TROPISM, INFECTIVITY, AND NEUTRALIZATION IN HIV

HIV 的趋向性、感染性和中和作用

• 批准号: 3748154
• 负责人: K PEDEN
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3748154
• 关键词: CD4 molecule; HIV envelope protein gp120; HIV envelope protein gp41; HIV infections; gene mutation; genetic strain; human immunodeficiency virus 1; tissue /cell culture; virus infection mechanism; virus receptors; virus replication

While all the determinants of tropism of HIV replication are still being elucidated, the major determinants reside in the envelope of the virus and are present in both the extracellular component (gp120) and the transmembrane component (gp41). However, other genes (gag, nef, vpr, vif) and cis-acting elements (the long terminal repeat, LTR) can also modulate replication in different cell types. Most primary isolates, particularly those of the NSI (non-syncytium inducing) class, fail to replicate in established CD4-positive cell lines, although peripheral blood mononuclear cells (PBMC) are almost always permissive even for NSI viruses. Viruses can frequently adapt to grow in cell lines, and such viruses have altered phenotypes. We have shown that the ELI strain of HIV-1 adapts to replicate in H9 and U937 cells, and the changes that confer this enhanced infectivity and expanded host range to this virus are in both gp120 and gp41. In particular, changes were found in the CD4-binding region of gp120 and the fusogenic region of gp41, thus identifying these regions as important determinants for tropism in cell lines. Concomitant with the increased infectivity was an increased ability of the virion to bind to CD4, although CD4 binding to the variant soluble gp120 was not affected. These results revealed that alterations in either gp120 or gp41 in the context of the virion can affect both the capacity of the envelope to interact with CD4 as well as infectivity, thus indicating the importance of these regions to the functional association of the two envelope components. To determine whether this result is general or specific to this particular strain of HIV-1, mutations were introduced at the corresponding position in the fusogenic region of the LAI and MAL strains of HIV-1. The aim was to obtain a virus with reduced replicative capacity and then by passage to obtain revertants that had restored the infectivity. The location of the changes in the revertants should identify interacting regions of gp41 or 120. The Leu of LAI was changed to Met and Val, and the Met of MAL was converted to Val. Substitution of the Met with a Val eliminated the infectivity of this virus. So far no revertants have been found. In LAI, substitution of Met for Leu had little perceptible effect on virus infectivity. However, replacing the Leu with Val resulted in a virus with lower infectivity. This latter virus was found to adapt to grow on CEM and H9 cells, and current work is engaged in determining the nucleotide changes that account for the increased infectivity of this virus.

尽管艾滋病毒复制取向的所有决定因素仍在 阐明，主要决定因素存在于病毒的包膜中 并存在于胞外成分(Gp120)和 跨膜成分(Gp41)。然而，其他基因(gag、nef、vpr、 Vif)和顺式作用元件(长末端重复序列，LTR)也可以 调节不同细胞类型的复制。大多数初级分离株， 尤其是NSI(非合胞体诱导)类的 在已建立的CD4阳性细胞系中复制，尽管是外周细胞 即使对于NSI，血液单个核细胞(PBMC)也几乎总是允许的 病毒。病毒可以经常适应在细胞系中生长，这样 病毒改变了表型。我们已经证明了伊利病毒株 HIV-1适应在H9和U937细胞中复制，而这种变化 使这种病毒具有更强的传染性和更大的宿主范围 在gp120和gp41中都有。特别是，在 Gp120的CD4结合区和gp41的融合区，因此 确定这些区域是细胞趋向性的重要决定因素 台词。随之而来的是传染性的增加 病毒粒子与CD_4结合的能力，尽管CD_4与变异体结合 可溶性gp120未受影响。这些结果表明，改变 在gp120或gp41中的病毒粒子的上下文中都可以影响 包膜与CD4相互作用的能力以及传染性， 从而表明这些区域对功能 两个信封组件的关联。以确定这是否 结果是针对这种特定的HIV-1毒株的一般或特定的结果， 在融合基因中的相应位置引入了突变 HIV-1的LAI和MAL毒株的区域。其目的是为了获得一种 复制能力降低的病毒，然后通过传代获得 恢复了传染性的回复变种。的位置。 反转体的变化应确定gp41或 120.赖的Leu改为Met和Val，Mal的Met是 已转换为Val。用Val替换Met消除了 这种病毒的传染性。到目前为止，还没有发现返回体。在……里面 赖氨酸、蛋氨酸替代亮氨酸对病毒作用不明显 传染性。然而，用Val替换Leu会导致病毒 传染性较低。后一种病毒被发现能够适应生长 CEM和H9细胞，目前的工作是确定 导致这种病毒传染性增加的核苷酸变化 病毒。