Shayakhmetov D M, Lieber A
Division of Medical Genetics, University of Washington, Seattle, Washington 98195, USA.
J Virol. 2000 Nov;74(22):10274-86. doi: 10.1128/jvi.74.22.10274-10286.2000.
One of the objectives in adenovirus (Ad) vector development is to target gene delivery to specific cell types. Major attention has been given to modification of the Ad fiber knob, which is thought to determine virus tropism. However, among the human Ad serotypes with different tissue tropisms, not only the knob but also the length of the fiber shaft domain varies significantly. In this study we attempted to delineate the role of fiber length in coxsackievirus-adenovirus receptor (CAR)- and non-CAR-mediated infection. A series of Ad serotype 5 (Ad5) capsid-based vectors containing long or short fibers with knob domains derived from Ad5, Ad9, or Ad35 was constructed and tested in adsorption, internalization, and transduction studies. For Ad5 or Ad9 knob-possessing vectors, a long-shafted fiber was critical for efficient adsorption/internalization and transduction of CAR/alphav integrin-expressing cells. Ad5 capids containing short CAR-recognizing fibers were affected in cell adsorption and infection. In contrast, for the chimeric vectors possessing Ad35 knobs, which enter cells by a CAR/alphav integrin-independent pathway, fiber shaft length had no significant influence on binding or infectibility on tested cells. The weak attachment of short-shafted Ad5 or Ad9 knob-possessing vectors seems to be causally associated with a charge-dependent repulsion between Ad5 capsid and acidic cell surface proteins. The differences between short- and long-shafted vectors in attachment or infection were abrogated by preincubation of cells with polycations. This study demonstrates that the fiber-CAR interaction is not the sole determinant for tropism of Ad vectors containing chimeric fibers. CAR- and alphav integrin-mediated infections are influenced by other factors, including the length of the fiber shaft.
腺病毒（Ad）载体研发的目标之一是将基因传递靶向特定细胞类型。人们主要关注Ad纤维末端的修饰，认为其决定病毒嗜性。然而，在具有不同组织嗜性的人Ad血清型中，不仅纤维末端不同，纤维杆状结构域的长度也有显著差异。在本研究中，我们试图阐明纤维长度在柯萨奇病毒-腺病毒受体（CAR）介导和非CAR介导的感染中的作用。构建了一系列基于Ad血清型5（Ad5）衣壳的载体，这些载体含有源自Ad5、Ad9或Ad35的长或短纤维以及纤维末端结构域，并在吸附、内化和转导研究中进行了测试。对于含有Ad5或Ad9纤维末端的载体，长杆状纤维对于高效吸附/内化以及转导表达CAR/αv整合素的细胞至关重要。含有短CAR识别纤维的Ad5衣壳在细胞吸附和感染方面受到影响。相比之下，对于具有Ad35纤维末端的嵌合载体，其通过不依赖CAR/αv整合素的途径进入细胞，纤维杆状结构域的长度对受试细胞的结合或感染性没有显著影响。具有短杆状Ad5或Ad9纤维末端的载体的弱附着似乎与Ad5衣壳和酸性细胞表面蛋白之间的电荷依赖性排斥有关。用聚阳离子预孵育细胞可消除短杆状和长杆状载体在附着或感染方面的差异。本研究表明，纤维与CAR的相互作用并非含有嵌合纤维的Ad载体嗜性的唯一决定因素。CAR和αv整合素介导的感染受其他因素影响，包括纤维杆状结构域的长度。
