Isolation and purification of a monoclonal antibody from a cell culture supernatant by multistage precipitation and solid-liquid extraction

A process of multistage pH mediated precipitation was developed for capture and purification of a monoclonal antibody (mAb) from a Chinese hamster ovary cell culture (CHO) harvest. The mAb was separated from low molecular mass impurities (LMWI) and high molecular weight impurities (HMWI) by a sequence of two precipitation steps or by a sequence of precipitation and solid-liquid extraction (SLE). In the former approach, HMWI were precipitated from the harvest at pH 5 in the presence of polyethylene glycol (PEG), whereas the obtained supernatant was subsequently subjected to precipitation at pH 8 to obtain the mAb of 96 % chromatographic purity in a precipitate form. In the latter approach, the mAb was precipitated from the harvest at pH 8 in the presence of PEG to isolate the mAb from LMWI, then the precipitate obtained was subjected to SLE to extract the mAb of 99 % purity in a form of liquid solution. The coupling of precipitation at pH 8 and SLE allowed effective removal of DNA from 9260 ng/mL in the feed to 1.4 ng/mL in the product of two-stage SLE, and host cell proteins (HCP) from 300 µg/mL to 0.07 µg/mL, which was not possible by the coupling of two precipitation stages at pH 5 and 8. Therefore, the combination of precipitation and SLE can be a promising technique for capture of mAbs from CHO cell harvests.