Graft-Resident CD11c Cells are Critical for the Maintenance of Tolerance Following Lung Transplantation

项目总结/摘要： 肺移植后的长期生存仍然受到移植物排斥反应的严重限制。 肺受体的免疫抑制是基于实体器官移植的经验，但可能 对肺移植物的存活具有有害影响，因为移植肺的命运 由移植物自身内的局部免疫细胞相互作用决定。支气管相关淋巴 组织（BALT）在耐受性肺同种异体移植物中形成，对于维持耐受性很重要。Balt 富含聚集在CD 11 c+细胞周围的Foxp 3+调节性T细胞。耗尽移植物驻留Foxp 3 + T细胞或CD 11 c+细胞导致抗体介导的排斥。细胞在BALT中如何相互作用 调节耐受性的方法仍然未知。我们的实验室惊奇地发现， T细胞不受CD 11 c+细胞耗竭的影响。CCL 17和CCL 22是表达的趋化因子 通过CD 11 c+细胞，可以参与CCR 4，一种主要在调节性T细胞上表达的受体。 我们实验室的初步数据显示，CCL 17和CCL 22的表达水平显著高于对照组。 与排斥肺中的CD 11 c+细胞相比，耐受肺移植物中的CD 11 c+细胞水平。我们 目的确定CD 11 c+细胞是否通过介导肺移植后的免疫耐受， 移植物内Foxp 3+细胞的空间组织。先前建立的小鼠肺再灌注模型， 移植将被用来测试我们的假设。将使用以下组合分析结果： 方法：流式细胞术、免疫组化和盲法组织学分析。一种新型 被称为活体双光子显微镜的成像技术将用于多个实验， 真实的实时观察Foxp 3+细胞和CD 11 c+细胞的运动和空间关系。结果 我们的提案将提供一个框架，以开发新的疗法，以改善肺 移植患者

PROJECT SUMMARY/ABSTRACT: Long-term survival after lung transplantation remains profoundly limited by graft rejection. Immunosuppression for lung recipients is based on experiences with solid organ transplants, but may be having deleterious effects to the survival of pulmonary grafts as the fate of the transplanted lungs is determined by local immune cell interactions within the graft itself. Bronchus-associated lymphoid tissue (BALT) forms in tolerant lung allografts and is important for the maintenance of tolerance. BALT is rich in Foxp3+ regulatory T cells that aggregate around CD11c+ cells. Depleting graft-resident Foxp3+ T cells or CD11c+ cells results in antibody mediated rejection. Exactly how cells interact within the BALT to regulate tolerance remains unknown. Our laboratory surprisingly found that the abundance of Foxp3+ T cells were not impacted by depletion of CD11c+ cells. CCL17 and CCL22 are chemokines expressed by CD11c+ cells that can engage CCR4, a receptor predominantly expressed on regulatory T cells. Preliminary data from our laboratory show that CCL17 and CCL22 are expressed at significantly higher levels by CD11c+ cells in tolerant lung grafts when compared to CD11c+ cells in rejecting lungs. We aim to determine whether CD11c+ cells maintain tolerance after lung transplantation by mediating the spatial organization of Foxp3+ cells within the graft. A previously established model of mouse lung re- transplantation will be used to test our hypotheses. Results will be analyzed using a combination of methods, including flow cytometry, immunohistochemistry and blinded histology analysis. A novel imaging technology, known as intravital two-photon microscopy, will be used in multiple experiments to study the movement and spatial relationships of Foxp3+ cells and CD11c+ cells in real time. The results of our proposal will provide a framework to develop novel therapies to improve outcomes for lung transplant patients.