Host Immune Responses in Cutaneous Gene Therapy

描述（由申请人提供）： 该提案的总体目标是开发遗传性皮肤病的基因疗法。皮肤基因治疗研究继续集中在开发有效的基因转移方法，导致长期的转基因表达。在改进载体和设计靶向干细胞的策略方面取得了相当大的成功。然而，我们缺乏对新抗原在皮肤中表达时宿主反应的理解。这些反应可能会使皮肤基因治疗试验复杂化，特别是当患者具有无效突变时。我们的研究表明，当新抗原在正常小鼠的皮肤中表达时，转基因表达被削减，并且转导的细胞通过免疫应答被排斥。从肝脏和肌肉的相关研究中获得的知识不太可能适用于皮肤，因为与这些组织不同，皮肤具有免疫相关功能。因此，本研究提案的目的是更好地了解对新抗原的皮肤特异性免疫反应，并制定避免这些反应的策略。基于一个新兴的知识体系，我们假设，宿主免疫反应是最适合在角质形成细胞中表达的抗原交叉呈递给T细胞的点调制。本提案中描述的实验旨在描述抗原转基因呈递和引发T细胞的机制，并探索将这些反应转向破坏性较小或致耐受性较低的反应的策略。提出了三个具体目标：1）检查角化细胞衍生的抗原的交叉呈递在诱导T细胞免疫中的作用; 2）描述炎症在抗原呈递细胞引发T细胞中的作用;和3）通过调节参与T细胞免疫起始的信号传导事件来诱导对角化细胞衍生的新抗原的耐受状态。预计开发新的策略来规避破坏性免疫反应将克服皮肤基因治疗临床应用的主要障碍。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to develop gene-based therapies for inherited disorders of skin. Cutaneous gene therapy research continues to focus on developing efficient gene transfer methods that lead to long-term transgene expression. Considerable success has been achieved with improvements in vectors and in devising strategies for targeting stem cells. However, we lack an understanding of host responses when a neoantigen is expressed in skin. These responses are likely to complicate cutaneous gene therapy trials, especially when a patient has a null mutation. Our studies demonstrate that when a neoantigen is expressed in the skin of normal mice, transgene expression is curtailed and the transduced cells are rejected through immune responses. The knowledge gained from related studies in liver and muscle is not likely to be applicable to skin as, unlike those tissues, skin has immune-associated functions. The aim of this research proposal therefore, is to develop an improved understanding of skin-specific immune responses to neoantigen and to develop strategies for avoiding these responses. Based on an emerging body of knowledge we hypothesize that host immune responses are most amenable to modulation at the point at which antigens expressed in keratinocytes are cross-presented to T cells. The experiments described in this proposal are designed to delineate the mechanism of antigenic transgene presentation and priming of T cells and to explore strategies to divert these responses toward less destructive or tolerogenic ones. Three specific aims are proposed: 1) To examine the role of cross-presentation of keratinocyte-derived antigens in inducing T cell immunity; 2) To delineate the role of inflammation in priming of T cells by antigen presenting cells; and 3) To induce a state of tolerance to keratinocyte-derived neoantigens by modulating the signaling events involved in initiation of T cell immunity. It is expected that development of new strategies to circumvent destructive immune responses will overcome a major obstacle to clinical applications of skin gene therapy.