Reshaping lymph node stroma for transplant tolerance

项目摘要/摘要 我的实验室主要致力于更好地理解淋巴转移(LN)的机制。 基质控制着移植的耐受性。我们已经花了很大的努力来定义 在Ln，Foxp3调节性T细胞(Treg)被诱导和激活。我们证明了在耐受期间 在共刺激阻断的诱导下，幼稚T细胞迁移到LN，但不迁移到脾。在公差期间 诱导后，幼稚的T细胞特异性地定位于LN的皮质脊(CR)，通过附近的高压区进入 内皮小静脉(HEV)。在CR中，它们被同种异体抗原提呈浆细胞样树突状细胞刺激 分化为诱导性Treg(ITreg)。 我们的数据表明，在耐受性条件下，iTreg主要形成于CR区，而T细胞 进入LN经验性无能的延髓。更具体地说，间质层粘连蛋白α4：α5的比率(参考 对同种异体抗原和iTreg形成的应答起关键作用。一个 高LAMA4/LAMA5比率促进耐受性，而低LAMA4/LAMA5比率促进移植 豁免权。在机制上，LAMA4促进CD4向CR迁移，促进Foxp3表达和iTreg 成熟，并抑制效应T细胞分化。相反，LAMA5抑制CD4细胞迁移到 HEV，但共刺激T细胞增殖和成熟为炎症性Th17。取消与此交互 中和抗体增强iTreg向CR区的迁移并显著延长同种异体心脏移植 生死存亡。我们的总体假设是，CR的LAMA4/LAMA5比率关键决定了 ITreg的形成和移植耐受。我们的总体目标是定义关键的细胞(FRC)和分子 (LTβR)控制LN的层粘连蛋白组成从而利用该微结构来 操纵对移植耐受的免疫力。为了研究这一假设，我们提出了以下建议 目标： 目的1.明确LN基质细胞在控制LAMA4和LAMA5平衡中的作用 同种免疫反应。 目的2.明确FRC的LTβR激活在诱导LAMA5形成中的关键作用。 目的3.共刺激分子抗CD40L单抗和抗层粘连蛋白α5单抗靶向LN的研究 以促进宽容。 总体而言，调节FRC的关键信号分子具有重塑LN层粘连蛋白和LAMA4/LAMA5的功能 比率决定了对炎症和免疫的免疫反应(低比率)或对抑制和 容忍度(高比率)。这些目标将实现我们定义关键细胞(FRC)和分子的总体目标 (LTβR)控制层粘连蛋白组成的机制。这些数据为以下方面奠定了基础 开发高度创新的靶向疗法来重新编程LN的微结构以促进移植 宽容。

Project Summary/Abstract My laboratory has contributed chiefly to the better understanding of the mechanisms by which lymph node (LN) stroma controls transplant tolerance. We have devoted much effort to defining specific compartments of the LN where Foxp3+ regulatory T cells (Treg) are induced and activated. We showed that during tolerance induction by costimulatory blockade, naïve T cells migrate to the LN, but not the spleen. During tolerance induction, naïve T cells specifically home to the cortical ridge (CR) of LN, entering via the nearby high endothelial venules (HEV). In the CR they are stimulated by alloantigen-presenting plasmacytoid dendritic cells to differentiate into induced Treg (iTreg). Our data indicate that in tolerogenic conditions iTreg are mostly formed within the CR region, whereas T cells which enter the medulla of LN experience anergy. More specifically, the ratio of stromal laminin α4:α5 (referred to as LAMA4/LAMA5) of the CR region critically determine the response to alloantigen and iTreg formation. A high LAMA4/LAMA5 ratio promotes tolerance, whereas a low LAMA4/LAMA5 ratio promotes transplant immunity. Mechanistically, LAMA4 promotes CD4 migration to the CR, promotes Foxp3 expression and iTreg maturation, and inhibits effector T cell differentiation. In contrast, LAMA5 inhibits migration of CD4 cells into HEV, yet costimulates T cell proliferation and maturation to inflammatory Th17. Abrogating this interaction with neutralizing antibodies enhances iTreg migration to the CR region and significantly prolongs heart allograft survival. Our overall hypothesis is that the LAMA4/LAMA5 ratio of the CR critically determines the fate of iTreg formation and transplant tolerance. Our overall goal is to define the key cellular (FRC) and molecular (LTβR) mechanisms which control the laminin composition of LN and thereby leverage this microstructure to manipulate immunity toward transplant tolerance. To investigate this hypothesis, we propose the following AIMS: Aim 1. Define the role of LN stromal cells in controlling the balance of LAMA4 and LAMA5 during alloimmune responses. Aim 2. Define the role of LTβR activation of FRC as a key pathway in inducing formation of LAMA5. Aim 3. Targeted delivery of costimulatory molecule anti-CD40L mAbs and anti-laminin α5 Abs to the LN to promote tolerance. Overall, key signaling molecules that regulate FRC function to remodel LN laminins and the LAMA4/LAMA5 ratio dictate the immune response toward inflammation and immunity (low ratio) or toward suppression and tolerance (high ratio). These Aims will achieve our overall goal to define the key cellular (FRC) and molecular (LTβR) mechanisms which control the laminin composition of LN. These data lay the groundwork for developing highly innovative targeted therapies to reprogram the microstructure of LN to promote transplant tolerance.