Post-load column wash in Protein A chromatography can effectively improve host cell protein (HCP) clearance. A commonly used wash additive for this purpose is sodium chloride. However, the adequate amount of sodium chloride required for effective HCP clearance is less consistent in literature. In this study we investigated the impact of different amounts of sodium chloride on HCP clearance with five monoclonal antibodies (mAbs). For each mAb, elution pool HCP levels from runs under different wash conditions are compared. For all five mAbs, the data suggested that 250 mM would be an adequate amount for the salt to largely achieve its HCP reducing effect. The same conclusion is also reached for calcium chloride, a less commonly used but equally effective Protein A wash additive for HCP clearance.

中文翻译：

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蛋白质A洗涤缓冲液中有足够量的氯化钠可有效清除宿主细胞中的蛋白质。

蛋白质A层析中的上样柱清洗可以有效提高宿主细胞蛋白质（HCP）的清除率。为此目的常用的洗涤添加剂是氯化钠。但是，有效清除HCP所需的足够量的氯化钠在文献中并不一致。在这项研究中，我们研究了五种单克隆抗体（mAb）对氯化钠清除量不同的氯化钠的影响。对于每种单克隆抗体，比较了在不同洗涤条件下运行的洗脱池HCP水平。对于所有五个mAb，数据表明250 mM足以使盐在很大程度上实现其降低HCP的作用。对于氯化钙来说，也得出了相同的结论，氯化钙是一种不常用但对HCP清除有效的蛋白A洗涤添加剂。