Regulation Of Hiv Replication By Host Factors

宿主因素对 HIV 复制的调节

• 批准号: 6669564
• 负责人: Audrey Lewis Kinter
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 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/6669564
• 关键词: HIV infections; antiviral agents; biological signal transduction; chemokine; clinical research; enzyme linked immunosorbent assay; extracellular matrix; flow cytometry; helper T lymphocyte; host organism interaction; human immunodeficiency virus; human tissue; immunopathology; immunoregulation; leukocyte activation /transformation; molecular pathology; polymerase chain reaction; virus replication

This project was designed to investigate the cellular and molecular pathways involved in the HIV regulatory effects of host and viral factors. HIV envelope protein (gp160) was found to stimulate the production of infectious virus from HIV-infected donor?s resting CD4+ T cells, a major cellular reservoir of HIV, without inducing markers of cellular activation, division or apoptosis. In a related project, this laboratory has found that individuals with detectible HIV replication in vivo (plasma HIV RNA > 500 copies/ml) harbor phenotypically resting CD4+ T cells that spontaneously produce low levels of HIV ex vivo, suggesting that these cells are in a state of partial activation that is not manifested by the expression of markers of classical T cell activation. Molecular analyses suggest that these observations are due to qualitative alterations in the HIV-infected resting CD4+ T cells reservoir rather than simply due to quantitative changes. This phenomena is HIV specific in that HIV secreting resting CD4+ T cells are not detectible in HIV/HCV co-infected donors with chronic antigenic exposure due to very high levels of HCV viremia if their HIV plasma RNA is negative (<50 copies/ml). In longitudinal analyses, the levels of HIV secreted by this cellular population closely parallel HIV viremia and the presence of these cells in the peripheral blood appears rapidly following the detection of low levels of virus in the plasma. These data suggest that HIV or HIV gene products, such as envelope protein and nef, interact with cellular components in the host to directly or indirectly generate intracellular signaling events that are sufficient for inducing HIV expression, but not classical T cell activation, in the HIV-infected resting CD4+ T cell reservoir. Using an in vitro human lymphoid tissue (tonsil) culture model, we have found that the lymphoid tissue microenvironment supports productive HIV infection of CD4+ T cells that exhibit the phenotype of ?resting? lymphocytes in that they lack both surface (CD69, CD25, CD38 and HLA-DR) and nuclear markers (DNA synthesis, Ki67, PCNA) of classical T cell activation. X4 HIV-exposed purified resting CD4+ T cells produced HIV mRNA, p24 protein and infectious virus while maintaining a resting, non-dividing T cell phenotype when re-introduced into the microenvironment of autologous lymphoid tissue, but not when cultured alone. Pro-inflammatory cytokine antagonists and the immunosuppressive cytokines interleukin (IL)-10 and transforming growth factor (TGF)-b, but not a potent inhibitor of T cell division/ full activation (mycophenoloic acid), effectively suppress X4 HIV production from resting CD4+ T cells in the lymphoid tissue demonstrating a role for endogenous proinflammatory cytokines in driving HIV production from this cellular population. These data repudiate the paradigm that HIV production in T cells requires classical T cell activation and demonstrate that the lymphoid tissue is an ideal microenvironment for ?suboptimal? cellular activation leading to HIV replication in phenotypically resting CD4+ T cells. . HIV replication in vivo represents, in part, a balance between the maintenance of an effective HIV-specific cellular immune response and the ability of HIV to replicate at optimal levels in activated CD4+ T cells. Ex vivo phenotypic analyses and in vitro functional analyses were performed to assess the possible role of CD4+CD25+ regulatory/suppressor cells in the pathogenesis of HIV infection. CD4+CD45RA-CD25+ T cells in the peripheral blood of HIV-infected viremic, but not aviremic, donors exhibited higher levels CTLA-4 co-expression (an associated, but not exclusive, marker for this regulatory subset) as compared to cells from uninfected donors. Isolation of CD4+ T cell subsets followed by functional analyses demonstrated that removal of CD4+ CD45RA- CD25+ T cells rescued HIV p24-induced proliferative responses in PBMC from most HIV-infected donors. In most cases, re-addition of this cellular population resulted in suppression of HIV-specific proliferative responses. In addition, the removal of CD4+CD25+ cells enhanced, and their re-addition suppressed, HIV gag peptide or p24-induced intracellular IFN-g and IL-2 production from both CD4+ and CD8+ T cells. In addition, preliminary data suggest that the CD4+CD25+ regulatory suppressor cells modulate, directly or indirectly, endogenous HIV replication in cultured patient cells.

该项目旨在研究与宿主和病毒因子的HIV调节作用有关的细胞和分子途径。发现HIV包膜蛋白（GP160）可刺激HIV感染者静止的CD4+ T细胞（HIV的主要细胞库）刺激感染性病毒的产生，而无需诱导细胞激活，分裂或凋亡的标记。 In a related project, this laboratory has found that individuals with detectible HIV replication in vivo (plasma HIV RNA > 500 copies/ml) harbor phenotypically resting CD4+ T cells that spontaneously produce low levels of HIV ex vivo, suggesting that these cells are in a state of partial activation that is not manifested by the expression of markers of classical T cell activation.分子分析表明，这些观察结果是由于HIV感染的静止CD4+ T细胞储层的定性改变引起的，而不是仅仅是由于定量变化。这种现象是特定于HIV的，因为在HIV/HCV共感染的供体中，由于HCV病毒性很高而导致的HIV/HCV共感染的供体在HIV/HCV共感染的供体中无法检测到HIV，如果HIV血浆RNA为阴性，则无法检测到HIV。在纵向分析中，该细胞群体分泌的HIV水平紧密平行HIV病毒血症，并且这些细胞在外周血中的存在在血浆中低水平的病毒水平后迅速出现。这些数据表明，HIV或HIV基因产物（例如包膜蛋白和NEF）与宿主中的细胞成分相互作用，以直接或间接产生足以诱导HIV表达但不是经典T细胞激活的细胞内信号传导事件，而不是HIV感染的HIV感染的HIV感染的静息CD4+ T细胞储层。使用体外人淋巴组织（扁桃体）培养模型，我们发现淋巴组织微环境支持表现出表现出静止表型的CD4+ T细胞的生产性HIV感染？淋巴细胞缺乏经典T细胞激活的表面（CD69，CD25，CD38和HLA-DR）和核标记（DNA合成，Ki67，PCNA）。 X4 HIV暴露的纯化的静息CD4+ T细胞产生了HIV mRNA，p24蛋白和感染性病毒，同时将静止的，非分裂的T细胞表型保持在自体淋巴机构的微环境中时，但在单独培养时并非培养。 Pro-inflammatory cytokine antagonists and the immunosuppressive cytokines interleukin (IL)-10 and transforming growth factor (TGF)-b, but not a potent inhibitor of T cell division/ full activation (mycophenoloic acid), effectively suppress X4 HIV production from resting CD4+ T cells in the lymphoid tissue demonstrating a role for endogenous proinflammatory cytokines in driving该细胞种群的HIV产生。这些数据否认了T细胞中HIV的产生需要经典的T细胞激活的范式，并证明淋巴组织是次优的理想微环境吗？细胞激活导致表型静止的CD4+ T细胞中的HIV复制。 。体内的HIV复制部分代表了有效HIV特异性细胞免疫反应的维持与HIV在激活的CD4+ T细胞中最佳水平复制的能力之间的平衡。进行了体内表型分析和体外功能分析，以评估CD4+ CD25+调节/抑制细胞在HIV感染的发病机理中的可能作用。与未感染的供体的细胞相比，供体的CD4+ CD45RA-CD25+ T细胞在HIV感染的病毒性病毒（但不是阿维病）的外周血液中表现出较高的CTLA-4共表达水平（这种调节子集的标志，但不是独特的标志）。 CD4+ T细胞子集的分离，然后进行功能分析，表明从大多数HIV感染者中救出了PBMC中救出HIV P24诱导的HIV P24诱导的增生反应的CD4+ CD45RA-CD25+ T细胞的去除。在大多数情况下，这种细胞种群的重新添加导致抑制HIV特异性增生反应。此外，CD4+ CD25+细胞的去除增强了，其重新结合抑制，HIV GAG肽或P24诱导的细胞内IFN-G和IL-2从CD4+和CD8+ T细胞产生。此外，初步数据表明，CD4+ CD25+调节抑制细胞在培养的患者细胞中直接或间接地调节内源性HIV复制。