PRECLINICAL HEPATIC GENE THERAPY

临床前肝脏基因治疗

• 批准号: 6116377
• 负责人: Mark A Kay
• 金额: $ 8.67万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6116377
• 关键词: Mammalia; Primates; biological products; gene therapy; immunology; inflammation; liver; model design /development

Recombinant adenoviral vectors offer great promise for hepatic gene therapy because of the high efficiency of gene transfer into this target organ. Gene expression does not persist over the long term and secondary gene transfer is not possible because of a robust immunological response directed against the viral antigens, many of which are synthesized at low levels from vector transduced cells. We have obtained partial success in mice by modifying the host response to enhance gene expression, by selectively blocking the interactions of costimulatory ligands on T lymphocytes and antigen-presenting cells (APC), which play an important role in the initiation of an effective, antigen-specific immunologic response. Blockade of the costimulatory interactions between CD28 on T cells with B7-1,-2 on APC using soluble CTLA4Ig has several potential advantages over cytoablative therapy (1) it results in transient immunosuppression, (2) it is not cytoablative and does not affect other cells (e.g., neutrophils) involved in innate immune responses, (3) it has minimal effect on pre-existing immunity, and (4) it is unlikely to result in immunological tolerance to wildtype adenovirus. Using single-dose immunotherapy with soluble murine CTLA4Ig, we have obtained indefinite periods of adenovirus-mediated hepatic gene expression in mice. In our current study, we challenged M. fascicularis with recombinant adenoviral vectors with or without the co-administration of human CTLA4Ig (approved for phase 1 clinical trials). Our preliminary evidence suggests that humoral and cell-mediated immune responses directed against the vector are decreased with CTLA4Ig therapy. The relative persistence of adenoviral-mediated gene expression has been more difficult to determine because we have found that gene expression is more persistent in nonhuman primates than in mice and dogs. The administration of human CTLA4Ig to nonhuman primates resulted in a decreased lymphoctye proliferation in response to adenoviral vector administration but did not affect the persistence of expression of the trangene, human alpha 1-antitrypsin. For reasons that are not clear, gene expression persisted for several months with or without CTLA4Ig administration. At this time, we have decided to postpone future experiments until an optimal less antigenic adenoviral vector can be produced.

重组腺病毒载体为肝基因疗法提供了巨大的希望，因为基因转移到该靶器官中的效率很高。 基因表达在长期内不持续，由于针对病毒抗原的强大免疫反应是不可能的，其中许多反应是从载体转导的细胞中低水平合成的。 通过选择性地阻断T淋巴细胞和抗原呈递细胞（APC）的共刺激配体的相互作用，我们通过修改宿主反应以增强基因表达而在小鼠中获得了部分成功，这在有效的，抗原特异性免疫学反应中起着重要作用。 使用可溶性CTLA4IG在T细胞上CD28对T细胞的CD28之间的共刺激相互作用的阻塞具有几种潜在的优势（1）导致瞬时免疫抑制，（2）它不受细胞影响，并且对其他细胞不影响其他细胞（例如，对中性粒细胞的影响），（例如，中性粒细胞），（3）（3）（3）（3）（3），（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3），（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3）（3免疫力，（4）不太可能导致对野生型腺病毒的免疫耐受性。 使用单剂量免疫疗法与可溶性鼠CTLA4IG，我们获得了小鼠腺病毒介导的肝基因表达的无限期。 在我们目前的研究中，我们通过有或没有人类CTLA4IG的重组腺病毒载体向筋膜分枝杆菌（批准用于1期临床试验）。 我们的初步证据表明，针对载体的体液和细胞介导的免疫反应通过CTLA4IG治疗降低。 腺病毒介导的基因表达的相对持久性更难确定，因为我们发现非人类灵长类动物中的基因表达比小鼠和狗更持久。 对非人类灵长类动物的人类CTLA4IG的给药导致对腺病毒载体给药的响应，淋巴细胞增生降低，但不影响trangene表达的人α1-抗抗素的表达持续性。 出于尚不清楚的原因，基因表达持续了几个月，无论有没有CTLA4IG给药。 目前，我们已决定推迟未来的实验，直到可以产生最佳的抗原性腺病毒载体。