Suárez Andrea Luísa, van Dyk Linda Faye
Department of Microbiology and Program in Molecular Biology, University of Colorado Denver School of Medicine, Aurora, Colorado, United States of America.
PLoS Pathog. 2008 Sep 12;4(9):e1000152. doi: 10.1371/journal.ppat.1000152.
A variety of human diseases are associated with gammaherpesviruses, including neoplasms of lymphocytes (e.g. Burkitt's lymphoma) and endothelial cells (e.g. Kaposi's sarcoma). Gammaherpesvirus infections usually result in either a productive lytic infection, characterized by expression of all viral genes and rapid cell lysis, or latent infection, characterized by limited viral gene expression and no cell lysis. Here, we report characterization of endothelial cell infection with murine gammaherpesvirus 68 (gammaHV68), a virus phylogenetically related and biologically similar to the human gammaherpesviruses. Endothelial cells supported gammaHV68 replication in vitro, but were unique in that a significant proportion of the cells escaped lysis, proliferated, and remained viable in culture for an extended time. Upon infection, endothelial cells became non-adherent and altered in size, complexity, and cell-surface protein expression. These cells were uniformly infected and expressed the lytic transcription program based on detection of abundant viral gene transcripts, GFP fluorescence from the viral genome, and viral surface protein expression. Additionally, endothelial cells continued to produce new infectious virions as late as 30 days post-infection. The outcome of this long-term infection was promoted by the gammaHV68 v-cyclin, because in the absence of the v-cyclin, viability was significantly reduced following infection. Importantly, infected primary endothelial cells also demonstrated increased viability relative to infected primary fibroblasts, and this increased viability was dependent on the v-cyclin. Finally, we provide evidence for infection of endothelial cells in vivo in immune-deficient mice. The extended viability and virus production of infected endothelial cells indicated that endothelial cells provided a source of prolonged virus production and identify a cell-type specific adaptation of gammaherpesvirus replication. While infected endothelial cells would likely be cleared in a healthy individual, persistently infected endothelial cells could provide a source of continued virus replication in immune-compromised individuals, a context in which gammaherpesvirus-associated pathology frequently occurs.
多种人类疾病与γ疱疹病毒有关，包括淋巴细胞肿瘤（如伯基特淋巴瘤）和内皮细胞肿瘤（如卡波西肉瘤）。γ疱疹病毒感染通常导致以下两种情况之一：一种是增殖性溶细胞感染，其特征是所有病毒基因表达且细胞迅速裂解；另一种是潜伏感染，其特征是病毒基因表达有限且无细胞裂解。在此，我们报告了用鼠γ疱疹病毒68（γHV68）感染内皮细胞的特征，γHV68在系统发育上与人类γ疱疹病毒相关且生物学特性相似。内皮细胞在体外支持γHV68复制，但独特之处在于相当一部分细胞逃脱裂解、增殖并在培养中长时间保持存活。感染后，内皮细胞变得不黏附，大小、复杂性和细胞表面蛋白表达发生改变。基于大量病毒基因转录本的检测、病毒基因组的绿色荧光蛋白（GFP）荧光以及病毒表面蛋白表达，这些细胞被均匀感染并表达溶细胞转录程序。此外，内皮细胞在感染后30天仍持续产生新的感染性病毒粒子。γHV68的v - 细胞周期蛋白促进了这种长期感染的结果，因为在没有v - 细胞周期蛋白的情况下，感染后细胞活力显著降低。重要的是，相对于感染的原代成纤维细胞，感染的原代内皮细胞也表现出活力增加，且这种活力增加依赖于v - 细胞周期蛋白。最后，我们提供了免疫缺陷小鼠体内内皮细胞被感染的证据。被感染内皮细胞的延长存活期和病毒产生表明内皮细胞提供了延长的病毒产生来源，并确定了γ疱疹病毒复制的细胞类型特异性适应性。虽然在健康个体中被感染的内皮细胞可能会被清除，但在免疫受损个体中，持续感染的内皮细胞可能会提供持续病毒复制的来源，而γ疱疹病毒相关病理通常在这种情况下发生。
