Fluidized bed centrifugation of precipitated and flocculated cell cultures: An intensified clarification approach for monoclonal antibodies

Abstract

Precipitation and flocculation pretreatments promise improved clarification of cell culture fluids (CCF) to intensify the production of monoclonal antibodies (mAb). However, such pretreatments pose the risks to alter the mAb and damage cells. This can be additionally exacerbated by the subsequent clarification process, for example by high shear forces during disk stack centrifugation, resulting in a release of host cell impurities. To overcome these limitations and enhance the clarification particularly of cell cultures with low viability and thus a high level of impurities, this study investigated low-pH precipitation and cationic polymer flocculation, each in combination with a mild fluidized bed centrifuge (FBC) separation and a subsequent filtration step. Therefore, low-viable CCF´s were pretreated and characterized to investigate the effects of additives on CCF composition and stability. In clarification experiments, both pretreatments achieved similar FBC throughput compared to an untreated reference but increased the maximum filter throughput up to four times. Furthermore, high mAb recoveries (> 91%), low turbidities (< 3.1 NTU) and high DNA removals (> 91%) were achieved. Similar glycan profiles and dimer ratios suggest consistent mAb quality. These findings have a great potential to intensify mAb downstream processing with both CCF pretreatments using a FBC clarification approach.

Keywords: Clarification; Downstream; Flocculation; Fluidized bed centrifuge; Monoclonal antibody; Precipitation.