Recombinant monoclonal antibodies (mAbs) manufactured from immortalized mammalian cell lines are becoming increasingly important as therapies. Ensuring the quality of expressed proteins is critical when developing manufacturing processes. Protein sequence variants (PSVs) are a type of product-related variant in which errors in the protein sequence are present. Detecting PSVs and determining their origins, either by DNA mutation or mRNA mistranslation, is critical. Mutations cannot be remediated without developing new clones, which can be costly and time-consuming. In contrast, mistranslation can usually be mitigated by optimizing cell culture conditions. In this work, we first developed a new method to detect low-abundance PSVs with improved sensitivity. Then, a statistical metric was proposed to determine whether the observed PSVs originate from mutation or mistranslation by characterizing the distribution of PSVs. This method was applied to the evaluation of 50 clones from five mAbs programs, allowing for identification of five mutation and 139 mistranslation PSVs. The presence of even a few mutations demonstrates the necessity of clone screening during process development.

中文翻译：

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密码子指导的治疗性蛋白质序列变异生物学原因的确定

从永生的哺乳动物细胞系生产的重组单克隆抗体（mAb）作为治疗方法变得越来越重要。开发生产工艺时，确保表达蛋白质的质量至关重要。蛋白质序列变异体（PSV）是一种与产品相关的变异体，其中存在蛋白质序列错误。通过DNA突变或mRNA错误翻译来检测PSV并确定其起源至关重要。如果不开发新克隆，就无法修复突变，这可能既昂贵又耗时。相反，通常可以通过优化细胞培养条件来缓解翻译错误。在这项工作中，我们首先开发了一种新方法，可以以更高的灵敏度检测低丰度PSV。然后，提出了一种统计量度，以通过表征PSV的分布来确定观察到的PSV是源自突变还是错误翻译。该方法用于评估来自五个mAb程序的50个克隆，从而鉴定出五个突变和139个错译PSV。甚至几个突变的存在证明了在工艺开发过程中进行克隆筛选的必要性。