Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent Universitygrid.5342.0, Ghent, Belgium.
ProGenTomics, Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent Universitygrid.5342.0, Ghent, Belgium.
J Virol. 2022 Dec 21;96(24):e0115822. doi: 10.1128/jvi.01158-22. Epub 2022 Dec 1.
Pseudorabies virus (PRV) is a member of the alphaherpesvirus subfamily and the causative agent of Aujeszky's disease in pigs. Driven by the large economic losses associated with PRV infection, several vaccines and vaccine programs have been developed. To this day, the attenuated Bartha strain, generated by serial passaging, represents the golden standard for PRV vaccination. However, a proteomic comparison of the Bartha virion to wild-type (WT) PRV virions is lacking. Here, we present a comprehensive mass spectrometry-based proteome comparison of the attenuated Bartha strain and three commonly used WT PRV strains: Becker, Kaplan, and NIA3. We report the detection of 40 structural and 14 presumed nonstructural proteins through a combination of data-dependent and data-independent acquisition. Interstrain comparisons revealed that packaging of the capsid and most envelope proteins is largely comparable in-between all four strains, except for the envelope protein pUL56, which is less abundant in Bartha virions. However, distinct differences were noted for several tegument proteins. Most strikingly, we noted a severely reduced incorporation of the tegument proteins IE180, VP11/12, pUS3, VP22, pUL41, pUS1, and pUL40 in Bartha virions. Moreover, and likely as a consequence, we also observed that Bartha virions are on average smaller and more icosahedral compared to WT virions. Finally, we detected at least 28 host proteins that were previously described in PRV virions and noticed considerable strain-specific differences with regard to host proteins, arguing that the potential role of packaged host proteins in PRV replication and spread should be further explored. The pseudorabies virus (PRV) vaccine strain Bartha-an attenuated strain created by serial passaging-represents an exceptional success story in alphaherpesvirus vaccination. Here, we used mass spectrometry to analyze the Bartha virion composition in comparison to three established WT PRV strains. Many viral tegument proteins that are considered nonessential for viral morphogenesis were drastically less abundant in Bartha virions compared to WT virions. Interestingly, many of the proteins that are less incorporated in Bartha participate in immune evasion strategies of alphaherpesviruses. In addition, we observed a reduced size and more icosahedral morphology of the Bartha virions compared to WT PRV. Given that the Bartha vaccine strain elicits potent immune responses, our findings here suggest that differences in protein packaging may contribute to its immunogenicity. Further exploration of these observations could aid the development of efficacious vaccines against other alphaherpesvirus vaccines such as HSV-1/2 or EHV-1.
伪狂犬病病毒（PRV）是α疱疹病毒亚科的成员，也是猪 Aujeszky 病的病原体。由于 PRV 感染带来的巨大经济损失，已经开发出几种疫苗和疫苗方案。时至今日，通过连续传代生成的弱毒巴氏株仍然是 PRV 疫苗接种的金标准。然而，巴氏病毒粒子与野生型（WT）PRV 病毒粒子的蛋白质组比较仍缺乏。在这里，我们通过组合数据依赖和非依赖性采集，对衰减的巴氏株和三种常用的 WT PRV 株（Becker、Kaplan 和 NIA3）进行了全面的基于质谱的蛋白质组比较。我们报告了通过组合数据依赖和非依赖性采集检测到 40 种结构蛋白和 14 种假定非结构蛋白。种间比较表明，除了包膜蛋白 pUL56 在外，所有四种菌株的衣壳和大多数包膜蛋白的包装在很大程度上是可比的。然而，几种被膜蛋白存在明显差异。最引人注目的是，我们注意到在巴氏病毒粒子中，被膜蛋白 IE180、VP11/12、pUS3、VP22、pUL41、pUS1 和 pUL40 的掺入量明显减少。此外，可能作为结果，我们还观察到巴氏病毒粒子的平均直径较小，且更接近二十面体。最后，我们检测到至少 28 种以前在 PRV 病毒粒子中描述过的宿主蛋白，并注意到宿主蛋白在不同菌株之间存在明显的差异，这表明包装的宿主蛋白在 PRV 复制和传播中的潜在作用应该进一步探索。伪狂犬病病毒（PRV）疫苗株巴氏株——通过连续传代产生的减毒株——是α疱疹病毒疫苗接种的一个杰出成功案例。在这里，我们使用质谱分析来比较巴氏病毒粒子的组成与三种已建立的 WT PRV 株。与 WT 病毒粒子相比，许多被认为对病毒形态发生非必需的病毒被膜蛋白在巴氏病毒粒子中的含量明显较低。有趣的是，许多在巴氏病毒粒子中含量较低的蛋白质参与了α疱疹病毒的免疫逃逸策略。此外，我们观察到巴氏病毒粒子的尺寸减小，更接近二十面体形态。鉴于巴氏疫苗株能引起强烈的免疫反应，我们的发现表明，蛋白包装的差异可能有助于其免疫原性。进一步探索这些观察结果可能有助于开发针对其他α疱疹病毒疫苗（如 HSV-1/2 或 EHV-1）的有效疫苗。
