Cellular Mechanisms of PTLD in Transplant Resipients

移植后淋巴增生性疾病(PTLD)是一种形态复杂的并发症 移植的范围从良性B细胞增生症到恶性淋巴瘤。爱泼斯坦-巴尔病毒 B细胞淋巴瘤是PTLD的标志，与显著的发病率和死亡率有关。 在之前的资金支持期间，我们确定了赋予生存优势的特定信号通路。 EBV感染的B细胞，尽管存在显著的EBV特异性CD8T细胞 移植受者的循环。我们还证实了免疫抑制剂西罗莫司(RAPA)可以 直接抑制EB病毒感染B细胞的生长。这项研究的目的是定义免疫 有助于EBV相关B细胞淋巴瘤自主生长的改变。要完成 这一目标，我们提出了三个具体目标。具体目标1将检查EBV- 感染的B细胞对死亡受体诱导的细胞凋亡具有抵抗力。近端事件，包括集结 Fas-Fas配体中的死亡诱导信号复合体(DISC)与TRAIL-DR4/DR5细胞死亡 这些通路将通过双向凝胶电泳法和DNA微阵列进行表征。这个 将研究诱骗受体DcR1和DcR2在抵抗TRAIL细胞毒性中的作用。这个 EBV潜伏基因LMP1和EBNA2在抵抗细胞凋亡中的作用也将被确定。在……里面 具体目的2将使用含有EBV抗原的免疫优势表位的MHC/多肽四聚体 鉴定移植受者中EBV特异性CD8？T细胞及其功能特性 将通过细胞内染色和细胞因子和细胞溶解功能的体外检测来评估。这个 免疫抑制对功能性EBV特异性CD8？T细胞生成的影响将被确定 在我们的SCID/EBV B细胞淋巴瘤模型中。具体目标3将确定RAPA 抑制EB病毒感染的B细胞的生长，特别关注细胞凋亡、细胞周期蛋白和 JAK/STAT通路。体内阻断IL-10途径对肿瘤生长的影响也将是 下定决心。阐明PTLD的免疫机制将为以下方面提供新的机会 针对器官移植这一严重并发症合理设计新的治疗方法。

Post-transplant lymphoproliferative disorder (PTLD) is a morphologically complex complication of transplantation that ranges from benign B cell hyperplasia to malignant lymphoma. Epstein-Barr virus (EBV) B cell lymphomas are the hallmark of PTLD and are associated with significant morbidity and mortality. During the previous funding period we identified specific signaling pathways that confer a survival advantage to EBV-infected B cells despite the presence of significant frequencies of EBV-specific CD8 ¿ T cells in the circulation of transplant recipients. We also established that the immunosuppressive sirolimus (RAPA) can directly inhibit the growth of EBV-infected B cells. The objective of this research is to define the immune alterations that contribute to the autonomous growth of EBV-associated B cell lymphomas. To accomplish this objective we propose three Specific Aims. Specific Aim 1 will examine the mechanism by which EBV- infected B cells are resistant to death receptor-induced apoptosis. The proximal events, including assembly of the death inducing signaling complex (DISC), in the Fas-Fas ligand and TRAIL-DR4/DR5 cell death pathways will be characterized by two-dimensional gel electrophoresis analysis and DNA microarray. The role of the decoy receptors DcR1 and DcR2 in resistance to TRAIL cytotoxicity will be examined. The contribution of the EBV latent genes LMP1 and EBNA2 to resistance to apoptosis will also be determined. In Specific Aim 2 MHC/peptide tetramers containing immunodominant epitopes of EBV antigens will be used to identify EBV-specific CD8 ¿ T cells in transplant recipients and the functional properties of these T cells will be assessed using intracellular staining and in vitro assays for cytokine and cytolytic function. The effects of immunosuppression on the generation of functional EBV-specific CD8 ¿ T cells will be determined in our SCID/EBV B cell lymphoma model. Specific Aim 3 will determine the mechanism by which RAPA inhibits growth of EBV-infected B cells with specific focus on apoptosis, cell cycle proteins and the Jak/STAT pathway. The effect of in vivo blockade of the IL-10 pathway on tumor growth will also be determined. Elucidation of the immune mechanisms involved in PTLD will provide novel opportunities for the rational design of new treatments for this serious complication of organ transplantation.