Improving gene transfer to provide intracellular immuniz

改善基因转移以提供细胞内免疫

• 批准号: 6988880
• 负责人: DAVID M. BODINE
• 金额: --
• 依托单位: NATIONAL HUMAN GENOME RESEARCH INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6988880
• 关键词: AIDS education /prevention; AIDS therapy; HIV infections; antiAIDS agent; biotechnology; cell cycle; cellular immunity; family genetics; gene delivery system; gene induction /repression; gene therapy; genetic counseling; genetic mapping; genetic screening; helper T lymphocyte; hematopoietic stem cells; human subject; immunogenetics; inborn immunodeficiency; laboratory mouse; patient oriented research; receptor binding; sheep; stem cell transplantation; technology /technique development; transfection /expression vector; vaccine development; virus envelope; virus genetics; virus receptors

Summary: The NHGRI intramural program has expanded research efforts to integrate virus vectors into adult hematopoietc stem cells (HSC) to combat HIV infection. The HSC is the ultimate progenitor of all peripheral blood cells, including the CD4+ lymphocytes that are infected by HIV and the macrophages that can sequester HIV for long periods of time in tissues. If an anti-HIV element can be introduced into HSC, it will be passed along to all of the progeny of that HSC, ensuring the continuous, life-long production of HIV resistant cells. If this therapy were completely successful, this treatment would permanently protect the patient from HIV spread and no further treatments would be required. The successful modification of HSC by viral vectors has three important steps. First the viral vector must bind to a specific receptor on the surface of the HSC. We have determined that the receptors for two novel retroviruses RD114 and FeLV-C are plentiful on HSC, unlike the conventional retrovirus receptors, which are not present on HSC. We have demonstrated high levels of gene transfer into human HSC using retrovirus vectors with these new envelopes using mouse and sheep xenograft models. In the coming year, we will extend these studies to include pseudotyping lentivirus vectors that carry anti HIV genes. The second important step in the modification of HSC requires the vector to become integrated into the DNA of the target cell. Because of new safety concerns regarding insertional leukemogenesis in a gene therapy trial, NHGRI intramural researchers are comparing the integration sites of lentivirus and oncoretrovirus vectors. We are also studying several genes that regulate hematopoietic cell cycle progression. The final important step for successful modification of HSC with anti-HIV elements is that the anti-HIV elements have to be produced in the mature progeny of the HSC at all times so that the cells are always prepared to interrupt HIV infection. Many groups have shown that viral vectors can become silenced over time and stop making the critical elements. To combat silencing, NHGRI intramural investigators are developing and evaluating different virus vectors that contain genetic elements to prevent silencing. Among the vectors under development are vectors containing insulator elements that prevent the type of changes associated with gene silencing. Novel insulators are being incorporated into vectors to evaluate gene silencing in mouse models. The combination of these three initiatives should significantly improve the prospects for successful HSC based AIDS gene therapy. It is anticipated that the results of these studies can be combined into a clinical trial for AIDS gene therapy in the near future. NHGRI has initiated a genetic approach to AIDS that takes full advantage of the strengths of the intramural NHGRI clinical research program. NHGRI clinical researchers study inherited immune disorders building knowledge that will bear on the ultiumate production of HIV vaccines and provide an understanding of how HIV deactivates the immune system. The NHGRI Genetic Counseling program will initiate an effort to counsel and educate individuals with AIDS. The Genetic Counseling program has completed an extensive study of the most effective counseling techniques for families with inherited immune disorders. The NHGRI AIDS initiative will compare counseling approaches that have been shown to be effective in inherited immunodeficiency diseases with counseling for AIDS families. Such psychological studies are expected to reveal whether different approaches are necessary to help families cope with AIDS and its consequences.

摘要：NHGRI内部计划扩大了研究力度，将病毒载体整合到成人造血干细胞(HSC)中，以对抗艾滋病毒感染。HSC是所有外周血细胞的终极祖细胞，包括感染艾滋病毒的CD4+淋巴细胞和能够在组织中长时间隔离艾滋病毒的巨噬细胞。如果一种抗艾滋病毒的成分能够被引入到HSC中，它将被遗传给该HSC的所有后代，确保持续、终身地生产抗艾滋病毒的细胞。如果这种疗法完全成功，这种疗法将永久保护患者免受艾滋病毒传播的影响，不需要进一步的治疗。病毒载体成功修饰HSC有三个重要步骤。首先，病毒载体必须与肝星状细胞表面的特定受体结合。我们已经确定，两种新型逆转录病毒RD114和FeLV-C的受体在HSC上丰富，不同于传统的逆转录病毒受体，HSC上不存在。我们已经在小鼠和羊的异种移植模型中证明了利用这些新的包膜使用逆转录病毒载体将高水平的基因转移到人的HSC中。在接下来的一年里，我们将扩大这些研究的范围，包括携带抗HIV基因的伪分型慢病毒载体。HSC修饰的第二个重要步骤要求载体整合到靶细胞的DNA中。由于对基因治疗试验中插入白血病发生的新的安全担忧，NHGRI内部研究人员正在比较慢病毒和肿瘤逆转录病毒载体的整合位置。我们还在研究几个调节造血细胞周期进程的基因。成功地用抗HIV成分修饰HSC的最后一个重要步骤是，抗HIV成分必须始终在HSC的成熟后代中产生，以便细胞始终准备好阻断HIV感染。许多研究小组已经证明，随着时间的推移，病毒载体会变得沉默，停止制造关键成分。为了对抗沉默，NHGRI内部调查人员正在开发和评估包含防止沉默的遗传元素的不同病毒载体。在开发中的载体中，有一些载体含有绝缘体元件，可以防止与基因沉默相关的类型变化。新型绝缘体正被整合到载体中，以评估小鼠模型中的基因沉默。这三项举措的结合将大大改善成功的基于HSC的艾滋病基因治疗的前景。预计在不久的将来，这些研究的结果可以合并成艾滋病基因治疗的临床试验。NHGRI启动了一种针对艾滋病的遗传方法，该方法充分利用了NHGRI内部临床研究计划的优势。NHGRI临床研究人员研究遗传性免疫紊乱，建立将与艾滋病毒疫苗的最终生产有关的知识，并提供对艾滋病毒如何使免疫系统失活的理解。NHGRI遗传咨询计划将发起一项努力，对艾滋病患者进行咨询和教育。遗传咨询计划完成了对遗传性免疫疾病家庭最有效咨询技术的广泛研究。NHGRI艾滋病倡议将比较已被证明对遗传性免疫缺陷疾病有效的咨询方法与针对艾滋病家庭的咨询方法。这类心理学研究预计将揭示是否有必要采取不同的方法来帮助家庭应对艾滋病及其后果。