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Expression of GnTIII in a recombinant anti‐CD20 CHO production cell line: Expression of antibodies with altered glycoforms leads to an increase in ADCC through higher affinity for FCγRIII
Author(s) -
Davies Julian,
Jiang LiYing,
Pan LiZhen,
LaBarre Michael J.,
Anderson Darrell,
Reff Mitchell
Publication year - 2001
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.1119
Subject(s) - chinese hamster ovary cell , antibody dependent cell mediated cytotoxicity , antibody , microbiology and biotechnology , cell culture , recombinant dna , glycosylation , biology , receptor , affinity chromatography , biochemistry , chemistry , enzyme , monoclonal antibody , gene , immunology , genetics
The gene encoding the rat glycosylation enzyme β1–4‐ N ‐acetylglucosaminyltransferase III (GnTIII) was cloned and coexpressed in a recombinant production Chinese hamster ovary (CHO) cell line expressing a chimeric mouse/human anti‐CD20 IgG1 antibody. The new cell lines expressed high levels of antibody and have growth kinetics similar to that of the parent. Relative QPCR showed the cell lines to express varying levels of mRNA. High‐performance liquid chromatography (HPLC) analysis showed the enzyme to have added bisecting N ‐acetylglucosamine (GlcNAc) residues in most (48% to 71%) of the N‐linked oligosaccharides isolated from antibody preparations purified from the cell lines. In an ADCC assay the new antibody preparations promoted killing of CD20‐positive target cells at approximately 10‐ to 20‐fold lower concentrations than the parent. This activity was blocked using an anti‐FcγRIII antibody, supporting the role of FcγRIII binding in this increase. In addition, cell binding assays showed the modified antibody bound better to FcγRIII‐expressing cells. The increase in ADCC activity is therefore likely due to an increased affinity of the modified antibody for the FcγRIII receptor. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 288–294, 2001.