title: Intravital imaging reveals improved Kupffer cell-mediated phagocytosis as a mode of action of glycoengineered anti-CD20 antibodies.
abstract: Anti-CD20 monoclonal antibodies (mAbs) represent an effective treatment for a number of B cell malignancies and autoimmune disorders. Glycoengineering of anti-CD20mAb may contribute to increased anti-tumor efficacy through enhanced antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADP) as reported by in vitro studies. However, where and how glycoengineered Ab may potentiate therapeutic responses in vivo is yet to be elucidated. Here, we have performed mouse liver transplants to demonstrate that the liver is sufficient to mediate systemic B cells depletion after anti-CD20 treatment. Relying on intravital two-photon imaging of human CD20-expressing mice, we provide evidence that ADP by Kupffer cells (KC) is a major mechanism for rituximab-mediated B cell depletion. Notably, a glycoengineered anti-mouse CD20 Ab but not its wild-type counterpart triggered potent KC-mediated B cell depletion at low doses. Finally, distinct thresholds for KC phagocytosis were also observed for GA101 (obinutuzumab), a humanized glycoengineered type II anti-CD20 Ab and rituximab. Thus, we propose that enhanced phagocytosis of circulating B cells by KC represents an important in vivo mechanism underlying the improved activity of glycoengineered anti-CD20 mAbs.
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: Capucine L
authors.initials: CL
authors.lastname: Grandjean
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: Fabricio
authors.initials: F
authors.lastname: Montalvao
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: Susanna
authors.initials: S
authors.lastname: Celli
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: David
authors.initials: D
authors.lastname: Michonneau
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Breart
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: Zacarias
authors.initials: Z
authors.lastname: Garcia
authors.affiliation: Roche Innovation Center Zurich, Roche Pharma Research &Early Development, Wagistrasse 18,8952 Schlieren, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Perro
authors.affiliation: Roche Innovation Center Zurich, Roche Pharma Research &Early Development, Wagistrasse 18,8952 Schlieren, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Freytag
authors.affiliation: Roche Innovation Center Zurich, Roche Pharma Research &Early Development, Wagistrasse 18,8952 Schlieren, Switzerland.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Gerdes
authors.affiliation: Dynamics of Immune Responses Unit, Equipe Labéllisée Ligue Contre le Cancer, Institut Pasteur, 75015 Paris, France.|INSERM U1223, 75015 Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bousso
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology; D018951:Antigens, CD20 / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology; D000069416:Intravital Microscopy; D007728:Kupffer Cells / Q000276:immunology / Q000473:pathology; D008099:Liver / Q000000981:diagnostic imaging / Q000276:immunology; D016031:Liver Transplantation; D008212:Lymphocyte Depletion / Q000379:methods; D051379:Mice; D018345:Mice, Knockout; D010587:Phagocytosis / Q000187:drug effects*; D015202:Protein Engineering; D000069283:Rituximab / Q000494:pharmacology*
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D018951:Antigens, CD20; D000069283:Rituximab; C543332:obinutuzumab