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Petralia LMC, Santha E, Behrens AJ, Nguyen DL, Ganatra MB, Taron CH, Khatri V, Kalyanasundaram R, van Diepen A, Hokke CH, Foster JM. Alteration of rhesus macaque serum N-glycome during infection with the human parasitic filarial nematode Brugia malayi. Sci Rep 2022; 12:15763. [PMID: 36131114 PMCID: PMC9491660 DOI: 10.1038/s41598-022-19964-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/07/2022] [Indexed: 11/09/2022] Open
Abstract
Serum N-glycan profiling studies during the past decades have shown robust associations between N-glycan changes and various biological conditions, including infections, in humans. Similar studies are scarcer for other mammals, despite the tremendous potential of serum N-glycans as biomarkers for infectious diseases in animal models of human disease and in the veterinary context. To expand the knowledge of serum N-glycan profiles in important mammalian model systems, in this study, we combined MALDI-TOF-MS analysis and HILIC-UPLC profiling of released N-glycans together with glycosidase treatments to characterize the glycan structures present in rhesus macaque serum. We used this baseline to monitor changes in serum N-glycans during infection with Brugia malayi, a parasitic nematode of humans responsible for lymphatic filariasis, in a longitudinal cohort of infected rhesus macaques. Alterations of the HILIC-UPLC profile, notably of abundant structures, became evident as early as 5 weeks post-infection. Given its prominent role in the immune response, contribution of immunoglobulin G to serum N-glycans was investigated. Finally, comparison with similar N-glycan profiling performed during infection with the dog heartworm Dirofilaria immitis suggests that many changes observed in rhesus macaque serum N-glycans are specific for lymphatic filariasis.
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Affiliation(s)
- Laudine M C Petralia
- Division of Protein Expression and Modification, New England Biolabs, Ipswich, MA, 01938, USA.
- Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
| | - Esrath Santha
- Division of Protein Expression and Modification, New England Biolabs, Ipswich, MA, 01938, USA
| | - Anna-Janina Behrens
- Division of Protein Expression and Modification, New England Biolabs, Ipswich, MA, 01938, USA
| | - D Linh Nguyen
- Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Mehul B Ganatra
- Division of Protein Expression and Modification, New England Biolabs, Ipswich, MA, 01938, USA
| | - Christopher H Taron
- Division of Protein Expression and Modification, New England Biolabs, Ipswich, MA, 01938, USA
| | - Vishal Khatri
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - Ramaswamy Kalyanasundaram
- Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, IL, USA
| | - Angela van Diepen
- Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Cornelis H Hokke
- Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Jeremy M Foster
- Division of Protein Expression and Modification, New England Biolabs, Ipswich, MA, 01938, USA.
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2
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Jaiman A, Thattai M. Golgi compartments enable controlled biomolecular assembly using promiscuous enzymes. eLife 2020; 9:49573. [PMID: 32597757 PMCID: PMC7360365 DOI: 10.7554/elife.49573] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 06/28/2020] [Indexed: 12/31/2022] Open
Abstract
The synthesis of eukaryotic glycans - branched sugar oligomers attached to cell-surface proteins and lipids - is organized like a factory assembly line. Specific enzymes within successive compartments of the Golgi apparatus determine where new monomer building blocks are linked to the growing oligomer. These enzymes act promiscuously and stochastically, causing microheterogeneity (molecule-to-molecule variability) in the final oligomer products. However, this variability is tightly controlled: a given eukaryotic protein type is typically associated with a narrow, specific glycan oligomer profile. Here, we use ideas from the mathematical theory of self-assembly to enumerate the enzymatic causes of oligomer variability and show how to eliminate each cause. We rigorously demonstrate that cells can specifically synthesize a larger repertoire of glycan oligomers by partitioning promiscuous enzymes across multiple Golgi compartments. This places limits on biomolecular assembly: glycan microheterogeneity becomes unavoidable when the number of compartments is limited, or enzymes are excessively promiscuous.
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Affiliation(s)
- Anjali Jaiman
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Mukund Thattai
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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3
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Behrens AJ, Duke RM, Petralia LM, Harvey DJ, Lehoux S, Magnelli PE, Taron CH, Foster JM. Glycosylation profiling of dog serum reveals differences compared to human serum. Glycobiology 2019; 28:825-831. [PMID: 30137320 PMCID: PMC6192460 DOI: 10.1093/glycob/cwy070] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/30/2018] [Indexed: 12/12/2022] Open
Abstract
Glycosylation is the most common post-translational modification of serum proteins, and changes in the type and abundance of glycans in human serum have been correlated with a growing number of human diseases. While the glycosylation pattern of human serum is well studied, little is known about the profiles of other mammalian species. Here, we report detailed glycosylation profiling of canine serum by hydrophilic interaction chromatography-ultraperformance liquid chromatography (HILIC-UPLC) and mass spectrometry. The domestic dog (Canis familiaris) is a widely used model organism and of considerable interest for a large veterinary community. We found significant differences in the serum N-glycosylation profile of dogs compared to that of humans, such as a lower abundance of galactosylated and sialylated glycans. We also compare the N-glycan profile of canine serum to that of canine IgG – the most abundant serum glycoprotein. Our data will serve as a baseline reference for future studies when performing serum analyses of various health and disease states in dogs.
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Affiliation(s)
| | - Rebecca M Duke
- New England Biolabs Inc., 240 County Road, Ipswich, MA, USA
| | | | - David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus.,Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, University Road, Southampton, UK
| | - Sylvain Lehoux
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA, USA
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4
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Jones RG, Martino A. Linear models of ovine IgG1 and IgG2 subclasses and predicted pepsin cleavage sites. J Pharm Biomed Anal 2016; 117:150-4. [DOI: 10.1016/j.jpba.2015.08.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/25/2015] [Accepted: 08/27/2015] [Indexed: 10/23/2022]
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5
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Cook MC, Kaldas SJ, Muradia G, Rosu-Myles M, Kunkel JP. Comparison of orthogonal chromatographic and lectin-affinity microarray methods for glycan profiling of a therapeutic monoclonal antibody. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 997:162-78. [DOI: 10.1016/j.jchromb.2015.05.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 10/23/2022]
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6
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Adamczyk B, Tharmalingam-Jaikaran T, Schomberg M, Szekrényes Á, Kelly RM, Karlsson NG, Guttman A, Rudd PM. Comparison of separation techniques for the elucidation of IgG N-glycans pooled from healthy mammalian species. Carbohydr Res 2014; 389:174-85. [PMID: 24680513 DOI: 10.1016/j.carres.2014.01.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 01/13/2014] [Accepted: 01/23/2014] [Indexed: 12/25/2022]
Abstract
The IgG N-glycome provides sufficient complexity and information content to serve as an excellent source for biomarker discovery in mammalian health. Since oligosaccharides play a significant role in many biological processes it is very important to understand their structure. The glycosylation is cell type specific as well as highly variable depending on the species producing the IgG. We evaluated the variation of N-linked glycosylation of human, bovine, ovine, equine, canine and feline IgG using three orthogonal glycan separation techniques: hydrophilic interaction liquid chromatography (HILIC)-UPLC, reversed phase (RP)-UPLC and capillary electrophoresis with laser induced fluorescence detection (CE-LIF). The separation of the glycans by these high resolution methods yielded different profiles due to diverse chemistries. However, the % abundance of structures obtained by CE-LIF and HILIC-UPLC were similar, whereas the analysis by RP-UPLC was difficult to compare as the structures were separated by classes of glycans (highly mannosylated, fucosylated, bisected, fucosylated and bisected) resulting in the co-elution of many structures. The IgGs from various species were selected due to the complexity and variation in their N-glycan composition thereby highlighting the complementarity of these separation techniques.
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Affiliation(s)
- Barbara Adamczyk
- GlycoScience Group, NIBRT-The National Institute for Bioprocessing Research and Training, Fosters Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland; Medical Biochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Tharmala Tharmalingam-Jaikaran
- GlycoScience Group, NIBRT-The National Institute for Bioprocessing Research and Training, Fosters Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland
| | - Michael Schomberg
- GlycoScience Group, NIBRT-The National Institute for Bioprocessing Research and Training, Fosters Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland
| | - Ákos Szekrényes
- Horváth Laboratory for Bioseparation Sciences, Research Center for Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Ronan M Kelly
- GlycoScience Group, NIBRT-The National Institute for Bioprocessing Research and Training, Fosters Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland
| | | | - Andràs Guttman
- Horváth Laboratory for Bioseparation Sciences, Research Center for Molecular Medicine, University of Debrecen, 4032 Debrecen, Hungary; MTA-TKI Translational Glycomics Research Group, University of Pannonia, Veszprem, Hungary
| | - Pauline M Rudd
- GlycoScience Group, NIBRT-The National Institute for Bioprocessing Research and Training, Fosters Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland.
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Hristodorov D, Fischer R, Linden L. With or without sugar? (A)glycosylation of therapeutic antibodies. Mol Biotechnol 2013; 54:1056-68. [PMID: 23097175 DOI: 10.1007/s12033-012-9612-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Antibodies and antibody-based drugs are currently the fastest-growing class of therapeutics. Over the last three decades, more than 30 therapeutic monoclonal antibodies and derivatives thereof have been approved for and successfully applied in diverse indication areas including cancer, organ transplants, autoimmune/inflammatory disorders, and cardiovascular disease. The isotype of choice for antibody therapeutics is human IgG, whose Fc region contains a ubiquitous asparagine residue (N297) that acts as an acceptor site for N-linked glycans. The nature of these glycans can decisively influence the therapeutic performance of a recombinant antibody, and their absence or modification can lead to the loss of Fc effector functions, greater immunogenicity, and unfavorable pharmacokinetic profiles. However, recent studies have shown that aglycosylated antibodies can be genetically engineered to display novel or enhanced effector functions and that favorable pharmacokinetic properties can be preserved. Furthermore, the ability to produce aglycosylated antibodies in lower eukaryotes and bacteria offers the potential to broaden and simplify the production platforms and avoid the problem of antibody heterogeneity, which occurs when mammalian cells are used for production. In this review, we discuss the importance of Fc glycosylation focusing on the use of aglycosylated and glyco-engineered antibodies as therapeutic proteins.
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Affiliation(s)
- Dmitrij Hristodorov
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Forckenbeckstrasse 6, 52074 Aachen, Germany
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Malphettes L, Freyvert Y, Chang J, Liu PQ, Chan E, Miller JC, Zhou Z, Nguyen T, Tsai C, Snowden AW, Collingwood TN, Gregory PD, Cost GJ. Highly efficient deletion of FUT8 in CHO cell lines using zinc-finger nucleases yields cells that produce completely nonfucosylated antibodies. Biotechnol Bioeng 2010; 106:774-83. [PMID: 20564614 DOI: 10.1002/bit.22751] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
IgG1 antibodies produced in Chinese hamster ovary (CHO) cells are heavily alpha1,6-fucosylated, a modification that reduces antibody-dependent cellular cytotoxicity (ADCC) and can inhibit therapeutic antibody function in vivo. Addition of fucose is catalyzed by Fut8, a alpha1,6-fucosyltransferase. FUT8(-/-) CHO cell lines produce completely nonfucosylated antibodies, but the difficulty of recapitulating the knockout in protein-production cell lines has prevented the widespread adoption of FUT8(-/-) cells as hosts for antibody production. We have created zinc-finger nucleases (ZFNs) that cleave the FUT8 gene in a region encoding the catalytic core of the enzyme, allowing the functional disruption of FUT8 in any CHO cell line. These reagents produce FUT8(-/-) CHO cells in 3 weeks at a frequency of 5% in the absence of any selection. Alternately, populations of ZFN-treated cells can be directly selected to give FUT8(-/-) cell pools in as few as 3 days. To demonstrate the utility of this method in bioprocess, FUT8 was disrupted in a CHO cell line used for stable protein production. ZFN-derived FUT8(-/-) cell lines were as transfectable as wild-type, had similar or better growth profiles, and produced equivalent amounts of antibody during transient transfection. Antibodies made in these lines completely lacked core fucosylation but had an otherwise normal glycosylation pattern. Cell lines stably expressing a model antibody were made from wild-type and ZFN-generated FUT8(-/-) cells. Clones from both lines had equivalent titer, specific productivity distributions, and integrated viable cell counts. Antibody titer in the best ZFN-generated FUT8(-/-) cell lines was fourfold higher than in the best-producing clones of FUT8(-/-) cells made by standard homologous recombination in a different CHO subtype. These data demonstrate the straightforward, ZFN-mediated transfer of the Fut8- phenotype to a production CHO cell line without adverse phenotypic effects. This process will speed the production of highly active, completely nonfucosylated therapeutic antibodies.
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Abstract
We report the structure of the Fc fragment of rabbit IgG at 1.95 A (1 A=0.1 nm) resolution. Rabbit IgG was the molecule for which Porter established the four-chain, Upsilon-shaped structure of the antibody molecule, and crystals of the Fc ('Fragment crystallisable') were first reported almost 50 years ago in this journal [Porter, R. R. (1959) Biochem. J. 73, 119-126]. This high-resolution analysis, apparently of the same crystal form, reveals several features of IgG-Fc structure that have not previously been described. More of the lower hinge region is visible in this structure than in others, demonstrating not only the acute bend in the IgG molecule that this region can mediate, as seen in receptor complexes, but also that this region has a tendency to adopt a bent structure even in the absence of receptor. As observed in other IgG-Fc structures, the Cgamma2 domains display greater mobility/disorder within the crystals than the Cgamma3 domains; unexpectedly the structure reveals partial cleavage of both Cgamma2 intra-domain disulphide bonds, whereas an alternative conformation for one of the cysteine residues in the intact bridge within the more ordered Cgamma3 domains is observed. The N-linked oligosaccharide chains at Asn(297) are well-defined and reveal two alternative conformations for the galactose units on each of the alpha(1-6)-linked branches. The presence of this galactose unit is important for stabilizing the structure of the entire branched carbohydrate chain, and its absence correlates with the severity of autoimmune conditions such as rheumatoid arthritis in both human clinical studies and in a rabbit model of the disease. Rabbit IgG, through this high-resolution structure of its Fc region, thus continues to offer new insights into antibody structure.
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Raju TS. Terminal sugars of Fc glycans influence antibody effector functions of IgGs. Curr Opin Immunol 2008; 20:471-8. [PMID: 18606225 DOI: 10.1016/j.coi.2008.06.007] [Citation(s) in RCA: 391] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 06/12/2008] [Accepted: 06/26/2008] [Indexed: 12/11/2022]
Abstract
IgG molecules contain glycans in the CH2 domain of the Fc fragment (N-glycosylation) which are highly heterogeneous, because of the presence of different terminal sugars. The heterogeneity of Fc glycans varies with species and expression system. Fc glycans influence the binding of IgG to Fc receptors and C1q, and are therefore important for IgG effector functions. Specifically, terminal sugars such as sialic acids, core fucose, bisecting N-acetylglucosamine, and mannose residues affect the binding of IgG to the FcgammaRIIIa receptor and thereby influence ADCC activity. By contrast, terminal galactose residues affect antibody binding to C1q and thereby modulate CDC activity. Structural studies indicate that the presence or absence of specific terminal sugars may affect hydrophilic and hydrophobic interactions between sugar residues and amino acid residues in the Fc fragment, which in turn may impact antibody effector functions.
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Affiliation(s)
- T Shantha Raju
- Discovery Research, Centocor R&D Inc., Radnor, PA 19087, USA.
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11
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Abstract
Heterogeneity of monoclonal antibodies is common due to the various modifications introduced over the lifespan of the molecules from the point of synthesis to the point of complete clearance from the subjects. The vast number of modifications presents great challenge to the thorough characterization of the molecules. This article reviews the current knowledge of enzymatic and nonenzymatic modifications of monoclonal antibodies including the common ones such as incomplete disulfide bond formation, glycosylation, N-terminal pyroglutamine cyclization, C-terminal lysine processing, deamidation, isomerization, and oxidation, and less common ones such as modification of the N-terminal amino acids by maleuric acid and amidation of the C-terminal amino acid. In addition, noncovalent associations with other molecules, conformational diversity and aggregation of monoclonal antibodies are also discussed. Through a complete understanding of the heterogeneity of monoclonal antibodies, strategies can be employed to better identify the potential modifications and thoroughly characterize the molecules.
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Affiliation(s)
- Hongcheng Liu
- Process Sciences Department, Abbott Bioresearch Center, 100 Research Drive, Worcester, Massachusetts 01605, USA.
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Warnock D, Bai X, Autote K, Gonzales J, Kinealy K, Yan B, Qian J, Stevenson T, Zopf D, Bayer RJ. In vitro galactosylation of human IgG at 1 kg scale using recombinant galactosyltransferase. Biotechnol Bioeng 2006; 92:831-42. [PMID: 16187338 DOI: 10.1002/bit.20658] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The Fc effector functions of immunoglobulin G (IgG) antibodies are in part determined by structural features of carbohydrates linked to each of the paired gamma heavy chains in the antibody constant domain (C(H)2). One glycoform that has been shown to be advantageous is G2, where both arms of complex bi-antennary N-glycans terminate in galactose. In vitro treatment with glycosyltransferases can remodel heterogeneous IgG glycoforms, enabling preparation of IgG molecules with homogeneous glycan chains. Here we describe optimization of conditions for use of a soluble recombinant galactosyltransferase in vitro to remodel glycans of human serum IgG, and we demonstrate a scaled-up reaction in which >98% of neutral glycans attached to 1 kg IgG are converted to the G2 glycoform. Removal of glycosylation reagents from the product is achieved in one step by affinity chromatography on immobilized Protein A.
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Affiliation(s)
- Dale Warnock
- Neose Technologies, Inc., 102 Witmer Road, Horsham, Pennsylvania 19044, USA
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Suzuki N, Khoo KH, Chen CM, Chen HC, Lee YC. N-glycan structures of pigeon IgG: a major serum glycoprotein containing Galalpha1-4 Gal termini.. J Biol Chem 2003; 278:46293-306. [PMID: 12966096 DOI: 10.1074/jbc.m307132200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We had shown previously that all major glycoproteins of pigeon egg white contain Galalpha1-4Gal epitopes (Suzuki, N., Khoo, K. H., Chen, H. C., Johnson, J. R., and Lee, Y. C. (2001) J. Biol. Chem. 276, 23221-23229). We now report that Galalpha1-4Gal-bearing glycoproteins are also present in pigeon serum, lymphocytes, and liver, as probed by Western blot with Griffonia simplicifolia-I lectin (specific for terminal alpha-Gal) and anti-P1 (specific for Galalpha1-4Galbeta1-4GlcNAcbeta1-) monoclonal antibody. One of the major glycoproteins from pigeon plasma was identified as IgG (also known as IgY), which has Galalpha1-4Gal in its heavy chains. High pressure liquid chromatography, mass spectrometric (MS), and MS/MS analyses revealed that N-glycans of pigeon serum IgG included (i) high mannose-type (33.3%), (ii) disialylated biantennary complex-type (19.2%), and (iii) alpha-galactosylated complex-type N-glycans (47.5%). Bi- and tri-antennary oligosaccharides with bisecting GlcNAc and alpha1-6 Fuc on the Asn-linked GlcNAc were abundant among N-glycans possessing terminal Galalpha1-4Gal sequences. Moreover, MS/MS analysis identified Galalpha1-4Galbeta1-4Galbeta1-4GlcNAc branch terminals, which are not found in pigeon egg white glycoproteins. An additional interesting aspect is that about two-thirds of high mannose-type N-glycans from pigeon IgG were monoglucosylated. Comparison of the N-glycan structures with chicken and quail IgG indicated that the presence of high mannose-type oligosaccharides may be a characteristic of these avian IgG.
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Affiliation(s)
- Noriko Suzuki
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
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Kunkel JP, Jan DC, Jamieson JC, Butler M. Dissolved oxygen concentration in serum-free continuous culture affects N-linked glycosylation of a monoclonal antibody. J Biotechnol 1998; 62:55-71. [PMID: 9684342 DOI: 10.1016/s0168-1656(98)00044-3] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The murine B-lymphocyte hybridoma, CC9C10, was grown at steady state in serum-free continuous culture at dissolved oxygen (DO) concentrations of 10, 50, and 100% of air saturation. The secreted mAb, an IgG1, was purified and subjected to both enzymatic deglycosylation using PNGase F and chemical deglycosylation by hydrazinolysis. Both methods resulted in complete removal of N-linked oligosaccharide chains. Isolated N-glycan pools were analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE) and high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The FACE profiles and corresponding HPAEC-PAD chromatograms of N-linked oligosaccharides obtained by PNGase F digestion and hydrazinolysis provided complementary and corroborating information. The predominant N-linked structures were core-fucosylated asialo biantennary chains with varying galactosylation. There were also minor amounts of monosialylated, and trace amounts of afucosyl, oligosaccharides. A definite shift towards decreased galactosylation of glycan chains was observed as DO concentration in continuous culture was reduced. The vast majority of N-linked glycosylation occurred on the heavy chain. There was no evidence for N-linked glycosylation of the light chain or for O-linked glycosylation of the mAb.
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Affiliation(s)
- J P Kunkel
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
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