Producing defucosylated antibodies with enhanced in vitro antibody‐dependent cellular cytotoxicity via <i>FUT8</i> knockout CHO‐S cells

Abstract

To engineer a host cell line that produces defucosylated mAbs with superior antibody-dependent cellular cytotoxicity, we disrupted α-1, 6 fucosyltransferase (<i>FUT8</i>) 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 <i>FUT8</i> gene knockout CHO-S (<i>FUT8</i> ^-/-) cells was comparable with wild type CHO-S cells. <i>FUT8</i> catalyzes the transfer of a fucose residue from GDP-fucose to <i>N</i>-glycans residue. Defucosylated IgG1 antibodies produced by <i>FUT8</i> ^-/- 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.