1
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Preclinical evaluation of immunotherapeutic regimens for fetal/neonatal alloimmune thrombocytopenia. Blood Adv 2021; 5:3552-3562. [PMID: 34470046 DOI: 10.1182/bloodadvances.2021004371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 05/10/2021] [Indexed: 11/20/2022] Open
Abstract
Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a life-threatening bleeding disorder caused by maternal antibodies directed against paternally inherited antigens present on the surface of fetal platelets. The human platelet alloantigen HPA-1a (formerly known as the PlA1 alloantigen), is the most frequently implicated HPA for causing FNAIT in Whites. A single Leu33Pro amino acid polymorphism residing within the ∼50-amino-acid plexin-semaphorin-integrin domain near the N-terminus of the integrin β3 subunit (platelet membrane glycoprotein IIIa [GPIIIa]) is responsible for generating the HPA-1a and HPA-1b epitopes in human GPIIIa and serves as the central target for alloantibody-mediated platelet destruction. To simulate the etiology of human FNAIT, wild-type female mice were pre-immunized with platelets derived from transgenic mice engineered to express the human HPA-1a epitope on a murine GPIIIa backbone. These mice developed a strong alloimmune response specific for HPA-1a, and when bred with HPA-1a+ males, gave birth to severely thrombocytopenic pups that exhibited an accompanying bleeding phenotype. Administering either polyclonal intravenous immunoglobulin G or a human monoclonal blocking antibody specific for the HPA-1a epitope into pregnant female mice resulted in significant elevation of the neonatal platelet count, normalized hemostasis, and prevented bleeding. The establishment of an alloantigen-specific murine model that recapitulates many of the clinically important features of FNAIT should pave the way for the preclinical development and testing of novel therapeutic and prophylactic modalities to treat or prevent FNAIT in humans.
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2
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Duan S, Wang M, Ding S, Chen Y, Wei S, Chen W, Zhang C, Li Y, Wang H. Application of lyophilised human platelets for antibody detection in solid phase red cell adherence assay. J Immunol Methods 2020; 487:112868. [PMID: 32941887 DOI: 10.1016/j.jim.2020.112868] [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: 03/14/2020] [Revised: 07/27/2020] [Accepted: 09/10/2020] [Indexed: 11/27/2022]
Abstract
Antibodies against human platelets cause a variety of thrombocytopenic disorders, which lead to potentially fatal haemorrhage. Therefore, their prompt detection is mandatory for successful patient treatment. Solid phase red cell adherence (SPRCA) assay allows for platelet antibody detection widely. However, preparation of fresh platelets with HLA-I and human platelet antigens (HPA)1-5,15 genotyped as target cells is inconvenient and fresh platelets have a short shelf life. In this study, the lyophilised human platelets for antibody detection in SPRCA were prepared. Firstly, platelets were resuspended in lyophilisation buffer and freeze-dried. Then the characteristics of lyophilised platelet were analysed. Rehydrated platelets were recovered with a mean rate of 80.91% ± 2.87%, and still retained spherical morphology. Indirect flow cytometry showed that glycoproteins IIb/IIIa, Ia/IIa, Ib/IX, IV, CD109, and HLA class I were present on the surface of the lyophilised platelets at a comparable level to that of fresh platelets. The consistent results obtained with WHO reference reagents containing anti-HPA-1a, anti-HPA-3a, and anti-HPA-5b, as well as clinical samples from the same donors containing anti-HLA antibodies when reacting with lyophilised versus fresh platelets confirmed good antigenicity preservation of platelets after freeze-drying. Further investigation showed that the lyophilised platelets could be stored at 2-8 °C for up to 14 months and the reconstituted suspension was stable for 48 h. Therefore, lyophilised platelets can be a convenient alternative to fresh platelets to use for anti-platelet antibody detection in SPRCA tests.
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Affiliation(s)
- Shengbao Duan
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | | | - Shaohua Ding
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China
| | - Yezhou Chen
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China
| | - Shuangshi Wei
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China
| | - Wei Chen
- Suzhou Blood Center, Suzhou, PR China
| | - Chun Zhang
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China
| | - Yong Li
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China
| | - Hongmei Wang
- Suzhou Institute of Biomedical Engineering and Technology (SIBET), Chinese Academy of Sciences (CAS), Suzhou, PR China.
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3
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Phage-Displayed Peptide of Keratinocyte Growth Factor and Its Biological Effects on Epidermal Cells. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-019-09873-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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4
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Abstract
Human platelet antibody (HPA) detection is necessary for the diagnosis and therapeutic decisions for refractoriness to platelet transfusions, post transfusion purpura and fetal and neonatal alloimmune thrombocytopenia. In the last four to five decades many new developments, both in knowledge and methods, have increased the quality of platelet serology. However, the quest for the optimal antibody detection method(s) encountered, sometimes unexpected, difficulties. In this review the various aspects concerning platelet antibody test methods and detection of platelet antibodies both for the diagnostic and screening setting are discussed.
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Affiliation(s)
- L Porcelijn
- Department of Immunohematology Diagnostics, Sanquin, Amsterdam, the Netherlands.
| | - E Huiskes
- Department of Immunohematology Diagnostics, Sanquin, Amsterdam, the Netherlands
| | - M de Haas
- Department of Immunohematology Diagnostics, Sanquin, Amsterdam, the Netherlands; Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands; Center for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands
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5
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Kjær M, Geisen C, Akkök ÇA, Wikman A, Sachs U, Bussel JB, Nielsen K, Walles K, Curtis BR, Vidarsson G, Järås K, Skogen B. Strategies to develop a prophylaxis for the prevention of HPA-1a immunization and fetal and neonatal alloimmune thrombocytopenia. Transfus Apher Sci 2019; 59:102712. [PMID: 31948915 DOI: 10.1016/j.transci.2019.102712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Indexed: 01/20/2023]
Abstract
Anti-HPA-1a-antibodies are the main cause of fetal and neonatal alloimmune thrombocytopenia (FNAIT) which may result in intracranial hemorrhage (ICH) and death among fetuses and newborns. Advances in understanding the pathogenesis of FNAIT and proof of concept for prophylaxis to prevent immunization suggest that development of hyperimmune anti-HPA-1a IgG aimed at preventing immunization against HPA-1a and FNAIT is feasible. Anti-HPA-1a IgG can be obtained either by isolating immunoglobulin from already-immunized women or by development of monoclonal anti-HPA-1a antibodies. Here we discuss recent advances that may lead to the development of a prenatal and postnatal prophylactic treatment for the prevention of HPA-1a-associated FNAIT and life-threatening FNAIT-induced complications.
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Affiliation(s)
- Mette Kjær
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway; Finnmark Hospital Trust, Hammerfest, Norway.
| | | | | | | | | | - James B Bussel
- Dept of Pediatrics, Weill Cornell Medicine, New York, NY, USA
| | | | | | | | | | | | - Bjørn Skogen
- Department of Medical Biology, UiT- The Artic University of Norway, Tromsø, Norway
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6
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Zhi H, Ahlen MT, Thinn AMM, Weiler H, Curtis BR, Skogen B, Zhu J, Newman PJ. High-resolution mapping of the polyclonal immune response to the human platelet alloantigen HPA-1a (Pl A1). Blood Adv 2018; 2:3001-3011. [PMID: 30413435 PMCID: PMC6234362 DOI: 10.1182/bloodadvances.2018023341] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
Antibodies to platelet-specific antigens are responsible for 2 clinically important bleeding disorders: posttransfusion purpura and fetal/neonatal alloimmune thrombocytopenia (FNAIT). The human platelet-specific alloantigen 1a/1b (HPA-1a/1b; also known as PlA1/A2) alloantigen system of human platelet membrane glycoprotein (GP) IIIa is controlled by a Leu33Pro polymorphism and is responsible for ∼80% of the cases of FNAIT. Local residues surrounding polymorphic residue 33 are suspected to have a profound effect on alloantibody binding and subsequent downstream effector events. To define the molecular requirements for HPA-1a alloantibody binding, we generated transgenic mice that expressed murine GPIIIa (muGPIIIa) isoforms harboring select humanized residues within the plexin-semaphorin-integrin (PSI) and epidermal growth factor 1 (EGF1) domains and examined their ability to support the binding of a series of monoclonal and polyclonal HPA-1a-specific antibodies. Humanizing the PSI domain of muGPIIIa was sufficient to recreate the HPA-1a epitope recognized by some HPA-1a-specific antibodies; however, humanizing distinct amino acids within the linearly distant but conformationally close EGF1 domain was required to enable binding of others. These results reveal the previously unsuspected complex heterogeneity of the polyclonal alloimmune response to this clinically important human platelet alloantigen system. High-resolution mapping of this alloimmune response may improve diagnosis of FNAIT and should facilitate the rational design and selection of contemplated prophylactic and therapeutic anti-HPA-1a reagents.
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Affiliation(s)
- Huiying Zhi
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
| | - Maria Therese Ahlen
- Immunology Research Group, Department of Medical Biology, The Arctic University of Norway, Tromsø, Norway
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Aye Myat Myat Thinn
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
- Department of Biochemistry
| | - Hartmut Weiler
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
| | - Brian R Curtis
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
| | - Bjørn Skogen
- Immunology Research Group, Department of Medical Biology, The Arctic University of Norway, Tromsø, Norway
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Jieqing Zhu
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
- Department of Biochemistry
| | - Peter J Newman
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI
- Department of Pharmacology, and
- Department of Cell Biology, Medical College of Wisconsin, Milwaukee, WI
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7
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Autonomous conformational regulation of β 3 integrin and the conformation-dependent property of HPA-1a alloantibodies. Proc Natl Acad Sci U S A 2018; 115:E9105-E9114. [PMID: 30209215 DOI: 10.1073/pnas.1806205115] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Integrin α/β heterodimer adopts a compact bent conformation in the resting state, and upon activation undergoes a large-scale conformational rearrangement. During the inside-out activation, signals impinging on the cytoplasmic tail of β subunit induce the α/β separation at the transmembrane and cytoplasmic domains, leading to the extended conformation of the ectodomain with the separated leg and the opening headpiece that is required for the high-affinity ligand binding. It remains enigmatic which integrin subunit drives the bent-to-extended conformational rearrangement in the inside-out activation. The β3 integrins, including αIIbβ3 and αVβ3, are the prototypes for understanding integrin structural regulation. The Leu33Pro polymorphism located at the β3 PSI domain defines the human platelet-specific alloantigen (HPA) 1a/b, which provokes the alloimmune response leading to clinically important bleeding disorders. Some, but not all, anti-HPA-1a alloantibodies can distinguish the αIIbβ3 from αVβ3 and affect their functions with unknown mechanisms. Here we designed a single-chain β3 subunit that mimics a separation of α/β heterodimer on inside-out activation. Our crystallographic and functional studies show that the single-chain β3 integrin folds into a bent conformation in solution but spontaneously extends on the cell surface. This demonstrates that the β3 subunit autonomously drives the membrane-dependent conformational rearrangement during integrin activation. Using the single-chain β3 integrin, we identified the conformation-dependent property of anti-HPA-1a alloantibodies, which enables them to differently recognize the β3 in the bent state vs. the extended state and in the complex with αIIb vs. αV This study provides deeper understandings of integrin conformational activation on the cell surface.
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8
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Zhou D, Thinn AMM, Zhao Y, Wang Z, Zhu J. Structure of an extended β 3 integrin. Blood 2018; 132:962-972. [PMID: 30018079 PMCID: PMC6117741 DOI: 10.1182/blood-2018-01-829572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 07/10/2018] [Indexed: 12/23/2022] Open
Abstract
Cells use adhesion receptor integrins to communicate with their surroundings. Integrin activation and cellular signaling are coupled with change from bent to extended conformation. β3 integrins, including αIIbβ3, which is essential for the function of platelets in hemostasis and thrombosis, and αVβ3, which plays multiple roles in diverse cell types, have been prototypes in understanding integrin structure and function. Despite extensive structural studies, a high-resolution integrin structure in an extended conformation remains to be determined. The human β3 Leu33Pro polymorphism, located at the PSI domain, defines human platelet-specific alloantigens 1a and 1b (HPA-1a/b), immune response to which is a cause of posttransfusion purpura and fetal/neonatal alloimmune thrombocytopenia. Leu33Pro substitution has also been suggested to be a risk factor for thrombosis. Here we report the crystal structure of the β3 headpiece in either Leu33 or Pro33 form, both of which reveal intermediate and fully extended conformations coexisting in 1 crystal. These were used to build high-resolution structures of full-length β3 integrin in the intermediate and fully extended states, agreeing well with the corresponding conformations observed by electron microscopy. Our structures reveal how β3 integrin becomes extended at its β-knee region and how the flexibility of β-leg domains is determined. In addition, our structures reveal conformational changes of the PSI and I-EGF1 domains upon β3 extension, which may affect the binding of conformation-dependent anti-HPA-1a alloantibodies. Our structural and functional data show that Leu33Pro substitution does not directly alter the conformation or ligand binding of β3 integrin.
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Affiliation(s)
- Dongwen Zhou
- Blood Research Institute, BloodCenter of Wisconsin, part of Versiti, Milwaukee, WI
| | - Aye Myat Myat Thinn
- Blood Research Institute, BloodCenter of Wisconsin, part of Versiti, Milwaukee, WI
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI; and
| | - Yan Zhao
- Blood Research Institute, BloodCenter of Wisconsin, part of Versiti, Milwaukee, WI
- Department of Physiology, School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhengli Wang
- Blood Research Institute, BloodCenter of Wisconsin, part of Versiti, Milwaukee, WI
| | - Jieqing Zhu
- Blood Research Institute, BloodCenter of Wisconsin, part of Versiti, Milwaukee, WI
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI; and
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9
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Eksteen M, Heide G, Tiller H, Zhou Y, Nedberg NH, Martinez-Zubiaurre I, Husebekk A, Skogen BR, Stuge TB, Kjær M. Anti-human platelet antigen (HPA)-1a antibodies may affect trophoblast functions crucial for placental development: a laboratory study using an in vitro model. Reprod Biol Endocrinol 2017; 15:28. [PMID: 28427432 PMCID: PMC5399428 DOI: 10.1186/s12958-017-0245-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 04/02/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a bleeding disorder caused by maternal antibodies against paternal human platelet antigens (HPAs) on fetal platelets. Antibodies against HPA-1a are accountable for the majority of FNAIT cases. We have previously shown that high levels of maternal anti-HPA-1a antibodies are associated with clinically significant reduced birth weight in newborn boys. Chronic inflammatory placental lesions are associated with increased risk of reduced birth weight and have previously been reported in connection with FNAIT pregnancies. The HPA-1a epitope is located on integrin β3 that is associated with integrin αIIb (the fibrinogen receptor) on platelets and megakaryocytes. Integrin β3 is also associated with integrin αV forming the αVβ3 integrin heterodimer, the vitronectin receptor, which is expressed on various cell types, including trophoblast cells. It is therefore thinkable that maternal anti-HPA-1a antibodies present during early pregnancy may affect placenta function through binding to the HPA-1a antigen epitope on invasive throphoblasts. The aim of the study was to examine whether interaction of a human anti-HPA-1a monoclonal antibody (mAb) with HPA-1a on trophoblast cells affect adhesion, migration and invasion of extravillous trophoblast cells. METHODS An in vitro model with human anti-HPA-1a mAb, clone 26.4, and the first trimester extravillous trophoblast cell line HTR8/SVneo was employed. The xCELLigence system was utilized to assess the possible effect of anti-HPA-1a mAb on adhesion and migration of HTR8/SVneo cells. Specially designed chambers precoated with Matrigel were used to assess the effect on the invasive capacity of cells. RESULTS We found that human anti-HPA-1a mAb 26.4 partially inhibits adhesion and migratory capacity of HTR8/SVneo cells. CONCLUSIONS Our findings suggest that anti-HPA-1a antibodies may affect trophoblast functions crucial for normal placental development. Future studies including primary throphoblast cells and polyclonal anti-HPA-1a antibodies are needed to confirm these results.
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Affiliation(s)
- Mariana Eksteen
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Gøril Heide
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Heidi Tiller
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
- Department of Obstetrics and Gynecology, University Hospital of North Norway, Tromsø, Norway
| | - Yan Zhou
- Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San-Francisco, CA USA
| | - Nora Hersoug Nedberg
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
- Prophylix Pharma AS, Tromsø, Norway
| | - Inigo Martinez-Zubiaurre
- Bone and Joint research group, Department of Clinical Medicine, UiT- The Arctic University of Norway, Tromsø, Norway
| | - Anne Husebekk
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Bjørn R. Skogen
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway
| | - Tor B. Stuge
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Mette Kjær
- Immunology research group, Department of Medical Biology, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
- Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway
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10
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Chong W, Turro E, Metcalfe P, Yusuf R, Mérieux Y, Rigal D, Porcelijn L, Huiskes E, Lucas G, Bendukidze N, Green A, Fontão-Wendel R, Husebekk A, Dixey J, Guest A, Mushens R, Ouwehand WH, Navarrete CV. A multicenter validation of recombinant β3 integrin-coupled beads to detect human platelet antigen-1 alloantibodies in 498 cases of fetomaternal alloimmune thrombocytopenia. Transfusion 2015; 55:2742-51. [DOI: 10.1111/trf.13222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/23/2015] [Accepted: 05/11/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Winnie Chong
- Histocompatibility and Immunogenetics Laboratories; National Health Service Blood and Transplant (NHSBT); Colindale, London UK
| | - Ernest Turro
- Department of Haematology; University of Cambridge and NHSBT Cambridge, Cambridge Biomedical Campus
- Medical Research Council Biostatistics Unit; Cambridge Biomedical Campus; Cambridge UK
| | - Paul Metcalfe
- National Institute for Biological Standards and Control Medicines and Healthcare Products Regulatory Agency; Potters Bar UK
| | - Rizwan Yusuf
- National Institute for Biological Standards and Control Medicines and Healthcare Products Regulatory Agency; Potters Bar UK
| | - Yves Mérieux
- Etablissement Français du Sang Rhône-Alpes (EFS); Lyon France
| | - Dominique Rigal
- Etablissement Français du Sang Rhône-Alpes (EFS); Lyon France
| | - Leendert Porcelijn
- Platelet and Leukocyte Serology Department; Sanquin Diagnostic Services; Amsterdam the Netherlands
| | - Elly Huiskes
- Platelet and Leukocyte Serology Department; Sanquin Diagnostic Services; Amsterdam the Netherlands
| | - Geoff Lucas
- Histocompatibility and Immunogenetics Laboratories; National Health Service Blood and Transplant (NHSBT); Filton, Bristol UK
| | - Nina Bendukidze
- Histocompatibility and Immunogenetics Laboratories; National Health Service Blood and Transplant (NHSBT); Filton, Bristol UK
| | - Ann Green
- Histocompatibility and Immunogenetics Laboratories; National Health Service Blood and Transplant (NHSBT); Filton, Bristol UK
| | | | | | - Jonathan Dixey
- International Blood Group Reference Laboratory (IBGRL); Filton Bristol UK
| | - Alan Guest
- International Blood Group Reference Laboratory (IBGRL); Filton Bristol UK
| | - Rosey Mushens
- International Blood Group Reference Laboratory (IBGRL); Filton Bristol UK
| | - Willem H. Ouwehand
- Department of Haematology; University of Cambridge and NHSBT Cambridge, Cambridge Biomedical Campus
| | - Cristina V. Navarrete
- Histocompatibility and Immunogenetics Laboratories; National Health Service Blood and Transplant (NHSBT); Colindale, London UK
- Division of Infection and Immunity; University College London; London UK
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11
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Modeling and molecular dynamics simulations of the V33 variant of the integrin subunit β3: Structural comparison with the L33 (HPA-1a) and P33 (HPA-1b) variants. Biochimie 2014; 105:84-90. [DOI: 10.1016/j.biochi.2014.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/21/2014] [Indexed: 11/21/2022]
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12
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Skaik Y, Battermann A, Hiller O, Meyer O, Figueiredo C, Salama A, Blasczyk R. Development of a single-antigen magnetic bead assay (SAMBA) for the sensitive detection of HPA-1a alloantibodies using tag-engineered recombinant soluble β3 integrin. J Immunol Methods 2013; 391:72-80. [DOI: 10.1016/j.jim.2013.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/21/2013] [Indexed: 10/27/2022]
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13
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Peterson JA, McFarland JG, Curtis BR, Aster RH. Neonatal alloimmune thrombocytopenia: pathogenesis, diagnosis and management. Br J Haematol 2013; 161:3-14. [PMID: 23384054 DOI: 10.1111/bjh.12235] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Neonatal alloimmune thrombocytopenia, (NAIT) is caused by maternal antibodies raised against alloantigens carried on fetal platelets. Although many cases are mild, NAIT is a significant cause of morbidity and mortality in newborns and is the most common cause of intracranial haemorrhage in full-term infants. In this report, we review the pathogenesis, clinical presentation, laboratory diagnosis and prenatal and post-natal management of NAIT and highlight areas of controversy that deserve the attention of clinical and laboratory investigators.
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Affiliation(s)
- Julie A Peterson
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI 53226-3548, US.
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14
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Keratinocyte growth factor phage model peptides can promote human oral mucosal epithelial cell proliferation. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:e92-7. [PMID: 23313229 DOI: 10.1016/j.oooo.2011.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 12/05/2011] [Accepted: 12/15/2011] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The objective of this study was to find keratinocyte growth factor (KGF) mimic peptides by a phage display library screening and to analyze their effects on proliferation of human oral mucosal epithelial cells (HOMECs). STUDY DESIGN A phage display library was screened by anti-KGF antibody. ELISA was performed to select monoclonal phages with higher binding activity. The promotion of the phage model peptides on HOMEC proliferation were analyzed by MTT and their cell affinities were confirmed by immunofluorescence assay. Their effect on KGFR, human beta-defensin 3, c-Fos, and c-Jun in HOMEC were analyzed by quantitative real-time PCR. RESULTS Two model peptides with higher affinity with HOMEC were found to have promotive activity on cell proliferation, similar to that of KGF. These 2 model peptides have no KGF-like promotion effect on the expression of c-Fos and c-Jun. CONCLUSIONS The 2 phage model peptides can promote the proliferation of HOMEC in vitro without tumorigenic effects, which suggests their possible usages in oral mucosal wound healing.
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15
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Jallu V, Poulain P, Fuchs PFJ, Kaplan C, de Brevern AG. Modeling and molecular dynamics of HPA-1a and -1b polymorphisms: effects on the structure of the β3 subunit of the αIIbβ3 integrin. PLoS One 2012; 7:e47304. [PMID: 23155369 PMCID: PMC3498292 DOI: 10.1371/journal.pone.0047304] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 09/11/2012] [Indexed: 11/18/2022] Open
Abstract
Background The HPA-1 alloimmune system carried by the platelet integrin αIIbβ3 is the primary cause of alloimmune thrombocytopenia in Caucasians and the HPA-1b allele might be a risk factor for thrombosis. HPA-1a and -1b alleles are defined by a leucine and a proline, respectively, at position 33 in the β3 subunit. Although the structure of αIIbβ3 is available, little is known about structural effects of the L33P substitution and its consequences on immune response and integrin functions. Methodology/Principal Findings A complete 3D model of the L33-β3 extracellular domain was built and a P33 model was obtained by in silico mutagenesis. We then performed molecular dynamics simulations. Analyses focused on the PSI, I-EGF-1, and I-EGF-2 domains and confirmed higher exposure of residue 33 in the L33 β3 form. These analyses also showed major structural flexibility of all three domains in both forms, but increased flexibility in the P33 β3 form. The L33P substitution does not alter the local structure (residues 33 to 35) of the PSI domain, but modifies the structural equilibrium of the three domains. Conclusions These results provide a better understanding of HPA-1 epitopes complexity and alloimmunization prevalence of HPA-1a. P33 gain of structure flexibility in the β3 knee may explain the increased adhesion capacity of HPA-1b platelets and the associated thrombotic risk. Our study provides important new insights into the relationship between HPA-1 variants and β3 structure that suggest possible effects on the alloimmune response and platelet function.
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Affiliation(s)
- Vincent Jallu
- Laboratoire d'Immunologie Plaquettaire, INTS, Paris, France
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Allen DL, Abrahamsson S, Murphy MF, Roberts DJ. Human platelet antigen 1a epitopes are dependent on the cation-regulated conformation of integrin α(IIb)β(3) (GPIIb/IIIa). J Immunol Methods 2011; 375:166-75. [PMID: 22036924 DOI: 10.1016/j.jim.2011.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 09/18/2011] [Accepted: 10/07/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND The HPA-1a (Leu(33)) polymorphism of platelet integrin αIIbβ3 is the target of alloantibodies in 70-80% cases of neonatal alloimmune thrombocytopenia (NAIT) in Caucasians and reliable detection of these antibodies is essential for appropriate clinical management. However, the ability to detect such antibodies is highly variable between laboratories and, in a number of clinical cases where there is a HPA-1 genotype mismatch between mother and neonate, HPA-1a antibodies are undetectable. Furthermore, some studies have not shown a consistent relationship between maternal anti-HPA-1a level and neonatal platelet count. Since the integrity and conformation of the αIIbβ3 complex are dependent on divalent cations, we investigated whether HPA-1a epitope integrity and/or conformation might be affected by the presence of the cation chelator EDTA in patient samples or in assay buffers, thus providing a possible explanation for the variable sensitivity of current assays. PRINCIPLE FINDINGS Exposure of the αIIbβ3 complex to EDTA resulted in reduced reactivity of three anti-HPA-1a mAbs (B2, 19-7 and 23-15). More significantly, cation chelation adversely affected detection of polyclonal anti-HPA-1a, not only in the platelet immunofluorescence assay, where alloantibody binding was reduced compared to control platelets (mean MFI reduction 44.5%, range 17.3-69.7%, n=4), but also in the commonly used monoclonal antibody specific immobilisation of platelet antigens assay (MAIPA) where both alloantibody and monoclonal capture antibody binding were reduced (mean OD reduction 82.8%, range 68.3-96.6%, n=9). CONCLUSIONS These data show that HPA-1a antibodies recognise epitopes on αIIbβ3 that are sensitive to EDTA treatment and that cation chelation grossly reduces the sensitivity of the MAIPA assay by diminishing not only HPA-1a alloantibody binding but also 'capture' monoclonal antibody binding. These findings may, in part, explain the current variability in antibody measurement and will guide the development of more sensitive tests for anti-integrin antibodies in NAIT and other conditions.
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Affiliation(s)
- David L Allen
- NHS Blood and Transplant, John Radcliffe Hospital, Oxford, UK.
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Chong W, Metcalfe P, Mushens R, Lucas G, Ouwehand WH, Navarrete CV. Detection of human platelet antigen-1a alloantibodies in cases of fetomaternal alloimmune thrombocytopenia using recombinant β3 integrin fragments coupled to fluorescently labeled beads. Transfusion 2010; 51:1261-70. [DOI: 10.1111/j.1537-2995.2010.02977.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Fujiwara K, Shimano K, Tanaka H, Sekine M, Kashiwase K, Uchikawa M, Satake M, Nakajima K. Application of bead array technology to simultaneous detection of human leucocyte antigen and human platelet antigen antibodies. Vox Sang 2009; 96:244-51. [DOI: 10.1111/j.1423-0410.2008.01140.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Socher I, Andrei-Selmer C, Bein G, Kroll H, Santoso S. Low-avidity HPA-1a alloantibodies in severe neonatal alloimmune thrombocytopenia are detectable with surface plasmon resonance technology. Transfusion 2009; 49:943-52. [PMID: 19175553 DOI: 10.1111/j.1537-2995.2008.02065.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is mostly caused by maternal alloantibodies directed against the human platelet alloantigen (HPA)-1a. Currently, the serologic diagnosis of FNAIT is based on the characterization of the HPA alloantibodies in monoclonal antibody-based antigen-capture assays (e.g., MAIPA assay). Accumulated current evidence indicated that such assays may overlook some HPA-1a antibodies. STUDY DESIGN AND METHODS This study employed surface plasmon resonance (SPR) technology using immunoaffinity-purified glycoprotein IIb/IIIa isoforms immobilized on biosensor chips to study the binding kinetics of HPA-1a alloantibodies from different FNAIT cases in real time. RESULTS Analysis of HPA-1a alloantibodies from FNAIT cases (n = 9) in SPR showed a moderate relative response (22.2-69.7 resonance units [RU]) and slow antibody dissociation. After the dissociation phase, varying amounts of bound antibodies (41%-79%) remained on the chip. In contrast in HPA-1a alloantibodies from a patient suffering from posttransfusion purpura, a high relative response (approximately 490 RU) was observed at the end of the association phase and no dissociation of antibody binding was detectable. Of particular relevance, by the use of this SPR technique, HPA-1a alloantibodies were detected in two severe FNAIT cases that had determined as false negative by MAIPA assay. In SPR, these HPA-1a alloantibodies showed low-avidity nature characterized by gradual dissociation of antibody during the association phase and complete detachment of antibody binding after the dissociation phase. This high "off-rate" character of low-avidity HPA-1a alloantibodies indicates that such antibody binding is easily detachable by the extensive washing procedure of the MAIPA. CONCLUSIONS Our results demonstrated that the SPR method can facilitate the diagnosis of clinically relevant low-avidity HPA-1a antibodies.
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Affiliation(s)
- Ines Socher
- Institute for Clinical Immunology and Transfusion Medicine, Giessen, Germany
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Stafford P, Garner SF, Rankin A, Kekomaki R, Watkins NA, Ouwehand WH. A single-nucleotide polymorphism in the humanITGB3gene is associated with the platelet-specific alloantigen Vaa(HPA-17bw) involved in fetal maternal alloimmune thrombocytopenia. Transfusion 2008; 48:1432-8. [DOI: 10.1111/j.1537-2995.2008.01737.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Stafford P, Garner SF, Huiskes E, Kaplan C, Kekomaki R, Santoso S, Tsuno NH, Watkins NA, Ouwehand WH. Three novel beta3 domain-deletion peptides for the sensitive and specific detection of HPA-4 and six low frequency beta3-HPA antibodies. J Thromb Haemost 2008; 6:376-83. [PMID: 18031296 DOI: 10.1111/j.1538-7836.2008.02843.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Antibodies against human platelet antigens (HPA) are clinically important in fetal-maternal alloimmune thrombocytopenia, refractoriness to platelet transfusions and post-transfusion purpura. Of the 16 HPAs, nine are located on the beta3 subunit of the alphaIIb beta3 integrin. Antibody detection is generally based on platelet-derived alphaIIb beta3 from HPA-genotyped donors. Recombinant allelic beta3 peptides, expressed at high levels would improve consistency in antibody detection, but the expression of soluble and monomeric integrins expressing complex dependent epitopes has previously proved challenging. OBJECTIVES We aimed to generate three recombinant beta3 peptides for the detection of antibodies against HPA-4, HPA-8bw and five of the six remaining low frequency beta3 alloantigens. METHODS The removal of the specificity-determining loop from the betaA domain and fusion of truncated beta3 to calmodulin was exploited to obtain expression of monomeric protein. Using site-directed mutagenesis, the mutations for HPA-4b and HPA-8bw were introduced in the ITGB3*001 haplotype. A third peptide for the detection of antibodies against HPA coded by non-synonymous single nucleotide polymorphisms of low frequency was generated by the introduction of five mutations forming the basis of HPA-6bw, -7bw, -10bw, -11bw, and -16bw antigens. RESULTS Reactivity of the three peptides with beta3-specific murine monoclonal antibodies and human HPA-1a phage antibodies confirmed the structural integrity of the recombinant fragments, and reactivity with a unique panel of polyclonal anti-HPA sera confirmed expression of the relevant HPA epitopes. CONCLUSIONS These data demonstrate that beta3 integrin domain-deletion fragments are suitable molecular targets for HPA antibody detection.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antigen-Antibody Reactions
- Antigens, Human Platelet/chemistry
- Antigens, Human Platelet/genetics
- Antigens, Human Platelet/immunology
- Blood Platelets/metabolism
- Epitopes/chemistry
- Epitopes/immunology
- Female
- Humans
- Infant, Newborn
- Integrin beta3/chemistry
- Integrin beta3/genetics
- Integrin beta3/immunology
- Isoantibodies/blood
- Isoantibodies/chemistry
- Isoantibodies/immunology
- Mice
- Models, Molecular
- Mutagenesis, Site-Directed
- Platelet Glycoprotein GPIIb-IIIa Complex/chemistry
- Platelet Glycoprotein GPIIb-IIIa Complex/immunology
- Polymorphism, Single Nucleotide
- Pregnancy
- Protein Binding
- Protein Conformation
- Protein Interaction Mapping
- Protein Structure, Tertiary
- Recombinant Fusion Proteins/immunology
- Sequence Deletion
- Thrombocytopenia, Neonatal Alloimmune/diagnosis
- Thrombocytopenia, Neonatal Alloimmune/immunology
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Affiliation(s)
- P Stafford
- Department of Haematology, University of Cambridge and National Health Service Blood and Transplant, Cambridge, UK
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