Minaya Miguel A, Jensen Travis L, Goll Johannes B, Korom Maria, Datla Sree H, Belshe Robert B, Morrison Lynda A
Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
The EMMES Corporation, Rockville, Maryland, USA.
J Virol. 2017 Nov 14;91(23). doi: 10.1128/JVI.00942-17. Print 2017 Dec 1.
Herpes simplex virus 1 (HSV-1) and HSV-2 are large, double-stranded DNA viruses that cause lifelong persistent infections characterized by periods of quiescence and recurrent disease. How HSV evolves within an infected individual experiencing multiple episodes of recurrent disease over time is not known. We determined the genome sequences of viruses isolated from two subjects in the Herpevac Trial for Women who experienced primary HSV-2 genital disease and compared them with sequences of viruses isolated from the subsequent fifth or sixth episode of recurrent disease in the same individuals. Each of the HSV-2 genome sequences was initially obtained using next-generation sequencing and completed with Sanger sequencing. Polymorphisms over the entire genomes were mapped, and amino acid variants resulting from nonsynonymous changes were analyzed based on the secondary and tertiary structures of a previously crystallized protein. A phylogenetic reconstruction was used to assess relationships among the four HSV-2 samples, other North American sequences, and reference sequences. Little genetic drift was detected in viruses shed by the same subjects following repeated reactivation events, suggesting strong selective pressure on the viral genome to maintain sequence fidelity during reactivations from its latent state within an individual host. Our results also demonstrate that some primary HSV-2 isolates from North America more closely resemble the HG52 laboratory strain from Scotland than the low-passage-number clinical isolate SD90e from South Africa or laboratory strain 333. Thus, one of the sequences reported here would be a logical choice as a reference strain for inclusion in future studies of North American HSV-2 isolates. The extent to which the HSV-2 genome evolves during multiple episodes of reactivation from its latent state within an infected individual is not known. We used next-generation sequencing techniques to determine whole-genome sequences of four viral samples from two subjects in the Herpevac Trial. The sequence of each subject's well-documented primary isolate was compared with the sequence of the isolate from their fifth or sixth episode of recurrent disease. Only 19 genetic polymorphisms unique to the primary or recurrent isolate were identified, 10 in subject A and 9 in subject B. These observations indicate remarkable genetic conservation between primary and recurrent episodes of HSV-2 infection and imply that strong selection pressures exist to maintain the fidelity of the viral genome during repeated reactivations from its latent state. The genome conservation observed also has implications for the potential success of a therapeutic vaccine.
单纯疱疹病毒1型（HSV-1）和单纯疱疹病毒2型（HSV-2）是大型双链DNA病毒，可引起终身持续性感染，其特征为静止期和复发性疾病。HSV在一个随着时间经历多次复发性疾病发作的受感染个体内如何演变尚不清楚。我们确定了在女性疱疹疫苗试验中从两名经历原发性HSV-2生殖器疾病的受试者中分离出的病毒的基因组序列，并将它们与从同一受试者随后的第五次或第六次复发性疾病发作中分离出的病毒序列进行比较。每个HSV-2基因组序列最初使用下一代测序获得，并通过桑格测序完成。绘制了整个基因组的多态性，并根据先前结晶蛋白的二级和三级结构分析了非同义变化产生的氨基酸变体。使用系统发育重建来评估四个HSV-2样本、其他北美序列和参考序列之间的关系。在同一受试者反复激活事件后释放的病毒中未检测到明显的基因漂移，这表明在病毒从个体宿主内的潜伏状态重新激活期间，对病毒基因组存在强大的选择压力以维持序列保真度。我们的结果还表明，一些来自北美的原发性HSV-2分离株与来自苏格兰的HG52实验室菌株的相似性高于来自南非的低传代临床分离株SD90e或实验室菌株333。因此，这里报告的序列之一将是作为北美HSV-2分离株未来研究中纳入的参考菌株的合理选择。HSV-2基因组在从受感染个体内的潜伏状态多次重新激活期间的进化程度尚不清楚。我们使用下一代测序技术确定了疱疹疫苗试验中两名受试者的四个病毒样本的全基因组序列。将每个受试者记录良好的原发性分离株的序列与其第五次或第六次复发性疾病发作的分离株的序列进行比较。仅鉴定出原发性或复发性分离株特有的19个基因多态性，受试者A中有10个，受试者B中有9个。这些观察结果表明HSV-2感染的原发性和复发性发作之间具有显著的基因保守性，并意味着在病毒从其潜伏状态反复重新激活期间存在强大的选择压力以维持病毒基因组的保真度。观察到的基因组保守性也对治疗性疫苗的潜在成功具有影响。
