ROLE OF CTL EFFECTOR MECHANISMS IN CHRONIC DEMYELINATION

JHM病毒(JHMV)感染致急性脑脊髓炎 伴随着原发性脱髓鞘。在急性疾病期间，一种强有力的，但 部分无效，免疫反应发生在中枢神经内 系统(CNS)。不能进行绝育免疫会导致 持续性中枢神经系统感染和慢性持续性脱髓鞘 类似于多发性硬化症的病理特征。两大优势 病毒清除的效应物已被确定：细胞毒性T淋巴细胞 (CTL)介导的细胞溶解和干扰素-γ(干扰素-γ)。我们的工作 假说是CD8+T细胞，利用组合穿孔素介导 细胞溶解和干扰素-γ分泌是主要的免疫效应系统。 可预防JHMV诱导的慢性脱髓鞘。要理解这个角色 从支持病毒的细胞中清除病毒的免疫反应 感染(星形胶质细胞、少突胶质细胞和小胶质细胞)，从而定义 预防持续性感染和慢性疾病的有效成分 疾病，这个项目有两个目标。第一部分分析了 穿孔素介导的细胞毒作用。这是病毒的主要效应者。 星形胶质细胞和小胶质细胞的清除。要实现的是CTL的目标 干扰素-γKO(GKO)小鼠将被转移到感染的SCID，GKO/穿孔素 KO(GKO/PKO)和PKO接受者。GKO CTL表现出优异的穿透性 介导细胞毒作用，但不分泌干扰素-γ。来自GKO捐赠者的CTL将 也被转移到受感染的转基因小鼠中，表达 限制元件(L/d)对少突胶质细胞具有专一性。第二个目标 确定干扰素-γ对病毒清除的贡献和 坚持不懈。干扰素-γ似乎是病毒的效应机制 少突胶质细胞的清除。这将通过转移来实现 从PKO供者的CTL转移到感染的SCID、PKO/GKO和GKO受体。 病毒载量、特定细胞类型受保护并进展为慢性 将对感染和脱髓鞘进行分析。CTL衍生能力的研究 改变少突胶质细胞复制的干扰素-γ将通过 PKO供体CTL在表达L/d的转基因小鼠体内的转移 少突胶质细胞。干扰素-γ改变人类免疫缺陷病毒感染的能力 少突胶质细胞和星形胶质细胞将通过表达显性 重组人干扰素-γ-α链负性受体转基因 PLP和GFAP启动子。转基因表达将使这些细胞 特别是对干扰素-伽马信号事件的抵抗。最后，短暂的 在DI载体的驱动下，受感染细胞的干扰素-γ表达将 确定干扰素-γ对疾病早期进展的影响 慢性脱髓鞘。

JHM virus (JHMV) infection results in an acute encephalomyelitis accompanied by primary demyelination. During acute disease a vigorous, but partially ineffective, immune response occurs within the central nervous system (CNS). The inability to effect sterilizing immunity results in persistent CNS infection and chronic ongoing demyelination with many pathological hallmarks similar to multiple sclerosis. Two predominant effectors of virus clearance have been identified: cytotoxic T lymphocyte (CTL) mediated cytolysis and interferon gamma (IFN-gamma). Our working hypothesis is that CD8+ T cells, using a combination of perforin mediated cytolysis and IFN-gamma secretion are the major immune effector systems which prevent JHMV-induced chronic demyelination. To understand the role of the immune response in clearing virus from the cells which support infection (astrocytes, oligodendroglia and microglia) and thereby define the components effective in preventing persistent infection and chronic disease, this project has two aims. The first analyzes the contribution of perforin mediated cytotoxicity. This is the major effector in virus clearance from astrocytes and microglia. To accomplish is goal CTL from IFN-gamma KO (GKO) mice will be transferred to infected SCID, GKO/perforin KO (GKO/PKO) and PKO recipients. GKO CTL exhibit excellent perforin mediated cytotoxicity but secrete no IFN-gamma. CTL from GKO donors will also be transferred into infected transgenic mice expressing the restriction element (L/d) exclusively on oligodendroglia. The second aim determines the contribution of IFN-gamma to viral clearance and persistence. IFN-gamma appears to be effector mechanism involved in virus clearance from oligodendroglia. This will be accomplished by the transfer of CTL from PKO donors into infected SCID, PKO/GKO and GKO recipients. Virus load, specific cell types protected and progression to chronic infection and demyelination will be analyzed. The ability of CTL derived IFN-gamma to alter replication in oligodendroglia will be examined by transfers of PKO donor CTL into transgenic mice which express L/d on oligodendroglia. The ability of IFN-gamma to modify infection in oligodendroglia and astrocytes will be examined by expressing a dominant negative IFN-gamma alpha chain receptor transgene under the control of the PLP and GFAP promoters. Transgene expression will render these cells specifically resistant to IFN-gamma signaling events. Finally, transient IFN-gamma expression from infected cells, driven by a DI vector, will determine the effects of IFN-gamma on early progression of disease to chronic demyelination.