Fas ligand+ blood cells to reduce transplant rejection

Fas配体血细胞减少移植排斥

• 批准号: 6570677
• 负责人: CURT I CIVIN
• 金额: $ 24.53万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6570677
• 关键词: CD95 molecule; NOD mouse; SCID mouse; apoptosis; artificial immunosuppression; autoimmunity; blood treatment; bone marrow transplantation; clinical research; dendritic cells; gene therapy; heart transplantation; hematopoietic stem cells; histocompatibility; human subject; immune tolerance /unresponsiveness; isoantigen; laboratory mouse; nonhuman therapy evaluation; stem cell transplantation; transfection; transplant rejection

DESCRIPTION (provided by applicant): The ability to stably transduce lymphohematopoietic stem-progenitor cells (HSCs) and progeny cells allows us to genetically engineer HSCs and progeny, especially dendritic cells (DCs), to serve as cellular tools to improve transplantation. Allogeneic (allo) blood and marrow transplantation (BMT) will continue to be an important treatment option in patients with many inherited and acquired diseases. Our recent Preliminary Results indicate that ex vivo or in vivo treatment with transduced FasL+ allog mouse DCs or HSCs suppressed the response to that alloantigen and increased engraftment of allo cells, without immunoablation or evident toxicity to the recipient mice. In Aims 1-2 of this proposal, we propose studies to test the concept and elucidate the principal mechanisms by which transduced DCs or HSCs constitutively expressing Fas ligand (FasL) appear to reduce the T (and NK) cells that mediate graft rejection without overwhelming organ toxicity or general immunologic impairment. Aims 1-2 attempt to accelerate and enhance the natural homeostatic role of FasL during the course of the alloimmune response, with the potential outcome that alloimmune T cells may be killed earlier in their activation/expansion, or killed more potently later during activation-induced cell death (AICD), by transduced FasL+ DCs (Aim 1) or HSCs/progeny (Aim 2), respectively. As we investigate this, we will examine the apoptotic pathways in alloimmune cells. In addition, since we expect that transduced FasL+ HSCs might potentially be toxic in vivo, we will in parallel investigate technologies to limit potential FasL toxicity, eg by transducing only a small percent of high quality HSCs, by employing a FasL deletion mutant that cannot be cleaved to release soluble FasL (sFasL), by eliminating the transduced cells themselves or their FasL expression after tolerance to HSCs has been generated, or by using lineage/stage-specific promoters to restrict FasL expression. A novel FasL+ cell therapy approach to reduce graft rejection may eventually be used in clinical allo BMT. Furthermore, achievement of stable lymphohematopoietic chimerism would also be predicted to generate tolerance for transplanted allo organs or pluripotent stem cells. Therefore, in Aim 3, we will assess tolerance to cardiac allografts in hematopoietic macro-chimeras, generated by this FasL strategy, with or without other immunosuppressive methodologies such as co-stimulatory blockade. SPECIFIC AIM 1: Assess whether FasL+ DCs specifically reduce an alloimmune response and enhance engraftment of allo HSCs SPECIFIC AIM 2: Determine whether FasL+ HSCs generate specific tolerance in allo BMT. SPECIFIC AIM 3: Evaluate tolerance to cardiac allografts in hematopoietic chimeras generated using FasL+ DCs/HSCs.

描述（由申请人提供）： 稳定转导淋巴造血干祖细胞 (HSC) 和子代细胞的能力使我们能够对 HSC 和子代细胞，特别是树突状细胞 (DC) 进行基因改造，作为改善移植的细胞工具。同种异体（allo）血液和骨髓移植（BMT）将继续成为许多遗传性和获得性疾病患者的重要治疗选择。我们最近的初步结果表明，用转导的 FasL+ 同种异体小鼠 DC 或 HSC 进行离体或体内治疗可抑制对该同种异体抗原的反应，并增加同种异体细胞的植入，且不会对受体小鼠产生免疫消融或明显毒性。在本提案的目标 1-2 中，我们提出研究来测试这一概念并阐明转导的 DC 或 HSC 组成型表达 Fas 配体 (FasL) 的主要机制，似乎可以减少介导移植物排斥的 T（和 NK）细胞，而不会压倒性的器官毒性或一般免疫损伤。目标 1-2 尝试在同种免疫反应过程中加速和增强 FasL 的自然稳态作用，其潜在结果是同种免疫 T 细胞可能在其激活/扩增过程中较早被杀死，或者在激活诱导过程中稍后被更有效地杀死分别由转导的 FasL+ DC（目标 1）或 HSC/子代（目标 2）引起的细胞死亡 (AICD)。当我们对此进行研究时，我们将检查同种免疫细胞中的凋亡途径。此外，由于我们预计转导的 FasL+ HSC 可能在体内具有潜在毒性，因此我们将同时研究限制潜在 FasL 毒性的技术，例如仅转导一小部分高质量 HSC，通过使用不能被转化的 FasL 缺失突变体。在 HSC 产生耐受性后，通过消除转导细胞本身或其 FasL 表达，或使用谱系/阶段特异性启动子，裂解释放可溶性 FasL (sFasL)限制 FasL 表达。一种减少移植排斥的新型 FasL+ 细胞治疗方法最终可能用于临床同种异体 BMT。此外，预计实现稳定的淋巴造血嵌合也会产生对移植的同种异体器官或多能干细胞的耐受性。因此，在目标 3 中，我们将评估由该 FasL 策略产生的造血大嵌合体对心脏同种异体移植物的耐受性，无论有或没有其他免疫抑制方法，例如共刺激阻断。 具体目标 1：评估 FasL+ DC 是否特异性降低同种免疫反应并增强同种异体 HSC 的植入 具体目标 2：确定 FasL+ HSC 是否在异体 BMT 中产生特定耐受性。 具体目标 3：评估使用 FasL+ DC/HSC 生成的造血嵌合体对心脏同种异体移植物的耐受性。