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鉴定HIV-1感染细胞，并发现HIV-1独立于gp120显著感染某些类型的CD4（-）细胞。进一步的研究表明，不仅CD4（-）细胞可以通过这种机制被HIV-1感染，CD4(+) t淋巴细胞也可以通过这种机制被HIV-1感染。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（-）细胞作为患者体内的病毒库；2) HIV-1可以通过降低Env在感染细胞中的表达来逃避宿主免疫应答，从而以潜伏状态长期低水平持续感染这些细胞。在这个应用中，我们将定量表征不依赖gp120的HIV-1感染，并阐明其发生的分子机制。在特异性目标1中，来自各种人体组织的CD4（-）细胞系将被三株HIV-1 Env（-）病毒感染。将研究CD4（-）细胞对HIV-1感染的易感性、病毒在感染细胞中的复制率、感染细胞的寿命以及这些细胞系中病毒基因的表达。Aim 1研究的结果将为评估患者CD4（-）细胞总体HIV-1感染的严重程度提供信息。在Specific Aim 2中，我们将研究不依赖gp120的感染机制。我们将描述HIV-1 gp120非依赖性感染的感染过程，包括病毒进入、逆转录、核转运、病毒DNA整合，以及使用HIV-1 Env（-）病毒感染的hiv易感CD4（-）细胞系LNCaP生成病毒RNA基因组。我们还将使用减法杂交鉴定与gp120无关的HIV-1感染有关的基因。这些研究的结果将为评估患者体内CD4（-）细胞宿主HIV-1储存库的严重性以及开发一种阻断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.