LAUSR

To engineer a host cell line that produces defucosylated mAbs with superior antibody‐dependent cellular cytotoxicity, we disrupted α‐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 FcγRIIIa 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.