Schnierle B S, Stitz J, Bosch V, Nocken F, Merget-Millitzer H, Engelstädter M, Kurth R, Groner B, Cichutek K
Institut für Experimentelle Krebsforschung, Klinik für Tumorbiologie, Breisacher Strasse 117, D-79106 Freiburg, Germany.
Proc Natl Acad Sci U S A. 1997 Aug 5;94(16):8640-5. doi: 10.1073/pnas.94.16.8640.
CD4-expressing T cells in lymphoid organs are infected by the primary strains of HIV and represent one of the main sources of virus replication. Gene therapy strategies are being developed that allow the transfer of exogenous genes into CD4(+) T lymphocytes whose expression might prevent viral infection or replication. Insights into the mechanisms that govern virus entry into the target cells can be exploited for this purpose. Major determinants of the tropism of infection are the CD4 molecules on the surface of the target cells and the viral envelope glycoproteins at the viral surface. The best characterized and most widely used gene transfer vectors are derived from Moloney murine leukemia virus (MuLV). To generate MuLV-based retroviral gene transfer vector particles with specificity of infection for CD4-expressing cells, we attempted to produce viral pseudotypes, consisting of MuLV capsid particles and the surface (SU) and transmembrane (TM) envelope glycoproteins gp120-SU and gp41-TM of HIV type 1 (HIV-1). Full-length HIV-1 envelope glycoproteins were expressed in the MuLV env-negative packaging cell line TELCeB6. Formation of infectious pseudotype particles was not observed. However, using a truncated variant of the transmembrane protein, lacking sequences of the carboxyl-terminal cytoplasmic domain, pseudotyped retroviruses were generated. Removal of the carboxyl-terminal domain of the transmembrane envelope protein of HIV-1 was therefore absolutely required for the generation of the viral pseudotypes. The virus was shown to infect CD4-expressing cell lines, and infection was prevented by antisera specific for gp120-SU. This retroviral vector should prove useful for the study of HIV infection events mediated by HIV-1 envelope glycoproteins, and for the targeting of CD4(+) cells during gene therapy of AIDS.
淋巴器官中表达CD4的T细胞会被HIV的原始毒株感染，是病毒复制的主要来源之一。目前正在开发基因治疗策略，使外源基因能够导入CD4(+) T淋巴细胞，其表达可能会阻止病毒感染或复制。为此，可以利用对病毒进入靶细胞机制的深入了解。感染嗜性的主要决定因素是靶细胞表面的CD4分子和病毒表面的病毒包膜糖蛋白。特征最明确、使用最广泛的基因转移载体源自莫洛尼鼠白血病病毒（MuLV）。为了生成对表达CD4的细胞具有感染特异性的基于MuLV的逆转录病毒基因转移载体颗粒，我们尝试生产病毒假型，其由MuLV衣壳颗粒以及1型HIV（HIV-1）的表面（SU）和跨膜（TM）包膜糖蛋白gp120-SU和gp41-TM组成。全长HIV-1包膜糖蛋白在MuLV env阴性包装细胞系TELCeB6中表达。未观察到感染性假型颗粒的形成。然而，使用跨膜蛋白的截短变体，缺少羧基末端胞质结构域的序列，生成了假型逆转录病毒。因此，生成病毒假型绝对需要去除HIV-1跨膜包膜蛋白的羧基末端结构域。该病毒被证明可感染表达CD4的细胞系，并且gp120-SU特异性抗血清可阻止感染。这种逆转录病毒载体应被证明对研究由HIV-1包膜糖蛋白介导的HIV感染事件以及在艾滋病基因治疗期间靶向CD4(+)细胞有用。
