Efficient production of recombinant mAbs mediated by a MAR-enhanced transposon vector combined with blasticidin selection in CHO cells

Recombinant antibodies, primarily produced in Chinese hamster ovary (CHO) cells, are widely used to treat various diseases. For industrial production, a rapid and efficient method to screen stable, high-expressing clones is essential. However, conventional screening based on random integration is often cumbersome and labor intensive. This study establishes a novel strategy for generating stable, high-yielding clones by combining a MAR-based piggyBac (PB) transposon semitargeted integration system with blasticidin (BSD) selection. Compared to the random integrated vector pMAR-mAb, the MAR-PB system increases the titers (3.95- to 5.61-fold) and specific protein productivity (Qp; 4.28- to 6.07-fold) of four monoclonal antibodies in stable cell pools. When compared to PB-only vectors, the MAR-PB transposon system enhances the titers (by up to 2.50-fold) and Qp (1.96- to 2.77-fold), respectively. The increased antibody production correlates with elevated mRNA expression. Furthermore, this approach increases the proportion of high-expressing clones by more than 10-fold and significantly improves volumetric yield. Importantly, this approach promotes the long-term stability of recombinant mAb expression for over 60 generations. Transcriptome analysis reveals that the system modulates genes involved in DNA binding, transcriptional regulation, and protein binding. In conclusion, the MAR-based PB transposon system combined with BSD selection presents a significant improvement for efficiently generating high-yielding and stable CHO cell clones, offering a valuable tool for recombinant antibody production.