Enhancers Improve the AID-Induced Hypermutation in Episomal Vector for Antibody Affinity Maturation in Mammalian Cell Display
Chuan Chen,
Jie Wang,
Yun Zhao,
Shaopeng Chen,
Zhishang Hu,
Long Chen,
Haiying Hang
Affiliations
Chuan Chen
Key Laboratory for Protein and Peptide Pharmaceuticals, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
Jie Wang
Key Laboratory for Protein and Peptide Pharmaceuticals, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
Yun Zhao
Key Laboratory for Protein and Peptide Pharmaceuticals, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
Shaopeng Chen
Hefei Institutes of Physical Science, Chinese Academy of Sciences, Institute of Technical Biology and Agriculture Engineering, 350 Shushanhu Road, Hefei 230031, Anhui, China
Zhishang Hu
National Institute of Metrology, No.18, Bei San Huan Dong Lu, Chaoyang Dist, Beijing 100101, China
Long Chen
Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
Haiying Hang
Key Laboratory for Protein and Peptide Pharmaceuticals, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
The induction of somatic hypermutation (SHM) in various cell lines by activation-induced cytidine deaminase (AID) has been used in protein-directed selection, especially in antibody affinity maturation. Several antibody affinity maturation systems based on mammalian cells have been developed in recent years, i.e., 293T, H1299, Raji and CHO cells. However, the efficiency of in vitro AID-induced hypermutation is low, restricting the application of such systems. In this study, we examined the role of Ig and Ek enhancers in enhancing SHM in the episomal vector pCEP4 that expresses an anti-high mobility group box 1 (HMGB1) full-length antibody. The plasmid containing the two enhancers exhibited two-fold improvement of mutation rate over pCEP4 in an AID expression H1299 cell line (H1299-AID). With the engineered episomal vector, we improved the affinity of this antibody in H1299-AID cells by 20-fold.
