Adenovirus interaction with platelets

描述(申请人提供)：重组腺病毒(Ad)载体的静脉注射用于基因治疗受到安全性和有效性问题的阻碍。我们最近发现了一种新的途径，它参与了常用的Ad5和AdB组病毒AD11衍生载体在小鼠体内的非特异性隔离和清除。静脉给药后，Ad5和AD11以不依赖纤维的方式与循环中的血小板结合。病毒结合导致血小板的激活/聚集，并被困在肝脏的微血管中，在那里病毒-血小板聚集物被库普弗细胞摄取。在载体注射之前，通过去除血小板可以减少肝脏中的AD隔离。在静脉注射Ad后，血小板耗竭增加了肝转移瘤的转导，这为研究Ad-血小板相互作用的机制提供了理论基础，最终目的是构建可去除与血小板结合的溶瘤Ad载体。这项建议的目的是确定病毒衣壳内参与Ad与血小板结合的结构成分/S，并生产可去除的用于血小板结合的载体。中心假设是这些修饰的载体在静脉注射后更有效地转导转移的肿瘤。虽然Ad5和AD11载体都存在血小板介导的降解，但在本方案中，我们将重点研究AD11的修饰，因为它与血小板的结合更强，这可能有助于研究Ad11与血小板的相互作用。此外，基于AD11的载体是一种很有前途的基因治疗工具。AD11主要通过CD46感染细胞，并有效地转导重要的基因治疗靶点，这些靶点是Ad5载体难以感染的，如肿瘤、树突状细胞和组织干细胞。与Ad5载体相比，AD11的其他优点包括较低的血清中和抗AD11抗体的流行率，以及静脉注射载体后没有肝脏转导。这项建议的研究将在以类似人类的模式表达CD46的小鼠和含有人类血小板的小鼠身上进行。 公共卫生相关性：该提案的最终目标是产生AD11载体(AD11？)为了与血小板结合而被消融。这一研究结果将对AD11介导的肿瘤基因治疗和疫苗接种具有重要意义，并有可能用于基于其他血清型的Ad载体的修饰。

DESCRIPTION (provided by applicant): Intravenous delivery of recombinant adenovirus (Ad) vectors for gene therapy is hampered by safety and efficacy problems. We have recently discovered a new pathway that is involved in unspecific sequestration and clearance of commonly used Ad5 and Ad B-group virus Ad11-derived vectors in mice. Rapidly after intravenous administration, Ad5 and Ad11 bind to circulating platelets in a fiber-independent manner. Virus binding results in activation/aggregation of platelets and trapping in micro-blood vessels of the liver, where the virus-platelet aggregates are taken up by Kupffer cells. Ad sequestration in liver can be reduced by platelet depletion prior to vector injection. Platelet depletion increases transduction of liver metastases after intravenous Ad injection, which provides a rationale for studying the mechanism of Ad-platelet interaction with the final goal of constructing oncolytic Ad vectors that are ablated for platelet binding. The goals of this proposal are to identify the structural component/s within the virus capsid that are involved in Ad binding to platelets, and to produce vectors that are ablated for platelet binding. The central hypothesis is that these modified vectors are more efficient in transduction of metastatic tumors after intravenous injection. Although platelet-mediated degradation occurs for both Ad5 and Ad11 vectors, in this proposal, we will focus on modifying Ad11 because of its stronger binding to platelets which might facilitate studying Ad-platelet interactions. Moreover, Ad11-based vector are promising tools for gene therapy. Ad11 infects cells predominantly through CD46, and efficiently transduces important gene therapy targets that are refractory to infection with Ad5 vectors, such as tumor, dendritic, and tissue stem cells. Other advantages of Ad11 over Ad5 vectors include the lower serum prevalence of neutralizing anti-Ad11 antibodies and absence of liver transduction after intravenous vector application. Studies in this proposal will be done in mice that express CD46 in a human like pattern and in mice that contain human platelets. Public Health Relevance: The final aim of this proposal is to produce Ad11 vectors (Ad11?) that are ablated for binding to platelets. The outcome of this study will be relevant for Ad11 mediated tumor gene therapy and vaccination and potentially for the modification of Ad vectors based on other serotypes.