RELATIONSHIP BETWEEN TROPISM, INFECTIVITY, AND NEUTRALIZATION IN HIV

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。我们已经证明了HIV-1的Eli毒株能够适应复制 在H9和U937细胞中，以及由此产生的变化增强了 这种病毒的传染性和扩大的宿主范围都在gp120和 Gp41-在gp120的CD4结合区和 Gp41。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。这一分析正在被 利用环境中这些区域的定点突变进行扩展。 HIV-1中有效的颗粒释放至少部分是由 辅助基因VPU。尽管没有相应的基因，艾滋病毒-2 粒子从细胞中释放的效率与HIV-1一样高。 为了绘制HIV-2中促进这一活动的病毒决定因素图，一个 在HIV-1和HIV-2之间构建了杂交病毒。的效率 通过比较颗粒释放的比例来评估颗粒释放 病毒粒子相关的和分泌的Gag与产生的总Gag的比较。 用HIV-2的Gag/Poll基因取代HIV-1的Gag/Poll基因没有 对粒子释放的影响。在VPU突变背景下，粒子释放 通过共转染法减少了病毒和VPU的供应 纠正了缺陷。当HIV-1包膜基因突变时， 共转染HIV-2提供的包膜颗粒的数量 释放已恢复，未检测到VPU的作用。因此， 对于HIV-2，有效释放颗粒的决定因素映射到HIV-2 与HIV-1不同，env基因和一种单独的蛋白质Vpu是不必要的。

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. 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 the CD4-binding region of gp120 and the fusogenic region of gp41. 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. This analysis is being extended using site-directed mutagenesis of these regions in Env. Efficient particle release in HIV-1 is mediated at least in part by the auxiliary gene vpu. Despite not having a corresponding gene, HIV-2 particles are released from the cell as efficiently as those of HIV-1. To map the viral determinants in HIV-2 that facilitate this activity, a hybrid virus was constructed between HIV-1 and HIV-2. The efficiency of particle release was assessed by comparing the proportion of virion-associated and secreted Gag compared with the total Gag produced. Replacing the gag/pol gene of HIV-1 with the HIV-2 gag/pol gene had no effect on particle release. In a Vpu mutant background, particle release was reduced in both viruses and supply of Vpu by co-transfection corrected the defect. When the HIV-1 envelope gene was mutated and the HIV-2 envelope supplied by co-transfection, the amount of particle release was restored and no effect of Vpu could be detected. Therefore, for HIV-2, determinants of efficient particle release map to the HIV-2 env gene and a separate protein, Vpu, is not required as it is for HIV-1.