Enhanced sialylation of a human chimeric IgG1 variant produced in human and rodent cell lines

Yusuke Mimura, Ronan M. Kelly, Louise Unwin, Simone Albrecht, Royston Jefferis, Margaret Goodall, Yoichi Mizukami, Yuka Mimura-kimura, Tsuneo Matsumoto, Hiroshi Ueoka, Pauline M. Rudd

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28 Citations (Scopus)
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Abstract

Glycosylation of the IgG-Fc is essential for optimal binding and activation of Fcγ receptors and the C1q component of complement. However, it has been reported that the effector functions are down-regulated when the Fc glycans terminate in sialic acid residues and that sialylated IgG mediates anti-inflammatory effects of intravenous immunoglobulin (IVIG). Although recombinant IgG is hypo-sialylated, Fc sialylation is shown to be markedly increased when a mouse/human chimeric IgG3 Phe243Ala (F243A) variant is expressed in Chinese hamster ovary (CHO)-K1 cells. Here we investigate whether sialylation is increased in IgG1 F243A when expressed in CHO-K1, mouse myeloma J558L and human embryonic kidney (HEK) 293. Although the sialylation level was 2–5% for IgG1 wild type (WT), it was increased to 31%, 10% and 33% for the variant from CHO-K1, J558L and HEK293 cells, respectively. Interestingly, an increased addition of bisecting GlcNAc and α(1-3)-galactose residues to the Fc glycan was observed for HEK293-derived and J558L-derived IgG1 F243A, respectively. Fucosylation of HEK293-derived IgG1 F243A was maintained despite increased bisecting GlcNAc content. Although sialic acid and bisecting GlcNAc residues are reported to have an opposing effect on antibody-dependent cellular cytotoxicity (ADCC), IgG1 F243A showed 7 times lower ADCC activities than IgG1 WT, irrespective of bisecting GlcNAc residue. Thus, highly sialylated, human cell-derived IgG1 F243A with lowered ADCC activity may be of interest for the development of therapeutic antibodies with anti-inflammatory properties as an alternative to IVIG.
Original languageEnglish
Pages (from-to)30-36
JournalJournal of Immunological Methods
Volume428
Early online date26 Nov 2015
DOIs
Publication statusPublished - Jan 2016

Keywords

  • Glycosylation
  • IgG
  • Intravenous immunoglobulin
  • Sialic acid
  • Therapeutic antibody

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