IMMUNOBIOLOGY OF PANCREATIC ISLET XENOGRAFTING

描述：（改编自申请人的摘要） 建议研究的基础是研究T细胞介导的免疫 识别异种细胞移植物，使用胰岛作为 相关模型系统。 在供资期间获得的数据显示， 表明异种胰岛识别的普遍模式是通过 受体CD 4 + T细胞识别抗原间接途径 淋巴细胞 在特定目标I a中，将使用几只免疫缺陷小鼠来确定 CD 4 + T淋巴细胞依赖性异种反应性对大鼠的作用机制 小岛 胰岛异种移植物在裸鼠和SCID中存活的概念 受体强烈表明，至少在小鼠受体中， 这类移植物依赖于T细胞。 此外，还获得了证据 在第一个资助期内，这种细胞反应是CD 4 + T 体内依赖细胞的。 本提案的第一个目标是分析 靶细胞破坏分子在异种移植排斥反应中的作用 通过直接裂解（穿孔素）、通过诱导凋亡（Fas L）和通过 炎症介质（IFN-g）。 穿孔蛋白缺陷小鼠（PKO），Fas L 缺陷小鼠（gld/gld）和IFN-g缺陷小鼠将被用作 CD 4 + T细胞，其将被转移到RAG 1-/-受体中。 RAG 1-/- （T和B细胞缺陷，不像SCID小鼠那样渗漏）受体将 之前移植了老鼠的胰岛 这个实验所验证的假设 一系列的实验表明，CD 4 T细胞介导的异种排斥反应， 胰岛需要引发炎症，但不需要 存在完整的细胞毒性介导分子。 因此 预期结果（由初步研究结果支持）是PKO CD 4细胞 将在与WT CD 4细胞相似的时间内诱导大鼠胰岛排斥， 而IFN-γ-缺陷型CD 4细胞在 介导移植物排斥。 虽然CD 4 + T细胞在异种胰岛排斥反应中的关键作用， 虽然已经建立，但不能正式排除非T细胞介导的 效应器机制可能有助于（部分或全部）观察到的 现象。 因此，提出具体目标I B，以探索这一工作 假说. 特异性目的I c将检验CD 4 + T细胞 异种移植物细胞介导的排斥反应可能不需要T细胞 受体介导的与移植的靶细胞的相互作用。 具体目标I d是集中在分析排斥反应的不协调胰岛移植在 猪到小鼠模型系统。 在《特定目标2》中，P.I.建议 研究介导诱导长期生存的机制 异种胰岛移植到小鼠体内， 抗LFA-1抗体。

DESCRIPTION: (Adapted from the applicant's abstract) The goal of the proposed research is to study the basis of T cell-mediated immune recognition of xenogeneic cellular grafts, using islets of Langerhans as a relevant model system. Data obtained during the funding period strongly suggests that the prevalent mode of xenogenic islet recognition is through the indirect pathway of antigen recognition by recipient's CD4+ T lymphocytes. In Specific Aim I a, several immunodeficient mice will be used to determine the mechanisms of CD4+ T lymphocyte-dependent xenoreactivity towards rat islets. The notion that islet xenografts survive in nude and SCID recipients strongly suggests that, it least in murine recipients, rejection of such grafts is dependent on T cells. Furthermore, evidence was obtained during the first funding period that such cellular response is CD4+ T cell-dependent in vivo. The first goal of this proposal is to analyze the role of molecules involved in target cell destruction in xenograft rejection via direct lysis (perforin), via induction of apoptosis (Fas L) and by mediation of inflammation (IFN-g). Perforin deficient mice (PKO), Fas L deficient mice (gld/gld) and IFN-g deficient mice will be used as donors of CD4+ T cells, which will be transferred into RAG1-/- recipients. RAG 1-/- (T and B cell deficient, not as leaky as SCID mice) recipients will be previously transplanted with rat islets. The hypothesis tested by this series of experiments is that CD4 T cell-mediated rejection of xenogeneic islets requires triggering of inflammation, but it does not require the presence of intact cell-cytotoxicity mediating molecules. Therefore the expected results (supported by preliminary findings) are that PKO CD4 cells will induce rat islet rejection in times similar to those of WT CD4 cells, while IFN-g-deficient CD4 cells will be significantly less efficient in mediating graft rejection. While the pivotal role of CD4+ T cells in xenogeneic islet rejection has been established, it can not be formally ruled out that non T cell-mediated effector mechanisms might contribute (partially or entirely) to the observed phenomena. Specific Aim I b is therefore set forth to explore this working hypothesis. Specific Aim I c will test the hypothesis that CD4+ T cell-mediated rejection of xenogeneic grafts might not require T cell receptor-mediated interaction with the grafted target cells. Specific Aim I d is focused on the analysis of rejection of discordant islet grafts in the pig to mouse model system. In Specific Aim II, the P.I. proposes to investigate the mechanisms that mediate the induction of long term survival of xenogeneic islets grafted in mice treated with a short course of anti-LFA-1 antibodies.