Enhanced Production of Anti-PD1 Antibody in CHO Cells through Transient Co-Transfection with Anti-Apoptotic Gene Bcl-x(L) Combined with Rapamycin

CHO cells are often used to produce monoclonal antibodies in mammalian cell expression systems. In the process of large-scale cell culture, apoptosis is related to cell survival and product quality. Over-expressing an anti-apoptotic gene to delay apoptosis and improve cell growth is one of the strategies for improving productivity of monoclonal antibodies. Autophagy inducer rapamycin can extend the culture duration of CHO cells and affect the yield of antibodies. A method was developed for transient co-transfection of anti-apoptotic genes and genes of interest combined with rapamycin to increase the transient expression of the anti-PD1 antibody. Under the optimal transfection conditions, the combination of Bcl-x(L) and rapamycin can significantly delay cell apoptosis, inhibit cell proliferation, and prolong cell life-time. As a result, anti-PD1 monoclonal antibody expression levels are increased by more than 2 times.