Impaired killing of HCMV-infected retinal pigment epithelial cells by anti-pp65 CD8+ cytotoxic T cells
Impaired killing of HCMV-infected retinal pigment epithelial cells by anti-pp65 CD8+ cytotoxic T cells
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DOI：
10.1167/iovs.02-0547
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发表时间：
2003-02-01
影响因子：
4.4
通讯作者：
Davrinche, C
中科院分区：
文献类型：
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作者：
Allart, S;Lulé, J;Davrinche, C
目的。宿主对人类巨细胞病毒（HCMV）感染的防御在很大程度上是由细胞毒性CD8(+) T淋巴细胞（ctl）直接针对被膜蛋白pp65来保证的。在病毒与细胞膜融合后，进入的pp65超立即释放到主要组织相容性复合体（MHC） I类途径中，提供了一种非常早期的防御机制。在视网膜色素上皮细胞（APE）中，已知HCMV通过内吞作用进入。这项研究是为了确定这种渗透到细胞中的方法是否会使病毒逃避免疫监视。HCMV AD169分别感染RPE细胞6小时、48小时和8天。通过流式细胞术、荧光显微镜和Western blot分析RPE细胞和星形细胞瘤参比细胞系U373MG细胞内pp65的表达。通过cr -51释放试验监测靶向pp65的hla - a2限制性CD8+ ctl对两种hcmv感染细胞系的杀伤作用。与U373MG相反，靶向pp65的ctl不能裂解RPE细胞。此外，这两种细胞系在感染后都没有被抗pp65 ctl杀死，这是因为HCMV独特的短蛋白（US2-11）具有MHC i类下调作用。在RPE细胞中，HCMV通过内吞作用进入和US蛋白的免疫抑制作用都可以使病毒在感染的任何阶段逃避免疫监视，这可能促进病毒在视网膜内扩散。
PURPOSE. Host defense against infection by human cytomegalovirus (HCMV) is ensured in great part by cytotoxic CD8(+) T lymphocytes (CTLs) directed against the tegument protein pp65. The hyperimmediate release of incoming pp65 into the major histocompatibility complex (MHC) class I pathway after fusion of the virus with the cell membrane provides a very early mechanism of defense. In retinal pigment epithelial (APE) cells HCMV is known to enter through endocytosis. This study was conducted to determine whether this means of penetration into the cells would allow the virus to elude immune surveillance.METHODS. Infection of RPE cells with HCMV AD169 was performed for 6 hours, 48 hours, and 8 days. Expression of intracellular pp65 in RPE cells and in the astrocytoma reference cell line U373MG was evaluated by flow cytometry, fluorescence microscopy, and Western blot analysis. Killing of both HCMV-infected cell lines by HLA-A2-restricted CD8+ CTLs directed against pp65 was monitored by Cr-51-release assays.RESULTS. RPE cells were not lysed by CTLs directed against incoming pp65, contrary to U373MG. Moreover, both cell lines were not killed by anti-pp65 CTLs later after infection, because of the MHC class-I-downregulating effect of HCMV unique short (US2-11) proteins.CONCLUSIONS. In RPE cells, both HCMV entry through endocytosis and the immunosuppressive effect of US proteins could allow the virus to evade immune surveillance at any stage of infection, which could promote viral spreading within the retina.