Role of PD-L2 in Antigen-Specific B Cell Responses in Transplantation

项目摘要/摘要 移植是终末期器官衰竭的根治性治疗方法。针对捐献者的抗体 人类白细胞抗原，被称为供者特异性抗体(DSA)，与排斥反应有关，并越来越多地被认为是 这是改善长期移植结果的障碍。在移植患者中使用DSA进行连续监测 先进的方法，但治疗策略是资源密集型的，疗效有限。记忆B细胞 在同种异体致敏后分化形成分化成抗体的细胞库 在抗原存在的情况下分泌浆细胞。尽管它们在DSA的形成中发挥了作用，但 记忆B细胞室没有临床评估，也没有有效的治疗策略 抑制它。最近的工作证实了PD-1通路在抑制适应性免疫中的重要性， 但PD-L2在B细胞上的作用还不是很清楚。在这项提议中，我们开发了一种尖端技术 研究小鼠同种异体B细胞从幼稚到记忆的所有分化阶段。vbl.使用 B细胞选择性PD-L2消融的方法，我们将评估生发中心的要求 同种异体记忆的依赖和独立形成。在目标1的指导K99阶段中，我们将 探讨PD-L2在继发性生发中心和浆母细胞分化中的作用 重新刺激。在目标2中，我们将研究B细胞表达的PD-L2对PD-1+CD4+T滤泡的影响 使用MHC第二类四聚体鉴定同种异体CD4+T细胞的人群。最后，在目标3中，在 独立R00期，我将调查肾移植患者血液中活化的B细胞亚群 移植后形成DSA。我们将研究增殖激活的B细胞 亚集可以作为DSA形成和排斥的生物标志物，与已知程度相结合 MHC II类基因座表位错配。最后，我们将评估PD-L2封锁的能力 在体外抑制B细胞增殖和抗体产生的单抗。建议的工作是 与NIAID确定治疗靶点以增强翻译能力的战略优先事项保持一致 通过临床前研究延长移植肾存活时间的努力。这些发现将导致新的 了解决定记忆B细胞潜能的关键因素以及决定记忆B细胞的细胞过程 导致DSA的形成。通过这项工作，我们希望确定新的治疗检查点，可以 用于抑制记忆B细胞的形成，防止DSA的形成和抗体介导的排斥反应。我是 以具有丰富T细胞经验的临床组织相容性研究员的身份申请K99/R00 免疫学家。该应用程序将支持作为B细胞免疫学家的广泛高级培训。我的长期生活 职业目标是成为一名拥有独立资助的基础科学实验室的人类白细胞抗原实验室主任。

Project Summary/Abstract Transplantation is curative treatment for end-stage organ failure. Antibodies that are directed against donor HLA, termed donor specific antibodies (DSA), are associated with rejection and are increasingly recognized as a barrier to improving long-term transplant outcomes. DSA are serially monitored in transplant patients using advanced methods, but treatment strategies are resource intensive and have limited efficacy. Memory B cells that differentiate following allogeneic sensitization form a cellular reservoir that differentiates into antibody secreting plasma cells in the presence of antigen. Despite their role in contributing to DSA formation, the memory B cell compartment is not assessed clinically and there are no effective therapeutic strategies that inhibit it. Recent work has established the importance of the PD-1 pathway in restraining adaptive immunity, but the role of PD-L2 on B cells is not well understood. In this proposal, we have developed a cutting-edge approach to study murine allogeneic B cells through all stages of differentiation from naïve to memory. Using an approach of selective PD-L2 ablation on B cells, we will assess the requirements for germinal center dependent and independent formation of allogeneic memory. In the mentored K99 Phase in Aim 1, we will assess the role of PD-L2 on the differentiation of secondary germinal centers and plasmablasts following restimulation. In Aim 2, we will investigate the effect of B cell expressed PD-L2 on PD-1+ CD4+ T follicular populations using MHC Class II tetramers to identify allogeneic CD4+ T cells. Finally, in Aim 3, during the independent R00 phase, I will investigate activated B cell subsets in the blood of renal transplant patients who form DSA following transplantation. We will examine the possibility that the proliferating activated B cell subsets can be used as a biomarker of DSA formation and rejection in conjunction with the degree of known epitope mismatches at MHC Class II loci. Finally, we will assess the ability of PD-L2 blockade with a monoclonal antibody to inhibit B cell proliferation and antibody production in vitro. The proposed work is aligned with the NIAID strategic priority of identifying therapeutic targets for the enhancement of translational efforts to extend renal allograft survival through preclinical research. These findings will lead to new understanding of the key factors that determine the potency of memory B cells and the cellular processes that lead to DSA formation. Through this work we hope to identify new therapeutic checkpoints that can be exploited to inhibit memory B cell formation and prevent DSA formation and antibody mediated rejection. I am applying for this K99/R00 as a clinical histocompatibility fellow with extensive experience as a T cell immunologist. This application will support extensive advanced training as a B cell immunologist. My long-term career goal is to become an HLA laboratory director with an independently funded basic science laboratory.