A robust monoclonal antibody (mAb) bioprocess requires physiological
parameters such as temperature, pH, or dissolved oxygen (DO) to be
well-controlled as even small variations in them could potentially
impact the final product quality. For instance, pH substantially affects
N-glycosylation, protein aggregation and charge variant profiles, as
well as mAb productivity. However, relatively less is known about how pH
jointly influences product quality and titer. In this study, we
investigated the effect of pH on culture performance, product titer and
quality profiles by applying longitudinal multi-omics profiling,
including transcriptomics, proteomics, metabolomics and glycomics, at
three different culture pH set points. The subsequent systematic
analysis of multi-omics data showed that pH set points differentially
regulated various intracellular pathways including intracellular
vesicular trafficking, cell cycle, and apoptosis, thereby resulting in
differences in specific productivity, product titer and quality
profiles. In addition, a time-dependent variation in mAb N-glycosylation
profiles, independent of pH was identified to be mainly due to the
accumulation of mAb proteins in the endoplasmic reticulum (ER) over
culture time, disrupting cellular homeostasis. Overall, this
multi-omics-based study provides an in-depth understanding of the
intracellular processes in mAb-producing CHO cell line under varied pH
conditions and could serve as a baseline for enabling the quality
optimization and control of mAb production.
STEP® vectors for rapid generation of stable transfected CHO cell pools and clones with high expression levels and product quality homogeneity of difficult-to-express proteins