Innate immunity to adenovirus vectors

描述(申请人提供)：本提案旨在确认腺病毒(Ad)感染的确切步骤(S)，该步骤负责在全身应用病毒时启动抗Ad急性炎症反应。在过去的二十年里，许多基于Ad的载体被开发出来用于基因治疗，其中许多目前正在进行临床试验。最近，对Ad的兴趣进一步扩大，因为它有可能成为针对炭疽等威胁生命的传染病的疫苗接种载体。虽然自然感染Ad基本上对人类无害，但静脉注射Ad可能会导致严重的炎症反应，这可能导致致命的后果。目前认为，这种急性全身性炎症的发生依赖于Ad衣壳与宿主细胞的相互作用。尽管在体外对Ad与细胞的相互作用有很大的了解，但控制Ad在体内的生物分布、肝脏趋向性和毒性的分子机制仍然知之甚少。最近，我们发现了一种新的体内感染Ad肝细胞的血液因子依赖途径。这一发现解释了全身应用后观察到的Ad在动物体内的生物分布，并为开发新的策略来改变Ad在体内的趋向性和病毒相关的毒性奠定了基础。在小鼠模型中，我们将分析静脉注射衣壳修饰的Ad突变体的先天免疫反应，这些突变体缺乏经历病毒感染的初始步骤的能力。我们的具体目标是分析1)与初级附着受体的相互作用；2)与整合素的相互作用，这有助于Ad的初始化；或3)与细胞因子的相互作用，使病毒从内体逃逸，在启动抗Ad炎症反应中的作用。基于所获得的数据，在我们的第四个特定目标中，我们将构建能够与已知病毒受体结合并能够通过另一种受体LDLR感染细胞的AHAd载体。通过将该载体应用于小鼠并评估其毒性，我们将检验这样一种假设，即修饰Ad衣壳是一种可行的方法，可以在全身应用时保持病毒基因转移的能力，同时减少急性Ad介导的炎症。这些研究将极大地提高我们对宿主防御病毒病原体的基本机制的理解，并最终可能导致开发安全有效的Ad载体来治疗广泛的先天和获得性人类疾病。

DESCRIPTION (provided by applicant): This proposal seeks to identify the exact step(s) of adenovirus (Ad) infection that is (are) responsible for the initiation of an anti-Ad acute inflammatory response upon systemic virus application. Over the last two decades numerous Ad-based vectors have been developed for gene therapy applications and many are currently being tested in clinical trials. Most recently, interest in Ad has further expanded due to its potential as a vector for vaccination against life threatening infectious agents such as anthrax. While natural infections with Ad are largely harmless to humans, intravenous Ad administration may result in a severe inflammatory response, which can lead to fatal outcomes. It is currently recognized that the initiation of this acute systemic inflammation depends on interactions of the Ad capsid with host cells. Despite significant knowledge regarding Ad interactions with cells in vitro, the molecular mechanisms governing Ad bio-distribution, hepatic tropism and toxicity in vivo remain poorly understood. Recently, we identified a novel blood factor-dependent pathway of Ad liver cell infection in vivo. This finding explained the observed Ad biodistribution in animals after systemic application and is fundamental for the development of novel strategies to modify both Ad tropism in vivo and virus-associated toxicity. In mouse models, we will analyze the innate immune response to intravenously applied capsid-modified Ad mutants deficient in their ability to undergo the initial steps of virus infection. Our specific aims are to analyze the role of Ad interactions 1) with primary attachment receptors; 2) with integrins, which facilitate Ad initialization; or 3) with cellular factors upon virus escape from endosomes, in the initiation of an anti-Ad inflammatory response. Based on the data obtained, in our fourth specific aim we will construct ah Ad vector ablated for binding to known virus receptors and capable of infecting cells via an alternative receptor, LDLR. By applying this vector in mice and evaluating its toxicity we will test the hypothesis that modification of the Ad capsid represents a feasible approach to reduce acute Ad-mediated inflammation while preserving virus gene transfer ability upon systemic application. These studies will significantly improve our understanding of fundamental mechanisms of the host defense against viral pathogens and may ultimately lead to the development of safe and efficient Ad vectors for the therapy of a wide range of inborn and acquired human diseases.