GP120 INDEPENDENT INFECTION OF CD4(-) CELLS BY HIV-1

我们开发了一种新的方法来敏感和定量地识别HIV-1感染的细胞，并发现HIV-1显著感染某些类型的不依赖gp120的CD4(-)细胞。进一步的研究表明，HIV-1不仅可以通过这种机制感染CD4(-)细胞，也可以感染CD4(+)T淋巴细胞。这些结果提出了两种非常重要的可能性：1)HIV-1可以利用某些类型的CD4(-)细胞作为患者的病毒库；2)HIV-1可以减少感染细胞中Env的表达，作为一种逃避宿主免疫反应的策略，从而以潜伏状态长期低水平持续感染这些细胞。在这项应用中，我们将定量表征gp120非依赖的HIV-1感染，并阐明其发生的分子机制。在特定目标1中，来自不同人体组织的CD4(-)细胞株将被三种HIV-1 Env(-)病毒株感染。将研究CD4(-)细胞对HIV-1感染的敏感性、病毒在感染细胞中的复制率、感染细胞的寿命以及病毒基因在这些细胞系中的表达。Aim 1研究的结果将为评估患者整体HIV-1感染CD4(-)细胞的严重性提供信息。在特定的目标2中，我们将研究gp120非依赖性感染的机制。我们将描述HIV-1gp120非依赖性感染的感染过程，包括病毒进入、逆转录、核运输、病毒DNA整合以及使用HIV-1Env(-)病毒感染的HIV敏感的CD4(-)细胞株LNCaP产生病毒RNA基因组。我们还将使用消减杂交技术识别与gp120非依赖性HIV-1感染相关的基因。这些研究的结果将为评估患者体内HIV-1宿主的CD4(-)细胞宿主的严重性和开发一种阻断HIV-1感染CD4(-)细胞的方法提供非常有用的信息。

We have developed a new approach to sensitively and quantitatively identify HIV-1-infected cells, and found that HIV-1 significantly infects some types of CD4(-) cells independently of gp120. Further studies have indicated that not only can CD4(-) cells be infected by HIV-1 through this mechanism, but also CD4(+) T-lymphocytes. These results propose two very important possibilities: 1) HIV-1 can exploit some types of CD4(-) cells to serve as viral reservoirs in patients; and 2) HIV-1 can reduce expression of Env in infected cells as a strategy to evade the host immune response and therefore reside in these cells as long-term low-level persistent infection in a latent state. In this application, we will quantitatively characterize gp120- independent HIV-1 infection, and elucidate the molecular mechanism by which this occurs. In Specific Aim 1, CD4(-) cell lines derived from various human tissues will be infected with three strains of HIV-1 Env(-) virus. The susceptibility of CD4(-) cells to HIV-1 infection, the rates of viral replication in infected cells, the life-span of the infected cells, and the expression of viral genes in these cell lines will be studied. The results from Aim 1 studies will be informative to assess the seriousness of overall HIV-1 infection of CD4(-) cells in patients. In Specific Aim 2, we will study the mechanism of gp120-independent infection. We will characterize the infection course of HIV-1 gp120- independent infection, including viral entry, reverse transcription, nuclear transportation, viral DNA integration, and the generation of viral RNA genomes using an HIV-susceptible CD4(-) cell line, LNCaP, infected by HIV-1 Env(-) virus. We will also identify genes that are involved in gp120-independent HIV-1 infection using subtractive hybridization. The results from these studies will be very informative for assessing the seriousness of CD4(-) cell hosted HIV-1 reservoirs in patients and for developing an approach to interrupt the infection of CD4(-) cells by HIV-1.