Hexon-modified adenovirus vectors

描述(申请人提供)：腺病毒载体(Ad)是美国临床试验中广泛使用的第二大病毒载体组。最近，由于其作为炭疽和其他威胁生命的感染剂的疫苗接种载体的潜力，人们对它的兴趣有所扩大。尽管在体外对Ad与细胞的相互作用了解很多，但系统应用的Ad的感染性、生物分布和毒性的分子机制仍然知之甚少。大量体内药代动力学研究表明，在全身应用后的最初几分钟内，超过90%的病毒被肝脏从循环中清除，并且在全身应用后，肝脏是转导Ad的主要器官。然而，我们最近的数据表明，肝脏介导的病毒清除通过两种不同的分子机制发生。第一种机制涉及纤维依赖受体介导的Ad与肝细胞的相互作用。第二种机制负责清除系统应用的大部分病毒，不依赖于纤维与肝细胞的相互作用。我们假设，主要的Ad结构蛋白Hexon是介导病毒在肝组织中捕获的主要决定因素，而不依赖于纤维-细胞受体的相互作用。这项研究的总体目标是进一步了解肝脏介导的Ad从血液中清除的分子机制，并构建一种安全的衣壳修饰载体，在较低剂量全身应用后有效地转导靶细胞。本研究的具体目的是：1.利用不同血清型的野生型AdS，评价Ad Hexon在清除血液中病毒的作用；2.构建突变的Ad5载体，并分析其在小鼠模型中的生物分布和循环持久性；3.分析Ad5突变载体在小鼠血管内给药的肿瘤细胞靶向性和全身毒性。这些研究将极大地提高我们对体内Ad-宿主相互作用机制的理解，并最终可能导致安全有效的Ad载体的开发，用于治疗广泛的先天和获得性人类疾病。

DESCRIPTION (provided by applicant): Adenovirus vectors (Ad) are the second largest group of viral vectors extensively used in clinical trials in the US. The interest in Ad has recently expanded due to its potential as a vector for vaccination against anthrax and other life threatening infection agents. Despite significant knowledge regarding Ad interactions with cells in vitro, the molecular mechanisms governing infectivity, bio-distribution and toxicity of systemically applied Ad remain poorly understood. Numerous studies of Ad pharmacokinetics in vivo have shown that within the first few minutes after systemic application, more than 90% of the virus is cleared from the circulation by the liver, and that the liver is the predominant organ in the body transduced with Ad after systemic application. Our recent data suggest, however, that liver-mediated virus clearance occurs via two distinct molecular mechanisms. The first mechanism involves fiber-dependent receptor-mediated interactions of Ad with liver cells. The second mechanism, responsible for clearance of the bulk of systemically applied virus, does not depend on fiber-hepatic cell interactions. We hypothesized that hexon, the major Ad structural protein, is the main determinant mediating virus trapping in liver tissue independently of fiber-cellular receptor interactions. The overall goal of this study is to further our understanding of molecular mechanisms underlying liver-mediated Ad clearance from the blood, and to construct a safe capsid-modified vector, efficiently transducing target cells after systemic application at lower administered doses. The specific aims of the current proposal are: 1. To evaluate the role of Ad hexon in virus clearance from the blood using wild type Ads of different serotypes; 2. To develop Ad5-based vectors with mutated hexons and analyze their bio-distribution and persistence in circulation in a mouse model; and 3. To analyze efficacy of tumor cell targeting and systemic toxicity of hexon-mutated Ad5-based vectors upon their intravascular administration in a mouse model. These studies will dramatically improve our understanding of the mechanisms governing Ad-host interactions in vivo 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.