Host Immune Responses in Cutaneous Gene Therapy

描述(由申请人提供)： 这项提议的总体目标是开发基于基因的皮肤遗传性疾病治疗方法。皮肤基因治疗的研究继续集中在开发高效的基因转移方法，从而导致转基因的长期表达。随着载体的改进和针对干细胞的策略的设计，已经取得了相当大的成功。然而，当新抗原在皮肤中表达时，我们缺乏对宿主反应的了解。这些反应可能会使皮肤基因治疗试验复杂化，特别是当患者有零突变的时候。我们的研究表明，当一种新的抗原在正常小鼠的皮肤中表达时，转基因表达被抑制，转导的细胞通过免疫反应被排斥。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，这项研究提案的目的是更好地了解皮肤对新抗原的特异性免疫反应，并制定避免这些反应的策略。基于一个新兴的知识体系，我们假设在角质形成细胞中表达的抗原交叉呈递到T细胞时，宿主免疫反应最容易受到调节。这项建议中描述的实验旨在描述T细胞的抗原性转基因呈递和启动的机制，并探索将这些反应转移到破坏性较小或耐受性较低的反应的策略。提出了三个具体的目标：1)研究角质形成细胞来源的抗原在诱导T细胞免疫中的交叉提呈作用；2)阐明炎症在抗原提呈细胞激活T细胞中的作用；3)通过调节与启动T细胞免疫有关的信号事件，诱导对角质形成细胞来源的新抗原的耐受状态。可以预期，规避破坏性免疫反应的新策略的开发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.