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Childers KC, Cowper B, Vaughan JD, McGill JR, Davulcu O, Lollar P, Doering CB, Coxon CH, Spiegel PC. Structural basis for inhibition of coagulation factor VIII reveals a shared antigenic hotspot on the C1 domain. J Thromb Haemost 2024; 22:2449-2459. [PMID: 38849084 PMCID: PMC11343672 DOI: 10.1016/j.jtha.2024.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 05/13/2024] [Accepted: 05/22/2024] [Indexed: 06/09/2024]
Abstract
BACKGROUND Hemophilia A arises from dysfunctional or deficient coagulation factor (F)VIII and leads to inefficient fibrin clot formation and uncontrolled bleeding events. The development of antibody inhibitors is a clinical complication in hemophilia A patients receiving FVIII replacement therapy. LE2E9 is an anti-C1 domain inhibitor previously isolated from a mild/moderate hemophilia A patient and disrupts FVIII interactions with von Willebrand factor and FIXa, though the intermolecular contacts that underpin LE2E9-mediated FVIII neutralization are undefined. OBJECTIVES To determine the structure of the complex between FVIII and LE2E9 and characterize its mechanism of inhibition. METHODS FVIII was bound to the antigen binding fragment (Fab) of NB2E9, a recombinant construct of LE2E9, and its structure was determined by cryogenic electron microscopy. RESULTS This report communicates the 3.46 Å structure of FVIII bound to NB2E9, with its epitope comprising FVIII residues S2040 to Y2043, K2065 to W2070, and R2150 to H2155. Structural analysis reveals that the LE2E9 epitope overlaps with portions of the epitope for 2A9, a murine-derived inhibitor, suggesting that these residues represent a shared antigenic region on the C1 domain between FVIII-/- mice and hemophilia A patients. Furthermore, the FVIII:NB2E9 structure elucidates the orientation of the LE2E9 glycan, illustrating how the glycan sterically blocks interactions between the FVIII C1 domain and the von Willebrand factor D' domain. A putative model of the FVIIIa:FIXa complex suggests potential clashing between the NB2E9 glycan and FIXa light chain. CONCLUSION These results describe an antigenic "hotspot" on the FVIII C1 domain and provide a structural basis for engineering FVIII replacement therapeutics with reduced antigenicity.
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Affiliation(s)
- Kenneth C Childers
- Chemistry Department, Western Washington University, Bellingham, Washington, USA
| | - Ben Cowper
- Medicines and Healthcare products Regulatory Agency, South Mimms Laboratories, Potters Bar, Hertfordshire, UK
| | - Jordan D Vaughan
- Chemistry Department, Western Washington University, Bellingham, Washington, USA
| | - Juliet R McGill
- Chemistry Department, Western Washington University, Bellingham, Washington, USA
| | - Omar Davulcu
- Pacific Northwest Center for Cryo-EM, Oregon Health & Science University, Portland, Oregon, USA; Pacific Northwest National Laboratory, Environmental Molecular Sciences Laboratory, Richland, Washington, USA
| | - Pete Lollar
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, Georgia, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | - Christopher B Doering
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, Georgia, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Expression Therapeutics, Inc, Tucker, Georgia, USA
| | - Carmen H Coxon
- Medicines and Healthcare products Regulatory Agency, South Mimms Laboratories, Potters Bar, Hertfordshire, UK
| | - Paul C Spiegel
- Chemistry Department, Western Washington University, Bellingham, Washington, USA.
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Nacer A, Kivi G, Pert R, Juronen E, Holenya P, Aliprandini E, Amino R, Silvie O, Quinkert D, Le Duff Y, Hurley M, Reimer U, Tover A, Draper SJ, Gilbert S, Ho MM, Bowyer PW. Expanding the Malaria Antibody Toolkit: Development and Characterisation of Plasmodium falciparum RH5, CyRPA, and CSP Recombinant Human Monoclonal Antibodies. Front Cell Infect Microbiol 2022; 12:901253. [PMID: 35782147 PMCID: PMC9243361 DOI: 10.3389/fcimb.2022.901253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
Malaria, an infection caused by apicomplexan parasites of the genus Plasmodium, continues to exact a significant toll on public health with over 200 million cases world-wide, and annual deaths in excess of 600,000. Considerable progress has been made to reduce malaria burden in endemic countries in the last two decades. However, parasite and mosquito resistance to frontline chemotherapies and insecticides, respectively, highlights the continuing need for the development of safe and effective vaccines. Here we describe the development of recombinant human antibodies to three target proteins from Plasmodium falciparum: reticulocyte binding protein homologue 5 (PfRH5), cysteine-rich protective antigen (PfCyRPA), and circumsporozoite protein (PfCSP). All three proteins are key targets in the development of vaccines for blood-stage or pre-erythrocytic stage infections. We have developed potent anti-PfRH5, PfCyRPA and PfCSP monoclonal antibodies that will prove useful tools for the standardisation of assays in preclinical research and the assessment of these antigens in clinical trials. We have generated some very potent anti-PfRH5 and anti-PfCyRPA antibodies with some clones >200 times more potent than the polyclonal anti-AMA-1 antibodies used for the evaluation of blood stage antigens. While the monoclonal and polyclonal antibodies are not directly comparable, the data provide evidence that these new antibodies are very good at blocking invasion. These antibodies will therefore provide a valuable resource and have potential as biological standards to help harmonise pre-clinical malaria research.
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Affiliation(s)
- Adéla Nacer
- Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Medicines and Healthcare products Regulatory Agency (MHRA), Potters Bar, United Kingdom
| | - Gaily Kivi
- Icosagen Cell Factory OÜ, Tartumaa, Estonia
| | - Raini Pert
- Icosagen Cell Factory OÜ, Tartumaa, Estonia
| | | | - Pavlo Holenya
- Research and Development, JPT Peptide Technologies GmbH, Berlin, Germany
| | | | - Rogerio Amino
- Malaria Infection & Immunity Unit, Institut Pasteur, Paris, France
| | - Olivier Silvie
- Sorbonne Université, INSERM, CNRS, Centre d’Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Doris Quinkert
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Yann Le Duff
- Centre for Aids Reagents, National Institute for Biological Standards and Control (NIBSC), Medicines and Healthcare products Regulatory Agency (MHRA), Potters Bar, United Kingdom
| | - Matthew Hurley
- Centre for Aids Reagents, National Institute for Biological Standards and Control (NIBSC), Medicines and Healthcare products Regulatory Agency (MHRA), Potters Bar, United Kingdom
| | - Ulf Reimer
- Research and Development, JPT Peptide Technologies GmbH, Berlin, Germany
| | | | - Simon J. Draper
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Sarah Gilbert
- Centre for Aids Reagents, National Institute for Biological Standards and Control (NIBSC), Medicines and Healthcare products Regulatory Agency (MHRA), Potters Bar, United Kingdom
| | - Mei Mei Ho
- Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Medicines and Healthcare products Regulatory Agency (MHRA), Potters Bar, United Kingdom
| | - Paul W. Bowyer
- Division of Bacteriology, National Institute for Biological Standards and Control (NIBSC), Medicines and Healthcare products Regulatory Agency (MHRA), Potters Bar, United Kingdom
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Arsiccio A, Beavis J, Raut S, Coxon CH. FVIII inhibitors display FV-neutralizing activity in the prothrombin time assay. J Thromb Haemost 2021; 19:1907-1913. [PMID: 33914406 PMCID: PMC8360109 DOI: 10.1111/jth.15355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 04/16/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The coagulation factors (F)V and VIII are homologous proteins that support hemostasis through their regulation of FX activity. Hemophilia A (HA) patients have reduced FVIII activity and a prolonged bleeding time that is corrected through the administration of exogenous FVIII. Around one-third of severe HA patients develop FVIII neutralizing antibodies, known as "inhibitors," which neutralize FVIII activity and preclude them from further FVIII therapy. OBJECTIVES We hypothesized that, based on the degree of homology between FV and FVIII (~40%), FVIII-neutralizing antibodies could cross react with FV. To test this hypothesis, a panel of recombinant, patient-derived, FVIII-neutralizing antibodies were screened for cross-reactivity against FV. METHODS Factor V and FVIII activity was measured using one-stage clotting assays; structural analysis was carried out using a structural approach. RESULTS We detected FV neutralizing activity with the anti-FVIII A2 domain antibody NB11B2. Because this antibody was derived from an HA inhibitor patient, FV-neutralizing activity was then evaluated in a number of HA inhibitor patient plasma samples; nine alloimmune samples had FV-neutralizing activity whereas no FV neutralizing activity was found in the two autoimmune samples available. We next examined the degree of surface homology between FV and FVIII and found that structural similarity could explain the cross reactivity of the anti-A2 antibody and likely accounts for the cross reactivity we observed in patient samples. CONCLUSIONS Although this novel observation is of interest, further work will be needed to determine whether FV neutralization in HA patient samples contributes to their bleeding diathesis.
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Affiliation(s)
- Andrea Arsiccio
- Department of Applied Science and TechnologyPolitecnico di TorinoTorinoItaly
| | - James Beavis
- Oxford Haemophilia CentreChurchill HospitalOxfordUK
| | - Sanj Raut
- National Institute for Biological Standards and ControlPotters BarUK
| | - Carmen H. Coxon
- National Institute for Biological Standards and ControlPotters BarUK
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