ENDOTHELIAL CELL INJURY BY CYTOLYTIC LYMPHOCYTES

描述(改编自调查人员摘要)：在慢性疾病的地点 在各种感染过程中引发的炎症， 自身免疫性疾病、同种异体排斥反应、移植物抗宿主病和 白介素2(IL-2)对肿瘤的免疫治疗 已知会发生细胞损伤，导致严重毒性的发病机制， 造成这种情况的根本原因尚不清楚。来自本实验室的研究 证明了多种激活的细胞毒性淋巴细胞[细胞毒性T 淋巴细胞(CTL)、淋巴因子激活的杀伤细胞(LAK)和 阴性(DN)T细胞]可以介导高效的MHC-无限制的裂解 靶细胞，包括内皮细胞，当通过CD44激活时。 CTL+IL-2导入受照小鼠可触发血管内皮细胞 细胞损伤和血管渗漏综合征(VLS)。此外，他们还 结果表明，穿孔素基因敲除(KO)和FasL缺陷小鼠表现出减少 IL-2诱导的VLS。目前的研究旨在阐明其发病机制。 以IL-2诱导的血管内皮细胞损伤为模型。它将测试 激活的CTL之间相互作用的失调假说 或表达CD44的LAK细胞和内皮细胞承担适当的 透明质酸(HA)等配体可导致内皮细胞溶解 和VLS的诱导。CD44在VLS的诱导中的作用将是 用CD44KO小鼠进行研究。关于这样的老鼠是否 对IL-2诱导的VLS的抵抗以及IL-2是否 来自这些小鼠的激活的CTL或LAK细胞可以触发VLS 地址。CD44不同异构体在黏附和修复中的作用 将使用CD44外显子特异性研究内皮细胞的细胞毒性 KO小鼠及CD44基因缺陷的异构体特异性构建物的转染 细胞溶解淋巴细胞。进一步检验VLS的原因是什么 血管内皮细胞直接裂解、FasL、穿孔素和肿瘤坏死因子在VLS中的作用 将使用双KO(FasL和穿孔素缺乏)和 TNFR-KO小鼠。最后，根据上述结果，将尝试 用可溶性CD44Rg融合蛋白阻断VLS的体内诱导 抗CD44变异异构体的单抗。CD44-透明质酸的作用 将使用突变融合来测试内皮细胞损伤中的相互作用 抗CD44单抗的蛋白(CD44MutRg)或Fab片段。 总之，这些研究应该会为基本机制带来新的曙光 参与细胞毒性-内皮细胞相互作用导致内皮细胞 细胞损伤和可能的治疗方法来防止这种情况，在 各种疾病状态，包括癌症的免疫疗法。

DESCRIPTION (Adapted from Investigator's Abstract): At sites of chronic inflammation induced during the course of a variety of infections, autoimmune diseases, allograft rejection, graft-versus-host disease and immunotherapy of cancer using interleukin-2 (IL-2), significant endothelial cell injury is known to occur, leading to pathogenesis of severe toxicity, the underlying reason for which remains unclear. Studies from this lab demonstrated that a variety of activated cytotoxic lymphocytes [cytotoxic T lymphocytes (CTL), lymphokine-activated killer (LAK) cells, and double negative (DN) T cells] can mediate efficient MHC-unrestricted lysis of target cells, including the endothelial cells, when activated through CD44. Also transfer of CTL+IL-2 into irradiated mice could trigger endothelial cell injury and vascular leak syndrome (VLS). Moreover, they have also shown that perforin knockout (KO) and FasL-defective mice exhibit decrease IL-2-induced VLS. The current study is to delineate the mechanism of endothelial cell injury by using IL-2-induced VLS as a model. It will test the hypothesis that dysregulation of the interaction between activated CTL or LAK cells expressing CD44 and endothelial cells bearing the appropriate ligand such as hyaluronic acid (HA), could lead to endothelial cell lysis and induction of VLS. The role of CD44 in the induction of VLS will be investigated using CD44 KO mice. The question of whether such mice are resistant to VLS induction upon IL-2 administration and whether IL-2 activated CTL or LAK cells from these mice can trigger VLS will be addressed. The role played by CD44 variant isoforms in adhesion and cytotoxicity of endothelial cells will be studies using CD44-exon specific KO mice and transfection of isoform-specific constructs in CD44-deficient cytolytic lymphocytes. To further test the hypothesis that VLS results from direct endothelial cell lysis, the role of FasL, perforin and TNF in VLS induction will be studied using double-KO (FasL and perforin-deficient) and TNFR-KO mice. Lastly, based on the above results, attempts will be made to block the VLS induction in vivo using soluble CD44Rg fusion proteins and mAbs against CD44 variant isoforms. The role of CD44-hyaluraonate interactions in endothelial cell injury will be tested using a mutant fusion protein (CD44MutRg) or Fab fragments of anti-CD44 mAbs. Together, the studies should shed new lights on the basic mechanisms involved in cytotoxic-endothelial cell interactions leading to endothelial cell injury and possible therapeutic approaches to prevent this, in a variety of disease states, including immunotherapy of cancer.