title: Anti-CD20 Antibody with Multimerized Fc Domains: A Novel Strategy To Deplete B Cells and Augment Treatment of Autoimmune Disease.
abstract: We developed a fully recombinant anti-CD20 protein derived from cDNA encoding one Fab domain, two IgG1 Fc regions, the IgG2 hinge, and an isoleucine zipper. This protein, called GB4542, contained both the homodimer and higher-order multimers. Binding studies revealed that GB4542 preferentially bound CD20(+) cells yet also recognized CD20(-)FcγR(+) PBMC. In contrast, a control mAb containing the identical Fab region, GB4500, failed to bind CD20(-)FcγR(+) PBMC. Consistent with these findings, interactions between GB4542 and the canonical FcγRs had substantially lower KD values than correlate interfaces between GB4500 and these receptors. At low concentrations, GB4542 showed enhanced Ab-dependent cellular cytotoxicity, Ab-dependent cellular phagocytosis, and complement-dependent cytotoxicity compared with GB4500. However, at higher concentrations, an Fc analog of GB4542 inhibited anti-CD20 mAb-mediated B cell clearance through direct blocking of both Fc-FcγR interactions and C1q deposition on target cells. Furthermore, the higher-order multimer fraction of GB4542 demonstrated greater binding avidity with the canonical FcγRs and was associated with inhibitory effects observed in Ab-dependent cellular phagocytosis and complement-dependent cytotoxicity assays. These data suggest that GB4542 might have utility in the treatment of autoimmune diseases by combining both mAb-mediated B cell depletion and multimerized Fc-mediated tolerogenic effects.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201;
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Gliknik Inc., Baltimore MD, 21201; and.
authors.forename: Henrik S
authors.initials: HS
authors.lastname: Olsen
authors.affiliation: Medical College of Xiamen University, Xiamen 361005, China.
authors.forename: Shaodong
authors.identifier: http://orcid.org/0000-0003-4727-5135
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201;
authors.forename: Edward
authors.initials: E
authors.lastname: So
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201;
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201;
authors.forename: Erin
authors.initials: E
authors.lastname: Burch
authors.affiliation: Gliknik Inc., Baltimore MD, 21201; and.
authors.forename: Emmanuel Y
authors.initials: EY
authors.lastname: Mérigeon
authors.affiliation: Gliknik Inc., Baltimore MD, 21201; and.
authors.forename: David S
authors.initials: DS
authors.lastname: Block
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201; sstrome@smail.umaryland.edu.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Strome
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D000915:Antibody Affinity; D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects / Q000276:immunology; D018951:Antigens, CD20 / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D017452:Receptors, IgG / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D020349:Surface Plasmon Resonance
chemical_list: D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D007141:Immunoglobulin Fc Fragments; D017452:Receptors, IgG; D011994:Recombinant Proteins