Engineering diversity of sugar structures on antibodies for enhanced efficacy

    Sci Rep 2021 - 11(1) 12969 - Grp Photo v2
    BTI researchers involved in the study: From Left: Dr. Yang Yuan Sheng, Dr. Nguyen Tran Bich Ngan, Ms. Mariati and Ms. Jessna Yeo.
    Dr. Yang conceived, designed the project. Dr. Nguyen designed and performed experiments. Ms. Mariati and Ms. Yeo contributed to the generation of expression platform.



    Therapeutic antibodies often carry complex sugar chains (N-glycans) consisting of many different components. The structure of these sugar chains can greatly influence the biological activity, function, and clearance from blood circulation of antibody drugs. However, current ways to produce antibodies result in limited or simplified N-glycan structures due to inefficiencies in navigating and modulating the complexity of sugar chains and their biosynthesis pathway. To overcome such issues, we developed a novel expression platform in Chinese Hamster Ovary (CHO) cells that could produce antibodies with a diverse range of N-glycan structures.


    Technical Summary

    We utilized recombinase-mediated-cassette-exchange (RMCE) technology to overexpress a panel of 42 human glycosylation genes in CHO cells to study their influence on antibody N-glycan structures. These genes regulate many core steps in the N-glycan biosynthesis pathway from synthesizing precursors, processing glycan branching, galactosylation to terminal sialylation. The critical genes that significantly influenced the IgG N-glycan outcomes were identified and further overexpressed in various combinations to produce an array of different N-glycan structures. As a result, we could produce antibodies with more than 80% galactosylation by overexpressing B4GalT1 gene alone in the CHO cells. Combinatorial overexpression of B4GalT1 and ST6Gal1 produced antibodies carrying more than 70% sialylated bi-antennary N-glycans. For the first time, antibodies with various tri-antennary N-glycans were obtained by overexpressing MGAT5 alone or in combination with B4GalT1 and ST6Gal1.


    Societal Impact

    Regulatory bodies consider N-glycosylation a critical quality attribute for antibody and antibody-like therapeutics because it influences the efficacy and safety of antibody drugs. Depending on the therapeutic application, certain N-glycan profiles are more desirable. The ability to engineer a diverse range of N-glycan structures on antibodies will fine-tune the development of antibody drugs for different therapeutic purposes.


    Sci Rep 2021 - 11(1) 12969 - Fig 1
    Figure 1. Targeted Integration technology developed in this work that enables production of antibodies with various N-glycan structures



    Nguyen NTB, Lin J, Tay SJ, Mariati, Yeo J, Nguyen-Khuong T, Yang Y. Multiplexed engineering glycosyltransferase genes in CHO cells via targeted integration for producing antibodies with diverse complex-type N-glycans. Sci Rep. 2021;11(1):12969. doi: 10.1038/s41598-021-92320-x.