title: Enhanced sialylation of a human chimeric IgG1 variant produced in human and rodent cell lines.
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.
authors.affiliation: Department of Clinical Research, NHO Yamaguchi-Ube Medical Center, 685 Higashi-Kiwa, Ube 755-0241, Japan; NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin 4, Ireland. Electronic address: mimuray@yamaguchi-hosp.jp.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Mimura
authors.affiliation: NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin 4, Ireland; Eli Lilly and Company, Indianapolis, USA.
authors.forename: Ronan M
authors.initials: RM
authors.lastname: Kelly
authors.affiliation: NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin 4, Ireland.
authors.forename: Louise
authors.initials: L
authors.lastname: Unwin
authors.affiliation: NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin 4, Ireland.
authors.forename: Simone
authors.initials: S
authors.lastname: Albrecht
authors.affiliation: School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Roy
authors.initials: R
authors.lastname: Jefferis
authors.affiliation: School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Margaret
authors.initials: M
authors.lastname: Goodall
authors.affiliation: Center for Gene Research, Yamaguchi University, 1-1-1 Minami-Kogushi, Ube 755-8505, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Mizukami
authors.affiliation: Department of Clinical Research, NHO Yamaguchi-Ube Medical Center, 685 Higashi-Kiwa, Ube 755-0241, Japan; NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin 4, Ireland.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Mimura-Kimura
authors.affiliation: Department of Clinical Research, NHO Yamaguchi-Ube Medical Center, 685 Higashi-Kiwa, Ube 755-0241, Japan.
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Department of Clinical Research, NHO Yamaguchi-Ube Medical Center, 685 Higashi-Kiwa, Ube 755-0241, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueoka
authors.affiliation: NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin 4, Ireland.
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Rudd
mesh_terms: D000818:Animals; D016466:CHO Cells; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D003412:Cricetulus; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D019158:N-Acetylneuraminic Acid / Q000032:analysis / Q000378:metabolism*
chemical_list: D007074:Immunoglobulin G; D019158:N-Acetylneuraminic Acid
keywords: Glycosylation; IgG; Intravenous immunoglobulin; Sialic acid; Therapeutic antibody