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Donadio-Andréi S, Chikh K, Heuclin C, Kuczewski E, Charrié A, Gauchez AS, Ronin C. Variability among TSH Measurements Can Be Reduced by Combining a Glycoengineered Calibrator to Epitope-Defined Immunoassays. Eur Thyroid J 2017; 6:3-11. [PMID: 28611942 PMCID: PMC5465719 DOI: 10.1159/000449463] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/30/2016] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Measuring protein markers with variable glycosylation, such as thyroid-stimulating hormone (TSH), with high accuracy is not an easy task. Despite highly sensitive third-generation tests, discrepancies among TSH assays still remain unsolved and are the focus of important standardization efforts. Earlier work from our group showed that a lack of similarity in epitope expression between standards and samples may account for discordant hormone measurements. In this study, we aimed at producing a glycoengineered TSH with serum-type glycosylation and compared its immunological behavior to that of the international standards. STUDY DESIGN Recombinant glycoengineered TSH (rgTSH) was produced in glycoengineered Chinese hamster ovary cells to express a highly sialylated TSH and tested in newly designed assays. Two groups of assays targeting defined epitopes were constructed and TSH levels were estimated in a panel of 84 clinical samples (2.1-22.4 mIU/l) based on the use of the current 3rd IS 81/565, the 1st IRP 94/674 and rgTSH calibrations. RESULTS Calibration based on rgTSH was found to significantly reduce the percentage difference means of assays compared to the pituitary standard. We also found that a switch from a mIU/l (3rd IS 81/565) to ng/l (rgTSH) basis can be established within the normal as well as in the mid to upper normal range of TSH levels. Of interest, TSH assays targeting the main immunogenic region displayed variable TSH values, indicating that, in this region, epitopes should be defined for assays to deliver similar values. CONCLUSIONS A glycoengineered TSH with serum-type glycosylation proved to be a new calibrator efficient in harmonizing TSH values.
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Affiliation(s)
| | - Karim Chikh
- CARMEN-INSERM U1060, Université Claude Bernard Lyon 1, Hospices Civils de Lyon, France
- CARMEN-INSERM U1060, Université Claude Bernard Lyon 1, Faculté de Médecine et de Maïeutique Lyon Sud - Charles Mérieux, Oullins, France
- Société Française de Médecine Nucléaire, Groupe de Biologie Spécialisée, Centre Antoine Béclère, Paris, France
| | - Christine Heuclin
- Laboratoire du Service de Médecine Nucléaire, BioSIMS Technologies, Seine Biopolis II, Rouen, France
| | - Elisabetta Kuczewski
- CARMEN-INSERM U1060, Université Claude Bernard Lyon 1, Hospices Civils de Lyon, France
| | - Anne Charrié
- CARMEN-INSERM U1060, Université Claude Bernard Lyon 1, Hospices Civils de Lyon, France
- CARMEN-INSERM U1060, Université Claude Bernard Lyon 1, Faculté de Médecine et de Maïeutique Lyon Sud - Charles Mérieux, Oullins, France
- Société Française de Médecine Nucléaire, Groupe de Biologie Spécialisée, Centre Antoine Béclère, Paris, France
| | - Anne-Sophie Gauchez
- Société Française de Médecine Nucléaire, Groupe de Biologie Spécialisée, Centre Antoine Béclère, Paris, France
- Laboratoire du Service de Médecine Nucléaire, Centre Hospitalier de Chambéry, Chambéry, Grenoble, France
- Pôle de Biologie, Centre Hospitalier et Universitaire de Grenoble, Grenoble, France
- Pôle de Biologie, Centre Hospitalier et Universitaire de Grenoble, UMR-S INSERM 1037, Grenoble, France
| | - Catherine Ronin
- Siamed'Xpress, Hôtel Technologique Morandat, Gardanne, France
- *Prof. Catherine Ronin, Siamed'Xpress, Hôtel Technologique Morandat, 1480 rue d'Arménie, FR−13120 Gardanne (France), E-Mail
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Zhang W, James PM, Ng BG, Li X, Xia B, Rong J, Asif G, Raymond K, Jones MA, Hegde M, Ju T, Cummings RD, Clarkson K, Wood T, Boerkoel CF, Freeze HH, He M. A Novel N-Tetrasaccharide in Patients with Congenital Disorders of Glycosylation, Including Asparagine-Linked Glycosylation Protein 1, Phosphomannomutase 2, and Mannose Phosphate Isomerase Deficiencies. Clin Chem 2015; 62:208-17. [PMID: 26430078 DOI: 10.1373/clinchem.2015.243279] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/25/2015] [Indexed: 01/02/2023]
Abstract
BACKGROUND Primary deficiencies in mannosylation of N-glycans are seen in a majority of patients with congenital disorders of glycosylation (CDG). We report the discovery of a series of novel N-glycans in sera, plasma, and cultured skin fibroblasts from patients with CDG having deficient mannosylation. METHOD We used LC-MS/MS and MALDI-TOF-MS analysis to identify and quantify a novel N-linked tetrasaccharide linked to the protein core, an N-tetrasaccharide (Neu5Acα2,6Galβ1,4-GlcNAcβ1,4GlcNAc) in plasma, serum glycoproteins, and a fibroblast lysate from patients with CDG caused by ALG1 [ALG1 (asparagine-linked glycosylation protein 1), chitobiosyldiphosphodolichol β-mannosyltransferase], PMM2 (phosphomannomutase 2), and MPI (mannose phosphate isomerase). RESULTS Glycoproteins in sera, plasma, or cell lysate from ALG1-CDG, PMM2-CDG, and MPI-CDG patients had substantially more N-tetrasaccharide than unaffected controls. We observed a >80% decline in relative concentrations of the N-tetrasaccharide in MPI-CDG plasma after mannose therapy in 1 patient and in ALG1-CDG fibroblasts in vitro supplemented with mannose. CONCLUSIONS This novel N-tetrasaccharide could serve as a diagnostic marker of ALG1-, PMM2-, or MPI-CDG for screening of these 3 common CDG subtypes that comprise >70% of CDG type I patients. Its quantification by LC-MS/MS may be useful for monitoring therapeutic efficacy of mannose. The discovery of these small N-glycans also indicates the presence of an alternative pathway in N-glycosylation not recognized previously, but its biological significance remains to be studied.
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Affiliation(s)
| | - Philip M James
- Division of Genetics, Department of Medicine, Children's Hospital Boston, Boston, MA; Department of Pediatrics, Harvard Medical School, Boston, MA
| | - Bobby G Ng
- Human Genetics Program, Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA
| | - Xueli Li
- Palmieri Metabolic Disease Laboratory, Children's Hospital of Philadelphia, Philadelphia, PA
| | | | | | | | - Kimiyo Raymond
- Mayo Biochemical Genetics Laboratory, Mayo Medical School, Rochester, MN
| | | | | | - Tongzhong Ju
- Palmieri Metabolic Disease Laboratory, Children's Hospital of Philadelphia, Philadelphia, PA
| | | | - Katie Clarkson
- Mayo Biochemical Genetics Laboratory, Mayo Medical School, Rochester, MN
| | - Tim Wood
- Greenwood Genetics Center, Greenwood, SC
| | - Cornelius F Boerkoel
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Hudson H Freeze
- Human Genetics Program, Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA
| | - Miao He
- Palmieri Metabolic Disease Laboratory, Children's Hospital of Philadelphia, Philadelphia, PA; Department of Pathology and Laboratory of Medicine, University of Pennsylvania, Philadelphia, PA.
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Asialoglycoprotein receptor mediated hepatocyte targeting — Strategies and applications. J Control Release 2015; 203:126-39. [DOI: 10.1016/j.jconrel.2015.02.022] [Citation(s) in RCA: 286] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/14/2015] [Accepted: 02/16/2015] [Indexed: 02/07/2023]
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Estrada JM, Soldin D, Buckey TM, Burman KD, Soldin OP. Thyrotropin isoforms: implications for thyrotropin analysis and clinical practice. Thyroid 2014; 24:411-23. [PMID: 24073798 PMCID: PMC3949435 DOI: 10.1089/thy.2013.0119] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Serum thyrotropin (TSH) is considered the single most sensitive and specific measure of thyroid function in the general population owing to its negative logarithmic association with free triiodothyronine and free thyroxine concentrations. It is therefore often the test of choice for screening, diagnosis, and monitoring of primary hypothyroidism. Serum TSH concentrations can be analyzed quantitatively using third-generation immunoassays, whereas its bioactivity can be measured by TSH activity assays in cell culture. Theoretically, if serum TSH concentrations are directly related to TSH activity, the two tests should yield comparable results. However, on occasion, the results are discordant, with serum concentrations being higher than TSH biological activity. This review focuses on the dissociation between the clinical state and serum TSH concentrations and addresses clinically important aspects of TSH analysis.
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Affiliation(s)
- Joshua M. Estrada
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia
| | - Danielle Soldin
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia
| | - Timothy M. Buckey
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia
| | - Kenneth D. Burman
- Endocrine Section, Medstar Washington Hospital Center, Washington, District of Columbia
| | - Offie P. Soldin
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, District of Columbia
- Department of Medicine, Georgetown University Medical Center, Washington, District of Columbia
- Department of Obstetrics and Gynecology, Georgetown University Medical Center, Washington, District of Columbia
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Yang SH, Heo D, Lee E, Kim E, Lim EK, Lee YH, Haam S, Suh JS, Huh YM, Yang J, Park SW. Galactosylated manganese ferrite nanoparticles for targeted MR imaging of asialoglycoprotein receptor. NANOTECHNOLOGY 2013; 24:475103. [PMID: 24192299 DOI: 10.1088/0957-4484/24/47/475103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cancer cells can express specific biomarkers, such as cell membrane proteins and signaling factors. Thus, finding biomarkers and delivering diagnostic agents are important in the diagnosis of cancer. In this study, we investigated a biomarker imaging agent for the diagnosis of hepatic cancers. The asialoglycoprotein receptor (ASGPr) was selected as a biomarker for hepatoma cells and the ASGPr-targetable imaging agent bearing a galactosyl group was prepared using manganese ferrite nanoparticles (MFNP) and galactosylgluconic acid. The utility of the ASGPr-targetable imaging agent, galactosylated MFNP (G-MFNP) was assessed by several methods in ASGPr-expressing HepG2 cells as target cells and ASGPr-deficient MCF7 cells. Physical and chemical properties of G-MFNP were examined using Fourier-transform infrared spectroscopy, dynamic light scattering, zeta potential analysis, and transmission electron microscopy. No significant cytotoxicity was observed in either cell line. Targeting ability was assessed using flow cytometry, magnetic resonance imaging, inductively coupled plasma atomic emission spectroscopy, absorbance analysis, dark-field microscopy, Prussian blue staining, and transmission electron microscopy. We demonstrated that G-MFNP target successfully and bind to ASGPr-expressing HepG2 cells specifically. We suggest that these results will be useful in strategies for cancer diagnoses based on magnetic resonance imaging.
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Sørensen ALT, Clausen H, Wandall HH. Carbohydrate clearance receptors in transfusion medicine. Biochim Biophys Acta Gen Subj 2012; 1820:1797-808. [PMID: 22846227 DOI: 10.1016/j.bbagen.2012.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/10/2012] [Accepted: 07/20/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Complex carbohydrates play important functions for circulation of proteins and cells. They provide protective shields and refraction from non-specific interactions with negative charges from sialic acids to enhance circulatory half-life. For recombinant protein therapeutics carbohydrates are especially important to enhance size and reduce glomerular filtration loss. Carbohydrates are, however, also ligands for a large number of carbohydrate-binding lectins exposed to the circulatory system that serve as scavenger receptors for the innate immune system, or have more specific roles in targeting of glycoproteins and cells. SCOPE OF REVIEW Here we provide an overview of the common lectin receptors that play roles for circulating glycoproteins and cells, and present a discussion of ways to engineer glycosylation of recombinant biologics and cells to improve therapeutic effects. MAJOR CONCLUSIONS While the pharmaceutical industry has learned how to exploit carbohydrates to improve pharmacokinetic properties of recombinant therapeutics, our understanding of how to improve cell-based therapies by manipulation of complex carbohydrates is still at its infancy. Progress with the latter has recently been achieved with cold-stored platelets, where exposure of uncapped glycans lead to rapid clearance from circulation by several lectin-mediated pathways. GENERAL SIGNIFICANCE Understanding lectin-mediated clearance pathways is essential for progress in development of biological pharmaceuticals.
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Pipe SW, Miao H, Butler SP, Calcaterra J, Velander WH. Functional factor VIII made with von Willebrand factor at high levels in transgenic milk. J Thromb Haemost 2011; 9:2235-42. [PMID: 21920013 PMCID: PMC3444248 DOI: 10.1111/j.1538-7836.2011.04505.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Current manufacturing methods for recombinant human factor VIII (rFVIII) within mammalian cell cultures are inefficient, hampering the production of sufficient amounts for affordable, worldwide treatment of hemophilia A. However, rFVIII has been expressed at very high levels by the transgenic mammary glands of mice, rabbits, sheep, and pigs. Unfortunately, it is secreted into milk with low specific activity, owing in part to the labile, heterodimeric structure that results from furin processing of its B domain. OBJECTIVES To express biologically active rFVIII in the milk of transgenic mice through targeted bioengineering. METHODS Transgenic mice were made with a mammary-specific FVIII gene (226/N6) bioengineered for efficient expression and stability, encoding a protein containing a B domain with no furin cleavage sites. 226/N6 was expressed with and without von Willebrand factor (VWF). 226/N6 was evaluated by ELISA, SDS-PAGE, western blot, and one-stage and two-stage clotting assays. The hemostatic activity of immunoaffinity-enriched 226/N6 was studied in vivo by infusion into hemophilia A knockout mice. RESULTS AND CONCLUSIONS With or without coexpression of VWF, 226/N6 was secreted into milk as a biologically active single-chain molecule that retained high specific activity, similar to therapeutic-grade FVIII. 226/N6 had > 450-fold higher IU mL(-1) than previously reported in cell culture for rFVIII. 226/N6 exhibited similar binding to plasma-derived VWF as therapeutic-grade rFVIII, and intravenous infusion of transgenic 226/N6 corrected the bleeding phenotype of hemophilia A mice. This provides proof-of-principle for the study of expression of 226/N6 and perhaps other single-chain bioengineered rFVIIIs in the milk of transgenic livestock.
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Affiliation(s)
- Steven W. Pipe
- Department of Pediatrics, University of Michigan, Ann Arbor, MI
| | - Hongzhi Miao
- Department of Pediatrics, University of Michigan, Ann Arbor, MI
| | - Stephen P. Butler
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Jennifer Calcaterra
- Department of Chemical & Biomolecular Engineering, University of Nebraska, Lincoln, NE
| | - William H. Velander
- Department of Chemical & Biomolecular Engineering, University of Nebraska, Lincoln, NE
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Berrios J, Altamirano C, Osses N, Gonzalez R. Continuous CHO cell cultures with improved recombinant protein productivity by using mannose as carbon source: Metabolic analysis and scale-up simulation. Chem Eng Sci 2011. [DOI: 10.1016/j.ces.2011.03.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Comprehensive characterization of the site-specific N-glycosylation of wild-type and recombinant human lactoferrin expressed in the milk of transgenic cloned cattle. Glycobiology 2010; 21:206-24. [DOI: 10.1093/glycob/cwq151] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Pasek M, Ramakrishnan B, Boeggeman E, Manzoni M, Waybright TJ, Qasba PK. Bioconjugation and detection of lactosamine moiety using alpha1,3-galactosyltransferase mutants that transfer C2-modified galactose with a chemical handle. Bioconjug Chem 2010; 20:608-18. [PMID: 19245254 DOI: 10.1021/bc800534r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Studies on wild-type and mutant glycosyltransferases have shown that they can transfer modified sugars with a versatile chemical handle, such as keto or azido group, that can be used for conjugation chemistry and detection of glycan residues on glycoconjugates. To detect the most prevalent glycan epitope, N-acetyllactosamine (LacNAc (Galbeta1-4GalNAcbeta)), we have mutated a bovine alpha1,3-galactosyltransferse (alpha3Gal-T)() enzyme which normally transfers Gal from UDP-Gal to the LacNAc acceptor, to transfer GalNAc or C2-modified galactose from their UDP derivatives. The alpha3Gal-T enzyme belongs to the alpha3Gal/GalNAc-T family that includes human blood group A and B glycosyltransferases, which transfer GalNAc and Gal, respectively, to the Gal moiety of the trisaccharide Fucalpha1-2Galbeta1-4GlcNAc. On the basis of the sequence and structure comparison of these enzymes, we have carried out rational mutation studies on the sugar donor-binding residues in bovine alpha3Gal-T at positions 280 to 282. A mutation of His280 to Leu/Thr/Ser/Ala or Gly and Ala281 and Ala282 to Gly resulted in the GalNAc transferase activity by the mutant alpha3Gal-T enzymes to 5-19% of their original Gal-T activity. We show that the mutants (280)SGG(282) and (280)AGG(282) with the highest GalNAc-T activity can also transfer modified sugars such as 2-keto-galactose or GalNAz from their respective UDP-sugar derivatives to LacNAc moiety present at the nonreducing end of glycans of asialofetuin, thus enabling the detection of LacNAc moiety of glycoproteins and glycolipids by a chemiluminescence method.
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Affiliation(s)
- Marta Pasek
- Structural Glycobiology Section, Nanobiology Program, NCI-Frederick, Frederick, MD 21702, USA
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Jansen S, Andries M, Vekemans K, Vanbilloen H, Verbruggen A, Bollen M. Rapid clearance of the circulating metastatic factor autotaxin by the scavenger receptors of liver sinusoidal endothelial cells. Cancer Lett 2009; 284:216-21. [DOI: 10.1016/j.canlet.2009.04.029] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Revised: 04/02/2009] [Accepted: 04/23/2009] [Indexed: 12/15/2022]
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Gil GC, Velander WH, Van Cott KE. Analysis of the N-glycans of recombinant human Factor IX purified from transgenic pig milk. Glycobiology 2008; 18:526-39. [PMID: 18456721 DOI: 10.1093/glycob/cwn035] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Glycosylation of recombinant proteins is of particular importance because it can play significant roles in the clinical properties of the glycoprotein. In this work, the N-glycan structures of recombinant human Factor IX (tg-FIX) produced in the transgenic pig mammary gland were determined. The majority of the N-glycans of transgenic pig-derived Factor IX (tg-FIX) are complex, bi-antennary with one or two terminal N-acetylneuraminic acid (Neu5Ac) moieties. We also found that the N-glycan structures of tg-FIX produced in the porcine mammary epithelial cells differed with respect to N-glycans from glycoproteins produced in other porcine tissues. tg-FIX contains no detectable Neu5Gc, the sialic acid commonly found in porcine glycoproteins produced in other tissues. Additionally, we were unable to detect glycans in tg-FIX that have a terminal Galalpha(1,3)Gal disaccharide sequence, which is strongly antigenic in humans. The N-glycan structures of tg-FIX are also compared to the published N-glycan structures of recombinant human glycoproteins produced in other transgenic animal species. While tg-FIX contains only complex structures, antithrombin III (goat), C1 inhibitor (rabbit), and lactoferrin (cow) have both high mannose and complex structures. Collectively, these data represent a beginning point for the future investigation of species-specific and tissue/cell-specific differences in N-glycan structures among animals used for transgenic animal bioreactors.
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Affiliation(s)
- Geun-Cheol Gil
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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Millward TA, Heitzmann M, Bill K, Längle U, Schumacher P, Forrer K. Effect of constant and variable domain glycosylation on pharmacokinetics of therapeutic antibodies in mice. Biologicals 2008; 36:41-7. [PMID: 17890101 DOI: 10.1016/j.biologicals.2007.05.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 04/23/2007] [Accepted: 05/05/2007] [Indexed: 11/25/2022] Open
Abstract
Previous studies on the effect of glycosylation on the elimination rate of antibodies have produced conflicting results. Here, we performed pharmacokinetic studies in mice with two preparations of a monoclonal IgG1 antibody enriched for complex type or high mannose type oligosaccharides at the Fc glycosylation site. No significant difference in the serum half-life was found between the two antibody glycoforms, nor was any difference observed in the serum half-lives of different complex type glycoforms. To evaluate the influence of glycosylation within the variable domain, a second monoclonal antibody, glycosylated in both the Fc and Fv domains, was separated into fractions containing different amounts of Fv-associated sialic acid and administered to mice. Again, no significant difference was found in the clearance rates of variants carrying different amounts of Fv-associated sialic acid or lacking Fv-glycosylation. These results suggest that glycosylation has little or no impact on the pharmacokinetic behavior of these two monoclonal antibodies in mice.
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Affiliation(s)
- Thomas A Millward
- Novartis Pharma AG, Biotechnology Development, Analytical Research and Development, 4002 Basel, Switzerland
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Donadio S, Pascual A, Dugas M, Ronin C. Standardisation des immunodosages de la TSH : production de nouveaux calibrateurs et harmonisation des tests. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.immbio.2005.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Donadio S, Pascual A, Thijssen JHH, Ronin C. Feasibility Study of New Calibrators for Thyroid-Stimulating Hormone (TSH) Immunoprocedures Based on Remodeling of Recombinant TSH to Mimic Glycoforms Circulating in Patients with Thyroid Disorders. Clin Chem 2006; 52:286-97. [PMID: 16306088 DOI: 10.1373/clinchem.2005.058172] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackground: Differences between the glycosylation patterns of a pituitary thyroid-stimulating hormone calibrator (pitTSH) and serum samples have been shown to be responsible for nonidentical epitope expression and for introducing discrepancies in TSH measurements. We studied the feasibility of developing new candidate reference materials by remodeling recombinant TSH (recTSH) to generate potential mimics of serum TSH.Methods: Terminal sialylation and/or inner fucosylation of recTSH were remodeled by a combination of enzyme treatments followed (or not) by lentil lectin-Sepharose affinity chromatography. The resulting TSH preparations were screened for epitope similarity in 23 immunoassays mapping 3 antigenic clusters common to the pitTSH 2nd International Reference Preparation (IRP) and the recTSH 1st IRP and then challenged against a pool of 63 patients with increased serum TSH (>60 mIU/L).Results: pitTSH was poorly correlated with serum TSH, with a mean (SD) slope of 2.124 (0.001), in contrast to recTSH [slope, 1.178 (0.056)]. Comparison of variably sialylated preparations with recTSH gave slopes of 0.860 (0.057) for desialylated TSH, 1.064 (0.057) for α2,3/6-oversialylated recTSH, and 0.953 (0.033) for α2,6-resialylated recTSH, indicating that TSH forms enriched in sialic acid closely resemble serum TSH. Further testing against serum TSH showed satisfactory agreement with both TSH preparations containing α2,6-sialic acid [slopes, 1.064 (0.057) and 0.953 (0.033)], particularly in the absence of nonfucosylated forms [0.985 (0.044)].Conclusions: Glyco-engineered recTSH preparations enriched in sialic acid and inner fucose are promising candidates for future reference materials. These preparations may have advantages over existing preparations used for standardizing TSH measurements.
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Affiliation(s)
- Sandrine Donadio
- Laboratory of Neuroglycobiology, Université de Provence, UMR 6149 et GDR 2590 CNRS/Université de Provence, Marseille, France
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Westerlind U, Westman J, Törnquist E, Smith CIE, Oscarson S, Lahmann M, Norberg T. Ligands of the asialoglycoprotein receptor for targeted gene delivery, part 1: Synthesis of and binding studies with biotinylated cluster glycosides containing N-acetylgalactosamine. Glycoconj J 2005; 21:227-41. [PMID: 15486455 DOI: 10.1023/b:glyc.0000045095.86867.c0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In order to develop the non-viral Bioplex vector system for targeted delivery of genes to hepatocytes, we have evaluated the structure-function relationship for a number of synthetic ligands designed for specific interaction with the hepatic lectin ASGPr. Biotinylated ligand derivatives containing two, three or six beta-linked N-acetylgalactosamine (GalNAc) residues were synthesized, bound to fluorescent-labeled streptavidin and tested for binding and uptake to HepG2 cells using flow cytometry analysis (FACS). Uptake efficiency increased with number of displayed GalNAc units per ligand, in a receptor dependent manner. Thus, a derivative displaying six GalNAc units showed the highest uptake efficacy both in terms of number of internalizing cells and increased amount of material taken up per each cell. However, this higher efficiency was shown to be due not so much to higher number of sugar units, but to higher accessibility of the sugar units for interaction with the receptor (longer spacer). Improving the flexibility and accessibility of a trimeric GalNAc ligand through use of a longer spacer markedly influenced the uptake efficiency, while increasing the number of GalNAc units per ligand above three only provided a minor contribution to the overall affinity. We hereby report the details of the chemical synthesis of the ligands and the structure-function studies in vitro.
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Affiliation(s)
- Ulrika Westerlind
- Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, S-750 07 Uppsala, Sweden
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