Control of Alphavirus Replication in the Nervous System

辛德毕斯病毒（SV）是一种感染神经元并导致小鼠急性脑脊髓炎的甲病毒。 结果是年龄依赖性的，新生小鼠发展致命的疾病，而断奶小鼠发展良好的- 特征性的免疫应答，其导致从感染中恢复，并提供了用于 研究病毒从神经元中清除的机制。重度联合 免疫缺陷（SCID）不产生SV特异性体液或细胞免疫应答， 清除病毒我们已经证明，感染性病毒可以从中枢神经系统（CMS）清除， SV E2糖蛋白的抗体（Ab），可从脊髓运动神经元中清除，但不能从皮质 或海马神经元的干扰素（IFN）γ。SV清除的这两个过程都涉及机制 不会损伤受感染的神经元Ab介导的细胞内病毒复制控制不依赖于 补体和白细胞，并需要在感染的表面上的E2糖蛋白的交联 cell. SV复制的下调与Na+K+ ATP酶依赖性阳离子通量的改善有关， 抑制病毒出芽、恢复宿主蛋白质合成和对IFN-o/p的应答。 清除与病毒RNA和蛋白质合成的瞬时增加有关， 基因组至亚基因组RNA，恢复细胞蛋白质合成，随后减少病毒蛋白质 合成和抑制病毒RNA转录。病毒清除的非细胞溶解机制导致 病毒RNA在CNS中的持续存在。在过去的一段时间里，我们已经证明了这两个年龄- 依赖性易感性和非细胞溶解性清除可用分化为 体外 在当前的应用中，我们提出确定年龄依赖性易感性的机制， 和免疫介导的细胞内病毒复制的控制，通过以下具体目的：（1） 确定为什么成熟的神经元比未成熟的神经元更能抵抗SV感染;（2）确定 与未成熟神经元相比，病毒复制的哪些步骤在成熟神经元中受到限制;（3） 确定IFN-D从成熟神经元中清除病毒的机制;和（4）确定IFN-γ在神经元中的作用。 抗E2抗体从成熟神经元中清除病毒的机制。

Sindbis virus (SV) is an alphavirus that infects neurons and causes acute encephalomyelitis in mice. Outcome is age-dependent and newborn mice develop fatal disease while weanling mice develop a well- characterized immune response that leads to recovery from infection and provides a model system for studying the mechanisms by which virus is cleared from neurons. Mice with severe combined immunodeficiency (SCID) do not develop an SV-specific humoral or cellular immune response and cannot clear virus. We have shown that infectious virus can be cleared from the central nervous system (CMS)by antibody (Ab) to the SV E2 glycoprotein and can be cleared from spinal cord motor neurons, but not cortical or hippocampal neurons by interferon (IFN)y. Both of these processes of SV clearance involve mechanisms that do not damage infected neurons. Ab-mediated control of intracellular virus replication is independent of complement and leukocytes and requires cross-linking of the E2 glycoprotein on the surface of the infected cell. Down-regulation of SV replication is associated with improved Na+K+ATPase-dependent cation flux, inhibition of virus budding, restoration of host protein synthesis and response to IFN-o/p. IFN-D-mediated clearance is associated with transient increases in viral RNA and protein synthesis with a decreased ratio of genomic to subgenomic RNA, recovery of cellular protein synthesis followed by reduced viral protein synthesis and inhibition of viral RNA transcription. Noncytolytic mechanisms for virus clearance result in persistence of viral RNA in the CNS. During the past granting period we have shown that both age- dependent susceptibility and noncytolytic clearance can be modeled with neuronal cell lines differentiated in vitro. In the current application we propose to determine the mechanisms of age-dependent susceptibility and of immune-mediated control of intracellular virus replication through the following specific aims: (1)To determine why mature neurons are more resistant to SV infection than immature neurons; (2)To determine what steps of virus replication are restricted in mature neurons compared to immature neurons; (3) To determine the mechanism by which IFN-D clears virus from mature neurons; and (4) To determine the mechanism by which anti-E2 antibody clears virus from mature neurons.