title: Increased in vivo effector function of human IgG4 isotype antibodies through afucosylation.
abstract: For some antibodies intended for use as human therapeutics, reduced effector function is desired to avoid toxicities that might be associated with depletion of target cells. Since effector function(s), including antibody-dependent cell-mediated cytotoxicity (ADCC), require the Fc portion to be glycosylated, reduced ADCC activity antibodies can be obtained through aglycosylation of the human IgG1 isotype. An alternative is to switch to an IgG4 isotype in which the glycosylated antibody is known to have reduced effector function relative to glycosylated IgG1 antibody. ADCC activity of glycosylated IgG1 antibodies is sensitive to the fucosylation status of the Fc glycan, with both in vitro and in vivo ADCC activity increased upon fucose removal ("afucosylation"). The effect of afucosylation on activity of IgG4 antibodies is less well characterized, but it has been shown to increase the in vitro ADCC activity of an anti-CD20 antibody. Here, we show that both in vitro and in vivo activity of anti-CD20 IgG4 isotype antibodies is increased via afucosylation. Using blends of material made in Chinese hamster ovary (CHO) and Fut8KO-CHO cells, we show that ADCC activity of an IgG4 version of an anti-human CD20 antibody is directly proportional to the fucose content. In mice transgenic for human FcγRIIIa, afucosylation of an IgG4 anti-mouse CD20 antibody increases the B cell depletion activity to a level approaching that of the mIgG2a antibody.
authors.affiliation: a Department of Immunology , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Gong
authors.affiliation: b Department of Antibody Engineering , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Meredith
authors.initials: M
authors.lastname: Hazen
authors.affiliation: c Department of Biological Technologies , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Brett
authors.initials: B
authors.lastname: Marshall
authors.affiliation: d Department of Preclinical and Translational Pharmacokinetics , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Susan R
authors.initials: SR
authors.lastname: Crowell
authors.affiliation: a Department of Immunology , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Ou
authors.affiliation: e Department of Early Stage Cell Culture , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Athena W
authors.initials: AW
authors.lastname: Wong
authors.affiliation: f Department of Protein Chemistry , Genentech Inc. , South San Francisco CA , USA.
authors.forename: Wilson
authors.initials: W
authors.lastname: Phung
authors.affiliation: g Department of Biochemical and Cellular Pharmacology , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Vernes
authors.affiliation: g Department of Biochemical and Cellular Pharmacology , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Y Gloria
authors.initials: YG
authors.lastname: Meng
authors.affiliation: c Department of Biological Technologies , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Max
authors.initials: M
authors.lastname: Tejada
authors.affiliation: h Department of Pharmaceutical Development , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Dana
authors.initials: D
authors.lastname: Andersen
authors.affiliation: i Department of Drug Delivery , Genentech Inc. , South San Francisco , CA , USA.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Kelley
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000920:Antibody-Dependent Cell Cytotoxicity; D018951:Antigens, CD20 / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D001769:Blood / Q000276:immunology; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005643:Fucose / Q000737:chemistry*; D006031:Glycosylation; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013154:Spleen / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D007074:Immunoglobulin G; D005643:Fucose
keywords: ADCC; B cell depletion; CD20; IgG subclass