CELLULAR IMMUNITY TO JC VIRUS IN AIDS ASSOCIATED PML

JC病毒（JCV）是进行性多灶性白质脑病（PML）的病因，PML是一种发生在潜在免疫抑制患者的少突胶质细胞的感染性感染。JCV感染90%的正常成年人，但在健康个体中不会引起任何疾病。4%的艾滋病患者会出现病毒再激活，其他免疫功能严重抑制的患者偶尔也会出现病毒再激活。这种再激活导致少突胶质细胞的抒情感染和相关的中枢神经系统脱髓鞘。在免疫正常的人群中含有病毒的免疫反应的性质，在免疫抑制的个体中失败，是未知的。抗jcv抗体对PML没有保护作用。因此，jcv特异性细胞免疫反应可能在抑制该病毒的复制中起关键作用。了解细胞对JCV的免疫反应的性质对于表征PML的免疫发病机制至关重要。细胞毒性T淋巴细胞（CTL）是参与抑制多种病毒感染的主要效应细胞。CTL通过它们的t细胞受体和被感染细胞的MHC I类分子呈现的病毒肽表位的相互作用来识别病毒感染的细胞。病毒特异性CTL可以通过功能性细胞毒性试验、四聚体MHC类I/病毒肽复合物染色淋巴细胞的流式细胞术分析和抗原刺激的细胞因子产生试验来检测。在本应用中描述的研究中，我们将描述人类jcv特异性CTL反应，并评估这种免疫反应在PML免疫发病机制中的作用。具体而言，我们将1)使用功能裂解法表征JCV特异性细胞毒性T淋巴细胞2)绘制PML患者的JCV CTL表位3)开发JCV特异性T淋巴细胞ELISPOT检测4)构建MHC类I/JCV肽四聚体复合物并确定JCV CTL表位免疫优势5)分析PML患者和对照组对JCV的细胞免疫应答。利用MHC I类/JCV肽四聚体复合体染色和ELISPOT检测6)确定脑脊液中细胞对JCV的免疫应答7)JCV特异性CTL的检测与PML患者免疫状态和临床病程的相关性

JC virus (JCV) is the etiologic agent of progressive multifocal leucoencephalopathy (PML), a lyric infection of oligodendrocytes occurring in patients with underlying immunosuppression. JCV infects 90% of normal adults, but does not cause any disease in healthy individuals. Viral reactivation occurs in 4% of patients with AIDS, and occasional other individuals who are profoundly immunosuppressed. This reactivation leads to a lyric infection of oligodendrocytes and an associated demyelination of the central nervous system. The nature of the immune response that contains the virus in immunocompetent people, and fails in immunosuppressed individuals, is unknown. Anti-JCV antibodies do not protect against PML. Therefore, the JCV-specific cellular immune response is likely to have a crucial role in containing replication of this virus. Understanding the nature of the cellular immune response to JCV is of central importance in characterizing the immunopathogenesis of PML. Cytotoxic T lymphocytes (CTL) are the major effector cells involved in containing many viral infections. CTL recognize virus-infected cells through the interaction of their T-cell receptor and a viral peptide epitope presented by the MHC class I molecule of the infected cell. Virus-specific CTL can be detected using functional cytotoxicity assays, by flow cytometric analyses through staining of lymphocytes with tetrameric MHC class I/viral peptide complexes, and in antigen-stimulated cytokine production assays. In the studies described in this application we will characterize the JCV-specific CTL response in humans and assess the role of this immune response in the immunopathogenesis of PML. Specifically, we will 1) characterize JCV-specific cytotoxic T lymphocytes using functional lysis assays 2) map JCV CTL epitopes in patients with PML 3) develop JCV-specific T lymphocyte ELISPOT assays 4) construct MHC class I/JCV peptide tetramer complexes and determine JCV CTL epitope immunodominance 5) analyze the cellular immune response to JCV in patients with PML and control subjects, using MHC class I/JCV peptide tetramer complex staining and ELISPOT assays 6) define the cellular immune response to JCV in the cerebrospinal fluid 7) correlate the detection of JCV-specific CTL with the immune status and clinical course of patients with PML