Sharma S, Miyanohara A, Friedmann T
Center for Molecular Genetics and Department of Pediatrics, University of California San Diego School of Medicine, La Jolla, California 92093-0634, USA.
J Virol. 2000 Nov;74(22):10790-5. doi: 10.1128/jvi.74.22.10790-10795.2000.
In the absence of viral envelope gene expression, cells expressing human immunodeficiency virus type 1 (HIV-1) gag and pol, accessory HIV functions, and a vector genome RNA produce and secrete large amount of noninfectious virus-like particles (VLPs) into the conditioned medium. After partial purification, such HIV-1 VLPs can be made infectious in cell-free conditions in vitro by complex formation with lipofection reagents or with the G protein of vesicular stomatitis virus (VSV-G). The resulting in vitro-modified HIV-1 particles are able to infect nondividing cells. Infectivity of envelope-free HIV VLPs can also be induced by prior modification of target cells through exposure to partially purified VSV-G vesicles. Similarly, infection can be carried out by attachment of envelope-free noninfectious VLPs to unmodified cells followed by subsequent treatment of cells with VSV-G. We interpret these findings to indicate that interaction between a viral envelope and a cell surface receptor is not necessary for the initial virus binding to the cells but is required for subsequent cell entry and infection.
在缺乏病毒包膜基因表达的情况下，表达人类免疫缺陷病毒1型（HIV-1）gag和pol、HIV辅助功能以及载体基因组RNA的细胞会产生大量无感染性的病毒样颗粒（VLP），并将其分泌到条件培养基中。经过部分纯化后，此类HIV-1 VLP可通过与脂质转染试剂或水泡性口炎病毒（VSV-G）的G蛋白形成复合物，在无细胞条件下体外获得感染性。由此产生的体外修饰HIV-1颗粒能够感染非分裂细胞。无包膜HIV VLP的感染性也可通过预先将靶细胞暴露于部分纯化的VSV-G囊泡进行修饰来诱导。同样，可通过将无包膜的无感染性VLP附着于未修饰的细胞，随后用VSV-G处理细胞来实现感染。我们将这些发现解释为表明病毒包膜与细胞表面受体之间的相互作用对于病毒最初与细胞的结合并非必要，但对于随后的细胞进入和感染却是必需的。
