HIV Evasion of NK Cells in Lymph Nodes

HIV 逃避淋巴结中的 NK 细胞

• 批准号: 7685075
• 负责人: Edward Barker
• 金额: $ 22.7万
• 依托单位: RUSH UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7685075
• 关键词: Active Sites; Affect; Autologous; Binding Proteins; Blood Cells; Cell Line; Cell physiology; Cell surface; Cell-Mediated Cytolysis; Cells; Data; Detection; Development; Effector Cell; Environment; Flow Cytometry; Functional disorder; HIV; HIV-1; HIV-2; HLA Antigens; Hand; Histocompatibility; Immune; Immune system; Individual; Inguinal lymph node group; Interleukin-12; Interleukin-2; Lead; Ligand Binding; Ligands; Lymphocyte; Lymphocyte Activation; Lymphoid; Mediating; NK Cell Activation; NTB-A; Natural Killer Cells; Population; Predisposition; Production; Receptor Activation; Resistance; Signal Transduction; Site; Surface; T-Lymphocyte; Testing; Tissues; Viral; Viral Proteins; Viremia; Virion; Virus; Virus Diseases; Virus Replication; cell killing; cytokine; cytotoxic; cytotoxicity; expectation; insight; killings; lymph nodes; peripheral blood; public health relevance; receptor; response; treatment strategy

DESCRIPTION (provided by applicant): A major site for productive HIV infection is the lymph node. HIV replication is robust in this tissue compartment despite the presence of lymphocytes such as natural killer (NK) cells that can potentially control HIV infection. Even more intriguing is the fact that robust viral replication takes place under circumstances that promote NK cell killing activity such as 1) the presence of elevated levels of cytokines (i.e., IL-2, -12 and -15) which enhance NK cell mediated cytotoxicity and promote the development of effector NK cells from na¿ve NK cells, 2) the decreased expression by infected cells of molecules [e.g., major histocompatibility molecules (MHC) class I molecules] that provide inhibitory signals to NK cells (i.e., HLA-A and -B) and, 3) the expression by infected cells of surface molecules that provide activating signals to NK cells (i.e., ULBPs). Our objective is to determine why HIV prevails in lymph nodes despite an environment that favors NK cell mediated killing of HIV infected cells. Our hypothesis is that HIV evades NK cells in the lymph node through 1) its ability to alter the makeup of the NK cell population in the lymph node so it consists mostly of unresponsive NK cells (i.e., CD56negCD16pos), and 2) its ability to decrease the expression of molecules on infected T-cells that trigger NK cell responses (i.e., CD48 and NTB-A) while maintaining the expression of inhibitory molecules (i.e., HLA-C). To test this hypothesis, inguinal lymph nodes will be obtained from HIV-infected and uninfected subjects, lymphoid NK cells will be isolated and the capacity of NK cells in the lymph node of HIV-infected individuals to destroy HIV infected cells will be determined. This will initially be accomplished by determining the overall cytotoxic capability of lymphoid NK cells to kill autologous peripheral blood CD4pos T-cells infected with a primary strain HIV-1SF162. The cytotoxic activity of NK cells will be compared with the levels of cytokines produced by cells in the lymph nodes. The distribution of the different lymphoid NK cell subsets will also be determined by multicolor flow cytometry. Moreover we will determine the various inhibitory and activating receptors on NK cells by multicolor flow cytometry. In addition, HIV-infected T-cells will be obtained from lymph nodes and the susceptibility of these cells to autologous lymphoid NK cells will be determined. The final step will be to characterize the expression on HIV-infected cell's surface of various ligands that bind to receptors that provide positive and negative signals to NK cells. Our expectation is that in the lymph node of HIV-infected individuals, NK cells will have impaired cytotoxicity and that infected lymphoid T-cells will be resistant to NK cells because of the simultaneous retention of inhibitory molecules and the decreased expression of activating molecules on the infected cell surface. The findings from this study will provide insights into the mechanisms by which HIV evades NK cells in lymph nodes. These insights, in turn, will provide the rationale for investigating new treatment strategies that can enhance the immune control of HIV. PUBLIC HEALTH RELEVANCE: This project will determine how HIV evades immune cells called natural killer cells in the lymph nodes, which is a major site for productive HIV infection. The results from this study will provide insights on the mechanisms by which HIV avoids detection and destruction by the immune system. These insights will point the way towards treatment strategies that will enhance the immune system's ability to control HIV.

描述（由申请人提供）：产生性 HIV 感染的主要部位是淋巴结，尽管存在自然杀伤 (NK) 细胞等淋巴细胞，这种细胞可以潜在地控制 HIV 感染。事实上，强大的病毒复制发生在促进 NK 细胞杀伤活性的情况下，例如 1) 细胞因子水平升高（即 IL-2、-12 和 -15），从而增强 NK 细胞介导的细胞毒性并促进效应 NK 细胞的发育ve NK 细胞，2) 受感染细胞的分子表达降低 [例如，主要组织相容性分子 (MHC) I 类分子]，向 NK 细胞提供抑制信号（即 HLA-A 和 -B），3) 表达通过向 NK 细胞（即 ULBP）提供激活信号的表面分子的感染细胞，我们的目标是确定为什么 HIV 在淋巴结中盛行，尽管环境有利于 NK 细胞介导。我们的假设是，HIV 通过以下方式逃避淋巴结中的 NK 细胞：1) 它能够改变淋巴结中 NK 细胞群的构成，使其主要由无反应的 NK 细胞（即 CD56negCD16pos）组成， 2) 它能够减少受感染 T 细胞上触发 NK 细胞反应的分子表达（即 CD48 和 NTB-A），同时维持抑制性表达为了检验这一假设，将从 HIV 感染者和未感染者身上获取腹股沟淋巴结，分离淋巴 NK 细胞，并研究 HIV 感染者淋巴结中 NK 细胞的能力。消灭 HIV 感染细胞的能力将首先通过确定淋巴 NK 细胞杀死被原代毒株感染的自体外周血 CD4pos T 细胞的总体细胞毒性能力来确定。 HIV-1SF162. NK 细胞的细胞毒性活性将与淋巴结中细胞产生的细胞因子的水平进行比较，不同淋巴 NK 细胞亚群的分布也将通过多色流式细胞术确定。通过多色流式细胞术检测 NK 细胞上的抑制性和激活性受体。此外，将从淋巴结获得 HIV 感染的 T 细胞，这些细胞对自体淋巴 NK 细胞的敏感性将提高。最后一步是表征 HIV 感染细胞表面各种配体的表达，这些配体与向 NK 细胞提供阳性和阴性信号的受体结合，我们的预期是，在 HIV 感染者的淋巴结中，NK 会被识别。细胞的细胞毒性将受损，并且受感染的淋巴 T 细胞将对 NK 细胞产生耐药性，因为受感染细胞表面上抑制性分子的同时保留和激活分子的表达减少。这项研究的结果将提供对 NK 细胞的抵抗力。反过来，这些见解将为研究可增强艾滋病毒免疫控制的新治疗策略提供依据。 公共卫生相关性：该项目将确定艾滋病毒如何逃避称为自然的免疫细胞。淋巴结中的杀伤细胞是艾滋病毒感染的主要部位，这项研究的结果将提供有关艾滋病毒避免被免疫系统检测和破坏的机制的见解，这些见解将为治疗策略指明方向。会增强免疫系统系统控制艾滋病毒的能力。