Natural Killer Cell Responses of Aged Mice to Primary Influenza Infection

老年小鼠对原发性流感感染的自然杀伤细胞反应

• 批准号: 8490266
• 负责人: Elizabeth M. Gardner
• 金额: $ 29.8万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8490266
• 关键词: Ablation; Acute; Address; Adoptive Transfer; Affect; Age; Age-Years; Animal Model; Antibodies; Apoptosis; Body Weight decreased; C57BL/6 Mouse; Cause of Death; Cell Count; Cell Proliferation; Cell physiology; Cells; Cessation of life; Cytokine Receptors; Cytolysis; Cytotoxic T-Lymphocytes; Data; Defect; Dendritic Cells; Dendritic cell activation; Dependence; Dose; Elderly; Environment; Exhibits; Family suidae; Future; Goals; Histology; Homing; Hospitalization; Human; Immune; Immune response; Immunoglobulin G; Individual; Infection; Infiltration; Influenza; Influenza A Virus, H1N1 Subtype; Influenza vaccination; Leucocytic infiltrate; Lung; Lytic; Measures; Mus; Natural Killer Cells; Pathology; Persons; Pneumonia; Population; Predisposition; Prevalence; Production; Recovery; Reporting; Research; Resistance; Role; Signal Transduction; Therapeutic; Transgenic Mice; United States; Vaccines; Virus; Virus Diseases; Vulnerable Populations; Weight Gain; age related; aged; base; cytokine; cytotoxicity; human old age (65+); in vivo; influenzavirus; mouse model; novel; prophylactic; public health relevance; receptor function; response; seasonal influenza; statistics

DESCRIPTION (provided by applicant): Despite vaccination, influenza and secondary pneumonias are the fourth leading cause of death in individuals 65 years and older. The recent emergence of the novel 2009-H1N1 influenza, to which vaccines are limited or unavailable, has the potential to cause 30,000-90,000 deaths in people under 65 years of age. These staggering statistics mandate the need to better understand age-related changes in primary immune responses to acute influenza infection. We have recently identified a critical role for natural killer (NK) cells in controlling early influenza infection ex vivo and in vivo. Aged C57BL/6 mice exhibited increased lung virus titers, weight loss, decreased NK cytotoxicity, and a reduced number of NK cells during early influenza infection. Importantly, in vivo NK cell depletion by anti-NK1.1 IgG antibody (PK136) treatment induced marked weight loss and increased lung virus titers after influenza infection of both young and aged mice. These data suggest that NK cells are essential in early control of influenza infection. Thus, our overarching hypothesis is that the induction of an effective NK cell response is vital for controlling early influenza infection in vulnerable populations, including the elderly. Our studies will characterize age-related changes in NK cell function, elucidate potential intrinsic and extrinsic mechanisms for impaired NK cell function, and establish the critical role of NK cells in controlling early infection to influenza virus in vivo. In Aim 1, age-related differences in susceptibility and the role of NK cell function during the first critical four days of infection will be assessed. We will perform influenza dose responses and measure age-related differences lung virus titers, pathology, histology and cellular infiltrates in lung, weight loss, and recovery from infection. Age-related changes in NK subsets, cytolytic function of NK cells, dendritic cell (DCs) function, and local and systemic cytokine production will be measured during infection. In Aim 2, we will elucidate age-related changes in intrinsic and extrinsic mechanism(s) for impaired NK cell function during influenza infection. Age-related differences in lytic efficiency, activation receptor function/signaling, and cytokine receptor/function will be measured in purified NK cells to identify intrinsic NK cell defects. Adoptive transfer studies will delineate between intrinsic and extrinsic effects on NK cell proliferation, apoptosis, and homing as related to susceptibility to influenza. We hypothesize that DCs are critical extrinsic effectors on NK cell function in early infection. Thus, we will measure DC activation of NK cells, DC cytokine production, and the effects of DC ablation on NK cell function. In Aim 3, we will validate the essential role of NK cells in controlling the in vivo response to influenza. In vivo NK cytolysis in young and aged mice will be assessed along with survival, weight loss, and lung virus titers. The specific role of NK cells in controlling susceptibility to influenza will be addressed in mice after NK depletion in vivo with PK136 or in RAG-1-/- or NKD transgenic mice. These three mouse models will afford a clear delineation of the specific contribution of NK cells in controlling the early response to influenza.

说明(申请人提供)：尽管接种了疫苗，流感和继发性肺炎仍是65岁及以上个人的第四大死因。最近出现的新型2009-H1N1流感疫苗有限或无法获得，有可能导致65岁以下人群死亡30,000-90,000人。这些令人震惊的统计数据要求更好地了解急性流感感染的初级免疫反应中与年龄相关的变化。我们最近确定了自然杀伤(NK)细胞在体内和体外控制早期流感感染中的关键作用。老年C57BL/6小鼠在早期流感感染过程中表现出肺部病毒滴度升高、体重减轻、NK细胞杀伤活性降低和NK细胞数量减少。重要的是，体内NK细胞被抗NK1.1抗体(PK136)去除后，幼年和老年小鼠感染流感后体重显著下降，肺病毒滴度增加。这些数据表明，NK细胞在流感感染的早期控制中是必不可少的。因此，我们的主要假设是，诱导有效的NK细胞反应对于控制包括老年人在内的易感人群的早期流感感染至关重要。我们的研究将描述与年龄相关的NK细胞功能的变化，阐明NK细胞功能受损的潜在内在和外在机制，并确立NK细胞在体内控制流感病毒早期感染的关键作用。在目标1中，将评估在感染的最初关键四天中与年龄相关的易感性差异和NK细胞功能的作用。我们将进行流感剂量反应，并测量与年龄相关的差异肺病毒滴度、病理、组织学和肺内细胞浸润、体重减轻和感染后恢复。在感染过程中，将测量与年龄相关的NK亚群、NK细胞的细胞溶解功能、树突状细胞(DC)功能以及局部和系统细胞因子的产生。在目标2中，我们将阐明流感感染时NK细胞功能受损的内在和外在机制(S)与年龄相关的变化。在纯化的NK细胞中，将测量与年龄相关的裂解效率、激活受体功能/信号和细胞因子受体/功能的差异，以确定固有的NK细胞缺陷。过继转移研究将描述与流感易感性有关的NK细胞增殖、凋亡和归巢的内在和外在效应。我们假设DC在感染早期是NK细胞功能的关键外在效应因子。因此，我们将检测NK细胞的DC激活，DC细胞因子的产生，以及DC消融对NK细胞功能的影响。在目标3中，我们将验证NK细胞在控制体内对流感的反应中的重要作用。在体内，年轻和老年小鼠的NK细胞溶解能力将与存活率、体重减轻和肺病毒滴度一起进行评估。NK细胞在控制流感易感性方面的特殊作用将在体内用PK136去除NK细胞后或在RAG-1/-或NKD转基因小鼠中得到解决。这三种小鼠模型将清楚地描述NK细胞在控制对流感的早期反应中的特定贡献。