Department of Microbiology, New York University School of Medicine, 522 First Ave., New York, NY 10016, USA.
J Virol. 2011 Jul;85(13):6263-74. doi: 10.1128/JVI.00346-11. Epub 2011 Apr 20.
The lentiviral accessory protein Vpx is thought to facilitate the infection of macrophages and dendritic cells by counteracting an unidentified host restriction factor. Although human immunodeficiency virus type 1 (HIV-1) does not encode Vpx, the accessory protein can be provided to monocyte-derived macrophages (MDM) and monocyte-derived dendritic cells (MDDC) in virus-like particles, dramatically enhancing their susceptibility to HIV-1. Vpx and the related accessory protein Vpr are packaged into virions through a virus-specific interaction with the p6 carboxy-terminal domain of Gag. We localized the minimal Vpx packaging motif of simian immunodeficiency virus SIVmac(239) p6 to a 10-amino-acid motif and introduced this sequence into an infectious HIV-1 provirus. The chimeric virus packaged Vpx that was provided in trans and was substantially more infectious on MDDC and MDM than the wild-type virus. We further modified the virus by introducing the Vpx coding sequence in place of nef. The resulting virus produced Vpx and replicated efficiently in MDDC and MDM. The virus also induced a potent type I interferon response in MDDC. In a coculture system, the Vpx-containing HIV-1 was more efficiently transmitted from MDDC to T cells. These findings suggest that in vivo, Vpx may facilitate transmission of the virus from dendritic cells to T cells. In addition, the chimeric virus could be used to design dendritic cell vaccines that induce an enhanced innate immune response. This approach could also be useful in the design of lentiviral vectors that transduce these relatively resistant cells.
慢病毒辅助蛋白 Vpx 被认为通过拮抗一种未知的宿主限制因子来促进巨噬细胞和树突状细胞的感染。虽然人类免疫缺陷病毒 1 型（HIV-1）不编码 Vpx，但辅助蛋白可以在病毒样颗粒中提供给单核细胞衍生的巨噬细胞（MDM）和单核细胞衍生的树突状细胞（MDDC），显著增强它们对 HIV-1 的易感性。Vpx 和相关辅助蛋白 Vpr 通过与 Gag 的羧基末端 p6 区域的病毒特异性相互作用被包装到病毒粒子中。我们将猿猴免疫缺陷病毒 SIVmac(239) p6 的最小 Vpx 包装基序定位到一个 10 个氨基酸基序，并将该序列引入感染性 HIV-1 前病毒中。嵌合病毒包装了通过转染提供的 Vpx，并且在 MDDC 和 MDM 上比野生型病毒更具感染力。我们进一步通过用 Vpx 编码序列替代 nef 来修饰病毒。结果病毒产生了 Vpx，并在 MDDC 和 MDM 中有效地复制。该病毒还在 MDDC 中诱导强烈的 I 型干扰素反应。在共培养系统中，含有 Vpx 的 HIV-1 从 MDDC 向 T 细胞的传递更有效。这些发现表明，在体内，Vpx 可能促进病毒从树突状细胞向 T 细胞的传播。此外，嵌合病毒可用于设计诱导增强的先天免疫反应的树突状细胞疫苗。这种方法也可用于设计转导这些相对抵抗的细胞的慢病毒载体。
