State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention (NCAIDS), Chinese Center for Disease Control and Prevention, Beijing, China.
PLoS One. 2013 Apr 12;8(4):e60557. doi: 10.1371/journal.pone.0060557. Print 2013.
Despite the worldwide eradication of smallpox in 1979, the potential bioterrorism threat from variola virus and the ongoing use of vaccinia virus (VACV) as a vector for vaccine development argue for continued research on VACV. In China, the VACV Tiantan strain (TT) was used in the smallpox eradication campaign. Its progeny strain is currently being used to develop a human immunodeficiency virus (HIV) vaccine. Here we sequenced the full genomes of five TT clones isolated by plaque purification from the TT (752-1) viral stock. Phylogenetic analysis with other commonly used VACV strains showed that TT (752-1) and its clones clustered and exhibited higher sequence diversity than that found in Dryvax clones. The ∼190 kbp genomes of TT appeared to encode 273 open reading frames (ORFs). ORFs located in the middle of the genome were more conserved than those located at the two termini, where many virulence and immunomodulation associated genes reside. Several patterns of nucleotide changes including point mutations, insertions and deletions were identified. The polymorphisms in seven virulence-associated proteins and six immunomodulation-related proteins were analyzed. We also investigated the neuro- and skin- virulence of TT clones in mice and rabbits, respectively. The TT clones exhibited significantly less virulence than the New York City Board of Health (NYCBH) strain, as evidenced by less extensive weight loss and morbidity in mice as well as produced smaller skin lesions and lower incidence of putrescence in rabbits. The complete genome sequences, ORF annotations, and phenotypic diversity yielded from this study aid our understanding of the Chinese historic TT strain and are useful for HIV vaccine projects employing TT as a vector.
尽管 1979 年已在全球范围内消灭了天花，但天花病毒的潜在生物恐怖主义威胁以及牛痘病毒（VACV）作为疫苗开发载体的持续使用，都证明了对 VACV 的持续研究是必要的。在中国，天坛株（TT）被用于天花根除运动。其衍生株目前正被用于开发人类免疫缺陷病毒（HIV）疫苗。在这里，我们通过噬菌斑纯化从 TT（752-1）病毒库存中分离出的五个 TT 克隆，对其全基因组进行了测序。与其他常用 VACV 株的系统发育分析表明，TT（752-1）及其克隆聚类，并表现出比 Dryvax 克隆更高的序列多样性。TT 的约 190 kbp 基因组似乎编码了 273 个开放阅读框（ORFs）。基因组中部的 ORFs 比两端的更保守，而许多毒力和免疫调节相关基因都位于两端。鉴定出了几种核苷酸变化模式，包括点突变、插入和缺失。对七个与毒力相关的蛋白和六个与免疫调节相关的蛋白的多态性进行了分析。我们还分别在小鼠和兔中研究了 TT 克隆的神经和皮肤毒力。TT 克隆的毒力明显低于纽约市卫生局（NYCBH）株，这一点从小鼠体重减轻和发病率较低以及兔子皮肤损伤较小和腐肉发生率较低中可以看出。本研究获得的全基因组序列、ORF 注释和表型多样性有助于我们了解中国历史悠久的 TT 株，并为使用 TT 作为载体的 HIV 疫苗项目提供了有用的信息。
