Abstract：
While purifying a regular monospecific antibody, we found that the Protein A step yield was much lower than expected. Further studies revealed that the antibody formed large-size aggregates that did not bind to the Protein A resin, hence leading to dropped recovery. In an attempt to solve this low yield issue, we found that mildly acidic pH or ammonium sulfate treatment can partially convert the aggregates into monomers. In addition, when acidic pH treated culture harvest was processed by Protein A chromatography, the yield was restored to the normal range, suggesting that the monomers recovered from aggregates regained Protein A binding capability. Thus, low pH treatment of culture harvest can be potentially used as a general approach for improving Protein A step yield in cases where non-binding antibody aggregates are formed through noncovalent interactions.
摘要：
在纯化常规单特异性抗体时，我们发现蛋白A步骤的产率远低于预期。进一步的研究表明，抗体形成了不与蛋白A树脂结合的大尺寸聚集体，从而导致复苏下降。为了解决这个低产量问题，我们发现，温和酸性pH或硫酸铵处理可以部分地将聚集体转化为单体。此外,当酸性pH处理的培养收获物通过蛋白A色谱处理时，产量恢复到正常范围，表明从聚集体中回收的单体恢复了蛋白A结合能力。因此，在通过非共价相互作用形成非结合抗体聚集体的情况下,培养收获物的低pH处理可以潜在地用作提高蛋白A步骤产量的一般方法。
