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Elwy A, Abdelrahman H, Specht J, Dhiman S, Christ TC, Lang J, Friebus-Kardash J, Recher M, Lang KS. Natural IgG protects against early dissemination of vesicular stomatitis virus. J Autoimmun 2024; 146:103230. [PMID: 38754237 DOI: 10.1016/j.jaut.2024.103230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/25/2024] [Accepted: 04/16/2024] [Indexed: 05/18/2024]
Abstract
Neonatal Fc receptor (FcRn) recycles immunoglobulin G, and inhibition of FcRn is used clinically for treatment of autoimmune diseases. In this work, using the vesicular stomatitis virus (VSV) mouse infection model system, we determined the role of FcRn during virus infection. While induction of neutralizing antibodies and long-term protection of these antibodies was hardly affected in FcRn deficient mice, FcRn deficiency limited the amount of natural IgG (VSV-specific) antibodies. Lack of natural antibodies (nAbs) limited early control of VSV in macrophages, accelerated propagation of virus in several organs, led to the spread of VSV to the neural tissue resulting in fatal outcomes. Adoptive transfer of natural IgG into FcRn deficient mice limited early propagation of VSV in FcRn deficient mice and enhanced survival of FcRn knockout mice. In line with this, vaccination of FcRn mice with very low dose of VSV prior to infection similarly prevented death after infection. In conclusion we determined the importance of nAbs during VSV infection. Lack of FcRn limited nAbs and thereby enhanced the susceptibility to virus infection.
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Affiliation(s)
- Abdelrahman Elwy
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany.
| | - Hossam Abdelrahman
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany
| | - Julia Specht
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany
| | - Swati Dhiman
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany
| | | | - Judith Lang
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany
| | - Justa Friebus-Kardash
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany; Department of Nephrology, University Hospital Essen, University Duisburg-Essen, 45147, Essen, Germany
| | - Mike Recher
- Immunodeficiency Laboratory, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Karl Sebastian Lang
- Institute of Immunology, Medical Faculty, University of Duisburg-Essen, 45147, Essen, Germany.
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2
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Ledo AM, Dimke T, Tschantz WR, Rowlands D, Growcott E. The role of airway mucus and diseased pulmonary epithelium on the absorption of inhaled antibodies. Int J Pharm 2023; 647:123519. [PMID: 37852310 DOI: 10.1016/j.ijpharm.2023.123519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/10/2023] [Accepted: 10/15/2023] [Indexed: 10/20/2023]
Abstract
Inhaled antibody therapy for the treatment of respiratory diseases is a promising strategy to maximize pulmonary exposure and reduce side effects associated with parenteral administration. However, the development of inhaled antibodies is often challenging due to a poor understanding of key mechanisms governing antibody absorption and clearance in healthy and diseased pulmonary epithelium. Here, we utilize well established Human Bronchial Epithelial Cell (HBEC) models grown at air-liquid interface to study the absorption process of antibodies and antibody fragments. With these cellular models, we recapitulate the morphology and function of healthy and diseased pulmonary epithelium, and incorporate the mucosal barrier to enable the investigation of both cellular permeability as well as mucodiffusion. We studied the saturation of antibody transport across the HBEC barriers and estimated the impact of disease-like epithelial barriers on antibody paracellular transport. Additionally, we identified a potential role of neonatal Fc receptor (FcRn)-independent and target-mediated transcytosis in the transport of Fragment antigen-binding (Fab) and F(ab)2 antibody fragments. Lastly, our models were able to pinpoint an impaired antibody diffusion across mucus gels. These mechanistic cellular models are promising in vitro tools to inform Physiologically-based Pharmacokinetic (PBPK) computational models for dose prediction toward de-risking the development of inhaled biologics.
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Affiliation(s)
- Adriana Martinez Ledo
- Disease Area X, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, United States
| | - Thomas Dimke
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, CH-4056 Basel, Switzerland
| | - William R Tschantz
- NIBR Biologics Center, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, United States
| | - David Rowlands
- Disease Area X, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, United States
| | - Ellena Growcott
- Disease Area X, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, United States.
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3
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De Sutter PJ, Gasthuys E, Vermeulen A. Comparison of monoclonal antibody disposition predictions using different physiologically based pharmacokinetic modelling platforms. J Pharmacokinet Pharmacodyn 2023:10.1007/s10928-023-09894-4. [PMID: 37952005 DOI: 10.1007/s10928-023-09894-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 10/17/2023] [Indexed: 11/14/2023]
Abstract
Physiologically based pharmacokinetic (PBPK) models can be used to leverage physiological and in vitro data to predict monoclonal antibody (mAb) concentrations in serum and tissues. However, it is currently not known how consistent predictions of mAb disposition are across PBPK modelling platforms. In this work PBPK simulations of IgG, adalimumab and infliximab were compared between three platforms (Simcyp, PK-Sim, and GastroPlus). Accuracy of predicted serum and tissue concentrations was assessed using observed data collected from the literature. Physiological and mAb related input parameters were also compared and sensitivity analyses were carried out to evaluate model behavior when input values were altered. Differences in serum kinetics of IgG between platforms were minimal for a dose of 1 mg/kg, but became more noticeable at higher dosages (> 100 mg/kg) and when reference (healthy) physiological input values were altered. Predicted serum concentrations of both adalimumab and infliximab were comparable across platforms, but were noticeably higher than observed values. Tissue concentrations differed remarkably between the platforms, both for total- and interstitial fluid (ISF) concentrations. The accuracy of total tissue concentrations was within a three-fold of observed values for all tissues, except for brain tissue concentrations, which were overpredicted. Predictions of tissue ISF concentrations were less accurate and were best captured by GastroPlus. Overall, these simulations show that the different PBPK platforms generally predict similar mAb serum concentrations, but variable tissue concentrations. Caution is therefore warranted when PBPK models are used to simulate effect site tissue concentrations of mAbs without data to verify the predictions.
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Affiliation(s)
- Pieter-Jan De Sutter
- Laboratory of Medical Biochemistry and Clinical Analysis, Department of Bioanalysis, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.
| | - Elke Gasthuys
- Laboratory of Medical Biochemistry and Clinical Analysis, Department of Bioanalysis, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - An Vermeulen
- Laboratory of Medical Biochemistry and Clinical Analysis, Department of Bioanalysis, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
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4
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Mimoun A, Bou-Jaoudeh M, Delignat S, Daventure V, Reyes Ruiz A, Lecerf M, Azam A, Noe R, Peyron I, Christophe OD, Lenting PJ, Proulle V, McIntosh J, Nathwani AC, Dimitrov JD, Denis CV, Lacroix-Desmazes S. Transplacental delivery of therapeutic proteins by engineered immunoglobulin G: a step toward perinatal replacement therapy. J Thromb Haemost 2023; 21:2405-2417. [PMID: 37271431 DOI: 10.1016/j.jtha.2023.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 05/02/2023] [Accepted: 05/21/2023] [Indexed: 06/06/2023]
Abstract
BACKGROUND Transplacental delivery of maternal immunoglobulin G (IgG) provides humoral protection during the first months of life until the newborn's immune system reaches maturity. The maternofetal interface has been exploited therapeutically to replace missing enzymes in the fetus, as shown in experimental mucopolysaccharidoses, or to shape adaptive immune repertoires during fetal development and induce tolerance to self-antigens or immunogenic therapeutic molecules. OBJECTIVES To investigate whether proteins that are administered to pregnant mice or endogenously present in their circulation may be delivered through the placenta. METHODS We engineered monovalent immunoglobulin G (FabFc) specific for different domains of human factor VIII (FVIII), a therapeutically relevant model antigen. FabFc was injected with exogenous FVIII into pregnant severe hemophilia A mice or pregnant mice expressing human FVIII following AAV8-mediated gene therapy. FabFc and FVIII were detected in the pregnant mice and/or fetuses by enzyme-linked immunosorbent assay and immunohistochemistry. RESULTS Administration of FabFc to pregnant mice allowed the maternofetal delivery of FVIII in a FcRn-dependent manner. FVIII antigen levels achieved in the fetuses represented 10% of normal plasma levels in the human. We identified antigen/FabFc complex stability, antigen size, and shielding of promiscuous protein patches as key parameters to foster optimal antigen delivery. CONCLUSION Our results pave the way toward the development of novel strategies for the in utero delivery of endogenous maternal proteins to replace genetically deficient fetal proteins or to educate the immune system and favor active immune tolerance upon protein encounter later in life.
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Affiliation(s)
- Angelina Mimoun
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Melissa Bou-Jaoudeh
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Sandrine Delignat
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Victoria Daventure
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Alejandra Reyes Ruiz
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Maxime Lecerf
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Aurélien Azam
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Remi Noe
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Ivan Peyron
- Laboratory for Hemostasis, Inflammation & Thrombosis, Unité Mixed de Recherche, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Olivier D Christophe
- Laboratory for Hemostasis, Inflammation & Thrombosis, Unité Mixed de Recherche, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Peter J Lenting
- Laboratory for Hemostasis, Inflammation & Thrombosis, Unité Mixed de Recherche, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Valérie Proulle
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France; Service d'Hématologie Biologique, Hôpital Cochin, AP-HP Centre, Paris, France
| | - Jenny McIntosh
- Deparment of Haematology, UCL Cancer Institute, London, UK
| | - Amit C Nathwani
- Deparment of Haematology, UCL Cancer Institute, London, UK; Katherine Dormandy Haemophilia and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK
| | - Jordan D Dimitrov
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Cécile V Denis
- Laboratory for Hemostasis, Inflammation & Thrombosis, Unité Mixed de Recherche, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Sébastien Lacroix-Desmazes
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherche des Cordeliers, CNRS, Sorbonne Université, Université Paris Cité, Paris, France.
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5
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Lim A, Sharma P, Stepanov O, Reddy VP. Application of Modelling and Simulation Approaches to Predict Pharmacokinetics of Therapeutic Monoclonal Antibodies in Pediatric Population. Pharmaceutics 2023; 15:pharmaceutics15051552. [PMID: 37242793 DOI: 10.3390/pharmaceutics15051552] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/11/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
Ethical regulations and limited paediatric participants are key challenges that contribute to a median delay of 6 years in paediatric mAb approval. To overcome these barriers, modelling and simulation methodologies have been adopted to design optimized paediatric clinical studies and reduce patient burden. The classical modelling approach in paediatric pharmacokinetic studies for regulatory submissions is to apply body weight-based or body surface area-based allometric scaling to adult PK parameters derived from a popPK model to inform the paediatric dosing regimen. However, this approach is limited in its ability to account for the rapidly changing physiology in paediatrics, especially in younger infants. To overcome this limitation, PBPK modelling, which accounts for the ontogeny of key physiological processes in paediatrics, is emerging as an alternative modelling strategy. While only a few mAb PBPK models have been published, PBPK modelling shows great promise demonstrating a similar prediction accuracy to popPK modelling in an Infliximab paediatric case study. To facilitate future PBPK studies, this review consolidated comprehensive data on the ontogeny of key physiological processes in paediatric mAb disposition. To conclude, this review discussed different use-cases for pop-PK and PBPK modelling and how they can complement each other to increase confidence in pharmacokinetic predictions.
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Affiliation(s)
- Andrew Lim
- Clinical Pharmacology and Pharmacometrics, Biopharmaceuticals R&D, AstraZeneca, Cambridge CB2 8PA, UK
- Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Pradeep Sharma
- Clinical Pharmacology and Pharmacometrics, Biopharmaceuticals R&D, AstraZeneca, Cambridge CB2 8PA, UK
| | - Oleg Stepanov
- Clinical Pharmacology and Pharmacometrics, Biopharmaceuticals R&D, AstraZeneca, Cambridge CB2 8PA, UK
| | - Venkatesh Pilla Reddy
- Clinical Pharmacology and Pharmacometrics, Biopharmaceuticals R&D, AstraZeneca, Cambridge CB2 8PA, UK
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6
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Zhou W, Graner M, Paucek P, Beseler C, Boisen M, Bubak A, Asturias F, George W, Graner A, Ormond D, Vollmer T, Alvarez E, Yu X. Multiple sclerosis plasma IgG aggregates induce complement-dependent neuronal apoptosis. Cell Death Dis 2023; 14:254. [PMID: 37031195 PMCID: PMC10082781 DOI: 10.1038/s41419-023-05783-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/10/2023]
Abstract
Grey matter pathology is central to the progression of multiple sclerosis (MS). We discovered that MS plasma immunoglobulin G (IgG) antibodies, mainly IgG1, form large aggregates (>100 nm) which are retained in the flow-through after binding to Protein A. Utilizing an annexin V live-cell apoptosis detection assay, we demonstrated six times higher levels of neuronal apoptosis induced by MS plasma IgG aggregates (n = 190, from two cohorts) compared to other neurological disorders (n = 116) and healthy donors (n = 44). MS IgG aggregate-mediated, complement-dependent neuronal apoptosis was evaluated in multiple model systems including primary human neurons, primary human astrocytes, neuroblastoma SH-SY5Y cells, and newborn mouse brain slices. Immunocytochemistry revealed the co-deposition of IgG, early and late complement activation products (C1q, C3b, and membrane attack complex C5b9), as well as active caspase 3 in treated neuronal cells. Furthermore, we found that MS plasma cytotoxic antibodies are not present in Protein G flow-through, nor in the paired plasma. The neuronal apoptosis can be inhibited by IgG depletion, disruption of IgG aggregates, pan-caspase inhibitor, and is completely abolished by digestion with IgG-cleaving enzyme IdeS. Transmission electron microscopy and nanoparticle tracking analysis revealed the sizes of MS IgG aggregates are greater than 100 nm. Our data support the pathological role of MS IgG antibodies and corroborate their connection to complement activation and axonal damage, suggesting that apoptosis may be a mechanism of neurodegeneration in MS.
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Affiliation(s)
- Wenbo Zhou
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Michael Graner
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Petr Paucek
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Cheryl Beseler
- Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Matthew Boisen
- Zalgen Labs, LLC, 12635 E. Montview Blvd., Suite 131, Aurora, Colorado, 80045, USA
| | - Andrew Bubak
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Francisco Asturias
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Woro George
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Arin Graner
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - David Ormond
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Timothy Vollmer
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Enrique Alvarez
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Xiaoli Yu
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA.
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7
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Baumrucker CR, Macrina AL, Bruckmaier RM. Colostrogenesis: Role and Mechanism of the Bovine Fc Receptor of the Neonate (FcRn). J Mammary Gland Biol Neoplasia 2021; 26:419-453. [PMID: 35080749 DOI: 10.1007/s10911-021-09506-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 12/10/2021] [Indexed: 11/28/2022] Open
Abstract
Colostrogenesis is a separate and unique phase of mammary epithelial cell activity occurring in the weeks before parturition and rather abruptly ending after birth in the bovine. It has been the focus of research to define what controls this process and how it produces high concentrations of specific biologically active components important for the neonate. In this review we consider colostrum composition and focus upon components that appear in first milked colostrum in concentrations exceeding that in blood serum. The Fc Receptor of the Neonate (FcRn) is recognized as the major immunoglobulin G (IgG) and albumin binding protein that accounts for the proteins' long half-lives. We integrate the action of the pinocytotic (fluid phase) uptake of extracellular components and merge them with FcRn in sorting endosomes. We define and explore the means of binding, sorting, and the transcytotic delivery of IgG1 while recycling IgG2 and albumin. We consider the means of releasing the ligands from the receptor within the endosome and describe a new secretion mechanism of cargo release into colostrum without the appearance of FcRn itself in colostrum. We integrate the insulin-like growth factor family, some of which are highly concentrated bioactive components of colostrum, with the mechanisms related to FcRn endosome action. In addition to secretion, we highlight the recent findings of a role of the FcRn in phagocytosis and antigen presentation and relate its significant and abrupt change in cellular location after parturition to a role in the prevention and resistance to mastitis infections.
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Affiliation(s)
- Craig R Baumrucker
- Department of Animal Science, Penn State University, University Park, PA, 16802, USA.
- Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland.
| | - Ann L Macrina
- Department of Animal Science, Penn State University, University Park, PA, 16802, USA
| | - Rupert M Bruckmaier
- Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3012, Bern, Switzerland
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8
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Azevedo C, Pinto S, Benjakul S, Nilsen J, Santos HA, Traverso G, Andersen JT, Sarmento B. Prevention of diabetes-associated fibrosis: Strategies in FcRn-targeted nanosystems for oral drug delivery. Adv Drug Deliv Rev 2021; 175:113778. [PMID: 33887405 DOI: 10.1016/j.addr.2021.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/29/2021] [Accepted: 04/16/2021] [Indexed: 01/02/2023]
Abstract
Diabetes mellitus is a chronic disease with an elevated risk of micro- and macrovascular complications, such as fibrosis. To prevent diabetes-associated fibrosis, the symptomatology of diabetes must be controlled, which is commonly done by subcutaneous injection of antidiabetic peptides. To minimize the pain and distress associated with such injections, there is an urgent need for non-invasive oral transmucosal drug delivery strategies. However, orally administered peptide-based drugs are exposed to harsh conditions in the gastrointestinal tract and poorly cross the selective intestinal epithelium. Thus, targeting of drugs to receptors expressed in epithelial cells, such as the neonatal Fc receptor (FcRn), may therefore enhance uptake and transport through mucosal barriers. This review compiles how in-depth studies of FcRn biology and engineering of receptor-binding molecules may pave the way for design of new classes of FcRn-targeted nanosystems. Tailored strategies may open new avenues for oral drug delivery and provide better treatment options for diabetes and, consequently, fibrosis prevention.
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9
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Fieux M, Le Quellec S, Bartier S, Coste A, Louis B, Giroudon C, Nourredine M, Bequignon E. FcRn as a Transporter for Nasal Delivery of Biologics: A Systematic Review. Int J Mol Sci 2021; 22:ijms22126475. [PMID: 34204226 PMCID: PMC8234196 DOI: 10.3390/ijms22126475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/07/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022] Open
Abstract
FcRn plays a major role in regulating immune homeostasis, but it is also able to transport biologics across cellular barriers. The question of whether FcRn could be an efficient transporter of biologics across the nasal epithelial barrier is of particular interest, as it would allow a less invasive strategy for the administration of biologics in comparison to subcutaneous, intramuscular or intravenous administrations, which are often used in clinical practice. A focused systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. It was registered on the international prospective register of systematic reviews PROSPERO, which helped in identifying articles that met the inclusion criteria. Clinical and preclinical studies involving FcRn and the nasal delivery of biologics were screened, and the risk of bias was assessed across studies using the Oral Health Assessment Tool (OHAT). Among the 12 studies finally included in this systematic review (out of the 758 studies screened), 11 demonstrated efficient transcytosis of biologics through the nasal epithelium. Only three studies evaluated the potential toxicity of biologics’ intranasal delivery, and they all showed that it was safe. This systematic review confirmed that FcRn is expressed in the nasal airway and the olfactory epithelium, and that FcRn may play a role in IgG and/or IgG-derived molecule-transcytosis across the airway epithelium. However, additional research is needed to better characterize the pharmacokinetic and pharmacodynamic properties of biologics after their intranasal delivery.
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Affiliation(s)
- Maxime Fieux
- Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Service d’ORL, D’otoneurochirurgie et de Chirurgie Cervico-Faciale, Pierre Bénite, CEDEX, F-69495 Lyon, France
- Université de Lyon, Université Lyon 1, F-69003 Lyon, France; (S.L.Q.); (M.N.)
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Créteil, France; (S.B.); (A.C.); (B.L.); (E.B.)
- CNRS ERL 7000, F-94010 Créteil, France
- Correspondence: ; Tel.: +33-4-7266-6415
| | - Sandra Le Quellec
- Université de Lyon, Université Lyon 1, F-69003 Lyon, France; (S.L.Q.); (M.N.)
- Hospices Civils de Lyon, Hôpital Cardiologique Louis Pradel, Unité D’hémostase Clinique, CEDEX, F-69500 Bron, France
- EA 4609 Hémostase et Cancer, Université Claude Bernard Lyon 1, F-69372 Lyon, France
- Hospices Civils de Lyon, Centre de Biologie et de Pathologie Est, Service D’hématologie Biologique, CEDEX, F-69500 Bron, France
| | - Sophie Bartier
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Créteil, France; (S.B.); (A.C.); (B.L.); (E.B.)
- CNRS ERL 7000, F-94010 Créteil, France
- Service d’ORL, de Chirurgie Cervico Faciale, Hôpital Henri Mondor, Assistance Publique des Hôpitaux de Paris, F-94000 Créteil, France
| | - André Coste
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Créteil, France; (S.B.); (A.C.); (B.L.); (E.B.)
- CNRS ERL 7000, F-94010 Créteil, France
- Service d’ORL, de Chirurgie Cervico Faciale, Centre Hospitalier Intercommunal de Créteil, F-94010 Créteil, France
| | - Bruno Louis
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Créteil, France; (S.B.); (A.C.); (B.L.); (E.B.)
- CNRS ERL 7000, F-94010 Créteil, France
| | - Caroline Giroudon
- Hospices Civils de Lyon, Service de la Documentation Centrale, CEDEX, F-69424 Lyon, France;
| | - Mikail Nourredine
- Université de Lyon, Université Lyon 1, F-69003 Lyon, France; (S.L.Q.); (M.N.)
- Hospices Civils de Lyon, Service de Biostatistique et Bioinformatique, F-69003 Lyon, France
- CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, F-69100 Villeurbanne, France
| | - Emilie Bequignon
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Créteil, France; (S.B.); (A.C.); (B.L.); (E.B.)
- CNRS ERL 7000, F-94010 Créteil, France
- Service d’ORL, de Chirurgie Cervico Faciale, Centre Hospitalier Intercommunal de Créteil, F-94010 Créteil, France
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10
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Pyzik M, Sand KMK, Hubbard JJ, Andersen JT, Sandlie I, Blumberg RS. The Neonatal Fc Receptor (FcRn): A Misnomer? Front Immunol 2019; 10:1540. [PMID: 31354709 PMCID: PMC6636548 DOI: 10.3389/fimmu.2019.01540] [Citation(s) in RCA: 257] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/20/2019] [Indexed: 12/13/2022] Open
Abstract
Antibodies are essential components of an adaptive immune response. Immunoglobulin G (IgG) is the most common type of antibody found in circulation and extracellular fluids. Although IgG alone can directly protect the body from infection through the activities of its antigen binding region, the majority of IgG immune functions are mediated via proteins and receptors expressed by specialized cell subsets that bind to the fragment crystallizable (Fc) region of IgG. Fc gamma (γ) receptors (FcγR) belong to a broad family of proteins that presently include classical membrane-bound surface receptors as well as atypical intracellular receptors and cytoplasmic glycoproteins. Among the atypical FcγRs, the neonatal Fc receptor (FcRn) has increasingly gained notoriety given its intimate influence on IgG biology and its ability to also bind to albumin. FcRn functions as a recycling or transcytosis receptor that is responsible for maintaining IgG and albumin in the circulation, and bidirectionally transporting these two ligands across polarized cellular barriers. More recently, it has been appreciated that FcRn acts as an immune receptor by interacting with and facilitating antigen presentation of peptides derived from IgG immune complexes (IC). Here we review FcRn biology and focus on newer advances including how emerging FcRn-targeted therapies may affect the immune responses to IgG and IgG IC.
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Affiliation(s)
- Michal Pyzik
- Division of Gastroenterology, Hepatology and Endoscopy, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States
| | - Kine M K Sand
- Division of Gastroenterology, Hepatology and Endoscopy, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jonathan J Hubbard
- Division of Gastroenterology, Hepatology and Endoscopy, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
| | - Jan Terje Andersen
- Department of Immunology, Oslo University Hospital Rikshospitalet, Oslo, Norway.,Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Inger Sandlie
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Richard S Blumberg
- Division of Gastroenterology, Hepatology and Endoscopy, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Harvard Digestive Diseases Center, Boston, MA, United States
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11
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Stapleton NM, Brinkhaus M, Armour KL, Bentlage AEH, de Taeye SW, Temming AR, Mok JY, Brasser G, Maas M, van Esch WJE, Clark MR, Williamson LM, van der Schoot CE, Vidarsson G. Reduced FcRn-mediated transcytosis of IgG2 due to a missing Glycine in its lower hinge. Sci Rep 2019; 9:7363. [PMID: 31089170 PMCID: PMC6517591 DOI: 10.1038/s41598-019-40731-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 02/19/2019] [Indexed: 11/09/2022] Open
Abstract
Neonatal Fc-receptor (FcRn), the major histocompatibility complex (MHC) class I-like Fc-receptor, transports immunoglobuline G (IgG) across cell layers, extending IgG half-life in circulation and providing newborns with humoral immunity. IgG1 and IgG2 have similar half-lives, yet IgG2 displays lower foetal than maternal concentration at term, despite all known FcRn binding residues being preserved between IgG1 and IgG2. We investigated FcRn mediated transcytosis of VH-matched IgG1 and IgG2 and mutated variants thereof lacking Fc-gamma receptor (FcγR) binding in human cells expressing FcRn. We observed that FcγR binding was not required for transport and that FcRn transported less IgG2 than IgG1. Transport of IgG1 with a shortened lower hinge (ΔGly236, absent in germline IgG2), was reduced to levels equivalent to IgG2. Conversely, transport of IgG2 + Gly236 was increased to IgG1 levels. Gly236 is not a contact residue between IgG and FcRn, suggesting that its absence leads to an altered conformation of IgG, possibly due to a less flexible Fab, positioned closer to the Fc portion. This may sterically hinder FcRn binding and transport. We conclude that the lack of Gly236 is sufficient to explain the reduced FcRn-mediated IgG2 transcytosis and accounts for the low maternal/fetal IgG2 ratio at term.
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Affiliation(s)
- Nigel M Stapleton
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands.,HALIX B.V., J.H. Oortweg 15/17, 2333 CH, Leiden, The Netherlands
| | - Maximilian Brinkhaus
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands
| | - Kathryn L Armour
- Department of Pathology, Division of Immunology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.,Department of Haematology, University of Cambridge, Cambridge, UK.,LifeArc, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - Arthur E H Bentlage
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands
| | - Steven W de Taeye
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands
| | - A Robin Temming
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands
| | | | | | | | | | - Mike R Clark
- Department of Pathology, Division of Immunology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.,Clark Antibodies Ltd, 10 Wellington Street, Cambridge, CB1 1HW, UK
| | - Lorna M Williamson
- Department of Haematology, University of Cambridge, Cambridge, UK.,NHS Blood and Transplant, Long Road, Cambridge, CB2 2PT, UK
| | - C Ellen van der Schoot
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands
| | - Gestur Vidarsson
- Sanquin Research, Department of Experimental Immunohematology, Amsterdam, The Netherlands, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands, Plesmanlaan 125, Amsterdam, 1066 CX, The Netherlands.
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12
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Fate of the Fc fusion protein aflibercept in retinal endothelial cells: competition of recycling and degradation. Graefes Arch Clin Exp Ophthalmol 2018; 257:83-94. [PMID: 30367290 PMCID: PMC6323079 DOI: 10.1007/s00417-018-4166-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 10/01/2018] [Accepted: 10/16/2018] [Indexed: 12/26/2022] Open
Abstract
PURPOSE Intravitreal injection of the VEGF-binding protein aflibercept is widely used to treat various ocular diseases. In vitro, immortalized bovine retinal endothelial cells (iBREC) take up and transport aflibercept through the cell layer in a serum-dependent manner, likely mediated through the neonatal Fc receptor (FcRn), but degradation of the Fc domain-containing protein might be a competing intracellular process. Therefore, aflibercept's associations with proteins either involved in FcRn-mediated transport or in the lysosomal pathway were studied. METHODS Confluent iBREC pre-cultivated with or without FBS were exposed for 4 h to in vivo achievable 250 μg/ml aflibercept, before cells were harvested for immunofluorescence staining or preparation of protein extracts. Intracellular localization of aflibercept and putative co-localizations with proteins involved in transport of IgG/FcRn complexes, i.e., endosomal Rab4 and Rab11, components of the cytoskeleton, motor proteins, or with marker proteins characteristic of multivesicular bodies or lysosomes were assessed by co-immunofluorescence stainings. Amounts of expressed endogenous proteins and of internalized aflibercept were determined by Western blot analyses. RESULTS Aflibercept-specific perinuclear staining overlapped with that of the motor protein dynein whereas double staining with an anti-kinesin antibody resulted in a patchy pattern. In addition, aflibercept was typically present close to microtubules and often co-localized with α-tubulin. Rab4 and Rab11 stainings partly overlapped with the perinuclear staining of aflibercept whereas co-localization with Rab7 (in late endosomes/lysosomes) was only rarely seen. Interestingly, aflibercept but not the IgG bevacizumab broadly co-localized with the cation-independent mannose 6-phosphate receptor characteristic of multivesicular endosomes. In accordance with partial degradation beside transcytosis, the amount of intracellular aflibercept increased when cells were treated with protease inhibitors MG-132 or MG-101. Serum-deprived iBREC expressed less Rab11 and dynein but slightly more Rab4. CONCLUSION After uptake by iBREC, aflibercept is present in organelles associated with FcRn-mediated transport, but part of the protein is subject to degradation. Transport inhibition of aflibercept during cultivation without FBS is likely a consequence of an attenuated exocytosis due to decreased expression of Rab11.
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13
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Malik P, Edginton A. Pediatric physiology in relation to the pharmacokinetics of monoclonal antibodies. Expert Opin Drug Metab Toxicol 2018; 14:585-599. [PMID: 29806953 DOI: 10.1080/17425255.2018.1482278] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
INTRODUCTION Dose design for pediatric trials with monoclonal antibodies (mAbs) is often extrapolated from the adult dose according to weight, age, or body surface area. While these methods account for the size differences between adults and children, they do not account for the maturation of processes that may play a key role in the pharmacokinetics and/or pharmacodynamics of mAbs. With the same weight-based dose, infants and young children typically receive lower plasma exposures when compared to adults. Areas covered: The mechanistic features of mAb distribution, elimination, and absorption are explored in detail and literature-based hypotheses are generated to describe their age-dependence. This knowledge can be incorporated into a physiologically based pharmacokinetic (PBPK) modeling approach to pediatric dose determination. Expert opinion: As data from pediatric clinical trials become increasingly available, we have the opportunity to reflect on the physiologic drivers of pharmacokinetics, safety, and efficacy in children with mathematical models. A modeling approach that accounts for the age-related features of mAb disposition can be used to derive first-in-pediatric doses, design optimal sampling schemes for children in clinical trials and even explore new pharmacokinetic end-points as predictors of safety and efficacy in children.
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Affiliation(s)
- Paul Malik
- a School of Pharmacy , University of Waterloo , Kitchener , Ontario , Canada
| | - Andrea Edginton
- a School of Pharmacy , University of Waterloo , Kitchener , Ontario , Canada
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14
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Malik P, Phipps C, Edginton A, Blay J. Pharmacokinetic Considerations for Antibody-Drug Conjugates against Cancer. Pharm Res 2017; 34:2579-2595. [PMID: 28924691 DOI: 10.1007/s11095-017-2259-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/09/2017] [Indexed: 12/26/2022]
Abstract
Antibody-drug conjugates (ADCs) are ushering in the next era of targeted therapy against cancer. An ADC for cancer therapy consists of a potent cytotoxic payload that is attached to a tumour-targeted antibody by a chemical linker, usually with an average drug-to-antibody ratio (DAR) of 3.5-4. The theory is to deliver potent cytotoxic payloads directly to tumour cells while sparing healthy cells. However, practical application has proven to be more difficult. At present there are only two ADCs approved for clinical use. Nevertheless, in the last decade there has been an explosion of options for ADC engineering to optimize target selection, Fc receptor interactions, linker, payload and more. Evaluation of these strategies requires an understanding of the mechanistic underpinnings of ADC pharmacokinetics. Development of ADCs for use in cancer further requires an understanding of tumour properties and kinetics within the tumour environment, and how the presence of cancer as a disease will impact distribution and elimination. Key pharmacokinetic considerations for the successful design and clinical application of ADCs in oncology are explored in this review, with a focus on the mechanistic determinants of distribution and elimination.
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Affiliation(s)
- Paul Malik
- School of Pharmacy, University of Waterloo, 10A Victoria St South, Kitchener, Ontario, N2G 1C5, Canada
| | - Colin Phipps
- School of Pharmacy, University of Waterloo, 10A Victoria St South, Kitchener, Ontario, N2G 1C5, Canada.,DMPK & Translational Modeling, Abbvie Inc., North Chicago, Illinois, 60064, USA
| | - Andrea Edginton
- School of Pharmacy, University of Waterloo, 10A Victoria St South, Kitchener, Ontario, N2G 1C5, Canada.
| | - Jonathan Blay
- School of Pharmacy, University of Waterloo, 10A Victoria St South, Kitchener, Ontario, N2G 1C5, Canada
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15
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Ryman JT, Meibohm B. Pharmacokinetics of Monoclonal Antibodies. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2017; 6:576-588. [PMID: 28653357 PMCID: PMC5613179 DOI: 10.1002/psp4.12224] [Citation(s) in RCA: 468] [Impact Index Per Article: 66.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 12/13/2022]
Abstract
Monoclonal antibodies (mAbs) have developed in the last two decades into the backbone of pharmacotherapeutic interventions in a variety of indications, with currently more than 40 mAbs approved by the US Food and Drug Administration, and several dozens more in clinical development. This tutorial will review major drug disposition processes relevant for mAbs, and will highlight product‐specific and patient‐specific factors that modulate their pharmacokinetic (PK) behavior and need to be considered for successful clinical therapy.
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Affiliation(s)
- Josiah T Ryman
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Bernd Meibohm
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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16
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Malik PRV, Hamadeh A, Phipps C, Edginton AN. Population PBPK modelling of trastuzumab: a framework for quantifying and predicting inter-individual variability. J Pharmacokinet Pharmacodyn 2017; 44:277-290. [PMID: 28260166 DOI: 10.1007/s10928-017-9515-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/01/2017] [Indexed: 12/11/2022]
Abstract
In this work we proposed a population physiologically-based pharmacokinetic (popPBPK) framework for quantifying and predicting inter-individual pharmacokinetic variability using the anti-HER2 monoclonal antibody (mAb) trastuzumab as an example. First, a PBPK model was developed to account for the possible mechanistic sources of variability. Within the model, five key factors that contribute to variability were identified and the nature of their contribution was quantified with local and global sensitivity analyses. The five key factors were the concentration of membrane-bound HER2 ([Formula: see text]), the convective flow rate of mAb through vascular pores ([Formula: see text]), the endocytic transport rate of mAb through vascular endothelium ([Formula: see text]), the degradation rate of mAb-HER2 complexes ([Formula: see text]) and the concentration of shed HER2 extracellular domain in circulation ([Formula: see text]). [Formula: see text] was the most important parameter governing trastuzumab distribution into tissues and primarily affected variability in the first 500 h post-administration. [Formula: see text] was the most significant contributor to variability in clearance. These findings were used together with population generation methods to accurately predict the observed variability in four experimental trials with trastuzumab. To explore anthropometric sources of variability, virtual populations were created to represent participants in the four experimental trials. Using populations with only their expected anthropometric diversity resulted in under-prediction of the observed inter-individual variability. Adapting the populations to include literature-based variability around the five key parameters enabled accurate predictions of the variability in the four trials. The successful application of this framework demonstrates the utility of popPBPK methods to understand the mechanistic underpinnings of pharmacokinetic variability.
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Affiliation(s)
- Paul R V Malik
- School of Pharmacy, University of Waterloo, 10A Victoria St S, Kitchener, ON, N2G 1C5, Canada
| | - Abdullah Hamadeh
- School of Pharmacy, University of Waterloo, 10A Victoria St S, Kitchener, ON, N2G 1C5, Canada
| | - Colin Phipps
- School of Pharmacy, University of Waterloo, 10A Victoria St S, Kitchener, ON, N2G 1C5, Canada
| | - Andrea N Edginton
- School of Pharmacy, University of Waterloo, 10A Victoria St S, Kitchener, ON, N2G 1C5, Canada.
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17
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Deissler HL, Lang GK, Lang GE. Neonatal Fc receptor FcRn is involved in intracellular transport of the Fc fusion protein aflibercept and its transition through retinal endothelial cells. Exp Eye Res 2016; 154:39-46. [PMID: 27836572 DOI: 10.1016/j.exer.2016.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/18/2016] [Accepted: 11/07/2016] [Indexed: 12/15/2022]
Abstract
Retinal endothelial cells (REC) likely contribute to the clearance of intravitreally injected IgG. Because this is of high relevance to the pharmacokinetic assessment of the widely used therapeutic Fc fusion protein aflibercept, we studied its transport through immortalized bovine REC (iBREC) in detail. For shuttling of IgG or Fc fusion proteins like aflibercept, endothelial cells use the highly conserved neonatal Fc receptor (FcRn) also expressed in iBREC where it is down regulated by serum depletion. Therefore, we focused on studying intracellular localization and transport of aflibercept under conditions affecting its interaction with the FcRn. Intracellular localization of aflibercept was assessed by Western-blot analyses of subcellular protein fractions or by immunofluorescence staining. After uptake in a temperature-dependent process, aflibercept co-localized with early endosomes, which harbor FcRn. Similar amounts of aflibercept were co-extracted with proteins from membranes/organelles irrespectively of the amount of FBS in the culture medium. Lowering the concentration of FBS resulted in a strong, but reversible association with cytoskeletal proteins suggesting a block in intracellular transport. In accordance with this finding, aflibercept's transport through an iBREC monolayer grown on porous membrane inserts was markedly delayed in the absence of FBS in the culture medium indicating that aflibercept is taken up but not exocytosed under these conditions. Transcytosis of aflibercept was also strongly delayed by inhibition of phosphatidylinositol 3-kinase with LY294002, which affects FcRn-mediated IgG transport. A similar inhibition of aflibercept's transport was observed with IgG-binding proteins (i.e. protein A or protein G) that block interaction between FcRn and aflibercept. Interfering with aflibercept's binding to the FcRn with protein A (or protein G) or the inhibitory FcRn-specific monoclonal antibody 1G3 resulted in a reduced amount of intracellular aflibercept. Taken together, our results strongly suggest that FcRn is involved in transport of aflibercept through REC in vitro.
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Affiliation(s)
- Heidrun L Deissler
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany.
| | - Gerhard K Lang
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
| | - Gabriele E Lang
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
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18
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IgG trafficking in the adult pig small intestine: one- or bidirectional transfer across the enterocyte brush border? Histochem Cell Biol 2016; 147:399-411. [PMID: 27646280 DOI: 10.1007/s00418-016-1492-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2016] [Indexed: 12/18/2022]
Abstract
Immunoglobulin G (IgG) transfer in opposite directions across the small intestinal brush border serves different purposes in early life and in adulthood. In the neonate, maternal IgG is taken up from the gut lumen into the blood, conferring passive immunity to the offspring, whereas in the adult immunoglobulins, including IgG made by plasma cells in the lamina propria, are secreted via the brush border to the lumen as part of the mucosal defense. Here, IgG has been proposed to perform a luminal immune surveillance which eventually includes a reuptake through the brush border as pathogen-containing immune complexes. In the present work, we studied luminal uptake of FITC-conjugated and gold-conjugated IgG in cultured pig jejunal mucosal explants. After 1 h, binding to the brush border was seen in upper crypts and lower parts of the villi. However, no endocytotic uptake into EEA-1-positive compartments was detected, neither at neutral nor acidic pH, despite an ongoing constitutive endocytosis from the brush border, visualized by the polar tracer CF594. The 40-kDa neonatal Fc receptor, FcRn, was present in the microvillus fraction, but noteworthy, a 37 kDa band, most likely a proteolytic cleavage product, bound IgG in a pH-dependent manner more efficiently than did the full-length FcRn. In conclusion, our work does not support the theory that bidirectional transfer of IgG across the intestinal brush border is part of the luminal immune surveillance in the adult.
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19
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Martins JP, Kennedy PJ, Santos HA, Barrias C, Sarmento B. A comprehensive review of the neonatal Fc receptor and its application in drug delivery. Pharmacol Ther 2016; 161:22-39. [PMID: 27016466 DOI: 10.1016/j.pharmthera.2016.03.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Advances in the understanding of neonatal Fc receptor (FcRn) biology and function have demonstrated that this receptor, primarily identified for the transfer of passive immunity from mother infant, is involved in several biological and immunological processes. In fact, FcRn is responsible for the long half-life of IgG and albumin in the serum, by creating an intracellular protein reservoir, which is protected from lysosomal degradation and, importantly, trafficked across the cell. Such discovery has led researchers to hypothesize the role for this unique receptor in the controlled delivery of therapeutic agents. A great amount of FcRn-based strategies are already under extensive investigation, in which FcRn reveals to have profound impact on the biodistribution and half-life extension of therapeutic agents. This review summarizes the main findings on FcRn biology, function and distribution throughout different tissues, together with the main advances on the FcRn-based therapeutic opportunities and model systems, which indicate that this receptor is a potential target for therapeutic regimen modification.
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Affiliation(s)
- João Pedro Martins
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge Viterbo 228, 4150-180 Porto, Portugal
| | - Patrick J Kennedy
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; ICBAS - Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge Viterbo 228, 4150-180 Porto, Portugal; Ipatimup - Instituto de Patologia e Imunologia Molecular da Universidade do Porto, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Hélder A Santos
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5 E, FI -00014 Helsinki, Finland
| | - Cristina Barrias
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Bruno Sarmento
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; CESPU - Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde and Instituto Universitário de Ciências da Saúde, 4585-116 Gandra, Portugal.
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20
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Foss S, Grevys A, Sand KMK, Bern M, Blundell P, Michaelsen TE, Pleass RJ, Sandlie I, Andersen JT. Enhanced FcRn-dependent transepithelial delivery of IgG by Fc-engineering and polymerization. J Control Release 2015; 223:42-52. [PMID: 26718855 DOI: 10.1016/j.jconrel.2015.12.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/14/2015] [Accepted: 12/19/2015] [Indexed: 01/28/2023]
Abstract
Monoclonal IgG antibodies (Abs) are used extensively in the clinic to treat cancer and autoimmune diseases. In addition, therapeutic proteins are genetically fused to the constant Fc part of IgG. In both cases, the Fc secures a long serum half-life and favourable pharmacokinetics due to its pH-dependent interaction with the neonatal Fc receptor (FcRn). FcRn also mediates transport of intact IgG across polarized epithelial barriers, a pathway that is attractive for delivery of Fc-containing therapeutics. So far, no study has thoroughly compared side-by-side how IgG and different Fc-fusion formats are transported across human polarizing epithelial cells. Here, we used an in vitro cellular transport assay based on the human polarizing epithelial cell line (T84) in which both IgG1 and Fc-fusions were transported in an FcRn-dependent manner. Furthermore, we found that the efficacy of transport was dependent on the format. We demonstrate that transepithelial delivery could be enhanced by Fc-engineering for improved FcRn binding as well as by Fc-polymerization. In both cases, transport was driven by pH-dependent binding kinetics and the pH at the luminal side. Hence, efficient transcellular delivery of IgG-based drugs across human epithelial cells requires optimal pH-dependent FcRn binding that can be manipulated by avidity and Fc-engineering, factors that should inspire the design of future therapeutics targeted for transmucosal delivery.
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Affiliation(s)
- Stian Foss
- Centre for Immune Regulation (CIR), Department of Biosciences, University of Oslo, N-0316, Oslo, Norway; Department of Immunology and CIR, Oslo University Hospital, Rikshospitalet, University of Oslo, N-0372, Oslo, Norway
| | - Algirdas Grevys
- Centre for Immune Regulation (CIR), Department of Biosciences, University of Oslo, N-0316, Oslo, Norway; Department of Immunology and CIR, Oslo University Hospital, Rikshospitalet, University of Oslo, N-0372, Oslo, Norway
| | - Kine Marita Knudsen Sand
- Centre for Immune Regulation (CIR), Department of Biosciences, University of Oslo, N-0316, Oslo, Norway; Department of Immunology and CIR, Oslo University Hospital, Rikshospitalet, University of Oslo, N-0372, Oslo, Norway
| | - Malin Bern
- Centre for Immune Regulation (CIR), Department of Biosciences, University of Oslo, N-0316, Oslo, Norway; Department of Immunology and CIR, Oslo University Hospital, Rikshospitalet, University of Oslo, N-0372, Oslo, Norway
| | - Pat Blundell
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Terje E Michaelsen
- Department of Bacteriology and Immunology, Norwegian Institute of Public Health, Oslo, Norway; Department of Chemical Pharmacy, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Richard J Pleass
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Inger Sandlie
- Centre for Immune Regulation (CIR), Department of Biosciences, University of Oslo, N-0316, Oslo, Norway; Department of Immunology and CIR, Oslo University Hospital, Rikshospitalet, University of Oslo, N-0372, Oslo, Norway
| | - Jan Terje Andersen
- Centre for Immune Regulation (CIR), Department of Biosciences, University of Oslo, N-0316, Oslo, Norway; Department of Immunology and CIR, Oslo University Hospital, Rikshospitalet, University of Oslo, N-0372, Oslo, Norway.
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Ward ES, Ober RJ. Commentary: "There's been a Flaw in Our Thinking". Front Immunol 2015; 6:351. [PMID: 26236309 PMCID: PMC4503918 DOI: 10.3389/fimmu.2015.00351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/28/2015] [Indexed: 12/16/2022] Open
Affiliation(s)
- E Sally Ward
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center , College Station, TX , USA ; Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center , Bryan, TX , USA ; Department of Immunology, University of Texas Southwestern Medical Center , Dallas, TX , USA
| | - Raimund J Ober
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center , College Station, TX , USA ; Department of Biomedical Engineering, Texas A&M University , College Station, TX , USA
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Tabata T, Petitt M, Zydek M, Fang-Hoover J, Larocque N, Tsuge M, Gormley M, Kauvar LM, Pereira L. Human cytomegalovirus infection interferes with the maintenance and differentiation of trophoblast progenitor cells of the human placenta. J Virol 2015; 89:5134-47. [PMID: 25741001 PMCID: PMC4403461 DOI: 10.1128/jvi.03674-14] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 01/19/2015] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Human cytomegalovirus (HCMV) is a major cause of birth defects that include severe neurological deficits, hearing and vision loss, and intrauterine growth restriction. Viral infection of the placenta leads to development of avascular villi, edema, and hypoxia associated with symptomatic congenital infection. Studies of primary cytotrophoblasts (CTBs) revealed that HCMV infection impedes terminal stages of differentiation and invasion by various molecular mechanisms. We recently discovered that HCMV arrests earlier stages involving development of human trophoblast progenitor cells (TBPCs), which give rise to the mature cell types of chorionic villi-syncytiotrophoblasts on the surfaces of floating villi and invasive CTBs that remodel the uterine vasculature. Here, we show that viral proteins are present in TBPCs of the chorion in cases of symptomatic congenital infection. In vitro studies revealed that HCMV replicates in continuously self-renewing TBPC lines derived from the chorion and alters expression and subcellular localization of proteins required for cell cycle progression, pluripotency, and early differentiation. In addition, treatment with a human monoclonal antibody to HCMV glycoprotein B rescues differentiation capacity, and thus, TBPCs have potential utility for evaluation of the efficacies of novel antiviral antibodies in protecting and restoring placental development. Our results suggest that HCMV replicates in TBPCs in the chorion in vivo, interfering with the earliest steps in the growth of new villi, contributing to virus transmission and impairing compensatory development. In cases of congenital infection, reduced responsiveness of the placenta to hypoxia limits the transport of substances from maternal blood and contributes to fetal growth restriction. IMPORTANCE Human cytomegalovirus (HCMV) is a leading cause of birth defects in the United States. Congenital infection can result in permanent neurological defects, mental retardation, hearing loss, visual impairment, and pregnancy complications, including intrauterine growth restriction, preterm delivery, and stillbirth. Currently, there is neither a vaccine nor any approved treatment for congenital HCMV infection during gestation. The molecular mechanisms underlying structural deficiencies in the placenta that undermine fetal development are poorly understood. Here we report that HCMV replicates in trophoblast progenitor cells (TBPCs)-precursors of the mature placental cells, syncytiotrophoblasts and cytotrophoblasts, in chorionic villi-in clinical cases of congenital infection. Virus replication in TBPCs in vitro dysregulates key proteins required for self-renewal and differentiation and inhibits normal division and development into mature placental cells. Our findings provide insights into the underlying molecular mechanisms by which HCMV replication interferes with placental maturation and transport functions.
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Affiliation(s)
- Takako Tabata
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, San Francisco, California, USA
| | - Matthew Petitt
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, San Francisco, California, USA
| | - Martin Zydek
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, San Francisco, California, USA
| | - June Fang-Hoover
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, San Francisco, California, USA
| | - Nicholas Larocque
- Center for Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA The Eli & Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, California, USA
| | - Mitsuru Tsuge
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, San Francisco, California, USA
| | - Matthew Gormley
- Center for Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA The Eli & Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, California, USA
| | | | - Lenore Pereira
- Department of Cell and Tissue Biology, School of Dentistry, University of California, San Francisco, San Francisco, California, USA
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Targeting FcRn for the modulation of antibody dynamics. Mol Immunol 2015; 67:131-41. [PMID: 25766596 DOI: 10.1016/j.molimm.2015.02.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 01/08/2023]
Abstract
The MHC class I-related receptor, FcRn, is a multitasking protein that transports its IgG ligand within and across cells of diverse origins. The role of this receptor as a global regulator of IgG homeostasis and transport, combined with knowledge of the molecular details of FcRn-IgG interactions, has led to opportunities to modulate the in vivo dynamics of antibodies and their antigens through protein engineering. Consequently, the generation of half-life extended antibodies has shown a rapid expansion over the past decade. Further, FcRn itself can be targeted by inhibitors to induce decreased levels of circulating IgGs, which could have applications in multiple clinical settings. The engineering of antibody-antigen interactions to reduce antibody-mediated buffering of soluble ligand has also developed into an active area of investigation, leading to novel antibody platforms designed to result in more effective antigen clearance. Similarly, the target-mediated elimination of antibodies by internalizing, membrane bound antigens (receptors) can be decreased using novel engineering approaches. These strategies, combined with subcellular trafficking analyses of antibody/antigen/FcRn behavior in cells to predict in vivo behavior, have considerable promise for the production of next generation therapeutics and diagnostics.
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Zhang J, Sadowska GB, Chen X, Park SY, Kim JE, Bodge CA, Cummings E, Lim YP, Makeyev O, Besio WG, Gaitanis J, Banks WA, Stonestreet BS. Anti-IL-6 neutralizing antibody modulates blood-brain barrier function in the ovine fetus. FASEB J 2015; 29:1739-53. [PMID: 25609424 DOI: 10.1096/fj.14-258822] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 12/22/2014] [Indexed: 12/15/2022]
Abstract
Impaired blood-brain barrier function represents an important component of hypoxic-ischemic brain injury in the perinatal period. Proinflammatory cytokines could contribute to ischemia-related blood-brain barrier dysfunction. IL-6 increases vascular endothelial cell monolayer permeability in vitro. However, contributions of IL-6 to blood-brain barrier abnormalities have not been examined in the immature brain in vivo. We generated pharmacologic quantities of ovine-specific neutralizing anti-IL-6 mAbs and systemically infused mAbs into fetal sheep at 126 days of gestation after exposure to brain ischemia. Anti-IL-6 mAbs were measured by ELISA in fetal plasma, cerebral cortex, and cerebrospinal fluid, blood-brain barrier permeability was quantified using the blood-to-brain transfer constant in brain regions, and IL-6, tight junction proteins, and plasmalemma vesicle protein (PLVAP) were detected by Western immunoblot. Anti-IL-6 mAb infusions resulted in increases in mAb (P < 0.05) in plasma, brain parenchyma, and cerebrospinal fluid and decreases in brain IL-6 protein. Twenty-four hours after ischemia, anti-IL-6 mAb infusions attenuated ischemia-related increases in blood-brain barrier permeability and modulated tight junction and PLVAP protein expression in fetal brain. We conclude that inhibiting the effects of IL-6 protein with systemic infusions of neutralizing antibodies attenuates ischemia-related increases in blood-brain barrier permeability by inhibiting IL-6 and modulates tight junction proteins after ischemia.
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Affiliation(s)
- Jiyong Zhang
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Grazyna B Sadowska
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Xiaodi Chen
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Seon Yeong Park
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Jeong-Eun Kim
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Courtney A Bodge
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Erin Cummings
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Yow-Pin Lim
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Oleksandr Makeyev
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Walter G Besio
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - John Gaitanis
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - William A Banks
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Barbara S Stonestreet
- *Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island, USA; ProThera Biologics, Incorporated, Providence, Rhode Island, USA; Department of Electrical, Computer, and Biomedical Engineering, University of Rhode Island, Kingston, Rhode Island, USA; Department of Neurology, Alpert Medical School of Brown University, Rhode Island Hospital, Providence, Rhode Island, USA; and Geriatric Research Educational, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
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Cui D, Zhang L, Li J, Zhao Y, Hu X, Dai Y, Zhang R, Li N. Bovine FcRn-mediated human immunoglobulin G transfer across the milk-blood barrier in transgenic mice. PLoS One 2014; 9:e115972. [PMID: 25546424 PMCID: PMC4278800 DOI: 10.1371/journal.pone.0115972] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 11/28/2014] [Indexed: 11/18/2022] Open
Abstract
Maternal-fetal IgGs transport occurs either prenatally or postnatally, which confers the newborns with passive immunity before their own immune system has matured. However, little is known about the mechanisms of postnatal IgGs passage in the mammary gland. To investigate how FcRn mediates the IgGs transport in the mammary gland, we first generated bFcRn and anti-HAV mAb transgenic mice, and then obtained HF transgenic mice expressing both transgenes by mating the above two strains. Transgene expression of bFcRn in the four lines was determined by qRT-PCR and western blot. We then localized the expression of bFcRn to the acinar epithelial cells in the mammary gland, and anti-HAV mAb was mainly detected in the acini with weak staining in the acinar epithelial cells. Human IgGs could be detected in both milk and serum of HF transgenic mice by western blot and ELISA. A significantly lower milk to serum ratio of human IgGs in HF mice compared with that of anti-HAV mAb mice, indicating that bFcRn could transport human IgGs across the milk-blood barrier from milk to serum during lactation in HF mice. While, there were no transport of murine IgGs, IgAs, or IgMs. These results provide understandings about the mechanisms of maternal-fetal immunity transfer in the mammary gland.
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Affiliation(s)
- Dan Cui
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
| | - Linlin Zhang
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
| | - Jia Li
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
| | - Yaofeng Zhao
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
| | - Xiaoxiang Hu
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
| | | | - Ran Zhang
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
- * E-mail: (RZ); (NL)
| | - Ning Li
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
- * E-mail: (RZ); (NL)
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Divergent outcomes following transcytosis of IgG targeting intracellular and extracellular chlamydial antigens. Immunol Cell Biol 2014; 92:417-26. [PMID: 24445600 DOI: 10.1038/icb.2013.110] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/11/2013] [Accepted: 12/12/2013] [Indexed: 12/12/2022]
Abstract
Antibodies can have a protective but non-essential role in natural chlamydial infections dependent on antigen specificity and antibody isotype. IgG is the dominant antibody in both male and female reproductive tract mucosal secretions, and is bi-directionally trafficked across epithelia by the neonatal Fc receptor (FcRn). Using pH-polarized epididymal epithelia grown on Transwells, IgG specifically targeted at an extracellular chlamydial antigen; the major outer membrane protein (MOMP), enhanced uptake and translocation of infection at pH 6-6.5 but not at neutral pH. This was dependent on FcRn expression. Conversely, FcRn-mediated transport of IgG targeting the intracellular chlamydial inclusion membrane protein A (IncA), induced aberrant inclusion morphology, recruited autophagic proteins independent of lysosomes and significantly reduced infection. Challenge of female mice with MOMP-specific IgG-opsonized Chlamydia muridarum delayed infection clearance but exacerbated oviduct occlusion. In male mice, MOMP-IgG elicited by immunization afforded no protection against testicular chlamydial infection, whereas the transcytosis of IncA-IgG significantly reduced testicular chlamydial burden. Together these data show that the protective and pathological effects of IgG are dependent on FcRn-mediated transport as well as the specificity of IgG for intracellular or extracellular antigens.
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28
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Chen N, Wang W, Fauty S, Fang Y, Hamuro L, Hussain A, Prueksaritanont T. The effect of the neonatal Fc receptor on human IgG biodistribution in mice. MAbs 2014; 6:502-8. [PMID: 24492305 DOI: 10.4161/mabs.27765] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The neonatal Fc receptor (FcRn) plays a pivotal role in IgG homeostasis, i.e., it salvages IgG antibodies from lysosomal degradation following fluid-phase pinocytosis, thus preventing rapid systemic elimination of IgG. Recombinant therapeutic antibodies are typically composed of human or humanized sequences, and their biodistribution, or tissue distribution, is often studied in murine models, although, the effect of FcRn on tissue distribution of human IgG in rodents has not been investigated. In this report, an (125)I-labeled human IgG1 antibody was studied in both wild type C57BL/6 (WT) and FcRn knockout (KO) mice. Total radioactivity in both plasma and tissues (0-96hr post-dose) was measured by gamma-counting. Plasma exposure of human IgG1 were significantly lower in FcRn KO mice, which is consistent with the primary function of FcRn. Differences in biodistribution of human IgG to selected tissues were also observed. Among the tissue examined, the fat, skin and muscle showed a decrease in tissue-to-blood (T/B) exposure ratio of human IgG1 in FcRn KO mice comparing to the WT mice, while the liver, spleen, kidney, and lung showed an increase in the T/B exposure ratio in FcRn KO mice. A time-dependent change in the T/B ratios of human IgG1 was also observed for many tissues in FcRn KO mice. These results suggest that, in addition to its role in IgG elimination, FcRn may also play a role in antibody biodistribution.
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Affiliation(s)
- Nancy Chen
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Merck Research Laboratories; West Point, PA USA
| | - Weirong Wang
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Merck Research Laboratories; West Point, PA USA
| | - Scott Fauty
- Department of Laboratory Animal Resources; Merck Research Laboratories; West Point, PA USA
| | - Yulin Fang
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Merck Research Laboratories; West Point, PA USA
| | - Lora Hamuro
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Merck Research Laboratories; West Point, PA USA
| | - Azher Hussain
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Merck Research Laboratories; West Point, PA USA
| | - Thomayant Prueksaritanont
- Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism; Merck Research Laboratories; West Point, PA USA
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Gurbaxani B, Dostalek M, Gardner I. Are endosomal trafficking parameters better targets for improving mAb pharmacokinetics than FcRn binding affinity? Mol Immunol 2013; 56:660-74. [PMID: 23917469 DOI: 10.1016/j.molimm.2013.05.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 05/09/2013] [Accepted: 05/14/2013] [Indexed: 12/21/2022]
Abstract
F.W.R. Brambell deduced the existence of a protective receptor for IgG, the neonatal Fc receptor (FcRn), long before its discovery in the early to mid-1990s. With the coincident, explosive development of IgG-based drugs, FcRn became a popular target for tuning the pharmacokinetics of monoclonal antibodies (mAbs). One aspect of Brambell's initial observation, however, that is seldom discussed since the discovery of the receptor, is the compliance in the mechanism that Brambell observed (saturating at 10s-100s of μM concentration), vs. the comparative stiffness of the receptor kinetics (saturating in the nM range for most species). Although some studies reported that increasing the already very high Fc-FcRn affinity at pH 6.0 further improved mAb half-life, in fact the results were mixed, with later studies increasingly implicating non-FcRn-dependent mechanisms as determinants of mAb pharmacokinetics. Mathematical modelling of the FcRn system has also indicated that the processes determining the pharmacokinetics of mAbs have more nuances than had at first been hypothesised. We propose, in keeping with the latest modelling and experimental evidence reviewed here, that the dynamics of endosomal sorting and trafficking have important roles in the compliant salvage mechanism that Brambell first observed nearly 50 years ago, and therefore also in the pharmacokinetics of mAbs. These ideas lead to many open questions regarding the endosomal trafficking of both FcRn and mAbs and also to what properties of a mAb can be altered to achieve an improvement in pharmacokinetics.
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Affiliation(s)
- Brian Gurbaxani
- Chronic Viral Diseases Branch, Division of High-Consequence Pathogens and Pathology, National Centre for Emerging and Zoonotic Infectious Diseases, Centres for Disease Control and Prevention, Atlanta, GA, USA.
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A novel hypothesis for an alkaline phosphatase 'rescue' mechanism in the hepatic acute phase immune response. Biochim Biophys Acta Mol Basis Dis 2013; 1832:2044-56. [PMID: 23899605 DOI: 10.1016/j.bbadis.2013.07.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 07/10/2013] [Accepted: 07/22/2013] [Indexed: 12/24/2022]
Abstract
The liver isoform of the enzyme alkaline phosphatase (AP) has been used classically as a serum biomarker for hepatic disease states such as hepatitis, steatosis, cirrhosis, drug-induced liver injury, and hepatocellular carcinoma. Recent studies have demonstrated a more general anti-inflammatory role for AP, as it is capable of dephosphorylating potentially deleterious molecules such as nucleotide phosphates, the pathogenic endotoxin lipopolysaccharide (LPS), and the contact clotting pathway activator polyphosphate (polyP), thereby reducing inflammation and coagulopathy systemically. Yet the mechanism underlying the observed increase in liver AP levels in circulation during inflammatory insults is largely unknown. This paper hypothesizes an immunological role for AP in the liver and the potential of this system for damping generalized inflammation along with a wide range of ancillary pathologies. Based on the provided framework, a mechanism is proposed in which AP undergoes transcytosis in hepatocytes from the canalicular membrane to the sinusoidal membrane during inflammation and the enzyme's expression is upregulated as a result. Through a tightly controlled, nucleotide-stimulated negative feedback process, AP is transported in this model as an immune complex with immunoglobulin G by the asialoglycoprotein receptor through the cell and secreted into the serum, likely using the receptor's State 1 pathway. The subsequent dephosphorylation of inflammatory stimuli by AP and uptake of the circulating immune complex by endothelial cells and macrophages may lead to decreased inflammation and coagulopathy while providing an early upstream signal for the induction of a number of anti-inflammatory gene products, including AP itself.
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Strazielle N, Ghersi-Egea JF. Physiology of blood-brain interfaces in relation to brain disposition of small compounds and macromolecules. Mol Pharm 2013; 10:1473-91. [PMID: 23298398 DOI: 10.1021/mp300518e] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The brain develops and functions within a strictly controlled environment resulting from the coordinated action of different cellular interfaces located between the blood and the extracellular fluids of the brain, which include the interstitial fluid and the cerebrospinal fluid (CSF). As a correlate, the delivery of pharmacologically active molecules and especially macromolecules to the brain is challenged by the barrier properties of these interfaces. Blood-brain interfaces comprise both the blood-brain barrier located at the endothelium of the brain microvessels and the blood-CSF barrier located at the epithelium of the choroid plexuses. Although both barriers develop extensive surface areas of exchange between the blood and the neuropil or the CSF, the molecular fluxes across these interfaces are tightly regulated. Cerebral microvessels acquire a barrier phenotype early during cerebral vasculogenesis under the influence of the Wnt/β-catenin pathway, and of recruited pericytes. Later in development, astrocytes also play a role in blood-brain barrier maintenance. The tight choroid plexus epithelium develops very early during embryogenesis. It is specified by various signaling molecules from the embryonic dorsal midline, such as bone morphogenic proteins, and grows under the influence of Sonic hedgehog protein. Tight junctions at each barrier comprise a distinctive set of claudins from the pore-forming and tightening categories that determine their respective paracellular barrier characteristics. Vesicular traffic is limited in the cerebral endothelium and abundant in the choroidal epithelium, yet without evidence of active fluid phase transcytosis. Inorganic ion transport is highly regulated across the barriers. Small organic compounds such as nutrients, micronutrients and hormones are transported into the brain by specific solute carriers. Other bioactive metabolites, lipophilic toxic xenobiotics or pharmacological agents are restrained from accumulating in the brain by several ATP-binding cassette efflux transporters, multispecific solute carriers, and detoxifying enzymes. These various molecular effectors differently distribute between the two barriers. Receptor-mediated endocytotic and transcytotic mechanisms are active in the barriers. They enable brain penetration of selected polypeptides and proteins, or inversely macromolecule efflux as it is the case for immnoglobulins G. An additional mechanism specific to the BCSFB mediates the transport of selected plasma proteins from blood into CSF in the developing brain. All these mechanisms could be explored and manipulated to improve macromolecule delivery to the brain.
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Affiliation(s)
- N Strazielle
- Brain-i, Lyon Neuroscience Research Center, Lyon, France.
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Abstract
Biologics, including monoclonal antibodies (mAbs) and other therapeutic proteins such as cytokines and growth hormones, have unique characteristics compared to small molecules. This paper starts from an overview of the pharmacokinetics (PK) of biologics from a mechanistic perspective, the determination of a starting dose for first-in-human (FIH) studies, and dosing regimen optimisation for phase II/III clinical trials. Subsequently, typical clinical pharmacology issues along the corresponding pathways for biologics development are summarised, including drug-drug interactions, QTc prolongation, immunogenicity, and studies in specific populations. The relationships between the molecular structure of biologics, their pharmacokinetic and pharmacodynamic characteristics, and the corresponding clinical pharmacology strategies are summarised and depicted in a schematic diagram.
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Zhao L, Shang EY, Sahajwalla CG. Application of pharmacokinetics-pharmacodynamics/clinical response modeling and simulation for biologics drug development. J Pharm Sci 2012; 101:4367-82. [PMID: 23018763 DOI: 10.1002/jps.23330] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 08/27/2012] [Accepted: 09/07/2012] [Indexed: 01/21/2023]
Abstract
Biologics, specifically monoclonal antibody (mAb) drugs, have unique pharmacokinetic (PK) and pharmacodynamic (PD) characteristics as opposed to small molecules. Under the paradigm of model-based drug development, PK-PD/clinical response models offer critical insight in guiding biologics development at various stages. On the basis of the molecular structure and corresponding properties of biologics, typical mechanism-based [target-mediated drug disposition (TMDD)], physiologically based PK, PK-PD, and dose-response meta-analysis models are summarized. Examples of using TMDD, PK-PD, and meta-analysis in helping starting dose determination in first-in-human studies and dosing regimen optimization in phase II/III trials are discussed. Instead of covering the entirety of model-based biologics development, this review focuses on the guiding principles and the core mathematical descriptions underlying the PK or PK-PD models most used.
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Affiliation(s)
- Liang Zhao
- Office of Clinical Pharmacology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA.
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Gan H, Feng S, Wu H, Sun Y, Hu R, Zhao Z, Zhang Z. Neonatal Fc receptor stimulation induces ubiquitin c-terminal hydrolase-1 overexpression in podocytes through activation of p38 mitogen-activated protein kinase. Hum Pathol 2012; 43:1482-90. [DOI: 10.1016/j.humpath.2011.10.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Revised: 10/20/2011] [Accepted: 10/21/2011] [Indexed: 11/24/2022]
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Proulx DP, Rouleau P, Paré I, Vallières-Noël MM, Bazin R. Interaction between intravenous immunoglobulin (IVIg) and the low-density lipoprotein receptor-related protein 1: a role for transcytosis across the blood brain barrier? J Neuroimmunol 2012; 251:39-44. [PMID: 22796178 DOI: 10.1016/j.jneuroim.2012.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 06/19/2012] [Accepted: 06/25/2012] [Indexed: 01/28/2023]
Abstract
Intravenous immunoglobulin (IVIg) is a therapeutic preparation of plasma-derived human IgG and is increasingly used for the treatment of several neurological inflammatory disorders. However, it is not clear whether the IgG molecules contained in IVIg can actually cross the BBB in treated patients. We recently showed that LRP1, an endocytic receptor involved in transcytosis of several proteins across the BBB was able to interact with IVIg. In the present study, we show that LRP1 is involved in IVIg internalization inside living cells. Our data also suggest that following internalization, IVIg is recycled to the cell surface, raising the possibility that LRP1 can mediate IVIg transcytosis across the BBB. Finally, we show that IVIg-LRP1 interaction leads to LRP1 tyrosine phosphorylation.
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Dirks NL, Meibohm B. Population pharmacokinetics of therapeutic monoclonal antibodies. Clin Pharmacokinet 2011; 49:633-59. [PMID: 20818831 DOI: 10.2165/11535960-000000000-00000] [Citation(s) in RCA: 359] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A growing number of population pharmacokinetic analyses of therapeutic monoclonal antibodies (mAbs) have been published in the scientific literature. The aims of this article are to summarize the findings from these studies and to relate the findings to the general pharmacokinetic and structural characteristics of therapeutic mAbs. A two-compartment model was used in the majority of the population analyses to describe the disposition of the mAb. Population estimates of the volumes of distribution in the central (V(1)) and peripheral (V(2)) compartments were typically small, with median (range) values of 3.1 (2.4-5.5) L and 2.8 (1.3-6.8) L, respectively. The estimated between-subject variability in the V(1) was usually moderate, with a median (range) coefficient of variation (CV) of 26% (12-84%). Between-subject variability in other distribution-related parameters such as the V(2) and intercompartmental clearance were often not estimated. Although the pharmacokinetic models used most frequently in the population analyses were models with linear clearance, other models with nonlinear, or parallel linear and nonlinear clearance pathways were also applied, as many therapeutic mAbs are eliminated via saturable target-mediated mechanisms. Population estimates of the maximum elimination rate (V(max)) and the mAb concentration at which elimination was at half maximum for Michaelis-Menten-type elimination pathways varied considerably among the different therapeutic mAbs. However, estimates of the total clearance (CL) of mAbs with linear clearance characteristics and of the clearance of mAbs via the linear clearance pathway (CL(L)) with parallel linear and nonlinear clearance were quite similar for the different mAbs and typically ranged from 0.2 to 0.5 L/day, which is relatively close to the estimated clearance of endogenous IgG of 0.21 L/day. The between-subject variability in the V(max), CL and CL(L) was moderate to high, with estimated CVs ranging from 15% to 65%. Measures of body size were the covariates most commonly identified as influencing the pharmacokinetics of therapeutic mAbs. In summary, many features of the population pharmacokinetics of currently used therapeutic mAbs are similar, despite differences in their pharmacological targets and studied patient populations.
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Affiliation(s)
- Nathanael L Dirks
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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Ye L, Zeng R, Bai Y, Roopenian DC, Zhu X. Efficient mucosal vaccination mediated by the neonatal Fc receptor. Nat Biotechnol 2011; 29:158-63. [PMID: 21240266 PMCID: PMC3197702 DOI: 10.1038/nbt.1742] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 12/01/2010] [Indexed: 11/09/2022]
Abstract
Vaccine strategies to prevent invasive mucosal pathogens are being sought because 80–90% of infectious diseases are initiated at mucosal surfaces. However, our ability to deliver an intact vaccine antigen across a mucosal barrier for induction of effective immunity is limited. The neonatal Fc receptor (FcRn) mediates the transport of IgG across polarized epithelial cells lining mucosal surfaces. By mimicking IgG transfer at mucosal surfaces, intranasal immunization with a model antigen, herpes simplex virus type-2 (HSV-2) glycoprotein gD fused with an IgG Fc fragment, in combination with the adjuvant CpG, resulted in complete protection of wild type, but not FcRn knockout, mice that were intravaginally challenged with virulent HSV-2 186. This immunization strategy induced efficient mucosal and systemic antibody, B and T cell immune responses, including memory immune responses, which remained stable at least 6 months post-vaccination and conferred protection for a majority of animals. These results demonstrate that the FcRn-IgG transcellular transport pathway may represent a novel mucosal vaccine delivery route for a subunit vaccine against abundant mucosal pathogens.
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Affiliation(s)
- Lilin Ye
- Laboratory of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
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Leong WS, Thomas KA, Chan CH, Stevenson GT. A standardized conversion of IgG antibody to bispecific form with inversely altered affinities for Fcγ-receptors II and III. Mol Immunol 2010; 48:760-8. [PMID: 21196049 DOI: 10.1016/j.molimm.2010.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 11/23/2010] [Accepted: 11/23/2010] [Indexed: 01/25/2023]
Abstract
This work aims to enhance killing of antibody-coated human tumor cells by altering the antibody's affinity for two effector-cell Fcγ-receptors (FcγR). Affinity for the activating FcγRIII is raised, affinity for the inhibitory FcγRIIB is reduced, with the ratio between the two association constants increasing >1000-fold. We use as a standard tool the Fab'γ from a monoclonal antibody specific for human FcγRIII. This Fab'γ module is bonded to an IgG antibody by a tandem thioether link running between cysteine residues in the hinge vicinity of each protein, thus forming a bispecific FabIgG construct. Simultaneously, effector function of the IgG module is adjusted by leaving its hinge open and adding negative charges. FabIgG constructs derived from the chimeric IgG1 antibody rituximab show the following properties. (1) The titer for antibody-dependent cellular cytotoxicity is enhanced by 12-100-fold, reflecting the affinity of the Fab'γ module for effector-cell FcγRIII. (2) Two functions of the construct's Fcγ, activation of complement and prolonged metabolic survival, are moderately reduced. (3) In contrast, affinities of the Fcγ for all FcγR are severely reduced, with two anticipated consequences. First, attacks by macrophages on antibody-coated cells are favored by reduced engagement of the inhibitory FcγRIIB. Second, reduced engagement of activating FcγR by the Fcγ lowers the probability of untoward crosslinkings of FcγR, which have been shown to provoke toxicity. If the Fab'γ module possesses human constant regions, the linkage strategy requires prior genetic deletion of at least one cysteine residue. With both Fab'γ and IgG modules available, FabIgG can be prepared in 35 h.
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Affiliation(s)
- Weng S Leong
- Tenovus Research Laboratory, Cancer Sciences Division, Southampton University School of Medicine, Southampton SO16 6YD, UK
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Ishii-Watabe A, Suzuki T, Tada M, Kawanishi T, Yamaguchi T, Kawasaki N. [FcRn, a critical regulator of antibody pharmacokinetics]. Nihon Yakurigaku Zasshi 2010; 136:280-284. [PMID: 21079367 DOI: 10.1254/fpj.136.280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Clinical ramifications of the MHC family Fc receptor FcRn. J Clin Immunol 2010; 30:790-7. [PMID: 20848168 DOI: 10.1007/s10875-010-9458-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 09/01/2010] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Knowledge that antibodies of the IgG isotype have remarkably extended persistence in circulation and are able to pass through cell barriers has substantial implications. While it is well established that so-called neonatal Fc receptor, FcRn, acts throughout life to confer these unusual properties, its ramifications on clinical medicine and therapeutic uses are not broadly appreciated. SCOPE Here we discuss basic principles and gaps in understanding of FcRn, including its management of IgG antibodies and along with albumin, its impact on use and design of antibody-based therapeutics, and its genetics.
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Jerdeva GV, Tesar DB, Huey-Tubman KE, Ladinsky MS, Fraser SE, Bjorkman PJ. Comparison of FcRn- and pIgR-mediated transport in MDCK cells by fluorescence confocal microscopy. Traffic 2010; 11:1205-20. [PMID: 20525015 PMCID: PMC2975666 DOI: 10.1111/j.1600-0854.2010.01083.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Protein delivery across polarized epithelia is controlled by receptor-mediated transcytosis. Many studies have examined basolateral-to-apical trafficking of polymeric IgA (pIgA) by the polymeric immunoglobulin receptor (pIgR). Less is known about apical-to-basolateral transcytosis, the direction the neonatal Fc receptor (FcRn) transports maternal IgGs across intestinal epithelia. To compare apical-to-basolateral and basolateral-to-apical transcytosis, we co-expressed FcRn and pIgR in Madin-Darby canine kidney (MDCK) cells and used pulse-chase experiments with confocal microscopy to examine transport of apically applied IgG Fcgamma and basolaterally applied pIgA. Fcgamma and pIgA trafficking routes were initially separate but intermixed at later chase times. Fcgamma was first localized near the apical surface, but became more equally distributed across the cell, consistent with concomitant transcytosis and recycling. By contrast, pIgA transport was strongly unidirectional: pIgA shifted from near the basolateral surface to an apical location with increasing time. Some Fcgamma and pIgA fluorescence colocalized in early (EEA1-positive), recycling (Rab11a-positive), and transferrin (Tf)-positive common/basolateral recycling endosomes. Fcgamma became more enriched in Tf-positive endosomes with time, whereas pIgA was sorted from these compartments. Live-cell imaging revealed that vesicles containing Fcgamma or pIgA shared similar mobility characteristics and were equivalently affected by depolymerizing microtubules, indicating that both trafficking routes depended to roughly the same extent on intact microtubules.
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Affiliation(s)
- Galina V Jerdeva
- Division of Biology, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
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Yeung YA, Wu X, Reyes AE, Vernes JM, Lien S, Lowe J, Maia M, Forrest WF, Meng YG, Damico LA, Ferrara N, Lowman HB. A therapeutic anti-VEGF antibody with increased potency independent of pharmacokinetic half-life. Cancer Res 2010; 70:3269-77. [PMID: 20354184 DOI: 10.1158/0008-5472.can-09-4580] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bevacizumab [Avastin; anti-vascular endothelial growth factor (VEGF) antibody] is an antiangiogenic IgG approved for treating patients with certain types of colon, breast, and lung cancer. In these indications, bevacizumab is administered every 2 to 3 weeks, prompting us to study ways to reduce the frequency of administration. Increasing affinity to neonatal Fc receptor (FcRn) may extend the pharmacokinetic half-life of an antibody, but the quantitative effect of FcRn affinity on clearance has not been clearly elucidated. To gain further insight into this relationship, we engineered a series of anti-VEGF antibody variants with minimal amino acid substitutions and showed a range of half-life improvements in primates. These results suggest that, if proven clinically safe and effective, a modified version of bevacizumab could potentially provide clinical benefit to patients on long-term anti-VEGF therapy through less-frequent dosing and improved compliance with drug therapy. Moreover, despite having half-life similar to that of wild-type in mice due to the species-specific FcRn binding effects, the variant T307Q/N434A exhibited superior in vivo potency in slowing the growth of certain human tumor lines in mouse xenograft models. These results further suggest that FcRn variants may achieve increased potency through unidentified mechanisms in addition to increased systemic exposure.
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Affiliation(s)
- Yik Andy Yeung
- Departments of Antibody Engineering, Genentech, Inc, South San Francisco, California, USA
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Baker K, Qiao SW, Kuo T, Kobayashi K, Yoshida M, Lencer WI, Blumberg RS. Immune and non-immune functions of the (not so) neonatal Fc receptor, FcRn. Semin Immunopathol 2009; 31:223-36. [PMID: 19495758 PMCID: PMC3898171 DOI: 10.1007/s00281-009-0160-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/14/2009] [Indexed: 02/06/2023]
Abstract
Careful regulation of the body's immunoglobulin-G (IgG) and albumin concentrations is necessitated by the importance of their respective functions. As such, the neonatal Fc receptor (FcRn) which, as a single receptor, is capable of regulating both of these molecules, has become an important focus of investigation. In addition to these essential protection functions, FcRn possesses a host of other functions that are equally as critical. During the very first stages of life, FcRn mediates the passive transfer of IgG from mother to offspring both before and after birth. In the adult, FcRn regulates the persistence of both IgG and albumin in the serum as well as the movement of IgG, and any bound cargo, between different compartments of the body. This shuttling allows for the movement not only of monomeric ligand but also of antigen/antibody complexes from one cell type to another in such a way as to facilitate the efficient initiation of immune responses towards opsonized pathogens. As such, FcRn continues to play the role of an immunological sensor throughout adult life, particularly in regions such as the gut which are exposed to a large number of infectious antigens. Increasing appreciation for the contributions of FcRn to both homeostatic and pathological states is generating an intense interest in the potential for therapeutic modulation of FcRn binding. A greater understanding of FcRn's pleiotropic roles is thus imperative for a variety of therapeutic purposes.
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Affiliation(s)
- Kristi Baker
- Division of Gastroenterology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Shuo-Wang Qiao
- Rikshospitalet University Hospital, 0027 Oslo, Norway, University of Oslo, 0027 Oslo, Norway
| | - Timothy Kuo
- Division of Gastroenterology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Kanna Kobayashi
- Division of Gastroenterology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Masaru Yoshida
- Department of Gastroenterology & The Integrated Center for Mass Spectrometry, Kobe University Graduate School of Medecine, Hyogo, Japan
| | - Wayne I. Lencer
- Harvard Digestive Diseases Center, Boston, MA 02115, USA, GI Cell Biology, Division of Pediatric Gastroenterology and Nutrition, Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Richard S. Blumberg
- Division of Gastroenterology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA, Department of Medicine, Harvard Medical School, Boston, MA 02115, USA, Harvard Digestive Diseases Center, Boston, MA 02115, USA
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Conditional deletion of the MHC class I-related receptor FcRn reveals the sites of IgG homeostasis in mice. Proc Natl Acad Sci U S A 2009; 106:2788-93. [PMID: 19188594 DOI: 10.1073/pnas.0810796106] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The MHC class I-related receptor FcRn regulates the levels and persistence of IgG in vivo. This receptor salvages IgG from lysosomal degradation within cells, and the binding properties of an IgG for FcRn correlate with in vivo half-life. FcRn is expressed at multiple different sites throughout adult life. However, the cell types and sites at which FcRn maintains IgG homeostasis are not well defined. Toward understanding the sites of FcRn function, we have generated a mouse strain in which this Fc receptor can be conditionally deleted. In combination with mice that express Cre recombinase under the control of the Tie2 promoter (Tie2-Cre), the effect of site-specific deletion of floxed FcRn in endothelial and hematopoietic cells on IgG persistence was analyzed. The pharmacokinetics and steady-state levels of IgG in Tie2-Cre mice that are homozygous for the floxed FcRn allele reveal a complete loss of FcRn function in regulating the half-lives of wild-type IgG. The primary sites for the maintenance of endogenous IgGs in mice are therefore endothelial and hematopoietic cells.
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Gan Z, Ram S, Vaccaro C, Ober RJ, Ward ES. Analyses of the recycling receptor, FcRn, in live cells reveal novel pathways for lysosomal delivery. Traffic 2009; 10:600-14. [PMID: 19192244 DOI: 10.1111/j.1600-0854.2009.00887.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lysosomes play a central role in the degradation of proteins and other macromolecules. The mechanisms by which receptors are transferred to lysosomes for constitutive degradation are poorly understood. We have analyzed the processes that lead to the lysosomal delivery of the Fc receptor, FcRn. These studies provide support for a novel pathway for receptor delivery. Specifically, unlike other receptors that enter intraluminal vesicles in late endosomes, FcRn is transferred from the limiting membrane of such endosomes to lysosomes, and is rapidly internalized into the lysosomal lumen. By contrast, LAMP-1 persists on the limiting membrane. Receptor transfer is mediated by tubular extensions from late endosomes to lysosomes, or by interactions of the two participating organelles in kiss-and-linger-like processes, whereas full fusion is rarely observed. The persistence of FcRn on the late endosomal limiting membrane, together with selective transfer to lysosomes, allows this receptor to undergo recycling or degradation. Consequently, late endosomes have functional plasticity, consistent with the presence of the Rab5 GTPase in discrete domains on these compartments.
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Affiliation(s)
- Zhuo Gan
- Biomedical Engineering Graduate Program, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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46
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Kuo TT, de Muinck EJ, Claypool SM, Yoshida M, Nagaishi T, Aveson VG, Lencer WI, Blumberg RS. N-Glycan Moieties in Neonatal Fc Receptor Determine Steady-state Membrane Distribution and Directional Transport of IgG. J Biol Chem 2009; 284:8292-300. [PMID: 19164298 DOI: 10.1074/jbc.m805877200] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The neonatal Fc receptor (FcRn) is a major histocompatibility complex class I-related molecule known to protect IgG and albumin from catabolism and transport IgG across polarized epithelial cells in a bidirectional manner. Previous studies have shown species-specific differences in ligand binding, IgG transport direction, and steady-state membrane distribution when expressed in polarized epithelial cells. We hypothesized that these differences may be due to the additional N-glycans expressed on the rat FcRn, because N-glycans have been proposed to function as apical targeting signals, and that two of the N-glycan moieties have been shown to contribute to the IgG binding of rat FcRn. A panel of mutant human FcRn variants was generated to resemble the N-glycan expression of rat FcRn in various combinations and subsequently transfected into Madin-Darby canine kidney II cells together with human beta2-microglobulin. Mutant human FcRn clones that contained additional N-glycan side-chain modifications, including that which was fully rodentized, still exhibited specificity for human IgG and failed to bind to mouse IgG. At steady state, the mutant human FcRn with additional N-glycans redistributed to the apical cell surface similar to that of rat FcRn. Furthermore, the rodentized human FcRn exhibited a reversal of IgG transport with predominant transcytosis from an apical-to-basolateral direction, which resembled that of the rat FcRn isoform. These studies show that the N-glycans in FcRn contribute significantly to the steady-state membrane distribution and direction of IgG transport in polarized epithelia.
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Affiliation(s)
- Timothy T Kuo
- Department of Gastroenterology, Brigham & Women's Hospital and Harvard Medical School, USA
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47
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Ward ES, Ober RJ. Chapter 4: Multitasking by exploitation of intracellular transport functions the many faces of FcRn. Adv Immunol 2009; 103:77-115. [PMID: 19755184 DOI: 10.1016/s0065-2776(09)03004-1] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The MHC Class I-related receptor, FcRn, transports antibodies of the immunoglobulin G (IgG) class within and across a diverse array of different cell types. Through this transport, FcRn serves multiple roles throughout adult life that extend well beyond its earlier defined function of transcytosing IgGs from mother to offspring. These roles include the maintenance of IgG levels and the delivery of antigen in the form of immune complexes to degradative compartments within cells. Recent studies have led to significant advances in knowledge of the intracellular trafficking of FcRn and (engineered) IgGs at both the molecular and cellular levels. The engineering of FcRn-IgG (or Fc) interactions to generate antibodies of increased longevity represents an area of active interest, particularly in the light of the expanding use of antibodies in therapy. The strict pH dependence of FcRn-IgG interactions, with binding at pH 6 that becomes essentially undetectable as near neutral pH is approached, is essential for efficient transport. The requirement for retention of low affinity at near neutral pH increases the complexity of engineering antibodies for increased half-life. Conversely, engineered IgGs that have gained significant binding for FcRn at this pH can be potent inhibitors of FcRn that lower endogenous IgG levels and have multiple potential uses as therapeutics. In addition, molecular studies of FcRn-IgG interactions indicate that mice have limitations as preclinical models for FcRn function, primarily due to cross-species differences in FcRn-binding specificity.
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Affiliation(s)
- E Sally Ward
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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48
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Andersen JT, Sandlie I. The Versatile MHC Class I-related FcRn Protects IgG and Albumin from Degradation: Implications for Development of New Diagnostics and Therapeutics. Drug Metab Pharmacokinet 2009; 24:318-32. [DOI: 10.2133/dmpk.24.318] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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49
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Mi W, Wanjie S, Lo ST, Gan Z, Pickl-Herk B, Ober RJ, Ward ES. Targeting the neonatal fc receptor for antigen delivery using engineered fc fragments. THE JOURNAL OF IMMUNOLOGY 2008; 181:7550-61. [PMID: 19017944 DOI: 10.4049/jimmunol.181.11.7550] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of approaches for Ag delivery to the appropriate subcellular compartments of APCs and the optimization of Ag persistence are both of central relevance for the induction of protective immunity or tolerance. The expression of the neonatal Fc receptor, FcRn, in APCs and its localization to the endosomal system suggest that it might serve as a target for Ag delivery using engineered Fc fragment-epitope fusions. The impact of FcRn binding characteristics of an Fc fragment on in vivo persistence allows this property to also be modulated. We have therefore generated recombinant Fc (mouse IgG1-derived) fusions containing the N-terminal epitope of myelin basic protein that is associated with experimental autoimmune encephalomyelitis in H-2(u) mice. The Fc fragments have distinct binding properties for FcRn that result in differences in intracellular trafficking and in vivo half-lives, allowing the impact of these characteristics on CD4(+) T cell responses to be evaluated. To dissect the relative roles of FcRn and the "classical" FcgammaRs in Ag delivery, analogous aglycosylated Fc-MBP fusions have been generated. We show that engineered Fc fragments with increased affinities for FcRn at pH 6.0-7.4 are more effective in delivering Ag to FcRn-expressing APCs in vitro relative to their lower affinity counterparts. However, higher affinity of the FcRn-Fc interaction at near neutral pH results in decreased in vivo persistence. The trade-off between improved FcRn targeting efficiency and lower half-life becomes apparent during analyses of T cell proliferative responses in mice, particularly when Fc-MBP fusions with both FcRn and FcgammaR binding activity are used.
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Affiliation(s)
- Wentao Mi
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9093, USA
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50
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He W, Ladinsky MS, Huey-Tubman KE, Jensen GJ, McIntosh JR, Björkman PJ. FcRn-mediated antibody transport across epithelial cells revealed by electron tomography. Nature 2008; 455:542-6. [PMID: 18818657 DOI: 10.1038/nature07255] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 07/14/2008] [Indexed: 01/15/2023]
Abstract
The neonatal Fc receptor (FcRn) transports maternal IgG across epithelial barriers, thereby providing the fetus or newborn with humoral immunity before its immune system is fully functional. In newborn rats, FcRn transfers IgG from milk to blood by apical-to-basolateral transcytosis across intestinal epithelial cells. The pH difference between the apical (pH 6.0-6.5) and basolateral (pH 7.4) sides of intestinal epithelial cells facilitates the efficient unidirectional transport of IgG, because FcRn binds IgG at pH 6.0-6.5 but not at pH 7 or more. As milk passes through the neonatal intestine, maternal IgG is removed by FcRn-expressing cells in the proximal small intestine (duodenum and jejunum); remaining proteins are absorbed and degraded by FcRn-negative cells in the distal small intestine (ileum). Here we use electron tomography to make jejunal transcytosis visible directly in space and time, developing new labelling and detection methods to map individual nanogold-labelled Fc within transport vesicles and simultaneously to characterize these vesicles by immunolabelling. Combining electron tomography with a non-perturbing endocytic label allowed us to conclusively identify receptor-bound ligands, resolve interconnecting vesicles, determine whether a vesicle was microtubule-associated, and accurately trace FcRn-mediated transport of IgG. Our results present a complex picture in which Fc moves through networks of entangled tubular and irregular vesicles, only some of which are microtubule-associated, as it migrates to the basolateral surface. New features of transcytosis are elucidated, including transport involving multivesicular body inner vesicles/tubules and exocytosis through clathrin-coated pits. Markers for early, late and recycling endosomes each labelled vesicles in different and overlapping morphological classes, revealing spatial complexity in endo-lysosomal trafficking.
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Affiliation(s)
- Wanzhong He
- Division of Biology 114-96, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
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