Defense Mechanisms Against CMV Brain Infection

巨细胞病毒脑部感染的防御机制

• 批准号: 7201550
• 负责人: James R Lokensgard
• 金额: $ 27.01万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7201550
• 关键词: Betaherpesvirinae; CD19 molecule; SCID mouse; cellular immunity; chemokine receptor; cytotoxic T lymphocyte; enzyme linked immunosorbent assay; flow cytometry; gene expression; genetically modified animals; helper T lymphocyte; immune response; immunocytochemistry; interferon gamma; interleukin 10; leukocyte activation /transformation; natural killer cells; neuroimmunomodulation; neutralizing antibody; reporter genes; tumor necrosis factor alpha; virus replication

DESCRIPTION (provided by applicant): Cytomegalovirus is a significant opportunistic pathogen in AIDS patients as well as the most common infectious cause of congenital brain disorders. We have recently developed a model of murine cytomegalovirus (MCMV) encephalitis in which immunocompetent and immunodeficient mice are infected through the intracerebroventricular (icv) route. Analogous t o t he situation in humans, immunocompetent m ice a re not susceptible t o M CMV encephalitis, w whereas mice with a severe immune deficit develop uncontrolled brain infection similar to that seen in patients with advanced AIDS. Adoptive transfer of splenocytes from MCMV-primed mice protects immunodeficient animals and this protection is associated with elevated brain levels of several lymphocyte chemoattractants. In this proposal, the central hypothesis to be tested is that glial cell-produced CXCR3 ligands recruit lymphocytes that control the intracerebral spread of MCMV via the production of antiviral cytokines. To test this hypothesis, we will individually deplete splenic lymphocyte subpopulations (i.e., T lymphocytes [CD4+ and CD8+], NK cells, and B-cells) prior to adoptive transfer into immunodeficient mice and determine the effect on viral spread following subsequent icv infection. We will then examine how disruption of chemokine networks by administration of neutralizing antibodies to each of the CXCR3 ligands affects viral expression and lymphocyte trafficking. Additionally, we will examine the role of CXCR3 ligands in trafficking of lymphocytes into infected brains following adoptive transfer of splenocytes from CXCR3 knockout mice. The effect of lymphocytes on chemokine production by glial cells will be investigated by determining if adoptive transfer amplifies CXCR3 ligand levels and identifying which glial cell types produce these ligands in response to MCMV infection. Transfer of lymphocytes from interleukin-10 knockout mice will be performed to determine if this cytokine is used to dampen glial cell chemokine production in response to infection. The role of antiviral cytokines in inhibiting viral replication in the brain will be addressed by examining differences in tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma, levels in the brains of infected mice with and without adoptively transferred splenocytes. Finally, adoptive transfer of splenic lymphocyte subpopulations, from TNF-alpha and IFN-gamma knockout mice will be used to determine if these cytokines alter viral replication and spread within the brain. The in vivo MCMV brain-infection model presented in this grant application provides us with the ability to investigate neuropathogenesis and defense of the brain occurring during viral encephalitis. The studies proposed in this competitive renewal application will provide new insights into the role of CXCR3 ligand production by activated glial cells in the control of viral replication, chemokine-mediated trafficking of lymphocytes into the brain, and the generation of chemokine-induced cytokine networks.

描述（由申请人提供）：巨细胞病毒是艾滋病患者中一种重要的机会性病原体，也是先天性脑部疾病的最常见感染原因。我们最近开发了一种小鼠巨细胞病毒（MCMV）脑炎模型，其中免疫功能正常和免疫缺陷的小鼠通过脑室内（icv）途径感染。与人类的情况类似，免疫功能正常的小鼠不易感染 M CMV 脑炎，而具有严重免疫缺陷的小鼠会出现不受控制的脑部感染，类似于晚期艾滋病患者的情况。从 MCMV 引发的小鼠中过继转移脾细胞可以保护免疫缺陷动物，这种保护与几种淋巴细胞趋化剂的脑水平升高有关。在该提议中，要测试的中心假设是神经胶质细胞产生的 CXCR3 配体招募淋巴细胞，通过产生抗病毒细胞因子来控制 MCMV 的脑内传播。为了检验这一假设，我们将在过继转移至免疫缺陷小鼠之前单独去除脾淋巴细胞亚群（即 T 淋巴细胞 [CD4+ 和 CD8+]、NK 细胞和 B 细胞），并确定随后的 icv 感染后对病毒传播的影响。然后，我们将研究通过对每个 CXCR3 配体施用中和抗体来破坏趋化因子网络如何影响病毒表达和淋巴细胞运输。此外，我们将研究 CXCR3 敲除小鼠脾细胞过继转移后，CXCR3 配体在淋巴细胞运输到受感染大脑中的作用。通过确定过继转移是否会放大 CXCR3 配体水平并确定哪些神经胶质细胞类型响应 MCMV 感染而产生这些配体，将研究淋巴细胞对神经胶质细胞产生趋化因子的影响。将进行来自白细胞介素 10 敲除小鼠的淋巴细胞转移，以确定该细胞因子是否用于抑制神经胶质细胞响应感染的趋化因子的产生。抗病毒细胞因子在抑制大脑中病毒复制中的作用将通过检查肿瘤坏死因子（TNF）-α和干扰素（IFN）-γ以及有和没有过继转移脾细胞的感染小鼠大脑中的水平差异来解决。最后，来自 TNF-α 和 IFN-γ 敲除小鼠的脾淋巴细胞亚群的过继转移将用于确定这些细胞因子是否改变病毒在大脑内的复制和传播。本次资助申请中提出的体内 MCMV 脑感染模型使我们能够研究病毒性脑炎期间发生的神经发病机制和大脑防御。这项竞争性更新申请中提出的研究将为激活的神经胶质细胞产生CXCR3配体在控制病毒复制、趋化因子介导的淋巴细胞运输到大脑以及趋化因子诱导的细胞因子网络的生成中的作用提供新的见解。