In recent years, assurance of clonality of the production cell line has been emphasized by health authorities during review of regulatory submissions. When insufficient assurance of clonality is provided, augmented control strategies may be required for a commercial production process. In this study, we conducted a retrospective assessment of clonality of a legacy cell line through analysis of subclones from the master cell bank (MCB). Twenty-four subclones were randomly selected based on a predetermined acceptance sampling plan. All these subclones share a conserved integration junction, thus providing a high level of assurance that the cell population in the MCB was derived from a single progenitor cell. However, Southern blot analysis indicates that at least four subpopulations possibly exist in the MCB. Additional characterization of these four subpopulations demonstrated that the resulting changes in product quality attributes of some subclones are not related to the genetic heterogeneity observed in Southern blot hybridization. Furthermore, process consistency, process comparability, and analytical comparability have been demonstrated in batches produced across varying manufacturing processes, scales, facilities, cell banks, and cell ages. Finally, process and product consistency together with a high level of assurance of clonal origin of the MCB helped clear the hurdle for regulatory approval without requirement of additional control strategies.

中文翻译：

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通过主细胞库的分析亚克隆对遗留细胞系的克隆性进行回顾性评估

近年来，卫生当局在审查监管提交时强调了生产细胞系的克隆性保证。当提供的克隆性保证不足时，商业生产过程可能需要增强控制策略。在这项研究中，我们通过分析来自主细胞库 (MCB) 的亚克隆，对传统细胞系的克隆性进行了回顾性评估。根据预先确定的验收抽样计划随机选择了 24 个亚克隆。所有这些亚克隆共享一个保守的整合连接，因此提供了高水平的保证，即 MCB 中的细胞群来自单个祖细胞。然而，Southern 印迹分析表明，MCB 中可能存在至少四个亚群。这四个亚群的其他特征表明，一些亚克隆的产品质量属性的变化与Southern印迹杂交中观察到的遗传异质性无关。此外，工艺一致性、工艺可比性和分析可比性已在不同制造工艺、规模、设施、细胞库和细胞年龄的批次中得到证明。最后，工艺和产品的一致性以及对 MCB 克隆来源的高度保证有助于清除监管批准的障碍，而无需额外的控制策略。工艺一致性、工艺可比性和分析可比性已在不同制造工艺、规模、设施、细胞库和细胞年龄的批次中得到证明。最后，工艺和产品的一致性以及对 MCB 克隆来源的高度保证有助于清除监管批准的障碍，而无需额外的控制策略。工艺一致性、工艺可比性和分析可比性已在不同制造工艺、规模、设施、细胞库和细胞年龄的批次中得到证明。最后，工艺和产品的一致性以及对 MCB 克隆来源的高度保证有助于清除监管批准的障碍，而无需额外的控制策略。