vivo, and can help to define the underlying molecular mechanisms of how Treg control Teff function in vivo. The specific aims of this proposal are: 1) To understand how Treg control the initial expansion and effector function of alloreactive CD4+ and CD8+ T cells in the naive and primed host to control graft rejection. Natural Treg (Treg) and adaptive Treg (Tr1) to a single, defined class ll-restricted, allogeneic epitope arrest Teff responses in vitro and in vivo. How Treg to a single defined epitope can arrest allogeneic responses across complete H-2 disparities will be the focus of this aim. The impact of antigen-specific Treg on CD4+ and CD8+ Teff growth, differentiation, effector function and gene expression will be explored, as well as the conditions that control Treg themselves. Finally, data suggests that Treg may also have the capacity to control memory T cell responses and thus it will be determined if Treg can mitigate graft rejection in the sensitized host. 2) To delineate the cellular mechanisms that allow for long-lived graft survival. While Treg initially establish a state of tolerance, evidence suggest that Treg are catalytic and "infectious". Studies are proposed to delineate how suppression spreads" over time. By creating alloreactive TCR Tg T cells (Treg and Teff) containing the Foxp3gfp knock- in allele (that expresses GFP upon Foxp3 expression), the differentiation of Teff to antigen-specific adaptive Treg in vivo can be determined. The functional importance of distinct Treg subsets to graft survival will be determined by using genetic strategies to delete defined Treg subsets following transfer. We hypothesize that over time, the relevant Treg subsets to graft survival will change. 3. To define the contact-dependent and soluble factors that control alloreactive T cell responses and allow long-lived graft survival. We focus on known (TGFb and IL-10) and new mediators with the intent of solving how these molecules control tolerance. Incisive studies to determine the contribution of TGFb and IL-10 to "infectious" aspects of tolerance are described. Second, data shows that granzyme B (GZB) production by Treg is involved in graft tolerance in vivo. Studies are presented to identify the cellular targets of GZB and its mode of action in sustaining graft survival. New evidence strongly implicates IL-9 and mast cells as elements that may be important to peripheral tolerance, and studies are presented to functionally implicate their involvement.

描述（由申请方提供）：免疫耐受被认为是通过接受同种异体皮肤移植物来测量的“无差异或无反应性”。虽然被认为是由于缺乏免疫反应，我们现在知道，除了克隆无能，主动抑制是必不可少的移植持久性。这项建议的重点是积极的，效应机制的基础上，在耐受受体同种异体移植物的寿命。移植物耐受的细胞复杂性可以通过使用明确定义的同种异体抗原特异性效应T细胞（Teff）和调节性T细胞（Treg）的TCR Tg群体来降低。我们提出了一种TCR Tg系统，可用于研究体内移植排斥和耐受的细胞动力学，并有助于确定Treg如何控制Teff功能的潜在分子机制。本提案的具体目的是：1）了解Treg如何控制初始和致敏宿主中同种异体反应性CD 4+和CD 8 + T细胞的初始扩增和效应器功能，以控制移植物排斥反应。天然Treg（Treg）和针对单一、定义的II类限制性、同种异体表位的适应性Treg（Tr 1）在体外和体内阻止Teff反应。针对单个确定表位的Treg如何能够跨越完全H-2差异来阻止同种异体应答将是该目标的焦点。将探索抗原特异性Treg对CD 4+和CD 8 + Teff生长、分化、效应子功能和基因表达的影响，以及控制Treg本身的条件。最后，数据表明Treg也可能具有控制记忆T细胞应答的能力，因此将确定Treg是否可以减轻致敏宿主中的移植物排斥。2)描述允许移植物长期存活的细胞机制。虽然Treg最初建立耐受状态，但证据表明Treg是催化性和“传染性”的。建议进行研究，以描述抑制如何随着时间的推移而传播。通过产生含有Foxp 3gfp敲入等位基因（其在Foxp 3表达时表达GFP）的同种异体反应性TCR Tg T细胞（Treg和Teff），可以确定Teff在体内分化为抗原特异性适应性Treg。不同Treg亚群对移植物存活的功能重要性将通过使用遗传策略在转移后删除定义的Treg亚群来确定。我们假设随着时间的推移，与移植物存活相关的Treg亚群会发生变化。3.确定控制同种异体反应性T细胞反应并使移植物长期存活的接触依赖性和可溶性因子。我们专注于已知的（TGF β和IL-10）和新的介质，旨在解决这些分子如何控制耐受性。深入的研究，以确定的贡献TGF β和IL-10的“传染性”方面的耐受性进行了说明。其次，数据显示Treg产生的颗粒酶B（GZ B）参与体内移植耐受。研究提出，以确定GZB的细胞靶点和其在维持移植物存活的作用模式。新的证据强烈暗示IL-9和肥大细胞的元素，可能是重要的外周耐受性，和研究功能上牵连他们的参与。