Development of novel strategies to modulate human NK cell response in xenotransplantation

项目摘要 异种移植（即在人类中使用猪器官的跨物种移植）提供了一种潜在的解决方案， 解决器官短缺问题器官短缺更严重地影响少数民族，如非洲人 美国人，亚洲人和西班牙人。然而，猪-人不相容性导致破坏性的人类免疫 反应和最终的排斥反应。这项提案的长期目标是制定一项有效的 预防人体对移植的猪细胞、组织和器官产生免疫反应的安全方法。 人NK细胞介导的对猪血管内皮细胞的直接杀伤是异种移植的障碍之一。 来自猪细胞配体和人NK细胞受体相互作用的信号平衡决定人NK细胞 细胞功能这项提案的重点是操纵猪细胞表面蛋白来抑制/阻断NK细胞 识别和激活。在我们的初步数据中，我们已经证明了猪HLA-G的表达， 细胞抑制NK细胞活化并减少促炎细胞因子产生。抗体介导的- 阻断NKG 2D受体可减少NK细胞活化。我们假设， 配体可以消除人NK细胞介导的细胞毒性。抑制性配体的表达和抑制性配体的去除 激活猪细胞上的配体可以诱导NK细胞耐受和抑制。假设是 在以下具体目的的实验中提出：1）确定通过以下方法抑制人NK细胞： 在猪细胞上共表达HLA I类分子HLA-C、HLA-E和HLA-G;和2）确定 消除NKG 2D猪配体是否阻断人NK细胞识别和活化。这 探索性研究将扩大我们对跨物种免疫识别机制的理解， 反应，开发一种新的方法来诱导局部免疫耐受/接受，并指导工程 猪以满足异种移植的需要。

PROJECT SUMMARY Xenotransplantation (i.e. cross-species transplantation using pig organ in human) offers a potential solution to address persistent organ shortage. Organ shortage more severely impacts minorities, such as African Americans, Asians, and Hispanics. However, pig-human incompatibility results in destructive human immune response and ultimate rejection of pig organs. The long-term goal of this proposal is to develop an effective and safe method to prevent the human immune response to transplanted pig cells, tissues, and organs. Human NK cell mediated-direct killing of porcine endothelial cells is one of the barriers in xenotransplantation. A balance of signals from porcine cell ligands and human NK cell receptors interaction determines human NK cell function. This proposal focuses on manipulation of porcine cell surface proteins to inhibit/block NK cells recognition and activation. In our preliminary data, we have demonstrated that expression of HLA-G on porcine cell inhibits NK cell activation and reduces pro-inflammatory cytokine production. An antibody mediated- blocking of NKG2D receptor can diminish NK cell activation. We hypothesize that manipulation of porcine ligands may abolish human NK cell-mediated cytotoxicity. Expression of inhibitory ligands and removal of activating ligands on porcine cells may induce NK cell tolerance and inhibition. The hypothesis will be addressed in the experiments of the following Specific Aims: 1) to determine the inhibition of human NK cell by co-expression of HLA class I molecules HLA-C, HLA-E, and HLA-G on porcine cells; and 2) to determine whether elimination of NKG2D porcine ligands blocks human NK cell recognition and activation. This exploratory study will expand our understanding of the mechanism of cross-species immune recognition and response, develop a novel approach to induce local immune tolerance/acceptance, and guide engineering of pigs to meet xenotransplantation needs.