NK Cell Interactions in Transplantation

描述（由申请人提供）：最近的证据表明先天免疫系统在实体器官移植中的移植物排斥和耐受诱导中的重要性。然而，参与这些过程的先天免疫系统的特定细胞类型和分子尚未确定。我们已经开始在实体器官移植的背景下定义自然杀伤（NK）细胞激活。我们已经表明，NK细胞构成了移植后早期肝脏浸润细胞的大部分。这些NK细胞具有功能活性，并产生大量IFN-？。此外，NK细胞的耗竭导致IFN-？和延长移植物存活。基于这些数据，我们提出了一种模型，其中手术应激和缺血/再灌注损伤刺激肝移植物诱导几种趋化因子的早期表达，这些趋化因子在移植后早期直接将免疫原性NK细胞募集到移植物中。IFN-？由NK细胞产生的免疫抑制剂进一步诱导活化的淋巴细胞向移植物的募集，从而增强效应子功能和移植物损伤。我们假设先天免疫系统，特别是NK细胞的激活，影响移植后的移植结果。这一假设将使用大鼠原位肝移植模型来检验NK细胞在移植物排斥和长期移植物存活期间的作用。在第一个具体目标中，我们将确定NK细胞在肝移植后移植物结局中的作用。我们将：1）分析移植后NK细胞的作用，2）确定NK细胞耗竭对趋化因子和IFN-？产生和移植后的细胞毒性，3）分析在不存在NK细胞的情况下混合嵌合体的建立和4）确定免疫抑制剂对NK细胞效应子功能的影响。第二个具体目标的目标是确定特定NK细胞受体在移植物结果中的功能意义。我们开发和组装的独特试剂将用于专门研究大鼠NK细胞受体在实体器官移植中的表达和功能意义。具体而言，我们将：1）确定移植后NK细胞活化受体的表达模式，2）确定通过NK细胞受体的信号传导是否诱导细胞因子产生和细胞毒性，和3）检查在移植模型中阻断NK细胞受体的功能结果。我们的研究将明确NK细胞在同种异体移植排斥和接受中的功能意义，并将导致诱导肝移植耐受的新方法。

DESCRIPTION (provided by applicant): Recent evidence indicates the importance of the innate immune system in both graft rejection and the induction of tolerance in solid organ transplantation. However, the specific cell types and molecules of the innate immune system involved in these processes have not been determined. We have begun to define natural killer (NK) cell activation in the context of solid organ transplantation. We have shown that NK cells comprise the majority of liver infiltrating cells early post-transplantation. These NK cells are functionally active and producing substantial amounts of IFN-?. Furthermore, depletion of NK cells results in decreased levels of IFN-? and prolonged graft survival. Based on these data we suggest a model in which surgical stress and ischemia/reperfusion injury stimulate the liver allograft to induce the early expression of several chemokines that direct the recruitment of recipient-derived NK cells into the allograft early after transplantation. IFN-? produced by NK cells further induces the recruitment of activated lymphocytes to the graft thereby augmenting effector function and graft damage. We hypothesize that the innate immune system, specifically the activation of NK cells, influences graft outcome post transplantation. This hypothesis will be tested using a rat orthotopic liver transplant model to examine the role of NK cells during graft rejection and long term graft survival. In the first Specific Aim we will determine the role of NK cells in graft outcome following liver transplantation. We will: 1) analyze the role of NK cells post-transplant, 2) determine the effect of NK cell depletion on chemokine and IFN-? production and cytotoxicity post-transplant, 3) analyze the establishment of mixed chimerism in the absence of NK cells and 4) determine the effect of Immunosuppressive agents on NK cell effector function. The goal of the second specific aim is to determine the functional significance of specific NK cell receptors in graft outcome. Unique reagents we have developed and assembled, will be used, to specifically address the expression and functional significance of the rat NK cell receptors in the context of solid organ transplantation. Specifically we will: 1) determine the expression pattern of NK cell activation receptors after transplant, 2) determine if signaling through NK cell receptors induces cytokine production and cytotoxicity, and 3) examine the functional outcome of blocking NK cell receptors in a transplant model. Our studies will specifically define the functional significance of NK cells in both allograft rejection and acceptance and will lead to new approaches to induce tolerance to liver allografts.