Chesnais Morgane, Bujaki Erika, Filhol Typhaine, Caval Vincent, Joffret Marie-Line, Martin Javier, Jouvenet Nolwenn, Bessaud Maël
Institut Pasteur, Université de Paris Cité, CNRS UMR 3569, Virus sensing and signaling Unit, 28 rue du Dr Roux, Paris 75 015, France.
Laboratoire associé au Centre national de référence pour les entérovirus & paréchovirus, 28 rue du Dr Roux, Paris 75 015, France.
Virus Evol. 2024 Jul 29;10(1):veae063. doi: 10.1093/ve/veae063. eCollection 2024.
Polioviruses (PVs) are positive strand RNA viruses responsible for poliomyelitis. Many PVs have been isolated and phenotypically characterized in the 1940s-50s for the purpose of identifying attenuated strains that could be used as vaccine strains. Among these historical PVs, only few are genetically characterized. We report here the sequencing of four PV strains stored for more than 60 years in a sealed box. These PVs are cold variants that were selected by Albert Sabin based on their capacity to multiply at relatively low temperatures. Inoculation of permissive cells at 25°C showed that two of the four historical virus stocks still contained infectious particles. Both viruses reached titres that were higher at 25°C than at 37°C, thus demonstrating that they were genuine cold variants. We obtained sequences that span virtually all the genome for three out of the four strains; a short sequence that partly covers the 5' untranslated region was recovered for the last one. Unexpectedly, the genome of one historical cold variant (which derives from PV-3 Glenn) displayed a very high nucleotide identity (above 95%) with that of a PV strain (PV-3 strain WIV14) sampled in China in 2014 and then classified as a highly evolved vaccine-derived PV. Our analyses made this hypothesis very unlikely and strongly suggested that Glenn and WIV14 shared a very recent common ancestor with one another. Some strains used to produce the inactivated polio vaccine were also very close to Glenn and WIV14 in the capsid-encoding region, but they had not been sequenced beyond the capsid. We therefore sequenced one of these strains, Saukett A, which was available in our collection. Saukett A and WIV14 featured an identity higher than 99% at the nucleotide level. This work provides original data on cold variants that were produced and studied decades ago. It also highlights that sequences of historical PV strains could be crucial to reliably characterize contemporary PVs in case of release from a natural reservoir or from a facility, which is of highest importance for the PV eradication program.
脊髓灰质炎病毒（PVs）是引起脊髓灰质炎的正链RNA病毒。在20世纪40年代至50年代，为了鉴定可作为疫苗株的减毒株，许多PVs被分离并进行了表型特征分析。在这些历史上的PVs中，只有少数进行了基因特征分析。我们在此报告了保存在密封盒中60多年的4株PVs的测序情况。这些PVs是冷适应变异株，由阿尔伯特·萨宾根据它们在相对低温下繁殖的能力筛选出来。在25°C接种允许细胞表明，这4株历史病毒株中的2株仍含有感染性颗粒。两种病毒在25°C时达到的滴度高于37°C时，从而证明它们是真正的冷适应变异株。我们获得了4株中的3株几乎覆盖整个基因组的序列；最后一株获得了部分覆盖5'非翻译区的短序列。出乎意料的是，一个历史冷适应变异株（源自PV-3 Glenn）的基因组与2014年在中国采样并随后被归类为高度进化的疫苗衍生PV的一株PV（PV-3株WIV14）显示出非常高的核苷酸同一性（超过95%）。我们的分析使这一假设极不可能成立，并强烈表明Glenn和WIV14彼此共享一个非常近的共同祖先。一些用于生产灭活脊髓灰质炎疫苗的毒株在衣壳编码区域也与Glenn和WIV14非常接近，但它们除衣壳外未进行测序。因此，我们对我们收藏中的其中一株Saukett A进行了测序。Saukett A和WIV14在核苷酸水平上的同一性高于99%。这项工作提供了关于数十年前产生和研究的冷适应变异株的原始数据。它还强调，历史PV株的序列对于在从天然宿主或设施中释放的情况下可靠地表征当代PVs可能至关重要，这对脊髓灰质炎根除计划至关重要。
