Innate immunity to adenovirus vectors

描述（由申请方提供）：本提案旨在确定腺病毒（Ad）感染的确切步骤，该步骤负责在全身性病毒应用后引发抗Ad急性炎症反应。在过去的二十年中，已经开发了许多基于Ad的载体用于基因治疗应用，并且许多载体目前正在临床试验中进行测试。最近，对Ad的兴趣由于其作为针对威胁生命的传染性病原体如炭疽的疫苗接种的载体的潜力而进一步扩大。虽然Ad的自然感染在很大程度上对人类无害，但静脉注射Ad可能导致严重的炎症反应，这可能导致致命的结果。目前认识到，这种急性全身性炎症的起始取决于Ad衣壳与宿主细胞的相互作用。尽管有大量关于Ad与体外细胞相互作用的知识，但体内Ad生物分布、肝向性和毒性的分子机制仍然知之甚少。最近，我们确定了一种新的血液因子依赖的途径，在体内的Ad肝细胞感染。这一发现解释了全身应用后观察到的Ad在动物中的生物分布，并且对于开发新的策略以修改体内Ad嗜性和病毒相关毒性是至关重要的。在小鼠模型中，我们将分析先天性免疫反应静脉应用captain修饰的Ad突变体缺乏他们的能力进行病毒感染的初始步骤。我们的具体目标是分析Ad相互作用的作用：1）与初级附着受体; 2）与整合素，这有助于Ad初始化;或3）与细胞因子后，病毒从内涵体逃逸，在启动抗Ad炎症反应。基于所获得的数据，在我们的第四个具体目标中，我们将构建经消融以结合已知病毒受体且能够经由替代受体LDLR感染细胞的Ad载体。通过在小鼠中应用该载体并评估其毒性，我们将测试这样的假设，即Ad衣壳的修饰代表了减少急性Ad介导的炎症的可行方法，同时在全身应用时保留病毒基因转移能力。这些研究将显著提高我们对宿主防御病毒病原体的基本机制的理解，并可能最终导致开发安全有效的Ad载体，用于治疗广泛的先天性和获得性人类疾病。

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.