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Sastre DE, Sultana N, V A S Navarro M, Huliciak M, Du J, Cifuente JO, Flowers M, Liu X, Lollar P, Trastoy B, Guerin ME, Sundberg EJ. Human gut microbes express functionally distinct endoglycosidases to metabolize the same N-glycan substrate. Nat Commun 2024; 15:5123. [PMID: 38879612 PMCID: PMC11180146 DOI: 10.1038/s41467-024-48802-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 05/15/2024] [Indexed: 06/18/2024] Open
Abstract
Bacteroidales (syn. Bacteroidetes) are prominent members of the human gastrointestinal ecosystem mainly due to their efficient glycan-degrading machinery, organized into gene clusters known as polysaccharide utilization loci (PULs). A single PUL was reported for catabolism of high-mannose (HM) N-glycan glyco-polypeptides in the gut symbiont Bacteroides thetaiotaomicron, encoding a surface endo-β-N-acetylglucosaminidase (ENGase), BT3987. Here, we discover an ENGase from the GH18 family in B. thetaiotaomicron, BT1285, encoded in a distinct PUL with its own repertoire of proteins for catabolism of the same HM N-glycan substrate as that of BT3987. We employ X-ray crystallography, electron microscopy, mass spectrometry-based activity measurements, alanine scanning mutagenesis and a broad range of biophysical methods to comprehensively define the molecular mechanism by which BT1285 recognizes and hydrolyzes HM N-glycans, revealing that the stabilities and activities of BT1285 and BT3987 were optimal in markedly different conditions. BT1285 exhibits significantly higher affinity and faster hydrolysis of poorly accessible HM N-glycans than does BT3987. We also find that two HM-processing endoglycosidases from the human gut-resident Alistipes finegoldii display condition-specific functional properties. Altogether, our data suggest that human gut microbes employ evolutionary strategies to express distinct ENGases in order to optimally metabolize the same N-glycan substrate in the gastroinstestinal tract.
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Affiliation(s)
- Diego E Sastre
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.
| | - Nazneen Sultana
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
- Structural Biochemistry Unit, National Institute of Dental and Craniofacial Research (NIDCR/NIH), Bethesda, MD, USA
| | - Marcos V A S Navarro
- Institute of Physics (IFSC-USP), University of São Paulo, São Carlos, SP, Brazil
- Center for Innovative Proteomics, Cornell University, Ithaca, NY, USA
| | - Maros Huliciak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Jonathan Du
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
- Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, Australia
| | - Javier O Cifuente
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, Leioa, Spain
| | - Maria Flowers
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Xu Liu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Pete Lollar
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Beatriz Trastoy
- Structural Glycoimmunology Laboratory, Biobizkaia Health Research Institute, Barakaldo, Bizkaia, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Marcelo E Guerin
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology, Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona Science Park, c/Baldiri Reixac 4-8, Tower R, Barcelona, Catalonia, Spain
| | - Eric J Sundberg
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA.
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2
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Aguilar Díaz de león JS, Thirumurty M, Ly N. Surface plasmon resonance microscopy identifies glycan heterogeneity in pancreatic cancer cells that influences mucin-4 binding interactions. PLoS One 2024; 19:e0304154. [PMID: 38776309 PMCID: PMC11111020 DOI: 10.1371/journal.pone.0304154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 05/07/2024] [Indexed: 05/24/2024] Open
Abstract
Membrane proteins are the main targets of therapeutic drugs and most of them are glycosylated. Glycans play pivotal roles in several biological processes, and glycosylation changes are a well-established hallmark of several types of cancer, including pancreatic cancer, that contribute to tumor growth. Mucin-4 (MUC-4) is a membrane glycoprotein which is associated with pancreatic cancer and metastasis, and it has been targeted as a promising vaccine candidate. In this study, Surface Plasmon Resonance Microscopy (SPRM) was implemented to study complex influences of the native N-glycan cellular environment on binding interactions to the MUC-4 receptor as this is currently the only commercially available label-free technique with high enough sensitivity and resolution to measure binding kinetics and heterogeneity on single cells. Such unique capability enables for a more accurate understanding of the "true" binding interactions on human cancer cells without disrupting the native environment of the target MUC-4 receptor. Removal of N-linked glycans in pancreatic cancer cells using PNGase F exposed heterogeneity in Concanavalin (Con A) binding by revealing three new binding populations with higher affinities than the glycosylated control cells. Anti-MUC-4 binding interactions of enzymatically N-linked deglycosylated pancreatic cancer cells produced a 25x faster association and 37x higher affinity relative to the glycosylated control cells. Lastly, four interaction modes were observed for Helix Pomatia Agglutinin (HPA) binding to the glycosylated control cells, but shifted and increased in activity upon removal of N-linked glycans. These results identified predominant interaction modes of glycan and MUC-4 in pancreatic cancer cells, the kinetics of their binding interactions were quantified, and the influence of N-linked glycans in MUC-4 binding interactions was revealed.
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Affiliation(s)
| | - Miyuki Thirumurty
- Biosensing Instrument Inc., Tempe, Arizona, United States of America
| | - Nguyen Ly
- Biosensing Instrument Inc., Tempe, Arizona, United States of America
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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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Wang R, Guo J, Li G, Wang X, Yang J, Li Q, Zhang G. Identification of the Linear Fc-Binding Site on the Bovine IgG1 Fc Receptor (boFcγRIII) Using Synthetic Peptides. Vet Sci 2024; 11:24. [PMID: 38250930 PMCID: PMC10818675 DOI: 10.3390/vetsci11010024] [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: 10/08/2023] [Revised: 12/18/2023] [Accepted: 01/03/2024] [Indexed: 01/23/2024] Open
Abstract
The bovine IgG1 Fc receptor (boFcγRIII) is a homologue to human FcγRIII (CD16) that binds bovine IgGI with medium-low affinity. In order to identify the Fc-binding site on the bovine IgG1 Fc receptor (boFcγRIII), peptides derived from the second extracellular domain (EC2) of boFcγRIII were synthesized and conjugated with the carrier protein. With a Dot-blot assay, the ability of the peptides to bind bovine IgG1 was determined, and the IgG1-binding peptide was also identified via truncation and mutation. The minimal peptide AQRVVN corresponding to the sequence 98-103 of boFcγRIII bound bovine IgG1 in Dot-blot, suggesting that it represents a linear ligand-binding site located in the putative A-B loop of the boFcγRIII EC2 domain. Mutation analysis of the peptide showed that the residues of Ala98, Gln99, Val101, Val102 and Asn103 within the Fc-binding site are critical for IgG1 binding on boFcγRIII. The functional peptide identified in this paper is of great value to the IgG-Fc interaction study and FcR-targeting drug development.
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Affiliation(s)
- Ruining Wang
- Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (R.W.); (J.G.); (J.Y.)
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economics, Zhengzhou 450046, China
| | - Junqing Guo
- Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (R.W.); (J.G.); (J.Y.)
| | - Ge Li
- College of Veterinary Medicine, Northwest A&F University, Xianyang 712100, China;
| | - Xun Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China;
| | - Jifei Yang
- Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (R.W.); (J.G.); (J.Y.)
| | - Qingmei Li
- Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (R.W.); (J.G.); (J.Y.)
| | - Gaiping Zhang
- Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; (R.W.); (J.G.); (J.Y.)
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China;
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou 225009, China
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5
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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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6
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Alasmari MM. A Review of Margetuximab-Based Therapies in Patients with HER2-Positive Metastatic Breast Cancer. Cancers (Basel) 2022; 15:cancers15010038. [PMID: 36612034 PMCID: PMC9817862 DOI: 10.3390/cancers15010038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Breast cancer (BC) is the most commonly diagnosed cancer globally, with high mortality rates. Targeted drug therapies have revolutionized cancer treatment. For example, treatment with human epidermal receptor 2 (HER2) antagonists has markedly improved the prognosis of patients with HER2-positive BC (HER2 + BC). However, HER2+ metastatic BC (MBC) remains prevalent owing to its resistance to conventional anti-HER2 drugs. Therefore, novel agents are needed to overcome the limitations of existing cancer treatments and to enhance the progression-free and overall survival rates. Progress has been made by optimizing the fragment crystallizable (Fc) domain of trastuzumab, an IgG1 monoclonal, chimeric anti-HER2 antibody, to develop margetuximab. The modified Fc domain of margetuximab enhances its binding affinity to CD16A and decreases its binding affinity to CD32B, thereby promoting its antitumor activity. This review summarizes studies on the efficacy of margetuximab, discusses its utility as an anti-HER2 monoclonal antibody drug for the treatment of HER2 + BC, and presents the latest advances in the treatment of BC. This review provides insights into the clinical implication of margetuximab in HER2 + MBC treatment.
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Affiliation(s)
- Moudi M. Alasmari
- College of Medicine, King Saud Bin Abdul Aziz University for Health Sciences (KSAU-HS), Jeddah 21461, Saudi Arabia;
- King Abdullah International Medical Research Centre (KAIMRC), Jeddah 21423, Saudi Arabia
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7
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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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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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9
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Single-dose HPV vaccine immunity: is there a role for non-neutralizing antibodies? Trends Immunol 2022; 43:815-825. [PMID: 35995705 DOI: 10.1016/j.it.2022.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 11/22/2022]
Abstract
A single dose of human papillomavirus (HPV) vaccine against HPV infection (prerequisite for cervical cancer) appears to be as efficacious as two or three doses, despite inducing lower antibody titers. Neutralizing antibodies are thought to be the primary mediator of protection, but the threshold for protection is unknown. Antibody functions beyond neutralization have not been explored for HPV vaccines. Here, we discuss the immune mechanisms of HPV vaccines, with a focus on non-neutralizing antibody effector functions. In the context of single-dose HPV vaccination where antibody is limiting, we propose that non-neutralizing antibody functions may contribute to preventing HPV infection. Understanding the immunological basis of protection for single-dose HPV vaccination will provide a rationale for implementing single-dose HPV vaccine regimens.
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10
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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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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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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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