Producing defucosylated antibodies with enhanced in vitro antibody-dependent cellular cytotoxicity via FUT8 knockout CHO-S cells

To engineer a host cell line that produces defucosylated mAbs with superior antibody dependent cellular cytotoxicity, we disrupted alpha-1,6 fucosyltransferase (FUT8) gene in CHO-S (CHO is Chinese hamster ovary) cells by clustered regularly interspaced short palindromic repeats-CRISPR associated nuclease 9. The gene knockout cell line was evaluated for growth, stability, and product quality. The growth profile of FUT8 gene knockout CHO-S (FUT8(-/-)) cells was comparable with wild type CHO-S cells. FUT8 catalyzes the transfer of a fucose residue from GDP-fucose to N-glycans residue. Defucosylated IgG1 antibodies produced by FUT8(-/-) cells showed increased binding affinities to human Fc gamma RIIIa and higher activities in mediating antibody-dependent cellular cytotoxicity, comparing with conventional fucosylated IgG1. Our results demonstrated the potential of using the clustered regularly interspaced short palindromic repeats-CRISPR associated nuclease 9 technology in cell line engineering for biopharmaceutical industrial applications.