Allograft Homing and Function of Regulatory T Cells Post-Transplant

目的1：检测CCR 7通路是否在决定宿主发育中起关键作用 同种异体反应虽然许多工作指出CC 7及其配体在调节DC和幼稚细胞中的重要性， T细胞归巢到次级淋巴组织，先前在CCR 7-/-受体中的研究未能确定任何T细胞归巢到次级淋巴组织。 在决定同种异体移植物存活率方面具有重要作用。然而，在探索这一领域时， CCR 7通路在决定胰岛移植物命运中的作用我们将用老鼠来扩展这些研究 缺乏CCR 7-/-或CCR 7趋化因子配体ELC（CCL 19）和SLC（CCL 21）。我们将寻求 证实CCR 7靶向的重要性（如将与较高水平中的治疗用途相关）。 通过在野生型同种异体移植受体中产生和使用CCL19.Ig融合蛋白， 通过应用抗mCCR 7抗体和CCR 7导向的小分子。为了进一步证明 原则上，我们还将测试具有CCX-CKR靶向缺失的小鼠，一种新描述的CCL 19- 清除受体，以评估是否可以实现长期移植物存活的存在下， CCR 7配体水平升高。 目的2：了解CCR 4趋化因子通路在调节性T细胞功能中的作用。 次级淋巴组织以及同种异体移植物。我们将研究CCR 4的上调， TCR 4与其他相关趋化因子受体（包括CCR 6和CCR 8）的不同程度， CCR 4 + T细胞在次级淋巴组织中的功能以及它们如何迁移到同种异体移植物中。他们 研究将使用CCR 4-/-小鼠和CCR 4配体、TARC（CCL 17）和MDC（CCL 22）缺陷小鼠 为了确定趋化因子梯度导致CCR 4 + TCR 4向同种异体移植物的募集是否是以下因素的结果： 宿主或供体细胞生产。我们还将利用基因组学方法， CCR 4阻断小分子。最后，我们将试图了解两种移植物中移植物内TGFAP的功能。 的方式首先，我们将建立在我们的初步数据表明，Treg募集到同种异体移植物导致局部 ILT 3的上调，其然后可以在进一步调节宿主T细胞应答中起作用。其次，我们将 进行再移植研究，因为我们的初步数据表明，移植物内TGFAP可以促进耐受性， 通过趋化因子依赖性机制的幼稚受体。 除了在严重白细胞耗竭的情况下，同种异体移植物被宿主白细胞浸润， 可引起急性或慢性排斥反应，或仅在移植物内持续存在，或可介导同种异体移植物耐受。我们 研究将剖析Treg细胞对宿主T细胞的作用方式， 淋巴组织和同种异体移植物内。我们希望从这个项目产生的数据将具有诊断， 对临床Tx的预后和治疗意义

Aim 1: Test whether the CCR7 pathway has a key role in determining the development of host alloresponses. While much work points to the importance of CC7 and its ligands in regulating DC and naive T cell homing to secondary lymphoid tissues, previous studies in CCR7-/- recipients failed to identify any significant role in determining allograft survival. However, on exploring this area we shown a key role for the CCR7 pathway in determining the fate of islet allografts. We will expand upon these studies using mice deficient in CCR7-/- or the CCR7 chemokine ligands ELC (CCL19) and SLC (CCL21). We will seek confirmation of the importance of CCR7 targeting (as would be relevant to therapeutic use in higher mammals) by production and use of CCL19.lg fusion protein in wild-type allograft recipients, as well as through the application of anti-mCCR7 antibodies and CCR7-directed small molecules. As a further proof of principle we will also test whether mice with targeted deletions of CCX-CKR, a newly described CCL19- scavenging receptor, so as to assess whether long-term allograft survival can be achieved in the presence of increased levels of CCR7 ligands. Aim 2: Understand the role of the CCR4 chemokine pathway in regulating Treg function within secondary lymphoid tissues as well as allografts. We will study the upregulation of CCR4 upregulation by Tregs, the extent that CCR4 differs from other relevant chemokine receptors (including CCR6 and CCR8), how CCR4+ Tregs function within secondary lymphoid tissues and how they migrate to allografts. They studies will utilize CCR4-/- mice and mice deficient in either CCR4 ligand, TARC (CCL17) and MDC (CCL22) to determine whether chemokine gradients leading to recruitment of CCR4+ Tregs to allografts are a result of host or donor cell production. We will also seek to confirm the importance of our data in wild-type mice using CCR4-blocking small molecules. Lastly, we will seek to understand the functions of intragraft Tregs in two ways. First, we will build on our preliminary data indicating that Treg recruitment to an allograft leads to local upregulation of ILT3, which can then play a role in further modulate host T cell responses. Secondly, we will undertake re-transplant studies since our initial data indicate that intragraft Tregs can promote tolerance in naive recipients through chemokine-dependent mechanisms. Except in the context of profound leukocyte depletion, allografts are infiltrated by host leukocytes that can cause acute or chronic rejection, or simply persist within grafts or can mediate allograft tolerance. Our studies will dissect the means by Treg cell are exert their effects on host T cells both within secondary lymphoid tissues and within allografts. We expect the data generated from this project will have diagnostic, prognostic and therapeutic significance in clinical Tx.