Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA.
Health Research Institute, Michigan Technological University, Houghton, Michigan, USA.
Biotechnol J. 2022 Feb;17(2):e2100320. doi: 10.1002/biot.202100320. Epub 2021 Dec 23.
Virus inactivation is a critical operation in therapeutic protein manufacturing. Low pH buffers are a widely used strategy to ensure robust enveloped virus clearance. However, the choice of model virus can give varying results in viral clearance studies. Pseudorabies virus (SuHV) or herpes simplex virus-1 (HSV-1) are frequently chosen as model viruses to demonstrate the inactivation for the herpes family.
In this study, SuHV, HSV-1, and equine arteritis virus (EAV) were used to compare the inactivation susceptibility at pH 4.0 and 4°C. SuHV and HSV-1 are from the same family, and EAV was chosen as a small, enveloped virus. Glycine, acetate, and citrate buffers at pH 4.0 and varying buffer strengths were studied. The inactivation susceptibility was found to be in the order of SuHV > HSV > EAV. The buffer effectiveness was found to be in the order of citrate > acetate > glycine. The smaller virus, EAV, remained stable and infectious in all the buffer types and compositions studied.
The variation in inactivation susceptibility of herpes viruses indicated that SuHV and HSV cannot be interchangeably used as a virus model for inactivation studies. Smaller viruses might remain adventitiously infective at moderately low pH.
病毒失活是治疗性蛋白生产中的关键操作。低 pH 缓冲液是确保有效清除包膜病毒的常用策略。然而，模型病毒的选择可能会导致病毒清除研究结果存在差异。猪疱疹病毒（SuHV）或单纯疱疹病毒-1（HSV-1）常被选为疱疹病毒家族的模型病毒，以证明其失活效果。
在这项研究中，我们使用 SuHV、HSV-1 和马动脉炎病毒（EAV）在 pH 4.0 和 4°C 下比较失活敏感性。SuHV 和 HSV-1 同属一个家族，而 EAV 则被选为一种小型包膜病毒。我们研究了 pH 4.0 下不同缓冲强度的甘氨酸、乙酸盐和柠檬酸盐缓冲液。结果发现，病毒失活敏感性的顺序为 SuHV > HSV > EAV。缓冲液的有效性的顺序为柠檬酸盐 > 乙酸盐 > 甘氨酸。在所有研究的缓冲液类型和组成中，较小的病毒 EAV 保持稳定且具有感染力。
疱疹病毒失活敏感性的差异表明，SuHV 和 HSV 不能互换用作失活研究的病毒模型。较小的病毒在中等低 pH 值下可能仍然会偶然感染。
