Generation of an industrially ideal host cell line for producing completely-defucosylated antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC)

Abstract

To generate industrially applicable new host cell lines for antibody production with optimizing antibody-dependent cellular cytotoxicity (ADCC) we focused on the most important carbohydraie structure ``facose residues attached to the innermost G1cNAc residue of N-linked oligosaccharides via alpha-1,6 linkage{''} (Shields, 2002; Shinkawa, 2003), and succeeded in disrupting both FUT8 (a- 1,6-fucosyltransferase gene) alleles in Chinese hamster ovary (CHO) cell line by sequential homologous recombination. FUT8-1- cell lines have morphology and growth kinetics similar to those of the parent. Antibodies produced by the engineered CHO cell lines strongly bound to human Fey receptor IIIa (Fc gamma RIIIa) and showed approximately two orders of magnitude higher ADCC than anti-CD20 antibodies (Rituxan (TM)) produced by parental cell lines without changing antigen-binding and complement-dependent cytotoxicity (CDC). Moreover, the engineered cell line remains stable, producing completely-defucosylated antibody with fixed quality and efficacy even in serum-free fed-batch culture. Thus, our approaches provide a new strategy for controlling the glycosylation profile of therapeutic recombinant proteins and could be a considerable advantage for the manufacture of glycoprotein therapeutics, especially antibodies.