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Kremer PG, Lampros EA, Blocker AM, Barb AW. One N-glycan regulates natural killer cell antibody-dependent cell-mediated cytotoxicity and modulates Fc γ receptor IIIa / CD16a structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.17.599285. [PMID: 38948809 PMCID: PMC11212880 DOI: 10.1101/2024.06.17.599285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Both endogenous antibodies and a subset of antibody therapeutics engage Fc gamma receptor (FcγR)IIIa / CD16a to stimulate a protective immune response. Increasing the FcγRIIIa/IgG1 interaction improves the immune response and thus represents a strategy to improve therapeutic efficacy. FcγRIIIa is a heavily glycosylated receptor and glycan composition affects antibody-binding affinity. Though our laboratory previously demonstrated that natural killer (NK) cell N-glycan composition affected the potency of one key protective mechanism, antibody-dependent cell-mediated cytotoxicity (ADCC), it was unclear if this effect was due to FcγRIIIa glycosylation. Furthermore, the structural mechanism linking glycan composition to affinity and cellular activation remained undescribed. To define the role of individual amino acid and N-glycan residues we measured affinity using multiple FcγRIIIa glycoforms. We observed stepwise affinity increases with each glycan truncation step with the most severely truncated glycoform displaying the highest affinity. Removing the N162 glycan demonstrated its predominant role in regulating antibody-binding affinity, in contrast to four other FcγRIIIa N-glycans. We next evaluated the impact of the N162 glycan on NK cell ADCC. NK cells expressing the FcγRIIIa V158 allotype exhibited increased ADCC following kifunensine treatment to limit N-glycan processing. Notably, an increase was not observed with cells expressing the FcγRIIIa V158 S164A variant that lacks N162 glycosylation, indicating the N162 glycan is required for increased NK cell ADCC. To gain structural insight into the mechanisms of N162 regulation, we applied a novel protein isotope labeling approach in combination with solution NMR spectroscopy. FG loop residues proximal to the N162 glycosylation site showed large chemical shift perturbations following glycan truncation. These data support a model for the regulation of FcγRIIIa affinity and NK cell ADCC whereby composition of the N162 glycan stabilizes the FG loop and thus the antibody-binding site.
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Affiliation(s)
- Paul G. Kremer
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Elizabeth A. Lampros
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Allison M. Blocker
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Adam W. Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA
- Department of Chemistry, University of Georgia, Athens, GA
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2
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Benavente MCR, Hakeem ZA, Davis AR, Murray NB, Azadi P, Mace EM, Barb AW. Distinct CD16a features on human NK cells observed by flow cytometry correlate with increased ADCC. Sci Rep 2024; 14:7938. [PMID: 38575779 PMCID: PMC10995120 DOI: 10.1038/s41598-024-58541-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 04/01/2024] [Indexed: 04/06/2024] Open
Abstract
Natural killer (NK) cells destroy tissue that have been opsonized with antibodies. Strategies to generate or identify cells with increased potency are expected to enhance NK cell-based immunotherapies. We previously generated NK cells with increased antibody-dependent cell mediated cytotoxicity (ADCC) following treatment with kifunensine, an inhibitor targeting mannosidases early in the N-glycan processing pathway. Kifunensine treatment also increased the antibody-binding affinity of Fc γ receptor IIIa/CD16a. Here we demonstrate that inhibiting NK cell N-glycan processing increased ADCC. We reduced N-glycan processing with the CRIPSR-CAS9 knockdown of MGAT1, another early-stage N-glycan processing enzyme, and showed that these cells likewise increased antibody binding affinity and ADCC. These experiments led to the observation that NK cells with diminished N-glycan processing capability also revealed a clear phenotype in flow cytometry experiments using the B73.1 and 3G8 antibodies binding two distinct CD16a epitopes. We evaluated this "affinity profiling" approach using primary NK cells and identified a distinct shift and differentiated populations by flow cytometry that correlated with increased ADCC.
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Affiliation(s)
- Maria C Rodriguez Benavente
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St., 30602, Athens, GA, Georgia
| | - Zainab A Hakeem
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St., 30602, Athens, GA, Georgia
| | - Alexander R Davis
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St., 30602, Athens, GA, Georgia
| | - Nathan B Murray
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, Georgia
| | - Parastoo Azadi
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St., 30602, Athens, GA, Georgia
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, Georgia
| | - Emily M Mace
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - Adam W Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St., 30602, Athens, GA, Georgia.
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, Georgia.
- Department of Chemistry, University of Georgia, Athens, GA, Georgia.
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3
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Pavan C, Abdoollah Z, Marrero Roche DE, Ryan HR, Moore E, Chandler KB. Site-Specific Glycosylation Analysis of Murine and Human Fcγ Receptors Reveals High Heterogeneity at Conserved N-Glycosylation Site. J Proteome Res 2024; 23:1088-1101. [PMID: 38363599 PMCID: PMC10913873 DOI: 10.1021/acs.jproteome.3c00835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/17/2024]
Abstract
Fc γ-receptors (FcγRs) on leukocytes bind immunoglobulin G (IgG) immune complexes to mediate effector functions. Dysregulation of FcγR-mediated processes contributes to multiple inflammatory diseases, including rheumatoid arthritis, lupus, and immune thrombocytopenia. Critically, immunoregulatory N-glycan modifications on both FcγRs and IgGs alter FcγR-IgG binding affinity. Rapid methods for the characterization of N-glycans across multiple Fcγ receptors are needed to propel investigations into disease-specific contributions of FcγR N-glycans. Here, we utilize nanoliquid chromatography tandem mass spectrometry (nLC-MS/MS) to characterize FcγR glycosylation and report quantitative and site-specific N-glycan characterization of recombinant human FcγRI, FcγRIIIA V158, and FcγRIIIA F158 from CHO cells and murine FcγRI, FcγRIII, and FcγRIV from NS0 cells. Data are available via ProteomeXchange with identifier PXD043966. Broad glycoform distribution (≥30) was observed at mouse FcγRIV site N159 and human FcγRIIIA site N162, an evolutionarily conserved site. Further, mouse FcγRIII N-glycopeptides spanning all four predicted N-glycosylation sequons were detected. Glycoform relative abundances for hFcγRIIIA V/F158 polymorphic variants are reported, demonstrating the clinical potential of this workflow to measure differences in glycosylation between common human FcγRIIIA allelic variants with disease-associated outcomes. The multi-Fcγ receptor glycoproteomic workflow reported here will empower studies focused on the role of FcγR N-glycosylation in autoimmune diseases.
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Affiliation(s)
- Carlos
H. Pavan
- Translational
Glycobiology Institute, Department of Translational Medicine, Herbert
Wertheim College of Medicine, Florida International
University, Miami, Florida 33199, United States
| | - Zaraah Abdoollah
- Translational
Glycobiology Institute, Department of Translational Medicine, Herbert
Wertheim College of Medicine, Florida International
University, Miami, Florida 33199, United States
| | - Daniel E. Marrero Roche
- Translational
Glycobiology Institute, Department of Translational Medicine, Herbert
Wertheim College of Medicine, Florida International
University, Miami, Florida 33199, United States
| | - Holly R. Ryan
- J.
Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Erika Moore
- Fischell
Department of Bioengineering, University
of Maryland, College Park, College
Park, Maryland 20742, United States
| | - Kevin Brown Chandler
- Translational
Glycobiology Institute, Department of Translational Medicine, Herbert
Wertheim College of Medicine, Florida International
University, Miami, Florida 33199, United States
- Biomolecular
Sciences Institute, Florida International
University, 11200 SW
8th St., Miami, Florida 33199, United States
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4
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Hale RC, Morais D, Chou J, Stowell SR. The role of glycosylation in clinical allergy and immunology. J Allergy Clin Immunol 2024; 153:55-66. [PMID: 37717626 PMCID: PMC10872775 DOI: 10.1016/j.jaci.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/19/2023]
Abstract
While glycans are among the most abundant macromolecules on the cell with widespread functions, their role in immunity has historically been challenging to study. This is in part due to difficulties assimilating glycan analysis into routine approaches used to interrogate immune cell function. Despite this, recent developments have illuminated fundamental roles for glycans in host immunity. The growing field of glycoimmunology continues to leverage new tools and approaches to uncover the function of glycans and glycan-binding proteins in immunity. Here we utilize clinical vignettes to examine key roles of glycosylation in allergy, inborn errors of immunity, and autoimmunity. We will discuss the diverse functions of glycans as epitopes, as modulators of antibody function, and as regulators of immune cell function. Finally, we will highlight immune modulatory therapies that harness the critical role of glycans in the immune system.
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Affiliation(s)
- Rebecca C Hale
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Mass; Department of Pathology, Joint Program in Transfusion Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Dominique Morais
- Department of Pathology, Joint Program in Transfusion Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Janet Chou
- Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, Mass.
| | - Sean R Stowell
- Department of Pathology, Joint Program in Transfusion Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass; Harvard Glycomics Center, Harvard Medical School, Boston, Mass.
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5
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Díaz de león JSA, Aguilar I, Barb AW. Macrophage N-glycan processing inhibits antibody-dependent cellular phagocytosis. Glycobiology 2023; 33:1182-1192. [PMID: 37792857 PMCID: PMC10876040 DOI: 10.1093/glycob/cwad078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/06/2023] Open
Abstract
Factors regulating macrophage effector function represent potential targets to optimize the efficacy of antibody-mediated therapies. Macrophages are myeloid cells capable of engulfing and destroying diseased or damaged target cells. Antibodies binding to the target cell surface can engage macrophage Fc gamma receptors (FcγRs) to elicit antibody-dependent cellular phagocytosis (ADCP), a process that contributes to treatments mediated by anti-tumor antibodies. Conversely, macrophage ADCP of apoptotic T cells is also linked to tolerance in the tumor environment. Here we evaluated the role of asparagine(N)-linked glycans in the function of macrophages derived from primary human monocytes. Macrophages treated with kifunensine, an inhibitor of N-glycan processing, exhibited greater target binding and ADCP of antibody-coated target cells. Kifunensine treatment increased ADCP of both rituximab-coated Raji B cells and trastuzumab-coated SKBR3 cells. ADCP required FcγRs; inhibiting CD64 / FcγRI led to the greatest reduction, followed by CD32 / FcγRII and then CD16 / FcγRIII in most donors. Kifunensine treatment also increased the antibody-binding affinity of CD16. Differences in the abundance of phosphorylated immune receptors, including Siglec-9, CD32a, and LAIR-1 correlated with the increased ADCP. These results demonstrate that N-glycan processing regulates macrophage effector function.
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Affiliation(s)
- Jesús S Aguilar Díaz de león
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St, Athens, GA 30602, United States
| | - Isaac Aguilar
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St, Athens, GA 30602, United States
| | - Adam W Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, 120 E. Green St, Athens, GA 30602, United States
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens, GA 30602, United States
- Department of Chemistry, University of Georgia, 120 E. Green St, Athens, GA 30602, United States
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6
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Benavente MCR, Hughes HB, Kremer PG, Subedi GP, Barb AW. Inhibiting N-glycan processing increases the antibody binding affinity and effector function of human natural killer cells. Immunology 2023; 170:202-213. [PMID: 37218360 PMCID: PMC10524233 DOI: 10.1111/imm.13662] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 05/09/2023] [Indexed: 05/24/2023] Open
Abstract
Novel approaches are required to improve the efficacy of immunotherapies and increase the proportion of patients who experience a benefit. Antibody-dependent cell-mediated cytotoxicity (ADCC) contributes to the efficacy of many monoclonal antibodies therapies. Natural killer (NK) cells mediate ADCC, though responses are highly variable and depend on prior treatment as well as other factors. Thus, strategies to increase NK cell activity are expected to improve multiple therapies. Both cytokine treatment and NK cell receptor engineering are being explored to increase ADCC. Post-translational modifications, including glycosylation, are widely recognized as mediators of cellular processes but minimally explored as an alternative strategy to increase ADCC. We evaluated the impact of treatment with kifunensine, an inhibitor of asparagine-linked (N-)glycan processing, on ADCC using primary and cultured human NK cells. We also probed affinity using binding assays and CD16a structure with nuclear magnetic resonance spectroscopy. Treating primary human NK cells and cultured YTS-CD16a cells with kifunensine doubled ADCC in a CD16a-dependent manner. Kifunensine treatment also increased the antibody-binding affinity of CD16a on the NK cell surface. Structural interrogation identified a single CD16a region, proximal to the N162 glycan and the antibody-binding interface, perturbed by the N-glycan composition. The observed increase in NK cell activity following kifunensine treatment synergized with afucosylated antibodies, further increasing ADCC by an additional 33%. These results demonstrate native N-glycan processing is an important factor that limits NK cell ADCC. Furthermore, optimal antibody and CD16a glycoforms are defined that provide the greatest ADCC activity.
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Affiliation(s)
| | - Harrison B. Hughes
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Paul G. Kremer
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Ganesh P. Subedi
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA
| | - Adam W. Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA
- Department of Chemistry, University of Georgia, Athens, GA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA
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7
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Nimmerjahn F, Vidarsson G, Cragg MS. Effect of posttranslational modifications and subclass on IgG activity: from immunity to immunotherapy. Nat Immunol 2023; 24:1244-1255. [PMID: 37414906 DOI: 10.1038/s41590-023-01544-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/15/2023] [Indexed: 07/08/2023]
Abstract
Humoral immune responses are characterized by complex mixtures of polyclonal antibody species varying in their isotype, target epitope specificity and affinity. Posttranslational modifications occurring during antibody production in both the antibody variable and constant domain create further complexity and can modulate antigen specificity and antibody Fc-dependent effector functions, respectively. Finally, modifications of the antibody backbone after secretion may further impact antibody activity. An in-depth understanding of how these posttranslational modifications impact antibody function, especially in the context of individual antibody isotypes and subclasses, is only starting to emerge. Indeed, only a minute proportion of this natural variability in the humoral immune response is currently reflected in therapeutic antibody preparations. In this Review, we summarize recent insights into how IgG subclass and posttranslational modifications impact IgG activity and discuss how these insights may be used to optimize therapeutic antibody development.
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Affiliation(s)
- Falk Nimmerjahn
- Division of Genetics, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany.
| | - Gestur Vidarsson
- Immunoglobulin Research Laboratory, Department of Experimental Immunohematology, Sanquin Research, Amsterdam, the Netherlands
- Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands
| | - Mark S Cragg
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, University of Southampton Faculty of Medicine, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
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8
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Cruz Amaya J, Walcheck B, Smith-Gagen J, Lombardi VC, Hudig D. Detection of Antibody-Dependent Cell-Mediated Cytotoxicity-Supporting Antibodies by NK-92-CD16A Cell Externalization of CD107a: Recognition of Antibody Afucosylation and Assay Optimization. Antibodies (Basel) 2023; 12:44. [PMID: 37489366 PMCID: PMC10366760 DOI: 10.3390/antib12030044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 07/26/2023] Open
Abstract
Antibody-dependent cell-mediated cytotoxicity (ADCC) by natural killer (NK) lymphocytes eliminates cells infected with viruses. Anti-viral ADCC requires three components: (1) antibody; (2) effector lymphocytes with the Fc-IgG receptor CD16A; and (3) viral proteins in infected cell membranes. Fc-afucosylated antibodies bind with greater affinity to CD16A than fucosylated antibodies; individuals' variation in afucosylation contributes to differences in ADCC. Current assays for afucosylated antibodies involve expensive methods. We report an improved bioassay for antibodies that supports ADCC, which encompasses afucosylation. This assay utilizes the externalization of CD107a by NK-92-CD16A cells after antibody recognition. We used anti-CD20 monoclonal antibodies, GA101 WT or glycoengineered (GE), 10% or ~50% afucosylated, and CD20-positive Raji target cells. CD107a increased detection 7-fold compared to flow cytometry to detect Raji-bound antibodies. WT and GE antibody effective concentrations (EC50s) for CD107a externalization differed by 20-fold, with afucosylated GA101-GE more detectable. The EC50s for CD107a externalization vs. 51Cr cell death were similar for NK-92-CD16A and blood NK cells. Notably, the % CD107a-positive cells were negatively correlated with dead Raji cells and were nearly undetectable at high NK:Raji ratios required for cytotoxicity. This bioassay is very sensitive and adaptable to assess anti-viral antibodies but unsuitable as a surrogate assay to monitor cell death after ADCC.
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Affiliation(s)
- Judith Cruz Amaya
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Bruce Walcheck
- Department of Veterinary and Biological Sciences, Center for Immunology and Masonic Cancer Center, University of Minnesota, 295J AS/VM Building, 1988 Fitch Avenue, Saint Paul, MN 55108, USA
| | - Julie Smith-Gagen
- School of Community Health Sciences, University of Nevada, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Vincent C. Lombardi
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, 1664 N. Virginia St., Reno, NV 89557, USA
| | - Dorothy Hudig
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, 1664 N. Virginia St., Reno, NV 89557, USA
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9
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Chong G, MacKerell AD. Spatial requirements for ITAM signaling in an intracellular natural killer cell model membrane. Biochim Biophys Acta Gen Subj 2022; 1866:130221. [PMID: 35933027 PMCID: PMC9420803 DOI: 10.1016/j.bbagen.2022.130221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/27/2022] [Accepted: 07/31/2022] [Indexed: 11/17/2022]
Abstract
FcγRIIIa-FcεRIγ complexes, upon stimulation by antibodies, cluster to initiate intracellular signaling and activate natural killer (NK) cells. Intracellular signaling involves Lck phosphorylation of ITAMs of each monomer of a FcεRIγ homodimer in a FcγRIIIa-FcεRIγ complex and subsequent binding of two phosphotyrosines (pY) in tandem by a Syk family kinase. However, how FcR clustering triggers ITAM signaling is not resolved. Molecular modeling and dynamics (MD) simulations are applied to generate ensembles of structures of the FcγRIIIa and FcεRIγ homodimeric cytoplasmic tails of FcγRIIIa-FcεRIγ complexes based on the transmembrane helices and cytoplasmic tails spaced 120, 80, and 50 Å apart to model different extents of clustering. Site-identification by ligand competitive saturation method with Monte Carlo sampling (SILCS-MC) is used to model how Lck could phosphorylate a diversity of ITAM conformations. At 80 Å separation between FcγRIIIa-FcεRIγ complexes, Lck can perform multiple phosphorylations on individual and multiple ITAMs across complexes, including potential sequential phosphorylation events. Syk may then potentially bind the two pYs within a single ITAM in tandem in isolated FcγRIIIa-FcεRIγ complexes, as observed in CD3ε and ζ chains of T cell receptors by the Syk family kinase ZAP-70. In addition, at 50 Å separation between complexes, unique to natural killer cells over T cells, Syk could potentially bind in tandem to pYs in different ITAMs across FcγRIIIa-FcεRIγ complexes. Thus, we predict that an ensemble of spatial orientations of the ITAMS of FcγRIIIa-FcεRIγ complexes that occur upon clustering lead to ITAM phosphorylation by Lck and subsequent Syk activity thereby facilitating downstream signaling.
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Affiliation(s)
- Gene Chong
- Computer Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, United States
| | - Alexander D MacKerell
- Computer Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, United States.
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Van Coillie J, Schulz MA, Bentlage AEH, de Haan N, Ye Z, Geerdes DM, van Esch WJE, Hafkenscheid L, Miller RL, Narimatsu Y, Vakhrushev SY, Yang Z, Vidarsson G, Clausen H. Role of N-Glycosylation in FcγRIIIa interaction with IgG. Front Immunol 2022; 13:987151. [PMID: 36189205 PMCID: PMC9524020 DOI: 10.3389/fimmu.2022.987151] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/16/2022] [Indexed: 01/09/2023] Open
Abstract
Immunoglobulins G (IgG) and their Fc gamma receptors (FcγRs) play important roles in our immune system. The conserved N-glycan in the Fc region of IgG1 impacts interaction of IgG with FcγRs and the resulting effector functions, which has led to the design of antibody therapeutics with greatly improved antibody-dependent cell cytotoxicity (ADCC) activities. Studies have suggested that also N-glycosylation of the FcγRIII affects receptor interactions with IgG, but detailed studies of the interaction of IgG1 and FcγRIIIa with distinct N-glycans have been hindered by the natural heterogeneity in N-glycosylation. In this study, we employed comprehensive genetic engineering of the N-glycosylation capacities in mammalian cell lines to express IgG1 and FcγRIIIa with different N-glycan structures to more generally explore the role of N-glycosylation in IgG1:FcγRIIIa binding interactions. We included FcγRIIIa variants of both the 158F and 158V allotypes and investigated the key N-glycan features that affected binding affinity. Our study confirms that afucosylated IgG1 has the highest binding affinity to oligomannose FcγRIIIa, a glycan structure commonly found on Asn162 on FcγRIIIa expressed by NK cells but not monocytes or recombinantly expressed FcγRIIIa.
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Affiliation(s)
- Julie Van Coillie
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, Netherlands
- Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Morten A. Schulz
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arthur E. H. Bentlage
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, Netherlands
- Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Noortje de Haan
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zilu Ye
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Lise Hafkenscheid
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rebecca L. Miller
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yoshiki Narimatsu
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- GlycoDisplay ApS, Copenhagen, Denmark
| | - Sergey Y. Vakhrushev
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zhang Yang
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
- GlycoDisplay ApS, Copenhagen, Denmark
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, Netherlands
- Department of Biomolecular Mass Spectrometry and Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Adams TM, Zhao P, Chapla D, Moremen KW, Wells L. Sequential in vitro enzymatic N-glycoprotein modification reveals site-specific rates of glycoenzyme processing. J Biol Chem 2022; 298:102474. [PMID: 36089065 PMCID: PMC9530959 DOI: 10.1016/j.jbc.2022.102474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/01/2022] [Accepted: 09/03/2022] [Indexed: 12/01/2022] Open
Abstract
N-glycosylation is an essential eukaryotic posttranslational modification that affects various glycoprotein properties, including folding, solubility, protein–protein interactions, and half-life. N-glycans are processed in the secretory pathway to form varied ensembles of structures, and diversity at a single site on a glycoprotein is termed ‘microheterogeneity’. To understand the factors that influence glycan microheterogeneity, we hypothesized that local steric and electrostatic factors surrounding each site influence glycan availability for enzymatic modification. We tested this hypothesis via expression of reporter N-linked glycoproteins in N-acetylglucosaminyltransferase MGAT1-null HEK293 cells to produce immature Man5GlcNAc2 glycoforms (38 glycan sites total). These glycoproteins were then sequentially modified in vitro from high mannose to hybrid and on to biantennary, core-fucosylated, complex structures by a panel of N-glycosylation enzymes, and each reaction time course was quantified by LC-MS/MS. Substantial differences in rates of in vitro enzymatic modification were observed between glycan sites on the same protein, and differences in modification rates varied depending on the glycoenzyme being evaluated. In comparison, proteolytic digestion of the reporters prior to N-glycan processing eliminated differences in in vitro enzymatic modification. Furthermore, comparison of in vitro rates of enzymatic modification with the glycan structures found on the mature reporters expressed in WT cells correlated well with the enzymatic bottlenecks observed in vivo. These data suggest higher order local structures surrounding each glycosylation site contribute to the efficiency of modification both in vitro and in vivo to establish the spectrum of microheterogeneity in N-linked glycoproteins.
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Affiliation(s)
- Trevor M Adams
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Peng Zhao
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Digantkumar Chapla
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Kelley W Moremen
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602.
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602.
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12
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Tolbert WD, Gohain N, Kremer PG, Hederman AP, Nguyen DN, Van V, Sherburn R, Lewis GK, Finzi A, Pollara J, Ackerman ME, Barb AW, Pazgier M. Decoding human-macaque interspecies differences in Fc-effector functions: The structural basis for CD16-dependent effector function in Rhesus macaques. Front Immunol 2022; 13:960411. [PMID: 36131913 PMCID: PMC9484259 DOI: 10.3389/fimmu.2022.960411] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/26/2022] [Indexed: 01/27/2023] Open
Abstract
Fc mediated effector functions of antibodies play important roles in immunotherapies and vaccine efficacy but assessing those functions in animal models can be challenging due to species differences. Rhesus macaques, Macaca mulatta (Mm) share approximately 93% sequence identity with humans but display important differences in their adaptive immune system that complicates their use in validating therapeutics and vaccines that rely on Fc effector functions. In contrast to humans, macaques only have one low affinity FcγRIII receptor, CD16, which shares a polymorphism at position 158 with human FcγRIIIa with Ile158 and Val158 variants. Here we describe structure-function relationships of the Ile/Val158 polymorphism in Mm FcγRIII. Our data indicate that the affinity of the allelic variants of Mm FcγRIII for the macaque IgG subclasses vary greatly with changes in glycan composition both on the Fc and the receptor. However, unlike the human Phe/Val158 polymorphism in FcγRIIIa, the higher affinity variant corresponds to the larger, more hydrophobic side chain, Ile, even though it is not directly involved in the binding interface. Instead, this side chain appears to modulate glycan-glycan interactions at the Fc/FcγRIII interface. Furthermore, changes in glycan composition on the receptor have a greater effect for the Val158 variant such that with oligomannose type glycans and with glycans only on Asn45 and Asn162, Val158 becomes the variant with higher affinity to Fc. These results have implications not only for the better interpretation of nonhuman primate studies but also for studies performed with human effector cells carrying different FcγRIIIa alleles.
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Affiliation(s)
- William D. Tolbert
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Neelakshi Gohain
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Paul G. Kremer
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Andrew P. Hederman
- Thayer School of Engineering, Dartmouth College, Hanover, NH, United States
| | - Dung N. Nguyen
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Verna Van
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Rebekah Sherburn
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - George K. Lewis
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Andrés Finzi
- Centre de recherche du CHUM, Montreal, QC, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, QC, Canada
| | - Justin Pollara
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
- Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States
- Center for Human Systems Immunology, Duke University School of Medicine, Durham, NC, United States
| | | | - Adam W. Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
- Department of Chemistry, University of Georgia, Athens, GA, United States
| | - Marzena Pazgier
- Infectious Disease Division, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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13
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Gonzalez JC, Chakraborty S, Thulin NK, Wang TT. Heterogeneity in IgG-CD16 signaling in infectious disease outcomes. Immunol Rev 2022; 309:64-74. [PMID: 35781671 PMCID: PMC9539944 DOI: 10.1111/imr.13109] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this review, we discuss how IgG antibodies can modulate inflammatory signaling during viral infections with a focus on CD16a-mediated functions. We describe the structural heterogeneity of IgG antibody ligands, including subclass and glycosylation that impact binding by and downstream activity of CD16a, as well as the heterogeneity of CD16a itself, including allele and expression density. While inflammation is a mechanism required for immune homeostasis and resolution of acute infections, we focus here on two infectious diseases that are driven by pathogenic inflammatory responses during infection. Specifically, we review and discuss the evolving body of literature showing that afucosylated IgG immune complex signaling through CD16a contributes to the overwhelming inflammatory response that is central to the pathogenesis of severe forms of dengue disease and coronavirus disease 2019 (COVID-19).
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Affiliation(s)
- Joseph C. Gonzalez
- Department of Medicine, Division of Infectious DiseasesStanford University School of MedicineStanfordCaliforniaUSA,Program in ImmunologyStanford University School of MedicineStanfordCaliforniaUSA
| | - Saborni Chakraborty
- Department of Medicine, Division of Infectious DiseasesStanford University School of MedicineStanfordCaliforniaUSA
| | - Natalie K. Thulin
- Department of ImmunologyUniversity of WashingtonSeattleWashingtonUSA
| | - Taia T. Wang
- Department of Medicine, Division of Infectious DiseasesStanford University School of MedicineStanfordCaliforniaUSA,Program in ImmunologyStanford University School of MedicineStanfordCaliforniaUSA,Department of Microbiology and ImmunologyStanford University School of MedicineStanfordCaliforniaUSA
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14
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Kremer PG, Barb AW. The weaker-binding Fc γ receptor IIIa F158 allotype retains sensitivity to N-glycan composition and exhibits a destabilized antibody-binding interface. J Biol Chem 2022; 298:102329. [PMID: 35921896 PMCID: PMC9436803 DOI: 10.1016/j.jbc.2022.102329] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 12/27/2022] Open
Abstract
Antibodies engage Fc γ receptors (FcγRs) to elicit healing cellular immune responses following binding to a target antigen. Fc γ receptor IIIa/CD16a triggers natural killer cells to destroy target tissues with cytotoxic proteins and enhances phagocytosis mediated by macrophages. Multiple variables affect CD16a antibody-binding strength and the resulting immune response, including a genetic polymorphism. The predominant CD16a F158 allotype binds antibodies with less affinity than the less common V158 allotype. This polymorphism likewise affects cellular immune responses and clinical efficacy of antibodies relying on CD16a engagement, though it remains unclear how V/F158 affects CD16a structure. Another relevant variable shown to affect affinity is composition of the CD16a asparagine-linked (N)-glycans. It is currently not known how N-glycan composition affects CD16a F158 affinity. Here, we determined N-glycan composition affects the V158 and F158 allotypes similarly, and N-glycan composition does not explain differences in V158 and F158 binding affinity. Our analysis of binding kinetics indicated the N162 glycan slows the binding event, and shortening the N-glycans or removing the N162 glycan increased the speed of binding. F158 displayed a slower binding rate than V158. Surprisingly, we found N-glycan composition had a smaller effect on the dissociation rate. We also identified conformational heterogeneity of CD16a F158 backbone amide and N162 glycan resonances using NMR spectroscopy. Residues exhibiting chemical shift perturbations between V158 and F158 mapped to the antibody-binding interface. These data support a model for CD16a F158 with increased interface conformational heterogeneity, reducing the population of binding-competent forms available and decreasing affinity.
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15
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Radovani B, Gudelj I. N-Glycosylation and Inflammation; the Not-So-Sweet Relation. Front Immunol 2022; 13:893365. [PMID: 35833138 PMCID: PMC9272703 DOI: 10.3389/fimmu.2022.893365] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/30/2022] [Indexed: 12/28/2022] Open
Abstract
Chronic inflammation is the main feature of many long-term inflammatory diseases such as autoimmune diseases, metabolic disorders, and cancer. There is a growing number of studies in which alterations of N-glycosylation have been observed in many pathophysiological conditions, yet studies of the underlying mechanisms that precede N-glycome changes are still sparse. Proinflammatory cytokines have been shown to alter the substrate synthesis pathways as well as the expression of glycosyltransferases required for the biosynthesis of N-glycans. The resulting N-glycosylation changes can further contribute to disease pathogenesis through modulation of various aspects of immune cell processes, including those relevant to pathogen recognition and fine-tuning the inflammatory response. This review summarizes our current knowledge of inflammation-induced N-glycosylation changes, with a particular focus on specific subsets of immune cells of innate and adaptive immunity and how these changes affect their effector functions, cell interactions, and signal transduction.
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Affiliation(s)
- Barbara Radovani
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| | - Ivan Gudelj
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
- Genos Glycoscience Research Laboratory, Zagreb, Croatia
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16
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Coënon L, Villalba M. From CD16a Biology to Antibody-Dependent Cell-Mediated Cytotoxicity Improvement. Front Immunol 2022; 13:913215. [PMID: 35720368 PMCID: PMC9203678 DOI: 10.3389/fimmu.2022.913215] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Antibody-dependent cell-mediated cytotoxicity (ADCC) is a potent cytotoxic mechanism that is mainly mediated in humans by natural killer (NK) cells. ADCC mediates the clinical benefit of several widely used cytolytic monoclonal antibodies (mAbs), and increasing its efficacy would improve cancer immunotherapy. CD16a is a receptor for the Fc portion of IgGs and is responsible to trigger NK cell-mediated ADCC. The knowledge of the mechanism of action of CD16a gave rise to several strategies to improve ADCC, by working on either the mAbs or the NK cell. In this review, we give an overview of CD16a biology and describe the latest strategies employed to improve antibody-dependent NK cell cytotoxicity.
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Affiliation(s)
- Loïs Coënon
- Institute for Regenerative Medicine and Biotherapy (IRMB), Univ Montpellier, Institut national de la santé et de la recherche médicale (INSERM), Montpellier, France
- Institut du Cancer Avignon-Provence Sainte Catherine, Avignon, France
- *Correspondence: Loïs Coënon,
| | - Martin Villalba
- Institut du Cancer Avignon-Provence Sainte Catherine, Avignon, France
- Institute for Regenerative Medicine and Biotherapy, Univ Montpellier, Institut national de la santé et de la recherche médicale (INSERM), Centre national de la recherche scientifique (CNRS), Centre hospitalier universitaire (CHU) Montpellier, Montpellier, France
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17
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Delidakis G, Kim JE, George K, Georgiou G. Improving Antibody Therapeutics by Manipulating the Fc Domain: Immunological and Structural Considerations. Annu Rev Biomed Eng 2022; 24:249-274. [PMID: 35363537 PMCID: PMC9648538 DOI: 10.1146/annurev-bioeng-082721-024500] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Interactions between the crystallizable fragment (Fc) domain of antibodies and a plethora of cellular Fc receptors (FcRs) or soluble proteins form a critical link between humoral and innate immunity. In particular, the immunoglobulin G Fc domain is critical for the clearance of target cells by processes that include (a) cytotoxicity, phagocytosis, or complement lysis; (b) modulation of inflammation; (c) antigen presentation; (d) antibody-mediated receptor clustering; and (e) cytokine release. More than 30 Fc-engineered antibodies aimed primarily at tailoring these effects for optimal therapeutic outcomes are in clinical evaluation or have already been approved. Nonetheless, our understanding of how FcR engagement impacts various immune cell phenotypes is still largely incomplete. Recent insights into FcR biology coupled with advances in Fc:FcR structural analysis, Fc engineering, and mouse models that recapitulate human biology are helping to fill in existing knowledge gaps. These advances will provide a blueprint on how to fine-tune the Fc domain to achieve optimal therapeutic efficacy. Expected final online publication date for the Annual Review of Biomedical Engineering, Volume 24 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- George Delidakis
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA;
| | - Jin Eyun Kim
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Katia George
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - George Georgiou
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA; .,Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
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18
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Woodall DW, Dillon TM, Kalenian K, Padaki R, Kuhns S, Semin DJ, Bondarenko PV. Non-targeted characterization of attributes affecting antibody-FcγRIIIa V158 (CD16a) binding via online affinity chromatography-mass spectrometry. MAbs 2022; 14:2004982. [PMID: 34978527 PMCID: PMC8741291 DOI: 10.1080/19420862.2021.2004982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Antibodies facilitate targeted cell killing by engaging with immune cells such as natural killer cells through weak binding interactions with Fcγ receptors on the cell surface. Here, we evaluate the binding affinity of the receptor FcγRIIIa V158 (CD16a) for several therapeutic antibody classes, isoforms, and Fc-fusion proteins using an immobilized receptor affinity liquid chromatography (LC) approach coupled with online mass spectrometry (MS) detection. Aglycosylated FcγRIIIa was used in the affinity chromatography and compared with published affinities using glycosylated receptors. Affinity LC-MS differentiated the IgG1 antibodies primarily according to their Fc glycosylation patterns, with highly galactosylated species having greater affinity for the immobilized receptors and thus eluting later from the column (M5< G0F < G0 afucosylated ≅ G1F < G2F). Sialylated species bound weaker to their asialylated counterparts as reported previously. High mannose glycoforms bound weaker than G0F, contrary to previously published studies using glycosylated receptors. Also, increased receptor binding affinity associated with afucosylated antibodies was not observed with the aglycosylated FcγRIIIa. This apparent difference from previous findings highlighted the importance of the glycans on the receptors for mediating stronger binding interactions. Characterization of temperature-stressed samples by LC-MS peptide mapping revealed over 200 chemical and post-translational modifications, but only the Fc glycans, deamidation of EU N325, and an unknown modification to either proline or cysteine residues of the hinge region were found to have a statistically significant impact on binding. Abbreviations: Antibody-dependent cell-mediated cytotoxicity (ADCC), chimeric antigen receptor (CAR), Chinese hamster ovary (CHO), dithiothreitol (DTT), electrospray ionization (ESI), hydrogen-deuterium exchange (HDX), filter aided-sample preparation (FASP), Fcγ receptor (FcγR), fragment crystallizable (Fc), high-pressure liquid chromatography (HPLC), immunoglobulin G (IgG), liquid chromatography (LC), monoclonal antibody (mAb), mass spectrometry (MS), natural killer (NK), N-glycolylneuraminic acid (NGNA), N-acetylneuraminic acid (NANA), principal component analysis (PCA), surface plasmon resonance (SPR), trifluoroacetic acid (TFA), and extracted mass chromatogram (XMC).
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Affiliation(s)
- Daniel W Woodall
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
| | - Thomas M Dillon
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
| | - Kevin Kalenian
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
| | - Rupa Padaki
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
| | - Scott Kuhns
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
| | - David J Semin
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
| | - Pavel V Bondarenko
- Attribute Sciences, Process Development, Amgen Inc, Thousand Oaks, California, USA
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19
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Lampros EA, Kremer PG, Aguilar Díaz de León JS, Roberts ET, Rodriguez Benavente MC, Amster IJ, Barb AW. The antibody-binding Fc gamma receptor IIIa / CD16a is N-glycosylated with high occupancy at all five sites. CURRENT RESEARCH IN IMMUNOLOGY 2022; 3:128-135. [PMID: 35712026 PMCID: PMC9193405 DOI: 10.1016/j.crimmu.2022.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/18/2022] [Accepted: 05/30/2022] [Indexed: 01/27/2023] Open
Abstract
The antibody-binding Fc γ receptors (FcγRs) trigger life-saving immune responses and many therapeutic monoclonal antibodies require FcγR engagement for full effect. One proven strategy to improve the efficacy of antibody therapies is to increase receptor binding affinity, in particular binding to FcγRIIIa/CD16a. Currently, affinities are measured using recombinantly-expressed soluble extracellular FcγR domains and CD16a-mediated antibody-dependent immune responses are characterized using cultured cells. It is notable that CD16a is highly processed with multiple N-glycosylation sites, and preventing individual N-glycan modifications affects affinity. Furthermore, multiple groups have demonstrated that CD16a N-glycan composition is variable and composition impacts antibody binding affinity. The level of N-glycosylation at each site is not known though computational prediction indicates low to moderate potential at each site based on primary sequence (40-70%). Here we quantify occupancy of the extracellular domains using complementary mass spectrometry-based methods. All five sites of the tighter-binding CD16a V158 allotype showed 65-100% N-glycan occupancy in proteomics-based experiments. These observations were confirmed using intact protein mass spectrometry that demonstrated the predominant species corresponded to CD16a V158 with five N-glycans, with a smaller contribution from CD16a with four N-glycans. Occupancy was likewise high for the membrane-bound receptor at all detected N-glycosylation sites using CD16a purified from cultured human natural killer cells. Occupancy of the N162 site, critical for antibody binding, appeared independent of N169 occupancy based on analysis of the T171A mutant protein. The weaker-binding CD16a F158 allotype showed higher occupancy of >93% at each site.
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Affiliation(s)
- Elizabeth A. Lampros
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Paul G. Kremer
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | | | | | | | - I. Jonathan Amster
- Department of Chemistry, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Adam W. Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
- Department of Chemistry, University of Georgia, Athens, GA, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Corresponding author. 20 E. Green St., Athens, GA, 30605, USA.
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20
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Method for Identifying Galectin Ligands on Lymphocyte Membrane Glycoproteins. Methods Mol Biol 2022; 2442:215-232. [PMID: 35320529 PMCID: PMC10174696 DOI: 10.1007/978-1-0716-2055-7_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Glycosylation is one of the most common protein posttranslational modifications. Most human lymphocyte membrane receptors are modified by diverse glycan structures, and functional studies have indicated that a family of glycan-binding proteins, galectins, can significantly modulate lymphocyte development and function by interacting with these glycans. Several galectins have a varying degree of affinity for the N-acetyllactosamine (LacNAc) disaccharide, and some critical lymphocyte receptors can be modified by glycan structures carrying this motif. However, the site-specific glycan composition on primary lymphocyte membrane receptors in healthy individuals is largely limited. The main reason for the limitation is low abundance of available material from a single donor and compositional heterogeneity in glycan structures that can potentially modify a protein. Donor-dependent variability in N-glycan structures on CD16a isolated from primary NK cells of healthy human donors was recently reported. NK cell CD16a is glycosylated at five N-glycosylation sites, and two of the five sites are modified, almost exclusively, by N-glycans with multiple LacNAc repeats which can serve as ligands for endogenous galectins. Thus, the protocol described in this section can be utilized to identify galectin ligands at specific glycosylation sites of endogenous membrane receptor from circulating primary human lymphocytes.
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21
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Patel KR, Roberts JT, Barb AW. Allotype-specific processing of the CD16a N45-glycan from primary human natural killer cells and monocytes. Glycobiology 2021; 30:427-432. [PMID: 31967297 DOI: 10.1093/glycob/cwaa002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/31/2019] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
Fc γ receptor IIIa/CD16a is an activating cell surface receptor with a well-defined role in natural killer (NK) cell and monocyte effector function. The extracellular domain is decorated with five asparagine (N)-linked glycans; N-glycans at N162 and N45 directly contribute to high-affinity antibody binding and protein stability. N-glycan structures at N162 showed significant donor-dependent variation in a recent study of CD16a isolated from primary human NK cells, but structures at N45 were relatively homogeneous. In this study, we identified variations in N45 glycan structures associated with a polymorphism coding for histidine instead of leucine at position 48 of CD16a from two heterozygous donors. It is known that H48 homozygous individuals suffer from immunodeficiency and recurrent viral infections. A mass spectrometry analysis of protein isolated from the primary natural killer cells of individuals expressing both CD16a L48 and H48 variants demonstrated clear processing differences at N45. CD16a H48 displayed a greater proportion of complex-type N45 glycans compared to the more common L48 allotype with predominantly hybrid N45-glycoforms. Structures at the four other N-glycosylation sites showed minimal differences from data collected on donors expressing only the predominant L48 variant. CD16a H48 purified from a pool of monocytes similarly displayed increased processing at N45. Here, we provide evidence that CD16a processing is affected by the H48 residue in primary NK cells and monocytes from healthy human donors.
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Affiliation(s)
- Kashyap R Patel
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Jacob T Roberts
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Adam W Barb
- Department of Biochemistry and Molecular Biology, University of Georgia, 122 Green Street, Athens, GA 30602, USA.,Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
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22
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On the Use of Surface Plasmon Resonance Biosensing to Understand IgG-FcγR Interactions. Int J Mol Sci 2021; 22:ijms22126616. [PMID: 34205578 PMCID: PMC8235063 DOI: 10.3390/ijms22126616] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 01/01/2023] Open
Abstract
Surface plasmon resonance (SPR)-based optical biosensors offer real-time and label-free analysis of protein interactions, which has extensively contributed to the discovery and development of therapeutic monoclonal antibodies (mAbs). As the biopharmaceutical market for these biologics and their biosimilars is rapidly growing, the role of SPR biosensors in drug discovery and quality assessment is becoming increasingly prominent. One of the critical quality attributes of mAbs is the N-glycosylation of their Fc region. Other than providing stability to the antibody, the Fc N-glycosylation influences immunoglobulin G (IgG) interactions with the Fcγ receptors (FcγRs), modulating the immune response. Over the past two decades, several studies have relied on SPR-based assays to characterize the influence of N-glycosylation upon the IgG-FcγR interactions. While these studies have unveiled key information, many conclusions are still debated in the literature. These discrepancies can be, in part, attributed to the design of the reported SPR-based assays as well as the methodology applied to SPR data analysis. In fact, the SPR biosensor best practices have evolved over the years, and several biases have been pointed out in the development of experimental SPR protocols. In parallel, newly developed algorithms and data analysis methods now allow taking into consideration complex biomolecular kinetics. In this review, we detail the use of different SPR biosensing approaches for characterizing the IgG-FcγR interactions, highlighting their merit and inherent experimental complexity. Furthermore, we review the latest SPR-derived conclusions on the influence of the N-glycosylation upon the IgG-FcγR interactions and underline the differences and similarities across the literature. Finally, we explore new avenues taking advantage of novel computational analysis of SPR results as well as the latest strategies to control the glycoprofile of mAbs during production, which could lead to a better understanding and modelling of the IgG-FcγRs interactions.
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23
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Allen JD, Watanabe Y, Chawla H, Newby ML, Crispin M. Subtle Influence of ACE2 Glycan Processing on SARS-CoV-2 Recognition. J Mol Biol 2021; 433:166762. [PMID: 33340519 PMCID: PMC7744274 DOI: 10.1016/j.jmb.2020.166762] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/03/2020] [Accepted: 12/11/2020] [Indexed: 02/08/2023]
Abstract
The severity of SARS-CoV-2 infection is highly variable and yet the molecular basis for this effect remains elusive. One potential contribution are differences in the glycosylation of target human cells, particularly as SARS-CoV-2 has the capacity to bind sialic acid which is a common, and highly variable, terminal modification of glycans. The viral spike glycoprotein (S) of SARS-CoV-2 and the human cellular receptor, angiotensin-converting enzyme 2 (ACE2) are both densely glycosylated. We therefore sought to investigate whether the glycosylation state of ACE2 impacts the interaction with SARS-CoV-2 viral spike. We generated a panel of engineered ACE2 glycoforms which were analyzed by mass spectrometry to reveal the site-specific glycan modifications. We then probed the impact of ACE2 glycosylation on S binding and revealed a subtle sensitivity with hypersialylated or oligomannose-type glycans slightly impeding the interaction. In contrast, deglycosylation of ACE2 did not influence SARS-CoV-2 binding. Overall, ACE2 glycosylation does not significantly influence viral spike binding. We suggest that any role of glycosylation in the pathobiology of SARS-CoV-2 will lie beyond its immediate impact of receptor glycosylation on virus binding.
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Affiliation(s)
- Joel D Allen
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Yasunori Watanabe
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK; Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford OX3 7BN, UK
| | - Himanshi Chawla
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Maddy L Newby
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK.
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Mimura Y, Saldova R, Mimura-Kimura Y, Rudd PM, Jefferis R. Importance and Monitoring of Therapeutic Immunoglobulin G Glycosylation. EXPERIENTIA SUPPLEMENTUM (2012) 2021; 112:481-517. [PMID: 34687020 DOI: 10.1007/978-3-030-76912-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The complex diantennary-type oligosaccharides at Asn297 residues of the IgG heavy chains have a profound impact on the safety and efficacy of therapeutic IgG monoclonal antibodies (mAbs). Fc glycosylation of a mAb is an established critical quality attribute (CQA), and its oligosaccharide profile is required to be thoroughly characterized by state-of-the-art analytical methods. The Fc oligosaccharides are highly heterogeneous, and the differentially glycosylated species (glycoforms) of IgG express unique biological activities. Glycoengineering is a promising approach for the production of selected mAb glycoforms with improved effector functions, and non- and low-fucosylated mAbs exhibiting enhanced antibody-dependent cellular cytotoxicity activity have been approved or are under clinical evaluation for treatment of cancers, autoimmune/chronic inflammatory diseases, and infection. Recently, the chemoenzymatic glycoengineering method that allows for the transfer of structurally defined oligosaccharides to Asn-linked GlcNAc residues with glycosynthase has been developed for remodeling of IgG-Fc oligosaccharides with high efficiency and flexibility. Additionally, various glycoengineering methods have been developed that utilize the Fc oligosaccharides of IgG as reaction handles to conjugate cytotoxic agents by "click chemistry", providing new routes to the design of antibody-drug conjugates (ADCs) with tightly controlled drug-antibody ratios (DARs) and homogeneity. This review focuses on current understanding of the biological relevance of individual IgG glycoforms and advances in the development of next-generation antibody therapeutics with improved efficacy and safety through glycoengineering.
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Affiliation(s)
- Yusuke Mimura
- Department of Clinical Research, National Hospital Organization Yamaguchi Ube Medical Center, Ube, Japan.
| | - Radka Saldova
- NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin, Ireland
- UCD School of Medicine, College of Health and Agricultural Science, University College Dublin, Belfield, Dublin, Ireland
| | - Yuka Mimura-Kimura
- Department of Clinical Research, National Hospital Organization Yamaguchi Ube Medical Center, Ube, Japan
| | - Pauline M Rudd
- NIBRT GlycoScience Group, National Institute for Bioprocessing Research and Training, Mount Merrion, Blackrock, Dublin, Ireland
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, Centros, Singapore
| | - Roy Jefferis
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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25
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Barb AW. Fc γ receptor compositional heterogeneity: Considerations for immunotherapy development. J Biol Chem 2021; 296:100057. [PMID: 33172893 PMCID: PMC7948983 DOI: 10.1074/jbc.rev120.013168] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022] Open
Abstract
The antibody-binding crystallizable fragment (Fc) γ receptors (FcγRs) are expressed by leukocytes and activate or suppress a cellular response once engaged with an antibody-coated target. Therapeutic mAbs that require FcγR binding for therapeutic efficacy are now frontline treatments for multiple diseases. However, substantially fewer development efforts are focused on the FcγRs, despite accounting for half of the antibody-receptor complex. The recent success of engineered cell-based immunotherapies now provides a mechanism to introduce modified FcγRs into the clinic. FcγRs are highly heterogeneous because of multiple functionally distinct alleles for many genes, the presence of membrane-tethered and soluble forms, and a high degree of post-translational modification, notably asparagine-linked glycans. One significant factor limiting FcγR improvement is the fundamental lack of knowledge regarding endogenous receptor forms present in the human body. This review describes the composition of FcγRs isolated from primary human leukocytes, summarizes recent efforts to engineer FcγRs, and concludes with a description of potential FcγR features to enrich for enhanced function. Further understanding FcγR biology could accelerate the development of new clinical therapies targeting immune-related disease.
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Affiliation(s)
- Adam W Barb
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
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26
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Patel KR, Rodriguez Benavente MC, Lorenz WW, Mace EM, Barb AW. Fc γ receptor IIIa/CD16a processing correlates with the expression of glycan-related genes in human natural killer cells. J Biol Chem 2020; 296:100183. [PMID: 33310702 PMCID: PMC7948478 DOI: 10.1074/jbc.ra120.015516] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/03/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022] Open
Abstract
Many therapeutic monoclonal antibodies require binding to Fc γ receptors (FcγRs) for full effect and increasing the binding affinity increases efficacy. Preeminent among the five activating human FcγRs is FcγRIIIa/CD16a expressed by natural killer (NK) cells. CD16a is heavily processed, and recent reports indicate that the composition of the five CD16a asparagine(N)-linked carbohydrates (glycans) impacts affinity. These observations indicate that specific manipulation of CD16a N-glycan composition in CD16a-expressing effector cells including NK cells may improve treatment efficacy. However, it is unclear if modifying the expression of select genes that encode processing enzymes in CD16a-expressing effector cells is sufficient to affect N-glycan composition. We identified substantial processing differences using a glycoproteomics approach by comparing CD16a isolated from two NK cell lines, NK92 and YTS, with CD16a expressed by HEK293F cells and previous reports of CD16a from primary NK cells. Gene expression profiling by RNA-Seq and qRT-PCR revealed expression levels for glycan-modifying genes that correlated with CD16a glycan composition. These results identified a high degree of variability between the processing of the same human protein by different human cell types. N-glycan processing correlated with the expression of glycan-modifying genes and thus explained the substantial differences in CD16a processing by NK cells of different origins.
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Affiliation(s)
- Kashyap R Patel
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | | | - W Walter Lorenz
- Georgia Genomics and Bioinformatics Core and Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
| | - Emily M Mace
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Adam W Barb
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
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27
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Roushan A, Wilson GM, Kletter D, Sen KI, Tang W, Kil YJ, Carlson E, Bern M. Peak Filtering, Peak Annotation, and Wildcard Search for Glycoproteomics. Mol Cell Proteomics 2020; 20:100011. [PMID: 33578083 PMCID: PMC8724605 DOI: 10.1074/mcp.ra120.002260] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 12/11/2022] Open
Abstract
Glycopeptides in peptide or digested protein samples pose a number of analytical and bioinformatics challenges beyond those posed by unmodified peptides or peptides with smaller posttranslational modifications. Exact structural elucidation of glycans is generally beyond the capability of a single mass spectrometry experiment, so a reasonable level of identification for tandem mass spectrometry, taken by several glycopeptide software tools, is that of peptide sequence and glycan composition, meaning the number of monosaccharides of each distinct mass, e.g., HexNAc(2)Hex(5) rather than man5. Even at this level, however, glycopeptide analysis poses challenges: finding glycopeptide spectra when they are a tiny fraction of the total spectra; assigning spectra with unanticipated glycans, not in the initial glycan database; and finding, scoring, and labeling diagnostic peaks in tandem mass spectra. Here, we discuss recent improvements to Byonic, a glycoproteomics search program, that address these three issues. Byonic now supports filtering spectra by m/z peaks, so that the user can limit attention to spectra with diagnostic peaks, e.g., at least two out of three of 204.087 for HexNAc, 274.092 for NeuAc (with water loss), and 366.139 for HexNAc-Hex, all within a set mass tolerance, e.g., ± 0.01 Da. Also, new is glycan "wildcard" search, which allows an unspecified mass within a user-set mass range to be applied to N- or O-linked glycans and enables assignment of spectra with unanticipated glycans. Finally, the next release of Byonic supports user-specified peak annotations from user-defined posttranslational modifications. We demonstrate the utility of these new software features by finding previously unrecognized glycopeptides in publicly available data, including glycosylated neuropeptides from rat brain.
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Affiliation(s)
- Abhishek Roushan
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - Gary M Wilson
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - Doron Kletter
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - K Ilker Sen
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - Wilfred Tang
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - Yong J Kil
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - Eric Carlson
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA
| | - Marshall Bern
- Research and Development Group, Protein Metrics Inc, Cupertino, California, USA.
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28
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Yamaguchi Y, Barb AW. A synopsis of recent developments defining how N-glycosylation impacts immunoglobulin G structure and function. Glycobiology 2020; 30:214-225. [PMID: 31822882 DOI: 10.1093/glycob/cwz068] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/26/2019] [Accepted: 08/21/2019] [Indexed: 12/21/2022] Open
Abstract
Therapeutic monoclonal antibodies (mAbs) are the fastest growing group of drugs with 11 new antibodies or antibody-drug conjugates approved by the Food and Drug Administration in 2018. Many mAbs require effector function for efficacy, including antibody-dependent cell-mediated cytotoxicity triggered following contact of an immunoglobulin G (IgG)-coated particle with activating crystallizable fragment (Fc) γ receptors (FcγRs) expressed by leukocytes. Interactions between IgG1 and the FcγRs require post-translational modification of the Fc with an asparagine-linked carbohydrate (N-glycan). Though the structure of IgG1 Fc and the role of Fc N-glycan composition on disease were known for decades, the underlying mechanism of how the N-glycan affected FcγR binding was not defined until recently. This review will describe the current understanding of how N-glycosylation impacts the structure and function of the IgG1 Fc and describe new techniques that are poised to provide the next critical breakthroughs.
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Affiliation(s)
| | - Adam W Barb
- Department of Biochemistry and Molecular Biology and Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, 30602
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29
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de Haan N, Falck D, Wuhrer M. Monitoring of immunoglobulin N- and O-glycosylation in health and disease. Glycobiology 2020; 30:226-240. [PMID: 31281930 PMCID: PMC7225405 DOI: 10.1093/glycob/cwz048] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 12/11/2022] Open
Abstract
Protein N- and O-glycosylation are well known co- and post-translational modifications of immunoglobulins. Antibody glycosylation on the Fab and Fc portion is known to influence antigen binding and effector functions, respectively. To study associations between antibody glycosylation profiles and (patho) physiological states as well as antibody functionality, advanced technologies and methods are required. In-depth structural characterization of antibody glycosylation usually relies on the separation and tandem mass spectrometric (MS) analysis of released glycans. Protein- and site-specific information, on the other hand, may be obtained by the MS analysis of glycopeptides. With the development of high-resolution mass spectrometers, antibody glycosylation analysis at the intact or middle-up level has gained more interest, providing an integrated view of different post-translational modifications (including glycosylation). Alongside the in-depth methods, there is also great interest in robust, high-throughput techniques for routine glycosylation profiling in biopharma and clinical laboratories. With an emphasis on IgG Fc glycosylation, several highly robust separation-based techniques are employed for this purpose. In this review, we describe recent advances in MS methods, separation techniques and orthogonal approaches for the characterization of immunoglobulin glycosylation in different settings. We put emphasis on the current status and expected developments of antibody glycosylation analysis in biomedical, biopharmaceutical and clinical research.
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Affiliation(s)
- Noortje de Haan
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - David Falck
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
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30
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Unione L, Ardá A, Jiménez-Barbero J, Millet O. NMR of glycoproteins: profiling, structure, conformation and interactions. Curr Opin Struct Biol 2020; 68:9-17. [PMID: 33129067 DOI: 10.1016/j.sbi.2020.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 02/07/2023]
Abstract
In glycoproteins, carbohydrates are responsible for the selective interaction and tight regulation of cellular processes, constituting the main information transducer interface in protein-glycoprotein interactions. Increasing experimental and computational evidence suggest that such interactions often induce allosteric changes in the host protein, underlining the importance of studying intact glycoproteins. Technical issues have precluded such studies for years but, nowadays, a promising era is emerging where NMR spectroscopy, among other techniques, allows the characterization of the composition, structure and segmental dynamics of glycoproteins. In this review, we discuss such advances and highlight some selected examples. This novel technology unravels multiple new functional mechanisms, subtly hidden within the sugar code.
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Affiliation(s)
- Luca Unione
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, and Bijvoet Center for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Ana Ardá
- Molecular Recognition and Host-Pathogen Interactions, CIC bioGUNE, Basque Research and Technology Alliance, BRTA, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Jesús Jiménez-Barbero
- Molecular Recognition and Host-Pathogen Interactions, CIC bioGUNE, Basque Research and Technology Alliance, BRTA, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Bizkaia, Spain
| | - Oscar Millet
- Molecular Recognition and Host-Pathogen Interactions, CIC bioGUNE, Basque Research and Technology Alliance, BRTA, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain.
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31
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Aggregates in blood filter chambers used from the plasma donations of anti-D donors: evaluation for monoclonal antibody discovery using phage display. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2020; 19:64-72. [PMID: 33085594 DOI: 10.2450/2020.0093-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/17/2020] [Indexed: 12/29/2022]
Abstract
BACKGROUND RhD-immunoglobulin (RhIg) prevents anti-D alloimmunisation in D-negative pregnant women when the fetus is D-positive, reducing the incidence of haemolytic disease of the fetus and newborn. Manufacturing RhIg is reliant on the limited supply of plasma donations with anti-D antibodies. Monoclonal antibody (mAb) development platforms such as phage display, require blood samples to be collected from anti-D donors, which may be a complicated process. The blood filter chamber (BFC) discarded after an anti-D donor's donation might provide a source of Ig-encoding RNA. This study aims to evaluate whether used BFCs are a suitable source of Ig-encoding RNA for phage display. MATERIAL AND METHODS Haemonetics PCS2 BFCs were obtained from 10 anti-D donors for total RNA extraction, cDNA synthesis and amplification of VH and VL IgG sequences for assembly of single-chain variable fragments (scFvs). A scFv-phage display library was constructed and 3 rounds of biopanning were performed using D-positive and D-negative red blood cells (RBCs). Positive phage clones were isolated, Sanger sequenced and, where possible, reformatted into full-length human IgGs to define specificity. The BFC aggregates from 2 anti-D donors underwent a Wright-Giemsa stain and hematological cell count. RESULTS Of 10 BFCs, a sufficient yield of total RNA for library construction was obtained from BFCs containing cellular aggregates (n=5). Aggregate analysis showed lymphocytes were the cellular source of Ig-encoding RNA. From the 5 samples with aggregates, scFvs were assembled from amplified IgG variable regions. The library constructed from 1 of these samples resulted in the isolation of clones binding to D-positive RBCs with IGHV3 gene usage. Of the 4 reformatted IgG, 3 were anti-D and 1 had undefined specificity. DISCUSSION BFC aggregates are a new and convenient source of Ig-encoding RNA which can be used to construct Ig gene libraries for mAb isolation and discovery via antibody phage display.
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32
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Wojcik I, Sénard T, de Graaf EL, Janssen GMC, de Ru AH, Mohammed Y, van Veelen PA, Vidarsson G, Wuhrer M, Falck D. Site-Specific Glycosylation Mapping of Fc Gamma Receptor IIIb from Neutrophils of Individual Healthy Donors. Anal Chem 2020; 92:13172-13181. [PMID: 32886488 PMCID: PMC7547861 DOI: 10.1021/acs.analchem.0c02342] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/04/2020] [Indexed: 12/30/2022]
Abstract
Fc gamma receptors (FcγRs) translate antigen recognition by immunoglobulin G (IgG) into various immune responses. A better understanding of this key element of immunity promises novel insights into mechanisms of (auto-/allo-)immune diseases and more rationally designed antibody-based drugs. Glycosylation on both IgG and FcγR impacts their interaction dramatically. Regarding FcγR glycosylation profiling, major analytical challenges are associated with the presence of multiple glycosylation sites in close proximity and large structural heterogeneity. To address these challenges, we developed a straightforward and comprehensive analytical methodology to map FcγRIIIb glycosylation in primary human cells. After neutrophil isolation and immunoprecipitation, glycopeptides containing a single site each were generated by a dual-protease in-gel digestion. The complex mixture was resolved by liquid chromatography-tandem mass spectrometry (LC-MS/MS) providing information on the level of individual donors. In contrast to recently published alternatives for FcγRIIIb, we assessed its site-specific glycosylation in a single LC-MS/MS run and simultaneously determined the donor allotype. Studying FcγRIIIb derived from healthy donor neutrophils, we observed profound differences as compared to the soluble variant and the homologous FcγRIIIa on natural killer cells. This method will allow assessment of differences in FcγRIII glycosylation between individuals, cell types, subcellular locations, and pathophysiological conditions.
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Affiliation(s)
- Iwona Wojcik
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
- Glycoscience
Research Laboratory, Genos Ltd., Zagreb 10000, Croatia
| | - Thomas Sénard
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
| | - Erik L. de Graaf
- Department
of Experimental Immunohematology, Sanquin Research, and Landsteiner
Laboratory, Academic Medical Center, University
of Amsterdam, 1066 CX Amsterdam, The Netherlands
| | - George M. C. Janssen
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
| | - Arnoud H. de Ru
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
| | - Yassene Mohammed
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
| | - Peter A. van Veelen
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
| | - Gestur Vidarsson
- Department
of Experimental Immunohematology, Sanquin Research, and Landsteiner
Laboratory, Academic Medical Center, University
of Amsterdam, 1066 CX Amsterdam, The Netherlands
| | - Manfred Wuhrer
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
| | - David Falck
- Center
for Proteomics and Metabolomics, Leiden
University Medical Center, 2300 RC Leiden, The Netherlands
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33
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Washburn N, Meccariello R, Duffner J, Getchell K, Holte K, Prod'homme T, Srinivasan K, Prenovitz R, Lansing J, Capila I, Kaundinya G, Manning AM, Bosques CJ. Characterization of Endogenous Human FcγRIII by Mass Spectrometry Reveals Site, Allele and Sequence Specific Glycosylation. Mol Cell Proteomics 2020; 18:534-545. [PMID: 30559323 PMCID: PMC6398215 DOI: 10.1074/mcp.ra118.001142] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 11/21/2018] [Indexed: 12/21/2022] Open
Abstract
Characterization of endogenous FcγRIII glycosylation from healthy donors with different FcγRIIIb genotypes reveals site specific, and allele specific differences in glycosylation as well as noncananonical sequence specific differences in glycosylation. We propose these differences in glycosylation may influence the differential activity seen for neutrophils across genotypes. The importance of IgG glycosylation, Fc-gamma receptor (FcγR) single nucleotide polymorphisms and FcγR copy number variations in fine tuning the immune response has been well established. There is a growing appreciation of the importance of glycosylation of FcγRs in modulating the FcγR-IgG interaction based on the association between the glycosylation of recombinant FcγRs and the kinetics and affinity of the FcγR-IgG interaction. Although glycosylation of recombinant FcγRs has been recently characterized, limited knowledge exists on the glycosylation of endogenous human FcγRs. In order to improve the structural understanding of FcγRs expressed on human cells we characterized the site specific glycosylation of native human FcγRIII from neutrophils of 50 healthy donors and from matched plasma for 43 of these individuals. Through this analysis we have confirmed site specific glycosylation patterns previously reported for soluble FcγRIII from a single donor, identified FcγRIIIb specific Asn45 glycosylation and an allelic effect on glycosylation at Asn162 of FcγRIIIb. Identification of FcγRIIIb specific glycosylation allows for assignment of FcγRIIIb alleles and relative copy number of the two alleles where DNA/RNA is not available. Intriguingly the types of structures found to be elevated at Asn162 in the NA2 allele have been shown to destabilize the Fc:FcγRIII interaction resulting in a faster dissociation rate. These differences in glycosylation may in part explain the differential activity reported for the two alleles which have similar in vitro affinity for IgG.
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Affiliation(s)
- Nathaniel Washburn
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142.
| | - Robin Meccariello
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Jay Duffner
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Kristen Getchell
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Kimberly Holte
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Thomas Prod'homme
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Karunya Srinivasan
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Robert Prenovitz
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Jonathan Lansing
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Ishan Capila
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Ganesh Kaundinya
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Anthony M Manning
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
| | - Carlos J Bosques
- From the ‡Research Department, Momenta Pharmaceuticals, 301 Binney St., Cambridge, Massachusetts 02142
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34
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Temming AR, Bentlage AEH, de Taeye SW, Bosman GP, Lissenberg-Thunnissen SN, Derksen NIL, Brasser G, Mok JY, van Esch WJE, Howie HL, Zimring JC, Vidarsson G. Cross-reactivity of mouse IgG subclasses to human Fc gamma receptors: Antibody deglycosylation only eliminates IgG2b binding. Mol Immunol 2020; 127:79-86. [PMID: 32947169 DOI: 10.1016/j.molimm.2020.08.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/14/2020] [Accepted: 08/24/2020] [Indexed: 12/16/2022]
Abstract
Immunoglobulin G (IgG) antibodies are important for protection against pathogens and exert effector functions through binding to IgG-Fc receptors (FcγRs) on myeloid and natural killer cells, resulting in destruction of opsonized target cells. Despite interspecies differences, IgG subclasses and FcγRs show substantial similarities and functional conservation between mammals. Accordingly, binding of human IgG (hIgG) to mouse FcγRs (mFcγRs) has been utilized to study effector functions of hIgG in mice. In other applications, such as immunostaining with mouse IgG monoclonal antibodies (mAbs), these cross-reactivities are undesired and prone to misinterpretation. Despite this drawback, the binding of mouse IgG (mIgG) subclasses to human FcγR (hFcγR) classes has never been fully documented. Here, we report detailed and quantifiable characterization of binding affinities for all mIgG subclasses to hFcγRs, including functional polymorphic variants. mIgG subclasses show the strongest binding to hFcγRIa, with relative affinities mIgG2a = mIgG2c > mIgG3 >> mIgG2b, and no binding by mIgG1. hFcγRIIa/b showed general low reactivities to all mIgG (mIgG1> mIgG2a/c > mIgG2b), with no reactivity to mIgG3. A particularly high affinity was observed for mIgG1 to the hFcγRIIa-R131 polymorphic variant. hFcγRIIIa showed lower binding (mIgG2a/c > mIgG3), slightly favouring binding to the hFcγRIIIa-V158 over the F158 polymorphic variant. No binding was observed of mIgG to hFcγRIIIb. Deglycosylation of mIgG1 did not abrogate binding to hFcγRIIa-R131, nor did deglycosylation of mIgG2a/c and mIgG3 prevent hFcγRIa binding. Importantly, deglycosylation of the least cross-reactive mIgG subclass, mIgG2b, abrogated reactivity to all hFcγRs. Together, these data document for the first time the full spectrum of cross-reactivities of mouse IgG to human FcγRs.
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Affiliation(s)
- A Robin Temming
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Arthur E H Bentlage
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Steven W de Taeye
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Gerlof P Bosman
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Suzanne N Lissenberg-Thunnissen
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ninotska I L Derksen
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Juk Yee Mok
- Sanquin Reagents, Amsterdam, The Netherlands
| | | | - Heather L Howie
- Department of Pathology, Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, United States
| | - James C Zimring
- Department of Pathology, Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, United States
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Murin CD. Considerations of Antibody Geometric Constraints on NK Cell Antibody Dependent Cellular Cytotoxicity. Front Immunol 2020; 11:1635. [PMID: 32849559 PMCID: PMC7406664 DOI: 10.3389/fimmu.2020.01635] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/18/2020] [Indexed: 12/31/2022] Open
Abstract
It has been well-established that antibody isotype, glycosylation, and epitope all play roles in the process of antibody dependent cellular cytotoxicity (ADCC). For natural killer (NK) cells, these phenotypes are linked to cellular activation through interaction with the IgG receptor FcγRIIIa, a single pass transmembrane receptor that participates in cytoplasmic signaling complexes. Therefore, it has been hypothesized that there may be underlying spatial and geometric principles that guide proper assembly of an activation complex within the NK cell immune synapse. Further, synergy of antibody phenotypic properties as well as allosteric changes upon antigen binding may also play an as-of-yet unknown role in ADCC. Understanding these facets, however, remains hampered by difficulties associated with studying immune synapse dynamics using classical approaches. In this review, I will discuss relevant NK cell biology related to ADCC, including the structural biology of Fc gamma receptors, and how the dynamics of the NK cell immune synapse are being studied using innovative microscopy techniques. I will provide examples from the literature demonstrating the effects of spatial and geometric constraints on the T cell receptor complex and how this relates to intracellular signaling and the molecular nature of lymphocyte activation complexes, including those of NK cells. Finally, I will examine how the integration of high-throughput and "omics" technologies will influence basic NK cell biology research moving forward. Overall, the goal of this review is to lay a basis for understanding the development of drugs and therapeutic antibodies aimed at augmenting appropriate NK cell ADCC activity in patients being treated for a wide range of illnesses.
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Affiliation(s)
- Charles D. Murin
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, CA, United States
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36
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Cambay F, Forest-Nault C, Dumoulin L, Seguin A, Henry O, Durocher Y, De Crescenzo G. Glycosylation of Fcγ receptors influences their interaction with various IgG1 glycoforms. Mol Immunol 2020; 121:144-158. [PMID: 32222585 DOI: 10.1016/j.molimm.2020.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/26/2020] [Accepted: 03/16/2020] [Indexed: 12/11/2022]
Abstract
Most of therapeutic monoclonal antibodies belong to the immunoglobulin G1 (IgG1) family; they interact with the Fcγ receptors (FcγRs) at the surface of immune cells to trigger effector functions. The IgG1-Fc N-glycans impact the interaction with FcγRs and are considered a critical quality attribute. Pioneer studies on FcγR N-glycans have unveiled an additional complexity in that the N-glycan linked on the Asn-162 of FcγRIIIa was shown to be directly involved in the strong affinity for afucosylated IgG1. The last few years have thus seen the emergence of many studies investigating the complex influence of FcγRIIIa N-glycans on the interaction with IgG1 through their glycosylation sites or their glycoprofiles. In this context, we performed site-directed mutagenesis along with glycoengineering on FcγRs (FcγRI, FcγRIIaH131/b and FcγRIIIaV158/F158) in an effort to elucidate the impact of FcγRs N-glycans on the interaction with IgG1. Furthermore, we assessed their binding to various trastuzumab glycoforms with an enhanced surface plasmon resonance assay. The FcγRIIIa N-glycans had the highest impact on the interaction with IgG1. More specifically, the N162 glycan positively influenced the affinity (15-fold) for afucosylated IgG1 while the N45 glycan presented a negative impact (2-fold) regardless of the IgG1 glycoforms. Interestingly, only the FcγRIIIa glycoprofile had an impact on the interaction with IgG1 with a 1.5-fold affinity increase when FcγRIIIa displays high-mannose glycans. These results provide invaluable insights into the complex and strong influence of N-glycosylation upon FcγRs/IgG1 binding and are instrumental to further understand the impact of FcγRs N-glycosylation in their natural forms.
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Affiliation(s)
- Florian Cambay
- Department of Chemical Engineering, Polytechnique Montréal, Montreal, Canada; Human Health Therapeutics Research Centre, National Research Council of Canada, Montreal, Canada
| | - Catherine Forest-Nault
- Department of Chemical Engineering, Polytechnique Montréal, Montreal, Canada; Human Health Therapeutics Research Centre, National Research Council of Canada, Montreal, Canada
| | - Lea Dumoulin
- Department of Chemical Engineering, Polytechnique Montréal, Montreal, Canada
| | - Alexis Seguin
- Department of Chemical Engineering, Polytechnique Montréal, Montreal, Canada
| | - Olivier Henry
- Department of Chemical Engineering, Polytechnique Montréal, Montreal, Canada
| | - Yves Durocher
- Human Health Therapeutics Research Centre, National Research Council of Canada, Montreal, Canada; Department of Biochemistry and Molecular Medicine, University of Montreal, Montreal, Canada.
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Blundell PA, Lu D, Dell A, Haslam S, Pleass RJ. Choice of Host Cell Line Is Essential for the Functional Glycosylation of the Fc Region of Human IgG1 Inhibitors of Influenza B Viruses. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:1022-1034. [PMID: 31907284 PMCID: PMC6994840 DOI: 10.4049/jimmunol.1901145] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 12/02/2019] [Indexed: 12/11/2022]
Abstract
Abs are glycoproteins that carry a conserved N-linked carbohydrate attached to the Fc whose presence and fine structure profoundly impacts on their in vivo immunogenicity, pharmacokinetics, and functional attributes. The host cell line used to produce IgG plays a major role in this glycosylation, as different systems express different glycosylation enzymes and transporters that contribute to the specificity and heterogeneity of the final IgG-Fc glycosylation profile. In this study, we compare two panels of glycan-adapted IgG1-Fc mutants expressed in either the human endothelial kidney 293-F or Chinese hamster ovary-K1 systems. We show that the types of N-linked glycans between matched pairs of Fc mutants vary greatly and in particular, with respect, to sialylation. These cell line effects on glycosylation profoundly influence the ability of the engineered Fcs to interact with either human or pathogen receptors. For example, we describe Fc mutants that potently disrupted influenza B-mediated agglutination of human erythrocytes when expressed in Chinese hamster ovary-K1, but not in human endothelial kidney 293-F cells.
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Affiliation(s)
- Patricia A Blundell
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom; and
| | - Dongli Lu
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Anne Dell
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Stuart Haslam
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Richard J Pleass
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom; and
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Roberts JT, Patel KR, Barb AW. Site-specific N-glycan Analysis of Antibody-binding Fc γ Receptors from Primary Human Monocytes. Mol Cell Proteomics 2020; 19:362-374. [PMID: 31888963 PMCID: PMC7000114 DOI: 10.1074/mcp.ra119.001733] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/10/2019] [Indexed: 12/29/2022] Open
Abstract
FcγRIIIa (CD16a) and FcγRIIa (CD32a) on monocytes are essential for proper effector functions including antibody dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Indeed, therapeutic monoclonal antibodies (mAbs) that bind FcγRs with greater affinity exhibit greater efficacy. Furthermore, post-translational modification impacts antibody binding affinity, most notably the composition of the asparagine(N)-linked glycan at N162 of CD16a. CD16a is widely recognized as the key receptor for the monocyte response, however the post-translational modifications of CD16a from endogenous monocytes are not described. Here we isolated monocytes from individual donors and characterized the composition of CD16a and CD32a N-glycans from all modified sites. The composition of CD16a N-glycans varied by glycosylation site and donor. CD16a displayed primarily complex-type biantennary N-glycans at N162, however some individuals expressed CD16a V158 with ∼20% hybrid and oligomannose types which increased affinity for IgG1 Fc according to surface plasmon resonance binding analyses. The CD16a N45-glycans contain markedly less processing than other sites with >75% hybrid and oligomannose forms. N38 and N74 of CD16a both contain highly processed complex-type N-glycans with N-acetyllactosamine repeats and complex-type biantennary N-glycans dominate at N169. The composition of CD16a N-glycans isolated from monocytes included a higher proportion of oligomannose-type N-glycans at N45 and less sialylation plus greater branch fucosylation than we observed in a recent analysis of NK cell CD16a. The additional analysis of CD32a from monocytes revealed different features than observed for CD16a including the presence of a predominantly biantennary complex-type N-glycans with two sialic acids at both sites (N64 and N145).
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Affiliation(s)
- Jacob T Roberts
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames Iowa 50011
| | - Kashyap R Patel
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames Iowa 50011
| | - Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames Iowa 50011
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
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39
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Kang H, Larson NR, White DR, Middaugh CR, Tolbert T, Schöneich C. Effects of Glycan Structure on the Stability and Receptor Binding of an IgG4-Fc. J Pharm Sci 2020; 109:677-689. [DOI: 10.1016/j.xphs.2019.10.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/17/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023]
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40
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Gimeno A, Valverde P, Ardá A, Jiménez-Barbero J. Glycan structures and their interactions with proteins. A NMR view. Curr Opin Struct Biol 2019; 62:22-30. [PMID: 31835069 PMCID: PMC7322516 DOI: 10.1016/j.sbi.2019.11.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/28/2022]
Abstract
Carbohydrate molecules are essential actors in key biological events, being involved as recognition points for cell-cell and cell-matrix interactions related to health and disease. Despite outstanding advances in cryoEM, X-ray crystallography and NMR still remain the most employed techniques to unravel their conformational features and to describe the structural details of their interactions with biomolecular receptors. Given the intrinsic flexibility of saccharides, NMR methods are of paramount importance to deduce the extent of motion around their glycosidic linkages and to explore their receptor-bound conformations. We herein present our particular view on the latest advances in NMR methodologies that are permitting to magnify their applications for deducing glycan conformation and dynamics and understanding the recognition events in which there are involved.
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Affiliation(s)
- Ana Gimeno
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Pablo Valverde
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Ana Ardá
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Jesús Jiménez-Barbero
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Bizkaia, Spain; Department of Organic Chemistry II, University of the Basque Country, UPV/EHU, 48940 Leioa, Bizkaia, Spain
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41
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Patel KR, Nott JD, Barb AW. Primary Human Natural Killer Cells Retain Proinflammatory IgG1 at the Cell Surface and Express CD16a Glycoforms with Donor-dependent Variability. Mol Cell Proteomics 2019; 18:2178-2190. [PMID: 31467031 PMCID: PMC6823852 DOI: 10.1074/mcp.ra119.001607] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/02/2019] [Indexed: 11/06/2022] Open
Abstract
Post-translational modification confers diverse functional properties to immune system proteins. The composition of serum proteins such as immunoglobulin G (IgG) strongly associates with disease including forms lacking a fucose modification of the crystallizable fragment (Fc) asparagine(N)-linked glycan that show increased effector function, however, virtually nothing is known about the composition of cell surface receptors or their bound ligands in situ because of low abundance in the circulating blood. We isolated primary NK cells from apheresis filters following plasma or platelet donation to characterize the compositional variability of Fc γ receptor IIIa/CD16a and its bound ligand, IgG1. CD16a N162-glycans showed the largest differences between donors; one donor displayed only oligomannose-type N-glycans at N162 that correlate with high affinity IgG1 Fc binding whereas the other donors displayed a high degree of compositional variability at this site. Hybrid-type N-glycans with intermediate processing dominated at N45 and highly modified, complex-type N-glycans decorated N38 and N74 from all donors. Analysis of the IgG1 ligand bound to NK cell CD16a revealed a sharp decrease in antibody fucosylation (43.2 ± 11.0%) versus serum from the same donors (89.7 ± 3.9%). Thus, NK cells express CD16a with unique modification patterns and preferentially bind IgG1 without the Fc fucose modification at the cell surface.
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Affiliation(s)
- Kashyap R Patel
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames IA 50011
| | - Joel D Nott
- Office of Biotechnology, Protein Facility, Iowa State University, Ames IA 50011
| | - Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames IA 50011; Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602; Complex Carbohydrate Research Center, University of Georgia, Athens 30602.
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42
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Lippold S, Nicolardi S, Domínguez-Vega E, Heidenreich AK, Vidarsson G, Reusch D, Haberger M, Wuhrer M, Falck D. Glycoform-resolved FcɣRIIIa affinity chromatography-mass spectrometry. MAbs 2019; 11:1191-1196. [PMID: 31276431 PMCID: PMC6748599 DOI: 10.1080/19420862.2019.1636602] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/11/2019] [Accepted: 06/24/2019] [Indexed: 01/20/2023] Open
Abstract
Determination of the impact of individual antibody glycoforms on FcɣRIIIa affinity, and consequently antibody-dependent cell-mediated cytotoxicity (ADCC) previously required high purity glycoengineering. We hyphenated FcɣRIIIa affinity chromatography to mass spectrometry, which allowed direct affinity comparison of glycoforms of intact monoclonal antibodies. The approach enabled reproduction and refinement of known glycosylation effects, and insights on afucosylation pairing as well as on low-abundant, unstudied glycoforms. Our method greatly improves the understanding of individual glycoform structure-function relationships. Thus, it is highly relevant for assessing Fc-glycosylation critical quality attributes related to ADCC.
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Affiliation(s)
- Steffen Lippold
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Simone Nicolardi
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Elena Domínguez-Vega
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Dietmar Reusch
- Pharma Technical Development Penzberg, Roche Diagnostics GmbH, Penzberg, Germany
| | - Markus Haberger
- Pharma Technical Development Penzberg, Roche Diagnostics GmbH, Penzberg, Germany
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - David Falck
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
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43
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Göritzer K, Turupcu A, Maresch D, Novak J, Altmann F, Oostenbrink C, Obinger C, Strasser R. Distinct Fcα receptor N-glycans modulate the binding affinity to immunoglobulin A (IgA) antibodies. J Biol Chem 2019; 294:13995-14008. [PMID: 31362986 PMCID: PMC6755811 DOI: 10.1074/jbc.ra119.009954] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/23/2019] [Indexed: 01/10/2023] Open
Abstract
Human immunoglobulin A (IgA) is the most prevalent antibody class at mucosal sites with an important role in mucosal defense. Little is known about the impact of N-glycan modifications of IgA1 and IgA2 on binding to the Fcα receptor (FcαRI), which is also heavily glycosylated at its extracellular domain. Here, we transiently expressed human epidermal growth factor receptor 2 (HER2)-binding monomeric IgA1, IgA2m(1), and IgA2m(2) variants in Nicotiana benthamiana ΔXT/FT plants lacking the enzymes responsible for generating nonhuman N-glycan structures. By coinfiltrating IgA with the respective glycan-modifying enzymes, we generated IgA carrying distinct homogenous N-glycans. We demonstrate that distinctly different N-glycan profiles did not influence antigen binding or the overall structure and integrity of the IgA antibodies but did affect their thermal stability. Using size-exclusion chromatography, differential scanning and isothermal titration calorimetry, surface plasmon resonance spectroscopy, and molecular modeling, we probed distinct IgA1 and IgA2 glycoforms for binding to four different FcαRI glycoforms and investigated the thermodynamics and kinetics of complex formation. Our results suggest that different N-glycans on the receptor significantly contribute to binding affinities for its cognate ligand. We also noted that full-length IgA and FcαRI form a mixture of 1:1 and 1:2 complexes tending toward a 1:1 stoichiometry due to different IgA tailpiece conformations that make it less likely that both binding sites are simultaneously occupied. In conclusion, N-glycans of human IgA do not affect its structure and integrity but its thermal stability, and FcαRI N-glycans significantly modulate binding affinity to IgA.
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Affiliation(s)
- Kathrin Göritzer
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Aysegül Turupcu
- Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Daniel Maresch
- Department of Chemistry, Division of Biochemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Jan Novak
- Department of Microbiology, University of Alabama, Birmingham, Alabama 35294
| | - Friedrich Altmann
- Department of Chemistry, Division of Biochemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Chris Oostenbrink
- Department of Material Sciences and Process Engineering, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Division of Biochemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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44
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Bhatti MM, Cai AG, Theunissen JW. Binding affinities of human IgG1 and chimerized pig and rabbit derivatives to human, pig and rabbit Fc gamma receptor IIIA. PLoS One 2019; 14:e0219999. [PMID: 31323052 PMCID: PMC6641210 DOI: 10.1371/journal.pone.0219999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/05/2019] [Indexed: 11/22/2022] Open
Abstract
While pigs and rabbits are used as models for human immune diseases, FcγR binding is poorly characterized in both test species. To evaluate antibody binding to FcγRIIIA, a receptor involved in antibody-dependent cellular cytotoxicity, chimerized antibodies were generated by grafting the variable regions of a human IgG1 onto scaffolds from both species. The affinities of the parent and chimeric antibodies to the FcγRIIIA proteins from all three species were determined. While the human IgG1 and rabbit IgG had similar affinities for each FcγRIIIA with notable differences across species, pig IgG1 only bound pig FcγRIIIA with appreciable affinity. Also, the functional pig and rabbit proteins described here can be used in future experiments, such as pharmacology and mechanism of action studies.
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Affiliation(s)
- Maryam M. Bhatti
- Iconic Therapeutics, South San Francisco, CA, United States of America
| | - Allen G. Cai
- Iconic Therapeutics, South San Francisco, CA, United States of America
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45
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de Taeye SW, Rispens T, Vidarsson G. The Ligands for Human IgG and Their Effector Functions. Antibodies (Basel) 2019; 8:E30. [PMID: 31544836 PMCID: PMC6640714 DOI: 10.3390/antib8020030] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 01/17/2023] Open
Abstract
Activation of the humoral immune system is initiated when antibodies recognize an antigen and trigger effector functions through the interaction with Fc engaging molecules. The most abundant immunoglobulin isotype in serum is Immunoglobulin G (IgG), which is involved in many humoral immune responses, strongly interacting with effector molecules. The IgG subclass, allotype, and glycosylation pattern, among other factors, determine the interaction strength of the IgG-Fc domain with these Fc engaging molecules, and thereby the potential strength of their effector potential. The molecules responsible for the effector phase include the classical IgG-Fc receptors (FcγR), the neonatal Fc-receptor (FcRn), the Tripartite motif-containing protein 21 (TRIM21), the first component of the classical complement cascade (C1), and possibly, the Fc-receptor-like receptors (FcRL4/5). Here we provide an overview of the interactions of IgG with effector molecules and discuss how natural variation on the antibody and effector molecule side shapes the biological activities of antibodies. The increasing knowledge on the Fc-mediated effector functions of antibodies drives the development of better therapeutic antibodies for cancer immunotherapy or treatment of autoimmune diseases.
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Affiliation(s)
- Steven W de Taeye
- Sanquin Research, Dept Immunopathology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
- Sanquin Research, Dept Experimental Immunohematology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
| | - Theo Rispens
- Sanquin Research, Dept Immunopathology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
| | - Gestur Vidarsson
- Sanquin Research, Dept Experimental Immunohematology and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
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46
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Tolbert WD, Subedi GP, Gohain N, Lewis GK, Patel KR, Barb AW, Pazgier M. From Rhesus macaque to human: structural evolutionary pathways for immunoglobulin G subclasses. MAbs 2019; 11:709-724. [PMID: 30939981 PMCID: PMC6601566 DOI: 10.1080/19420862.2019.1589852] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/15/2019] [Accepted: 02/22/2019] [Indexed: 10/27/2022] Open
Abstract
The Old World monkey, Rhesus macaque (Macaca mulatta, Mm), is frequently used as a primate model organism in the study of human disease and to test new vaccines/antibody treatments despite diverging before chimpanzees and orangutans. Mm and humans share 93% genome identity with substantial differences in the genes of the adaptive immune system that lead to different functional IgG subclass characteristics, Fcγ receptors expressed on innate immune cells, and biological interactions. These differences put limitations on Mm use as a primary animal model in the study of human disease and to test new vaccines/antibody treatments. Here, we comprehensively analyzed molecular properties of the Fc domain of the four IgG subclasses of Rhesus macaque to describe potential mechanisms for their interactions with effector cell Fc receptors. Our studies revealed less diversity in the overall structure among the Mm IgG Fc, with MmIgG1 Fc being the most structurally like human IgG3, although its CH2 loops and N297 glycan mobility are comparable to human IgG1. Furthermore, the Fcs of Mm IgG3 and 4 lack the structural properties typical for their human orthologues that determine IgG3's reduced interaction with the neonatal receptor and IgG4's ability for Fab-arm exchange and its weaker Fcγ receptor interactions. Taken together, our data indicate that MmIgG1-4 are less structurally divergent than the human IgGs, with only MmIgG1 matching the molecular properties of human IgG1 and 3, the most active IgGs in terms of Fcγ receptor binding and Fc-mediated functions. PDB accession numbers for deposited structures are 6D4E, 6D4I, 6D4M, and 6D4N for MmIgG1 Fc, MmIgG2 Fc, MmIgG3 Fc, and MmIgG4 Fc, respectively.
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Affiliation(s)
- William David Tolbert
- Division of Vaccine Research, Institute of Human Virology of University of Maryland School of Medicine, Baltimore, MD, USA
- Infectious Disease Division, Uniformed Services University of the Health Sciences, Bethesda, MD
| | - Ganesh Prasad Subedi
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology of Iowa State University, Ames, IA, USA
| | - Neelakshi Gohain
- Division of Vaccine Research, Institute of Human Virology of University of Maryland School of Medicine, Baltimore, MD, USA
| | - George Kenneth Lewis
- Division of Vaccine Research, Institute of Human Virology of University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kashyap Rajesh Patel
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology of Iowa State University, Ames, IA, USA
| | - Adam Wesley Barb
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology of Iowa State University, Ames, IA, USA
| | - Marzena Pazgier
- Division of Vaccine Research, Institute of Human Virology of University of Maryland School of Medicine, Baltimore, MD, USA
- Infectious Disease Division, Uniformed Services University of the Health Sciences, Bethesda, MD
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47
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Kang TH, Lee CH, Delidakis G, Jung J, Richard-Le Goff O, Lee J, Kim JE, Charab W, Bruhns P, Georgiou G. An Engineered Human Fc variant With Exquisite Selectivity for FcγRIIIa V158 Reveals That Ligation of FcγRIIIa Mediates Potent Antibody Dependent Cellular Phagocytosis With GM-CSF-Differentiated Macrophages. Front Immunol 2019; 10:562. [PMID: 30984171 PMCID: PMC6448688 DOI: 10.3389/fimmu.2019.00562] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/04/2019] [Indexed: 01/27/2023] Open
Abstract
IgG antibodies mediate the clearance of target cells via the engagement of Fc gamma receptors (FcγRs) on effector cells by eliciting antibody-dependent cellular cytotoxicity and phagocytosis (ADCC and ADCP, respectively). Because (i) the IgG Fc domain binds to multiple FcγRs with varying affinities; (ii) even low Fc:FcγRs affinity interactions can play a significant role when antibodies are engaged in high avidity immune complexes and (iii) most effector cells express multiple FcγRs, the clearance mechanisms that can be mediated by individual FcγR are not well-understood. Human FcγRIIIa (hFcγRIIIa; CD16a), which exists as two polymorphic variants at position 158, hFcγRIIIaV158 and hFcγRIIIaF158, is widely considered to only trigger ADCC, especially with natural killer (NK) cells as effectors. To evaluate the role of hFcγRIIIa ligation in myeloid-derived effector cells, and in particular on macrophages and monocytes which express multiple FcγRs, we engineered an aglycosylated engineered human Fc (hFc) variant, Fc3aV, which binds exclusively to hFcγRIIIaV158. Antibodies formatted with the Fc3aV variant bind to the hFcγRIIIaV158 allotype with a somewhat lower KD than their wild type IgG1 counterparts, but not to any other hFcγR. The exceptional selectivity for hFcγRIIIaV158 was demonstrated by SPR using increased avidity, dimerized GST-fused versions of the ectodomains of hFcγRs and from the absence of binding of large immune complex (IC) to CHO cells expressing each of the hFcγRs, including notably, the FcγRIIIaF158 variant or the highly homologous FcγRIIIb. We show that even though monocyte-derived GM-CSF differentiated macrophages express hFcγRIIIa at substantially lower levels than the other two major activating receptors, namely hFcγRI or hFcγRIIa, Fc3aV-formatted Rituximab and Herceptin perform ADCP toward CD20- and Her2-expressing cancer cells, respectively, at a level comparable to that of the respective wild-type antibodies. We further show that hFcγRIIIa activation plays a significant role on ADCC by human peripheral monocytes. Our data highlight the utility of Fc3aV and other similarly engineered exquisitely selective, aglycosylated Fc variants toward other hFcγRs as tools for the detailed molecular understanding of hFcγR biology.
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Affiliation(s)
- Tae Hyun Kang
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Chang-Han Lee
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - George Delidakis
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Jiwon Jung
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Odile Richard-Le Goff
- Unit of Antibodies in Therapy and Pathology, Department of Immunology, Institut Pasteur, Paris, France
| | - Jiwon Lee
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Jin Eyun Kim
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Wissam Charab
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Pierre Bruhns
- Unit of Antibodies in Therapy and Pathology, Department of Immunology, Institut Pasteur, Paris, France.,INSERM, U1222, Paris, France
| | - George Georgiou
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States.,Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX, United States.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, United States
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48
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Abstract
Receptors recognizing the Fc-part of immunoglobulins (FcR) are important in the engagement of phagocytes with opsonized micro-organisms, but they also play a major role in the pathogenesis of chronic inflammatory diseases. Different FcRs are specifically recognizing and binding the different classes of immunoglobulins, transmitting different signals into the cell. The function of IgG (FcγR's) and IgA (FcαR) recognizing receptors is controlled by cellular signals evoked by activation of heterologous receptors in a process generally referred to as inside-out control. This concept is clearly described for the regulation of integrin receptors. Inside-out control can be achieved at different levels by modulation of: (i) receptor affinity, (ii) receptor avidity/valency, (iii) interaction with signaling chains, (iv) interaction with other receptors and (v) localization in functionally different membrane domains. The inside-out control of FcRs is an interesting target for novel therapy by therapeutical antibodies as it can potentiate or decrease the functionality of the response to the antibodies depending on the mechanisms of the diseases they are applied for.
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Affiliation(s)
- Leo Koenderman
- Department of Respiratory Medicine and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
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49
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Patel KR, Roberts JT, Barb AW. Multiple Variables at the Leukocyte Cell Surface Impact Fc γ Receptor-Dependent Mechanisms. Front Immunol 2019; 10:223. [PMID: 30837990 PMCID: PMC6382684 DOI: 10.3389/fimmu.2019.00223] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/25/2019] [Indexed: 12/18/2022] Open
Abstract
Fc γ receptors (FcγR) expressed on the surface of human leukocytes bind clusters of immunoglobulin G (IgG) to induce a variety of responses. Many therapeutic antibodies and vaccine-elicited antibodies prevent or treat infectious diseases, cancers and autoimmune disorders by binding FcγRs, thus there is a need to fully define the variables that impact antibody-induced mechanisms to properly evaluate candidate therapies and design new intervention strategies. A multitude of factors influence the IgG-FcγR interaction; one well-described factor is the differential affinity of the six distinct FcγRs for the four human IgG subclasses. However, there are several other recently described factors that may prove more relevant for disease treatment. This review covers recent reports of several aspects found at the leukocyte membrane or outside the cell that contribute to the cell-based response to antibody-coated targets. One major focus is recent reports covering post-translational modification of the FcγRs, including asparagine-linked glycosylation. This review also covers the organization of FcγRs at the cell surface, and properties of the immune complex. Recent technical advances provide high-resolution measurements of these often-overlooked variables in leukocyte function and immune system activation.
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Affiliation(s)
- Kashyap R Patel
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Jacob T Roberts
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
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50
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Abstract
Immunoglobulin G (IgG) antibodies function, in part, through ligation of cell-surface Fc receptors such as FcγRIIIA (also known as CD16A). IgG glycosylation is known to impact antibody function, but the role of FcγRIIIA glycans, if any, is unclear. Patel et al. now reveal that these glycans do impact protein conformation and IgG affinity and display cell-specific glycosylation patterns, leading to a potential model in which the affinity and possibly function of Fc receptors is dictated by the cell type and its surface glycome.
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Affiliation(s)
- Kelsey D Oliva
- From the Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44107
| | - Jill M Cavanaugh
- From the Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44107
| | - Brian A Cobb
- From the Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44107
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