Di Paolo Nelson C, Kalyuzhniy Oleksandr, Shayakhmetov Dmitry M
Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195-7720, USA.
J Virol. 2007 Nov;81(22):12249-59. doi: 10.1128/JVI.01584-07. Epub 2007 Sep 12.
The molecular mechanisms governing the infectivity of adenovirus (Ad) toward specific cell and tissue types in vivo remain poorly understood. The direct Ad binding to hepatic heparan sulfate proteoglycans via the KKTK motif within the fiber shaft domain was suggested to be the major mechanism of Ad liver cell infection in vivo. Here, we describe the generation and in vitro and in vivo infectivity studies of Ad5-based vectors possessing long Ad31- or Ad41-derived fiber shaft domains, which lack the KKTK motif. We found that all the critical early steps of Ad infection, including attachment to the cellular receptor, internalization, and virus genome transfer into the nucleus, occurred with similar levels of efficiency for fiber shaft-chimeric vectors and unmodified Ad5. Upon intravenous delivery into mice, fiber shaft-chimeric vectors accumulated in liver tissue, transduced liver cells, and induced the production of proinflammatory cytokines (tumor necrosis factor alpha and interleukin-6) and the chemokine monocyte chemoattractant protein 1 at levels indistinguishable from those observed for Ad5. Thus, our data provide evidence that the Ad5 fiber shaft amino acid sequence does not play any substantial role in determining adenovirus infectivity toward hepatic cells in vivo. The data obtained contribute to improving our understanding of the molecular mechanisms determining Ad infectivity and biodistribution in vivo and may aid in designing novel Ad-based vectors for gene therapy applications.
腺病毒（Ad）在体内对特定细胞和组织类型的感染性所涉及的分子机制仍知之甚少。有研究表明，Ad通过纤维杆状结构域内的KKTK基序与肝硫酸乙酰肝素蛋白聚糖直接结合，是其在体内感染肝细胞的主要机制。在此，我们描述了具有长Ad31或Ad41衍生纤维杆状结构域（缺乏KKTK基序）的基于Ad5的载体的构建及其体外和体内感染性研究。我们发现，Ad感染的所有关键早期步骤，包括与细胞受体的附着、内化以及病毒基因组转移到细胞核，对于纤维杆状嵌合载体和未修饰的Ad5而言，其发生效率相似。经静脉注射到小鼠体内后，纤维杆状嵌合载体在肝组织中积累，转导肝细胞，并诱导促炎细胞因子（肿瘤坏死因子α和白细胞介素-6）以及趋化因子单核细胞趋化蛋白1的产生，其水平与Ad5观察到的水平无明显差异。因此，我们的数据表明，Ad5纤维杆状氨基酸序列在体内确定腺病毒对肝细胞的感染性方面不发挥任何实质性作用。所获得的数据有助于增进我们对决定Ad在体内感染性和生物分布的分子机制的理解，并可能有助于设计用于基因治疗应用的新型基于Ad的载体。
