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Wang TY, Rukundo JL, Mao Z, Krylov SN. Maximizing the Accuracy of Equilibrium Dissociation Constants for Affinity Complexes: From Theory to Practical Recommendations. ACS Chem Biol 2024. [PMID: 39121869 DOI: 10.1021/acschembio.4c00259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2024]
Abstract
The equilibrium dissociation constant (Kd) is a major characteristic of affinity complexes and one of the most frequently determined physicochemical parameters. Despite its significance, the values of Kd obtained for the same complex under similar conditions often exhibit considerable discrepancies and sometimes vary by orders of magnitude. These inconsistencies highlight the susceptibility of Kd determination to large systematic errors, even when random errors are small. It is imperative to both minimize and quantitatively assess the systematic errors inherent in Kd determination. Traditionally, Kd values are determined through nonlinear regression of binding isotherms. This analysis utilizes three variables: concentrations of two reactants and a fraction R of unbound limiting reactant. The systematic errors in Kd arise directly from systematic errors in these variables. Therefore, to maximize the accuracy of Kd, this study thoroughly analyzes the sources of systematic errors within the three variables, including (i) non-additive signals to calculate R, (ii) mis-calibrated experimental instruments, (iii) inaccurate calibration parameters, (iv) insufficient incubation time, (v) unsaturated binding isotherm, (vi) impurities in the reactants, and (vii) solute adsorption onto surfaces. Through this analysis, we illustrate how each source contributes to inaccuracies in the determination of Kd and propose strategies to minimize these contributions. Additionally, we introduce a method for quantitatively assessing the confidence intervals of systematic errors in concentrations, a crucial step toward quantitatively evaluating the accuracy of Kd. While presenting original findings, this paper also reiterates the fundamentals of Kd determination, hence guiding researchers across all proficiency levels. By shedding light on the sources of systematic errors and offering strategies for their mitigation, our work will help researchers enhance the accuracy of Kd determination, thereby making binding studies more reliable and the conclusions drawn from such studies more robust.
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Affiliation(s)
- Tong Ye Wang
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
- Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Jean-Luc Rukundo
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
- Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Zhiyuan Mao
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
- Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Sergey N Krylov
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
- Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
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2
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Maniya NH, Kumar S, Franklin JL, Higginbotham JN, Scott AM, Gan HK, Coffey RJ, Senapati S, Chang HC. An anion exchange membrane sensor detects EGFR and its activity state in plasma CD63 extracellular vesicles from patients with glioblastoma. Commun Biol 2024; 7:677. [PMID: 38830977 PMCID: PMC11148014 DOI: 10.1038/s42003-024-06385-1] [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: 08/29/2023] [Accepted: 05/27/2024] [Indexed: 06/05/2024] Open
Abstract
We present a quantitative sandwich immunoassay for CD63 Extracellular Vesicles (EVs) and a constituent surface cargo, EGFR and its activity state, that provides a sensitive, selective, fluorophore-free and rapid alternative to current EV-based diagnostic methods. Our sensing design utilizes a charge-gating strategy, with a hydrophilic anion exchange membrane functionalized with capture antibodies and a charged silica nanoparticle reporter functionalized with detection antibodies. With sensitivity and robustness enhancement by the ion-depletion action of the membrane, this hydrophilic design with charged reporters minimizes interference from dispersed proteins, thus enabling direct plasma analysis without the need for EV isolation or sensor blocking. With a LOD of 30 EVs/μL and a high relative sensitivity of 0.01% for targeted proteomic subfractions, our assay enables accurate quantification of the EV marker, CD63, with colocalized EGFR by an operator/sample insensitive universal normalized calibration. We analysed untreated clinical samples of Glioblastoma to demonstrate this new platform. Notably, we target both total and "active" EGFR on EVs; with a monoclonal antibody mAb806 that recognizes a normally hidden epitope on overexpressed or mutant variant III EGFR. Analysis of samples yielded an area-under-the-curve (AUC) value of 0.99 and a low p-value of 0.000033, surpassing the performance of existing assays and markers.
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Affiliation(s)
- Nalin H Maniya
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Sonu Kumar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jeffrey L Franklin
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - James N Higginbotham
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Andrew M Scott
- Tumour Targeting Laboratory, Olivia Newton-John Cancer Research Institute, Melbourne, VIC, Australia
- Department of Molecular Imaging and Therapy, Austin Health, Melbourne, VIC, Australia
- School of Cancer Medicine, La Trobe University, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Hui K Gan
- Tumour Targeting Laboratory, Olivia Newton-John Cancer Research Institute, Melbourne, VIC, Australia
- School of Cancer Medicine, La Trobe University, Melbourne, VIC, Australia
- Department of Medicine, University of Melbourne, Melbourne, VIC, Australia
| | - Robert J Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Satyajyoti Senapati
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA.
| | - Hsueh-Chia Chang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA.
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3
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Anzai I, Fujita J, Ono C, Kosaka Y, Miyamoto Y, Shichinohe S, Takada K, Torii S, Taguwa S, Suzuki K, Makino F, Kajita T, Inoue T, Namba K, Watanabe T, Matsuura Y. Characterization of a neutralizing antibody that recognizes a loop region adjacent to the receptor-binding interface of the SARS-CoV-2 spike receptor-binding domain. Microbiol Spectr 2024; 12:e0365523. [PMID: 38415660 PMCID: PMC10986471 DOI: 10.1128/spectrum.03655-23] [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: 10/11/2023] [Accepted: 02/12/2024] [Indexed: 02/29/2024] Open
Abstract
Although the global crisis caused by the coronavirus disease 2019 (COVID-19) pandemic is over, the global epidemic of the disease continues. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the cause of COVID-19, initiates infection via the binding of the receptor-binding domain (RBD) of its spike protein to the human angiotensin-converting enzyme II (ACE2) receptor, and this interaction has been the primary target for the development of COVID-19 therapeutics. Here, we identified neutralizing antibodies against SARS-CoV-2 by screening mouse monoclonal antibodies and characterized an antibody, CSW1-1805, that targets a narrow region at the RBD ridge of the spike protein. CSW1-1805 neutralized several variants in vitro and completely protected mice from SARS-CoV-2 infection. Cryo-EM and biochemical analyses revealed that this antibody recognizes the loop region adjacent to the ACE2-binding interface with the RBD in both a receptor-inaccessible "down" state and a receptor-accessible "up" state and could stabilize the RBD conformation in the up-state. CSW1-1805 also showed different binding orientations and complementarity determining region properties compared to other RBD ridge-targeting antibodies with similar binding epitopes. It is important to continuously characterize neutralizing antibodies to address new variants that continue to emerge. Our characterization of this antibody that recognizes the RBD ridge of the spike protein will aid in the development of future neutralizing antibodies.IMPORTANCESARS-CoV-2 cell entry is initiated by the interaction of the viral spike protein with the host cell receptor. Therefore, mechanistic findings regarding receptor recognition by the spike protein help uncover the molecular mechanism of SARS-CoV-2 infection and guide neutralizing antibody development. Here, we characterized a SARS-CoV-2 neutralizing antibody that recognizes an epitope, a loop region adjacent to the receptor-binding interface, that may be involved in the conformational transition of the receptor-binding domain (RBD) of the spike protein from a receptor-inaccessible "down" state into a receptor-accessible "up" state, and also stabilizes the RBD in the up-state. Our mechanistic findings provide new insights into SARS-CoV-2 receptor recognition and guidance for neutralizing antibody development.
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Grants
- JP16H06429, JP16K21723, JP16H06432 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP16H06429, JP16K21723, JP16H06434 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H02521 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP21K15042 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP21H02736 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP25K000013 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP20K22630 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP223fa627002, JP22am0401030, JP23fk0108659, JP20jk0210021, JP22gm1610010, JP19fk0108113 Japan Agency for Medical Research and Development (AMED)
- JP223fa627002 Japan Agency for Medical Research and Development (AMED)
- JP19fk0108113, JP20fk0108281, JP20pc0101047 Japan Agency for Medical Research and Development (AMED)
- JP20fk0108401, JP21fk0108493 Japan Agency for Medical Research and Development (AMED)
- JP21am0101117, JP17pc0101020 Japan Agency for Medical Research and Development (AMED)
- JPMJOP1861 MEXT | Japan Science and Technology Agency (JST)
- JPMJMS2025 MEXT | Japan Science and Technology Agency (JST)
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Affiliation(s)
- Itsuki Anzai
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
| | - Junso Fujita
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Osaka, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Chikako Ono
- Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
- Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | | | | | - Shintaro Shichinohe
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Kosuke Takada
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Shiho Torii
- Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Shuhei Taguwa
- Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
- Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- Center for Advanced Modalities and DDS, Osaka University, Suita, Osaka, Japan
| | - Koichiro Suzuki
- The Research Foundation for Microbial Diseases of Osaka University (BIKEN), Suita, Osaka, Japan
| | - Fumiaki Makino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Osaka, Japan
- JEOL Ltd., Akishima, Tokyo, Japan
| | | | - Tsuyoshi Inoue
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Osaka, Japan
- RIKEN Center for Biosystems Dynamics Research and Spring-8 Center, Suita, Osaka, Japan
| | - Tokiko Watanabe
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
- Center for Advanced Modalities and DDS, Osaka University, Suita, Osaka, Japan
| | - Yoshiharu Matsuura
- Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Osaka, Japan
- Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- Center for Advanced Modalities and DDS, Osaka University, Suita, Osaka, Japan
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4
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Denamur S, Chazeirat T, Maszota-Zieleniak M, Vivès RR, Saidi A, Zhang F, Linhardt RJ, Labarthe F, Samsonov SA, Lalmanach G, Lecaille F. Binding of heparan sulfate to human cystatin C modulates inhibition of cathepsin L: Putative consequences in mucopolysaccharidosis. Carbohydr Polym 2022; 293:119734. [DOI: 10.1016/j.carbpol.2022.119734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/30/2022] [Accepted: 06/11/2022] [Indexed: 11/02/2022]
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5
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Mendoza SR, Liedke SC, de La Noval CR, da Silva Ferreira M, Gomes KX, Honorato L, Nimrichter L, Peralta JM, Guimarães AJ. In vitro and in vivo efficacies of Dectin-1-Fc(IgG)(s) fusion proteins against invasive fungal infections. Med Mycol 2022; 60:6648754. [PMID: 35867978 DOI: 10.1093/mmy/myac050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 06/22/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Fungal infections have increased in the last years, particularly associated to an increment in the number of immunocompromised individuals and the emergence of known or new resistant species, despite the difficulties in the often time-consuming diagnosis. The controversial efficacy of the currently available strategies for their clinical management, apart from their high toxicity and severe side effects, have renewed the interest in the research and development of new broad antifungal alternatives. These encompass vaccines and passive immunization strategies with monoclonal antibodies (mAbs), recognizing ubiquitous fungal targets, such as fungal cell wall β-1,3-glucan polysaccharides, which could be used in early therapeutic intervention without the need for the diagnosis at species-level. As additional alternatives, based on the Dectin-1 great affinity to β-1,3-glucan, our group developed broad antibody-like Dectin1-Fc(IgG)(s) from distinct subclasses (IgG2a and IgG2b) and compared their antifungal in vitro and passive immunizations in vivo performances. Dectin1-Fc(IgG2a) and Dectin1-Fc(IgG2b) demonstrated high affinity to laminarin and the fungal cell wall by ELISA, flow cytometry and microscopy. Both Dectin-1-Fc(IgG)(s) inhibited H. capsulatum and C. neoformans growth in a dose-dependent fashion. For C. albicans, such inhibitory effect was observed with concentrations as low as 0.098 and 0.049 µg/mL, respectively, which correlated with the impairment of the kinetics and lengths of germ tubes in comparison to controls. Previous opsonization with Dectin-1-Fc(IgG)(s) enhanced considerably the macrophage antifungal effector functions, increasing the fungi macrophages-interactions and significantly reducing the intraphagosome fungal survival, as lower CFUs were observed. The administration of both Dectin1-Fc(IgG)(s) reduced the fungal burden and mortality in murine histoplasmosis and candidiasis models, in accordance with previous evaluations in aspergillosis model. These results altogether strongly suggested that therapeutic interventions with Dectin-1-Fc(IgG)(s) fusion proteins could directly impact the innate immunity and disease outcome in favor of the host, by direct neutralization, opsonization, phagocytosis, and fungal elimination, providing interesting information on the potential of these new strategies for the control of invasive fungal infections.
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Affiliation(s)
- S R Mendoza
- Laboratório de Bioquímica e Imunologia das Micoses, Instituto Biomédico, Fluminense Federal University, Brazil.,Programa de Pós-Graduação em Imunologia e Inflamação, Federal University of Rio de Janeiro, Brazil
| | - S C Liedke
- Laboratório de Diagnóstico Imunológico e Molecular de Doenças Infecciosas e Parasitárias, Federal University of Rio de Janeiro, Brazil
| | - C R de La Noval
- Laboratório de Bioquímica e Imunologia das Micoses, Instituto Biomédico, Fluminense Federal University, Brazil.,Laboratório de Glicobiologia de Eucariotos, Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Brazil
| | - M da Silva Ferreira
- Laboratório de Bioquímica e Imunologia das Micoses, Instituto Biomédico, Fluminense Federal University, Brazil.,Programa de Pós-Graduação em Imunologia e Inflamação, Federal University of Rio de Janeiro, Brazil
| | - K X Gomes
- Laboratório de Bioquímica e Imunologia das Micoses, Instituto Biomédico, Fluminense Federal University, Brazil.,Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), RJ, Brazil
| | - L Honorato
- Laboratório de Glicobiologia de Eucariotos, Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Brazil
| | - L Nimrichter
- Laboratório de Glicobiologia de Eucariotos, Instituto de Microbiologia Paulo de Góes, Federal University of Rio de Janeiro, Brazil.,Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), RJ, Brazil
| | - J M Peralta
- Laboratório de Diagnóstico Imunológico e Molecular de Doenças Infecciosas e Parasitárias, Federal University of Rio de Janeiro, Brazil
| | - A J Guimarães
- Laboratório de Bioquímica e Imunologia das Micoses, Instituto Biomédico, Fluminense Federal University, Brazil.,Programa de Pós-Graduação em Imunologia e Inflamação, Federal University of Rio de Janeiro, Brazil.,Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), RJ, Brazil.,Pós-Graduação em Microbiologia e Parasitologia Aplicadas, Instituto Biomédico, Fluminense Federal University, Brazil
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6
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Chantran Y, Capron J, Doukhi D, Felix J, Féroul M, Kruse F, Chaigneau T, Dorothée G, Allou T, Ayrignac X, Barrou Z, de Broucker T, Cret C, Turc G, Peres R, Wacongne A, Sarazin M, Renard D, Cordonnier C, Alamowitch S, Aucouturier P. Letter to the editor: Serum anti-Aβ antibodies in cerebral amyloid angiopathy. Autoimmun Rev 2021; 20:102870. [PMID: 34118456 DOI: 10.1016/j.autrev.2021.102870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 10/21/2022]
Affiliation(s)
- Yannick Chantran
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France; Département d'Immunologie Biologique, Hôpital Saint-Antoine, AP-HP, Paris, France
| | - Jean Capron
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France; Service de Neurologie et d'Urgences Neurovasculaires, Hôpital Saint-Antoine, AP-HP, Paris, France
| | - Diana Doukhi
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France
| | - Johanna Felix
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France
| | - Mélanie Féroul
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France
| | - Florian Kruse
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France
| | - Thomas Chaigneau
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France
| | - Guillaume Dorothée
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France
| | | | - Xavier Ayrignac
- Service de Neurologie, CHU Montpellier, Hôpital Guy de Chauliac, Montpellier, France
| | - Zina Barrou
- Service de Gériatrie, Hôpital Pitié Salpêtrière, AP-HP, Paris, France
| | - Thomas de Broucker
- Service de Neurologie, Centre Hospitalier de Saint-Denis, Saint-Denis, France
| | - Corina Cret
- Service de Neurologie, Centre Hospitalier de Meaux, Meaux, France
| | - Guillaume Turc
- Service de Neurologie, GHU Paris Psychiatrie et Neurosciences, Université de Paris, INSERM U1266, FHU NeuroVasc, Paris, France
| | - Roxane Peres
- Service de Neurologie, Hôpital Lariboisière, AP-HP, Paris, France
| | - Anne Wacongne
- Service de Neurologie, CHU Nîmes, Hôpital Caremeau, Nîmes, France
| | - Marie Sarazin
- Service de Neurologie de la Mémoire et du Langage, Centre Hospitalier Sainte-Anne, Université Sorbonne Paris Cité, Paris, France
| | - Dimitri Renard
- Service de Neurologie, CHU Nîmes, Hôpital Caremeau, Nîmes, France
| | - Charlotte Cordonnier
- U1172 - LilNCog - Lille Neuroscience & Cognition, Inserm, CHU Lille, Univ. Lille, Lille, France
| | - Sonia Alamowitch
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France; Service de Neurologie et d'Urgences Neurovasculaires, Hôpital Saint-Antoine, AP-HP, Paris, France
| | - Pierre Aucouturier
- UMRS 938, Hôpital St-Antoine, Sorbonne Université, Inserm, Paris, France; Département d'Immunologie Biologique, Hôpital Saint-Antoine, AP-HP, Paris, France.
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7
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Toraño A, Moreno I, Infantes JA, Domínguez M. Development of a competitive inhibition kinetic ELISA to determine the inhibition constant (K i) of monoclonal antibodies. J Immunol Methods 2021; 493:113042. [PMID: 33757841 DOI: 10.1016/j.jim.2021.113042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
Antibody-antigen interactions are mediated by the same molecular recognition mechanisms as those of an enzyme and its substrate. On this basis, we developed a competitive inhibition kinetic ELISA to measure monoclonal antibody (mAb) inhibition constants. Serially diluted samples of ligand (mAb) and inhibitor (soluble antigen) were incubated to equilibrium in ELISA plates coated with a fixed concentration of antigen (receptor). Plates were washed, and bound mAb measured with antiglobulin-peroxidase. Initial velocity data of receptor-bound mAb at various ligand and inhibitor concentrations were analyzed with enzyme linear competitive inhibition methods by non-linear regression (NLR), linear transformations (Cornish-Bowden, Lineweaver-Burk, Hanes-Woolf, Dixon, Cortés [1/i0.5 vs. Vi/Vmax], Ascenzi [Ks/Vmax/Ks,0/Vmax vs. [I]]) and NLR IC50 plots, to derive mAb inhibition constants (Ki). We obtained similar mAb Ki and Kd values by ELISA and surface plasmon resonance, which confirmed the accuracy of the ELISA method. This competitive inhibition ELISA is a simple (it requires no labeling or prior knowledge of antibody concentration), sensitive (it detects Ki values in the low nanomolar range by conventional colorimetry), and reproducible method with which to calculate mAb inhibition constants.
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Affiliation(s)
- Alfredo Toraño
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid 28220, Spain.
| | - Inmaculada Moreno
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid 28220, Spain
| | - José Antonio Infantes
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid 28220, Spain
| | - Mercedes Domínguez
- Unidad de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid 28220, Spain
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8
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Baaklini I, Gonçalves CDC, Lukacs GL, Young JC. Selective Binding of HSC70 and its Co-Chaperones to Structural Hotspots on CFTR. Sci Rep 2020; 10:4176. [PMID: 32144307 PMCID: PMC7060200 DOI: 10.1038/s41598-020-61107-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/07/2020] [Indexed: 12/17/2022] Open
Abstract
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) channel cause cystic fibrosis. Chaperones, including HSC70, DNAJA1 and DNAJA2, play key roles in both the folding and degradation of wild-type and mutant CFTR at multiple cellular locations. DNAJA1 and HSC70 promote the folding of newly synthesized CFTR at the endoplasmic reticulum (ER), but are required for the rapid turnover of misfolded channel at the plasma membrane (PM). DNAJA2 and HSC70 are also involved in the ER-associated degradation (ERAD) of misfolded CFTR, while they assist the refolding of destabilized channel at the PM. These outcomes may depend on the binding of chaperones to specific sites within CFTR, which would be exposed in non-native states. A CFTR peptide library was used to identify binding sites for HSC70, DNAJA1 and DNAJA2, validated by competition and functional assays. Each chaperone had a distinct binding pattern, and sites were distributed between the surfaces of the CFTR cytosolic domains, and domain interfaces known to be important for channel assembly. The accessibility of sites to chaperones will depend on the degree of CFTR folding or unfolding. Different folded states may be recognized by unique combinations of HSC70, DNAJA1 and DNAJA2, leading to divergent biological effects.
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Affiliation(s)
- Imad Baaklini
- McGill University, Department of Biochemistry, Montreal, H3G 1Y6, Canada
| | | | - Gergely L Lukacs
- McGill University, Department of Biochemistry, Montreal, H3G 1Y6, Canada.,McGill University, Department of Physiology, Montreal, H3G 1Y6, Canada
| | - Jason C Young
- McGill University, Department of Biochemistry, Montreal, H3G 1Y6, Canada.
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9
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Vlasenko AE, Kuznetsov VG, Petrova IY, Magarlamov TY. Development of a polyclonal antibody-based indirect competitive ELISA for the determination of tetrodotoxins in marine ribbon worms (NEMERTEA) and its comparison with high performance liquid chromatography-tandem mass spectrometry. Toxicon 2020; 176:30-33. [PMID: 31975690 DOI: 10.1016/j.toxicon.2020.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 12/24/2022]
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin frequently occurring in marine organisms along with its numerous analogues. To determine the total TTX content, we developed an enzyme-linked immunosorbent assay (ELISA) technique utilizing polyclonal antibodies against TTX. The technique was tested using extracts of marine worms of the phylum Nemertea and confirmed by HPLC-MS/MS. It proved to be suitable for a preliminary assessment of the toxicity of marine organisms.
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Affiliation(s)
- A E Vlasenko
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, 690041, Russia
| | - V G Kuznetsov
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, 690041, Russia; School of Natural Sciences, Far Eastern Federal University, Vladivostok, 690092, Russia
| | - I Yu Petrova
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, 690041, Russia
| | - T Yu Magarlamov
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, 690041, Russia; School of Biomedicine, Far Eastern Federal University, Vladivostok, 690092, Russia.
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10
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Law ECY, Leung DTM, Tam FCH, Cheung KKT, Cheng NHY, Lim PL. IgM Antibodies Can Access Cryptic Antigens Denied to IgG: Hypothesis on Novel Binding Mechanism. Front Immunol 2019; 10:1820. [PMID: 31428101 PMCID: PMC6688401 DOI: 10.3389/fimmu.2019.01820] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/18/2019] [Indexed: 11/13/2022] Open
Abstract
Antibodies are well-known protein mediators of immunity. IgM is the primordial member and the neglected sibling of the later-evolved and more proficient IgG in regard to their therapeutic and diagnostic use. Serendipitously, however, we found a paradox: While murine IgM antibodies specific for guanosine triphosphate (GTP) were able to recognize native guanylyl antigens found in primate or rat muscle tissues by immunofluorescence assays (which mimicked the auto-antibodies from autoimmune patients to skeletal or smooth muscle), the murine and human IgG counterparts failed. The results were replicated in cell-free direct binding assays using small latex microspheres decorated densely with GTP. The IgG antibodies could bind, however, if GTP was presented more spaciously on larger particles or as a univalent hapten. Accordingly, oligomerization of GTP (30-mer) destroyed the binding of the IgG antibodies but enhanced that of the IgMs in inhibition ELISA. We reason that, contrary to current belief, IgM does not bind in a lock-and-key manner like IgG. We hypothesize that whereas the intact and rigid antigen-binding site of IgG hinders the antibody from docking with antigens that are obstructed, in IgM, the two component polypeptides of the antigen-binding site can dissociate from each other and navigate individually through obstacles like the ancestral single-polypeptide antibodies found in sharks and camelids, both components eventually re-grouping around the antigen. We further speculate that polyreactive IgMs, which enigmatically bind to more than one type of antigen, use the same modus operandi. These findings call for a re-look at the clinical potential of IgM antibodies particularly in specific areas of cancer therapy, tissue pathology and vaccine design, where IgG antibodies have failed due to target inaccessibility.
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Affiliation(s)
- Eric Chun Yiu Law
- Clinical Immunology Unit, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Frankie Chi Hang Tam
- Clinical Immunology Unit, The Chinese University of Hong Kong, Hong Kong, China.,IgGENE, FoTan, Hong Kong, China
| | | | - Naomi Hua Yin Cheng
- Clinical Immunology Unit, The Chinese University of Hong Kong, Hong Kong, China
| | - Pak Leong Lim
- Clinical Immunology Unit, The Chinese University of Hong Kong, Hong Kong, China.,IgGENE, FoTan, Hong Kong, China
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11
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Kawasaki E, Okada A, Uchida A, Fukuyama T, Sagara Y, Nakano Y, Tamai H, Tojikubo M, Koga N. Discrepancy of glutamic acid decarboxylase 65 autoantibody results between RSR radioimmunoassay and enzyme-linked immunosorbent assay in patients with type 1 diabetes is related to autoantibody affinity. J Diabetes Investig 2019; 10:990-996. [PMID: 30582775 PMCID: PMC6626941 DOI: 10.1111/jdi.12996] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/18/2018] [Accepted: 12/20/2018] [Indexed: 11/28/2022] Open
Abstract
AIM/INTRODUCTION Autoantibodies to the 65 kDa isoform of glutamic acid decarboxylase (GADA) are a valuable diagnostic and predictive marker for type 1 diabetes. Recently, it has been reported that a significant proportion of sera in the commercial RSR radioimmunoassay (RIA) that have tested positive for GADA have then turned negative in RSR enzyme-linked immunosorbent assay (ELISA) tests in patients with type 1 diabetes. The present study aimed to investigate whether the GADA result discrepancies between RSR-RIA and RSR-ELISA are related to autoantibody affinity. METHODS GADA affinity was measured by a competitive binding experiment using unlabeled recombinant human GAD65 in 12 discordant samples (5 RIA[+]/ELISA[-] and 7 RIA[-]/ELISA[+] sera). Furthermore, the effect of the initial incubation time on the GADA positivity was also examined using the ELISA test. RESULTS GADA affinities were >1010 L/mol in two of five RIA(+)/ELISA(-) and all of seven RIA(-)/ELISA(+) sera. After an initial incubation time longer than the recommended 1 h, the GADA titer in three of five RIA(+)/ELISA(-) sera and all RIA(-)/ELISA(+) sera increased 1.6- to 100-fold. However, the titer in 12 GADA-negative sera from healthy controls remained unchanged after the longer incubation. The increment ratio of GADA titer was positively correlated with GADA affinity (r = 0.991, P < 0.001). CONCLUSIONS The RSR-RIA test identifies both high- and low-affinity GADA, whereas the RSR-ELISA test identifies only high-affinity GADA. A longer initial incubation time in the RSR-ELISA test increases the sensitivity of GADA with the same specificity in patients with type 1 diabetes.
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Affiliation(s)
- Eiji Kawasaki
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | | | - Aira Uchida
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | - Takahiro Fukuyama
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | - Yoko Sagara
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | - Yuko Nakano
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | - Hidekazu Tamai
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | - Masayuki Tojikubo
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
| | - Nobuhiko Koga
- Department of Diabetes and EndocrinologyShin‐Koga HospitalKurumeJapan
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12
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Downs AM, McCallum C, Pennathur S. Confinement effects on DNA hybridization in electrokinetic micro- and nanofluidic systems. Electrophoresis 2019; 40:792-798. [PMID: 30597594 DOI: 10.1002/elps.201800356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/29/2018] [Accepted: 12/02/2018] [Indexed: 11/09/2022]
Abstract
Spatial confinement, within cells or micro- and nanofabricated devices, impacts the conformation and binding kinetics of biomolecules. Understanding the role of spatial confinement on molecular behavior is important for comprehending diverse biological phenomena, as well as for designing biosensors. Specifically, the behavior of molecular binding under an applied electric field is of importance in the development of electrokinetic biosensors. Here, we investigate whether confinement of DNA oligomers in capillary electrophoresis impacts the binding kinetics of the DNA. To infer the role of confinement on hybridization dynamics, we perform capillary electrophoresis measurements on DNA oligomers within micro- and nanochannels, then apply first-order reaction dynamics theory to extract kinetic parameters from electropherogram data. We find that the apparent dissociation constants at the nanoscale (i.e., within a 100 nm channel) are lower than at the microscale (i.e., within a 1 μm channel), indicating stronger binding with increased confinement. This confirms, for the first time, that confinement-based enhancement of DNA hybridization persists under application of an electric field.
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Affiliation(s)
- Alex M Downs
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Christopher McCallum
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Sumita Pennathur
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
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13
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Lakhan N, Stevens NE, Diener KR, Hayball JD. CoVaccine HT™ adjuvant is superior to Freund's adjuvants in eliciting antibodies against the endogenous alarmin HMGB1. J Immunol Methods 2016; 439:37-43. [PMID: 27693642 DOI: 10.1016/j.jim.2016.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 12/29/2022]
Abstract
Adjuvants are used to enhance the immune response against specific antigens for the production of antibodies, with the choice of adjuvant most critical for poorly immunogenic and self-antigens. This study quantitatively and qualitatively evaluated CoVaccine HT™ and Freund's adjuvants for eliciting therapeutic ovine polyclonal antibodies targeting the endogenous alarmin, high mobility group box-1 (HMGB1). Sheep were immunised with HMGB1 protein in CoVaccine HT™ or Freund's adjuvants, with injection site reactions and antibody titres periodically assessed. The binding affinity of antibodies for HMGB1 and their neutralisation activity was determined in-vitro, with in vivo activity confirmed using a murine model of endotoxemia. Results indicated that CoVaccine HT™ elicited significantly higher antibody tires with stronger affinity and more functional potency than antibodies induced with Freund's adjuvants. These studies provide evidence that CoVaccine HT™ is superior to Freund's adjuvants for the production of antibodies to antigens with low immunogenicity and supports the use of this alternative adjuvant for clinical and experimental use antibodies.
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Affiliation(s)
- Nerissa Lakhan
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, School of Pharmacy and Medical Science, University of South Australia, SA, 5000, Australia; Robinson Research Institute, Discipline of Obstetrics and Gynaecology, School of Medicine, The University of Adelaide, SA, 5005, Australia
| | - Natalie E Stevens
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, School of Pharmacy and Medical Science, University of South Australia, SA, 5000, Australia
| | - Kerrilyn R Diener
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, School of Pharmacy and Medical Science, University of South Australia, SA, 5000, Australia; Robinson Research Institute, Discipline of Obstetrics and Gynaecology, School of Medicine, The University of Adelaide, SA, 5005, Australia.
| | - John D Hayball
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, School of Pharmacy and Medical Science, University of South Australia, SA, 5000, Australia; Robinson Research Institute, Discipline of Obstetrics and Gynaecology, School of Medicine, The University of Adelaide, SA, 5005, Australia.
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14
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Moradi-Kalbolandi S, Habibi-Anbouhi M, Golkar M, Behdani M, Rezaei G, Ghazizadeh L, Abolhassani M, Shokrgozar MA. Datasets of a novel bivalent single chain antibody constructed by overlapping oligonucleotide annealing method targeting human CD123. Data Brief 2016; 8:1137-43. [PMID: 27536714 PMCID: PMC4976644 DOI: 10.1016/j.dib.2016.07.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/30/2016] [Accepted: 07/11/2016] [Indexed: 11/30/2022] Open
Abstract
Current therapies for acute myeloid leukemia (AML), are associated with high relapse rates. Hence, development of new therapeutic strategies is crucial to circumvent this problem. Bivalent antibody technology has been used to engineer novel antibody fragments with increased avidity, by assembling two scFv in a single molecule. Here, we present accompanying data from construction and characterization experiments of a biscFv antibody targeting CD123, the most important biomarker of leukemic cancer stem cells which play a key role in relapsed AML after chemotherapy. Data in this article are related to the research paper “Development of a novel engineered antibody targeting human CD123” Moradi-Kalbolandi S. et al. (2016) [1].
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Affiliation(s)
| | | | - Majid Golkar
- Parasitology Department, Pasteur Institute of Iran, Tehran, Iran
| | - Mahdi Behdani
- Biotechnology Research Center, Venom & Bio therapeutics Molecules Lab, Pasteur Institute of Iran, Tehran, Iran
| | - Gashin Rezaei
- National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, Iran
| | - Leila Ghazizadeh
- National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, Iran
| | - Mohsen Abolhassani
- Immunology Department, Hybridoma Lab, Pasteur Institute of Iran, Tehran, Iran
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15
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Zhang B, Wang B, Morales AW, Scudder J, Bhattacharyya MK, Ye JY. Study of the Interactions of Fusarium virguliforme Toxin FvTox1 with Synthetic Peptides by Molecular Simulations and a Label-Free Biosensor. Anal Chem 2016; 88:3024-30. [PMID: 26859241 DOI: 10.1021/acs.analchem.5b02442] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Fusarium virguliforme is a soil borne pathogen that causes sudden death syndrome (SDS) in soybean plants. This pathogenic disease may result in severe soybean yield suppression and can cause serious economic harm. It has been shown that the FvTox1 toxin produced by the pathogen may be the root cause of foliar SDS. Anti-FvTox1 single-chain variable fragment antibody expressed in transgenic soybean plants was shown to neutralize the FvTox1 toxin involved in foliar SDS development. Here, we have investigated the binding affinities of FvTox1 with four FvTox1-interacting peptides of 7 to 12 amino acids identified from phage display libraries using both bioinformatics-based molecular simulations and label-free bioassays with a unique photonic crystal biosensor. Results from the molecular simulations have predicted the interaction energies and 3-dimensional (3D) structures of FvTox1 and FvTox1-interacting peptide complexes. Our label-free binding assays have further provided the interaction strength of FvTox1 with four different FvTox1-interacting peptides and experimentally confirmed the simulation results obtained from bioinformatics-based molecular calculations.
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Affiliation(s)
- Bailin Zhang
- Department of Biomedical Engineering, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - Bing Wang
- Department of Agronomy, Iowa State University , Ames, Iowa 50011, United States
| | - Andres W Morales
- Department of Biomedical Engineering, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - Jonathan Scudder
- Department of Biomedical Engineering, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | | | - Jing Yong Ye
- Department of Biomedical Engineering, University of Texas at San Antonio , San Antonio, Texas 78249, United States
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16
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Stangner T, Angioletti-Uberti S, Knappe D, Singer D, Wagner C, Hoffmann R, Kremer F. Epitope mapping of monoclonal antibody HPT-101: a study combining dynamic force spectroscopy, ELISA and molecular dynamics simulations. Phys Biol 2015; 12:066018. [PMID: 26689558 DOI: 10.1088/1478-3975/12/6/066018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
By combining enzyme-linked immunosorbent assay (ELISA) and optical tweezers-assisted dynamic force spectroscopy (DFS), we identify for the first time the binding epitope of the phosphorylation-specific monoclonal antibody (mAb) HPT-101 to the Alzheimer's disease relevant peptide tau[pThr231/pSer235] on the level of single amino acids. In particular, seven tau isoforms are synthesized by replacing binding relevant amino acids by a neutral alanine (alanine scanning). From the binding between mAb HPT-101 and the alanine-scan derivatives, we extract specific binding parameters such as bond lifetime τ0, binding length x(ts), free energy of activation ΔG (DFS) and affinity constant K(a) (ELISA, DFS). Based on these quantities, we propose criteria to identify essential, secondary and non-essential amino acids, being representative of the antibody binding epitope. The obtained results are found to be in full accord for both experimental techniques. In order to elucidate the microscopic origin of the change in binding parameters, we perform molecular dynamics (MD) simulations of the free epitope in solution for both its parent and modified form. By taking the end-to-end distance d(E-E) and the distance between the α-carbons d(C-C) of the phosphorylated residues as gauging parameters, we measure how the structure of the epitope depends on the type of substitution. In particular, whereas d(C-C) is sometimes conserved between the parent and modified form, d(E-E) strongly changes depending on the type of substitution, correlating well with the experimental data. These results are highly significant, offering a detailed microscopic picture of molecular recognition.
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Affiliation(s)
- Tim Stangner
- Leipzig University, Department of Experimental Physics I, Linnéstraβe 5, D-04103 Leipzig, Germany
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17
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Voronov-Goldman M, Yaniv O, Gul O, Yoffe H, Salama-Alber O, Slutzki M, Levy-Assaraf M, Jindou S, Shimon LJW, Borovok I, Bayer EA, Lamed R, Frolow F. Standalone cohesin as a molecular shuttle in cellulosome assembly. FEBS Lett 2015; 589:1569-76. [PMID: 25896019 DOI: 10.1016/j.febslet.2015.04.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/06/2015] [Accepted: 04/08/2015] [Indexed: 11/20/2022]
Abstract
The cellulolytic bacterium Ruminococcus flavefaciens of the herbivore rumen produces an elaborate cellulosome system, anchored to the bacterial cell wall via the covalently bound scaffoldin ScaE. Dockerin-bearing scaffoldins also bind to an autonomous cohesin of unknown function, called cohesin G (CohG). Here, we demonstrate that CohG binds to the scaffoldin-borne dockerin in opposite orientation on a distinct site, relative to that of ScaE. Based on these structural data, we propose that the complexed dockerin is still available to bind ScaE on the cell surface. CohG may thus serve as a molecular shuttle for delivery of scaffoldins to the bacterial cell surface.
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Affiliation(s)
- Milana Voronov-Goldman
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978, Israel
| | - Oren Yaniv
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978, Israel
| | - Ozgur Gul
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hagar Yoffe
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978, Israel
| | - Orly Salama-Alber
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Slutzki
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Maly Levy-Assaraf
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978, Israel
| | - Sadanari Jindou
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; Faculty of Agriculture, Meijo University, Nagoya 468-8502, Japan
| | - Linda J W Shimon
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel
| | - Edward A Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978, Israel.
| | - Felix Frolow
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, 69978, Israel; The Daniella Rich Institute for Structural Biology, Tel Aviv University, 69978, Israel
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18
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Sultana A, Lee JE. Measuring Protein‐Protein and Protein‐Nucleic Acid Interactions by Biolayer Interferometry. ACTA ACUST UNITED AC 2015; 79:19.25.1-19.25.26. [DOI: 10.1002/0471140864.ps1925s79] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Azmiri Sultana
- Department of Laboratory Medicine and Pathobiology, University of Toronto Toronto Ontario Canada
| | - Jeffrey E. Lee
- Department of Laboratory Medicine and Pathobiology, University of Toronto Toronto Ontario Canada
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19
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Yao Y, Shams-Ud-Doha K, Daneshfar R, Kitova EN, Klassen JS. Quantifying protein-carbohydrate interactions using liquid sample desorption electrospray ionization mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:98-106. [PMID: 25315460 DOI: 10.1007/s13361-014-1008-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/03/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
The application of liquid sample desorption electrospray ionization mass spectrometry (liquid sample DESI-MS) for quantifying protein-carbohydrate interactions in vitro is described. Association constants for the interactions between lysozyme and β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc and β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc, and between a single chain antibody and α-D-Galp-(1 → 2)-[α-D-Abep-(1 → 3)]-α-D-Manp-OCH3 and β-D-Glcp-(1 → 2)-[α-D-Abep-(1 → 3)]-α-D-Manp-OCH3 measured using liquid sample DESI-MS were found to be in good agreement with values measured by isothermal titration calorimetry and the direct ESI-MS assay. The reference protein method, which was originally developed to correct ESI mass spectra for the occurrence of nonspecific ligand-protein binding, was shown to reliably correct liquid sample DESI mass spectra for nonspecific binding. The suitability of liquid sample DESI-MS for quantitative binding measurements carried out using solutions containing high concentrations of the nonvolatile biological buffer phosphate buffered saline (PBS) was also explored. Binding of lysozyme to β-D-GlcNAc-(1 → 4)-β-D-GlcNAc-(1 → 4)-D-GlcNAc in aqueous solutions containing up to 1× PBS was successfully monitored using liquid sample DESI-MS; with ESI-MS the binding measurements were limited to concentrations less than 0.02 X PBS.
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Affiliation(s)
- Yuyu Yao
- Alberta Glycomics Center and Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
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20
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Hsu YR, Kang YW, Fang JY, Lee GY, Chyi JI, Chang CK, Huang CC, Hsu CP, Huang TH, Huang YF, Sun YC, Hsu CH, Chen CC, Li SS, Yeh JA, Yao DJ, Ren F, Wang YL. Investigation of C-terminal domain of SARS nucleocapsid protein-Duplex DNA interaction using transistors and binding-site models. SENSORS AND ACTUATORS. B, CHEMICAL 2014; 193:334-339. [PMID: 32288246 PMCID: PMC7126644 DOI: 10.1016/j.snb.2013.11.087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 11/12/2013] [Accepted: 11/17/2013] [Indexed: 05/28/2023]
Abstract
AlGaN/GaN high electron mobility transistors (HEMTs) were used to sense the binding between double stranded DNA (dsDNA) and the severe acute respiratory syndrome coronavirus (SARS-CoV) nucleocapsid protein (N protein). The sensing signals were the drain current change of the HEMTs induced by the protein-dsDNA binding. Binding-site models using surface coverage ratios were utilized to analyze the signals from the HEMT-based sensors to extract the dissociation constants and predict the number of binding sites. Two dissociation constants, K D1 = 0.0955 nM, K D2 = 51.23 nM, were obtained by fitting the experimental results into the two-binding-site model. The result shows that this technique is more competitive than isotope-labeling electrophoretic mobility shift assay (EMSA). We demonstrated that AlGaN/GaN HEMTs were highly potential in constructing a semiconductor-based-sensor binding assay to extract the dissociation constants of nucleotide-protein interaction.
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Affiliation(s)
- You-Ren Hsu
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Yen-Wen Kang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Jung-Ying Fang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Geng-Yen Lee
- Department of Electrical engineering, National Central University, Jhongli, Taoyuan 32001, Taiwan, ROC
| | - Jen-Inn Chyi
- Department of Electrical engineering, National Central University, Jhongli, Taoyuan 32001, Taiwan, ROC
| | - Chung-ke Chang
- Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC
| | - Chih-Cheng Huang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Chen-Pin Hsu
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Tai-huang Huang
- Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC
| | - Yu-Fen Huang
- Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC
| | - Yuh-Chang Sun
- Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC
| | - Chia-Hsien Hsu
- Division of Medical Engineering, National Health Research Institutes, MiaoLi, Taiwan, ROC
| | - Chih-Chen Chen
- Division of Medical Engineering, National Health Research Institutes, MiaoLi, Taiwan, ROC
| | - Sheng-Shian Li
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - J. Andrew Yeh
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Da-Jeng Yao
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Fan Ren
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Yu-Lin Wang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
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21
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Wang Y, Huang C, Kang Y. Incorporation of ligand–receptor binding‐site models and transistor‐based sensors for resolving dissociation constants and number of binding sites. IET Nanobiotechnol 2014; 8:10-7. [DOI: 10.1049/iet-nbt.2013.0031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Yu‐Lin Wang
- Institute of Nanoengineering and MicrosystemsNational Tsing Hua UniversityHsinchu 30013Taiwan
| | - Chih‐Cheng Huang
- Institute of Nanoengineering and MicrosystemsNational Tsing Hua UniversityHsinchu 30013Taiwan
| | - Yen‐Wen Kang
- Institute of Nanoengineering and MicrosystemsNational Tsing Hua UniversityHsinchu 30013Taiwan
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22
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Avalos AM, Bilate AM, Witte MD, Tai AK, He J, Frushicheva MP, Thill PD, Meyer-Wentrup F, Theile CS, Chakraborty AK, Zhuang X, Ploegh HL. Monovalent engagement of the BCR activates ovalbumin-specific transnuclear B cells. ACTA ACUST UNITED AC 2014; 211:365-79. [PMID: 24493799 PMCID: PMC3920557 DOI: 10.1084/jem.20131603] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Monovalent engagement can trigger BCR signal transduction, and fine-tuning of BCR-ligand recognition can lead to B cell nonresponsiveness, activation, or inhibition. Valency requirements for B cell activation upon antigen encounter are poorly understood. OB1 transnuclear B cells express an IgG1 B cell receptor (BCR) specific for ovalbumin (OVA), the epitope of which can be mimicked using short synthetic peptides to allow antigen-specific engagement of the BCR. By altering length and valency of epitope-bearing synthetic peptides, we examined the properties of ligands required for optimal OB1 B cell activation. Monovalent engagement of the BCR with an epitope-bearing 17-mer synthetic peptide readily activated OB1 B cells. Dimers of the minimal peptide epitope oriented in an N to N configuration were more stimulatory than their C to C counterparts. Although shorter length correlated with less activation, a monomeric 8-mer peptide epitope behaved as a weak agonist that blocked responses to cell-bound peptide antigen, a blockade which could not be reversed by CD40 ligation. The 8-mer not only delivered a suboptimal signal, which blocked subsequent responses to OVA, anti-IgG, and anti-kappa, but also competed for binding with OVA. Our results show that fine-tuning of BCR-ligand recognition can lead to B cell nonresponsiveness, activation, or inhibition.
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Affiliation(s)
- Ana M Avalos
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
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Kwon I, Hong SY, Kim YD, Nam HS, Kang S, Yang SH, Heo JH. Thrombolytic effects of the snake venom disintegrin saxatilin determined by novel assessment methods: a FeCl3-induced thrombosis model in mice. PLoS One 2013; 8:e81165. [PMID: 24260554 PMCID: PMC3832438 DOI: 10.1371/journal.pone.0081165] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 10/09/2013] [Indexed: 01/19/2023] Open
Abstract
Saxatilin, a novel disintegrin purified and cloned from the venom of the Korean snake Gloydius saxatilis, strongly inhibits activation and aggregation of platelets. Glycoprotein (GP) IIb/IIIa receptor antagonists can resolve thrombus, so saxatilin might also have thrombolytic effects. We investigated the thrombolytic effects of saxatilin in mice using a ferric chloride-induced carotid arterial thrombosis model. Thrombotic occlusion and thrombus resolution were evaluated quantitatively by measuring blood flow in the carotid artery with an ultrasonic flow meter and calculating the degree of flow restoration on a minute-by-minute basis; results were confirmed by histological examination. Saxatilin dissolved thrombi in a dose-dependent manner. Saxatilin at 5 mg/kg restored blood flow to baseline levels. As saxatilin dose increased, time to recanalization decreased. A bolus injection of 10% of a complete dose with continuous infusion of the remaining dose for 60 minutes resulted in effective recanalization without reocclusion. The thrombolytic effect of saxatilin was also demonstrated in vitro using platelet aggregometry by administering saxatilin in preformed thrombi. Bleeding complications were observed in 2 of 71 mice that received saxatilin. Fibrin/fibrinogen zymography and platelet aggregometry studies indicated that saxatilin does not have fibrinolytic activity, but exerted its action on platelets. Integrin-binding assays showed that saxatilin inhibited multiple integrins, specifically α2bβ3 (GP IIb/IIIa), α5β1, αvβ3, αvβ1, and αvβ5, which act on platelet adhesion/aggregation. Saxatilin inhibited multiple integrins by acting on platelets, and was safe and effective in resolving thrombi in mice.
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Affiliation(s)
- Il Kwon
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Sung-Yu Hong
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Product Evaluation Center, Yonsei University College of Medicine, Seoul, Korea
| | - Young Dae Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Hyo Suk Nam
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Sungsoo Kang
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Product Evaluation Center, Yonsei University College of Medicine, Seoul, Korea
| | - Seung-Hee Yang
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Ji Hoe Heo
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
- Severance Integrative Research Institute for Cerebral and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul, Korea
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
- * E-mail:
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Tortelli F, Pisano M, Briquez PS, Martino MM, Hubbell JA. Fibronectin binding modulates CXCL11 activity and facilitates wound healing. PLoS One 2013; 8:e79610. [PMID: 24205388 PMCID: PMC3808276 DOI: 10.1371/journal.pone.0079610] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 09/24/2013] [Indexed: 11/18/2022] Open
Abstract
Engineered biomatrices offer the potential to recapitulate the regenerative microenvironment, with important implications in tissue repair. In this context, investigation of the molecular interactions occurring between growth factors, cytokines and extracellular matrix (ECM) has gained increasing interest. Here, we sought to investigate the possible interactions between the ECM proteins fibronectin (FN) and fibrinogen (Fg) with the CXCR3 ligands CXCL9, CXCL10 and CXCL11, which are expressed during wound healing. New binding interactions were observed and characterized. Heparin-binding domains within Fg (residues 15-66 of the β chain, Fg β15-66) and FN (FNI1-5, but not FNIII12-14) were involved in binding to CXCL10 and CXCL11 but not CXCL9. To investigate a possible influence of FN and Fg interactions with CXCL11 in mediating its role during re-epithelialization, we investigated human keratinocyte migration in vitro and wound healing in vivo in diabetic db/db mice. A synergistic effect on CXCL11-induced keratinocyte migration was observed when cells were treated with CXCL11 in combination with FN in a transmigration assay. Moreover, wound healing was enhanced in full thickness excisional wounds treated with fibrin matrices functionalized with FN and containing CXCL11. These findings highlight the importance of the interactions occurring between cytokines and ECM and point to design concepts to develop functional matrices for regenerative medicine.
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Affiliation(s)
- Federico Tortelli
- Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marco Pisano
- Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Priscilla S. Briquez
- Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Mikaël M. Martino
- Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jeffrey A. Hubbell
- Institute of Bioengineering, School of Life Sciences and School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- * E-mail:
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Yeung D, Chmielewski D, Mihai C, Agarwal G. Oligomerization of DDR1 ECD affects receptor-ligand binding. J Struct Biol 2013; 183:495-500. [PMID: 23810922 DOI: 10.1016/j.jsb.2013.06.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 05/15/2013] [Accepted: 06/20/2013] [Indexed: 01/22/2023]
Abstract
Discoidin domain receptor 1 (DDR1) is a widely expressed receptor tyrosine kinase (RTK) which regulates cell differentiation, proliferation and migration and remodeling of the extracellular matrix. Collagen(s) are the only known ligand for DDR1. We have previously reported that collagen stimulation leads to oligomerization of the full length receptor. In this study we investigated the effect of oligomerization of the DDR1 extracellular domain (ECD) pre and post ligand binding. Solid phase binding assays showed that oligomers of recombinant DDR1-Fc bound more strongly to collagen compared to dimeric DDR1-Fc alone. In addition, DDR1-Fc itself could oligomerize upon in-vitro binding to collagen when examined using atomic force microscopy. Inhibition of dynamin mediated receptor endocytosis could prevent ligand induced endocytosis of DDR1b-YFP in live cells. However inhibition of receptor endocytosis did not affect DDR1 oligomerization. In summary our results demonstrate that DDR1 ECD plays a crucial role in receptor oligomerization which mediates high-affinity interactions with its ligand.
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Affiliation(s)
- David Yeung
- Biomedical Engineering Department, 270 Bevis Hall, 1080 Carmack Road, The Ohio State University Columbus, OH 43210, USA
| | - David Chmielewski
- Davis Heart and Lung Research Institute, 473 West 12th Ave., Columbus, OH 43210, USA
| | - Cosmin Mihai
- Davis Heart and Lung Research Institute, 473 West 12th Ave., Columbus, OH 43210, USA
| | - Gunjan Agarwal
- Biomedical Engineering Department, 270 Bevis Hall, 1080 Carmack Road, The Ohio State University Columbus, OH 43210, USA; Davis Heart and Lung Research Institute, 473 West 12th Ave., Columbus, OH 43210, USA.
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26
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Zhang JB, Wang ZY, Chen J, Wu XD, Zhou B, Yie SM. The expression of human leukocyte antigen G (HLA-G) is associated with sacroiliitis stages of ankylosing spondylitis. Immunol Lett 2013; 152:121-5. [PMID: 23644157 DOI: 10.1016/j.imlet.2013.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 03/28/2013] [Accepted: 04/22/2013] [Indexed: 11/19/2022]
Abstract
Recent studies have demonstrated that human leukocyte antigen G (HLA-G) may play an important role in autoimmune diseases. The present study is to investigate whether or not HLA-G is associated with sacroiliitis stages of ankylosing spondylitis (AS), a systemic autoimmune disease. Plasma levels of soluble HLA-G (sHLA-G) and HLA-G expression on the surface of peripheral blood mononuclear cells (PBMCs) were measured in 55 AS patients and 49 healthy controls by using a specific HLA-G ELISA and flow cytometric (FCM) analysis, respectively. Association of HLA-G expression with sacroiliitis stages of the patients was statistically analyzed. The plasma sHLA-G concentrations were noticeably lower in the AS patients when compared to the healthy controls while the mean fluorescence intensity (MFI) of the HLA-G expression on the surface of PBMCs was significantly higher in the AS patients than in the healthy controls (both P<0.0001). The HLA-G expression on the surface of PBMCs, plasma sHLA-G levels and HLA-B27 expression were significantly correlated to each other. Moreover, the plasma sHLA-G was inversely associated with the sacroiliitis stages (P=0.008), while the HLA-G expression on the surface of PBMCs increased from stage 0 to II but decreased in stage III (P=0.001). The significant association of HLA-G expressions with AS sacroiliitis stages suggests that HLA-G is possibly involved in the pathology of the disease. The detection of HLA-G expression may therefore be a useful laboratory test to reveal disease process in AS patients.
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Affiliation(s)
- Jian-Bo Zhang
- Core Laboratory, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, PR China
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27
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Huang CC, Lee GY, Chyi JI, Cheng HT, Hsu CP, Hsu YR, Hsu CH, Huang YF, Sun YC, Chen CC, Li SS, Andrew Yeh J, Yao DJ, Ren F, Wang YL. AlGaN/GaN high electron mobility transistors for protein-peptide binding affinity study. Biosens Bioelectron 2013; 41:717-22. [PMID: 23102432 PMCID: PMC7157921 DOI: 10.1016/j.bios.2012.09.066] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/14/2012] [Accepted: 09/27/2012] [Indexed: 01/09/2023]
Abstract
Antibody-immobilized AlGaN/GaN high electron mobility transistors (HEMTs) were used to detect a short peptide consisting of 20 amino acids. One-binding-site model and two-binding-site model were used for the analysis of the electrical signals, revealing the number of binding sites on an antibody and the dissociation constants between the antibody and the short peptide. In the binding-site models, the surface coverage ratio of the short peptide on the sensor surface is relevant to the electrical signals resulted from the peptide-antibody binding on the HEMTs. Two binding sites on an antibody were observed and two dissociation constants, 4.404×10(-11) M and 1.596×10(-9) M, were extracted from the binding-site model through the analysis of the surface coverage ratio of the short peptide on the sensor surface. We have also shown that the conventional method to extract the dissociation constant from the linear regression of curve-fitting with Langmuir isotherm equation may lead to an incorrect information if the receptor has more than one binding site for the ligand. The limit of detection (LOD) of the sensor observed in the experimental result (~10 pM of the short peptide) is very close to the LOD (around 2.7-3.4 pM) predicted from the value of the smallest dissociation constants. The sensitivity of the sensor is not only dependent on the transistors, but also highly relies on the affinity of the ligand-receptor pair. The results demonstrate that the AlGaN/GaN HEMTs cannot only be used for biosensors, but also for the biological affinity study.
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Affiliation(s)
- Chih-Cheng Huang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Geng-Yen Lee
- Department of Electrical engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan, ROC
| | - Jen-Inn Chyi
- Department of Electrical engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan, ROC
| | - Hui-Teng Cheng
- Department of Nephrology, National Taiwan University Hospital, Hsinchu branch, Hsinchu 300, Taiwan, ROC
| | - Chen-Pin Hsu
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - You-Ren Hsu
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Chia-Hsien Hsu
- Division of Medical Engineering, National Health Research Institutes, MiaoLi, Taiwan, ROC
| | - Yu-Fen Huang
- Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC
| | - Yuh-Chang Sun
- Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC
| | - Chih-Chen Chen
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Sheng-Shian Li
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - J. Andrew Yeh
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Da-Jeng Yao
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
| | - Fan Ren
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Yu-Lin Wang
- Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu, 300, Taiwan, ROC
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Atmanene C, Wagner-Rousset E, Corvaïa N, Van Dorsselaer A, Beck A, Sanglier-Cianférani S. Noncovalent mass spectrometry for the characterization of antibody/antigen complexes. Methods Mol Biol 2013; 988:243-268. [PMID: 23475725 DOI: 10.1007/978-1-62703-327-5_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Monoclonal antibodies (mAbs) have taken on an increasing importance for the treatment of various diseases including cancers, immunological disorders, and other pathologies. These large biomolecules display specific structural features, which affect their efficiency and need therefore to be extensively characterized using sensitive and orthogonal analytical techniques. Among them, mass spectrometry (MS) has become the method of choice to study mAb amino acid sequences as well as their posttranslational modifications with the aim of reducing their chemistry, manufacturing, and control liabilities. This chapter will provide the reader with a description of the general approach allowing antibody/antigen systems to be characterized by noncovalent MS. In the present chapter, we describe how recent noncovalent MS technologies are used to characterize immune complexes involving both murine and humanized mAb 6F4 directed against human JAM-A, a newly identified antigenic protein (Ag) over-expressed in tumor cells. We will detail experimental conditions (sample preparation, optimization of instrumental parameters, etc.) required for the detection of noncovalent antibody/antigen complexes by MS. We will then focus on the type and the reliability of the information that we get from noncovalent MS data, with emphasis on the determination of the stoichiometry of antibody/antigen systems. Noncovalent MS appears as an additional supporting technique for therapeutic mAbs lead characterization and development.
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Affiliation(s)
- Cédric Atmanene
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, CNRS, UMR7178, Université de Strasbourg, Strasbourg, France
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29
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Mislovičová D, Katrlík J, Paulovičová E, Gemeiner P, Tkac J. Comparison of three distinct ELLA protocols for determination of apparent affinity constants between Con A and glycoproteins. Colloids Surf B Biointerfaces 2012; 94:163-9. [DOI: 10.1016/j.colsurfb.2012.01.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/22/2011] [Accepted: 01/23/2012] [Indexed: 11/28/2022]
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30
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Cao M, Yie SM, Liu J, Ye SR, Xia D, Gao E. Plasma soluble HLA-G is a potential biomarker for diagnosis of colorectal, gastric, esophageal and lung cancer. ACTA ACUST UNITED AC 2012; 78:120-8. [PMID: 21726203 DOI: 10.1111/j.1399-0039.2011.01716.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human leukocyte antigen-G (HLA-G) is a novel tumor marker and its soluble isoforms produce secretory proteins. Increased soluble HLA-G (sHLA-G) levels have been reported in patients with melanoma, neuroblastoma, lymphoproliferative disorders, breast, ovarian and colorectal carcinoma when compared to healthy controls or subjects with benign neoplasms. The aim of this study is to investigate whether or not plasma sHLA-G can be used as a potential biomarker for cancer diagnosis. We measured plasma sHLA-G levels in 166 patients with early stages of colorectal cancer (CRC, n = 37), gastric cancer (GC, n = 28), esophageal squamous cell carcinoma (ESCC, n = 58) and non-small cell lung cancer (NSCLC, n = 43), and compared them to healthy controls (n = 260) by using a specific HLA-G enzyme-linked immunosorbent assay (ELISA). We found that plasma sHLA-G levels were significantly higher in cancer patients than in healthy controls (all P < 0.0001). The areas under the receiver-operating characteristic (ROC) curves for sHLA-G were 0.97, 0.91, 0.98 and 0.80 for healthy controls vs CRC, GC, ESCC and NSCLC, respectively. At 100% specificity, the highest sensitivity achieved to detect CRC, GC, ESCC and NSCLC was 94% [95% confidence interval (CI), 89-99], 85% (95% CI, 76-94), 91% (95% CI, 88-94) and 51% (95% CI, 43-59) at a cutoff value of 49 U/ml, respectively. These findings suggest that plasma sHLA-G may be a useful molecule in the differential diagnosis of these malignancies against healthy controls.
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Affiliation(s)
- M Cao
- Core Laboratory, Sichuan Academy of Medical Sciences, Chengdu, Sichuan, PR China
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31
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Wuellner U, Gavrilyuk JI, Barbas CF. Expanding the concept of chemically programmable antibodies to RNA aptamers: chemically programmed biotherapeutics. Angew Chem Int Ed Engl 2010; 49:5934-7. [PMID: 20645365 DOI: 10.1002/anie.201001736] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Ulrich Wuellner
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Dragusanu M, Petre BA, Slamnoiu S, Vlad C, Tu T, Przybylski M. On-line bioaffinity-electrospray mass spectrometry for simultaneous detection, identification, and quantification of protein-ligand interactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:1643-1648. [PMID: 20692851 DOI: 10.1016/j.jasms.2010.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 06/18/2010] [Accepted: 06/18/2010] [Indexed: 05/29/2023]
Abstract
We describe here an on-line combination of a surface acoustic wave (SAW) biosensor with electrospray ionization mass spectrometry (SAW-ESI-MS) that enables the direct detection, identification, and quantification of affinity-bound ligands from a protein-ligand complex on a biosensor chip. A trapping column was used between the SAW-biosensor and the electrospray mass spectrometer equipped with a micro-guard column, which provides simultaneous sample concentration and desalting for the mass spectrometric analysis of the dissociated ligand. First applications of the on-line SAW-ESI-MS combination include (1), differentiation of β-amyloid (Aβ) epitope peptides bound to anti-Aβ antibodies; (2), the identification of immobilized Substance P peptide-calmodulin complex; (3), identification and quantification of the interaction of 3-nitrotyrosine-modified peptides with nitrotyrosine-specific antibodies; and (4), identification of immobilized anti-α-synuclein-human α-synuclein complex. Quantitative determinations of protein-ligand complexes by SAW yielded dissociation constants (K(D)) from micro-to low nanomolar sample concentrations. The on-line bioaffinity-ESI-MS combination presented here is expected to enable broad bioanalytical application to the simultaneous, label-free determination and quantification of biopolymer-ligand interactions, as diverse as antigen-antibody and lectin-carbohydrate complexes.
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Affiliation(s)
- Mihaela Dragusanu
- Laboratory of Analytical Chemistry and Biopolymer Structure Analysis, Department of Chemistry, University of Konstanz, Konstanz, Germany
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33
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Wuellner U, Gavrilyuk J, Barbas C. Expanding the Concept of Chemically Programmable Antibodies to RNA Aptamers: Chemically Programmed Biotherapeutics. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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34
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Liu F, Dubey M, Takahashi H, Castner DG, Grainger DW. Immobilized antibody orientation analysis using secondary ion mass spectrometry and fluorescence imaging of affinity-generated patterns. Anal Chem 2010; 82:2947-58. [PMID: 20230047 PMCID: PMC2854834 DOI: 10.1021/ac902964q] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study assesses the capability of high-resolution surface analytical tools to distinguish immobilized antibody orientations on patterned surfaces designed for antibody affinity capture. High-fidelity, side-by-side copatterning of protein A (antibody Fc domain affinity reagent) and fluorescein (antibody Fab domain hapten) was achieved photolithographically on commercial amine-reactive hydrogel polymer surfaces. This was verified from fluorescence imaging using fluorescently labeled protein A and intrinsic fluorescence from fluorescein. Subsequently, dye-labeled murine antifluorescein antibody (4-4-20) and antibody Fab and Fc fragments were immobilized from solution onto respective protein A- and fluorescein- copatterned or control surfaces using antibody-ligand affinity interactions. Fluorescence assays support specific immobilization to fluorescein hapten- and protein A-patterned regions through antigen-antibody recognition and natural protein A-Fc domain interactions, respectively. Affinity-based antibody immobilization on the two different copatterned surfaces generated side-by-side full antibody "heads-up" and "tails-up" oriented surface patterns. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis, sensitive to chemical information from the top 2 to 3 nm of the surface, provided ion-specific images of these antibody patterned regions, imaging and distinguishing characteristic ions from amino acids enriched in Fab domains for antibodies oriented in "heads-up" regions, and ions from amino acids enriched in Fc domains for antibodies oriented in "tails-up" regions. Principal component analysis (PCA) improved the distinct TOF-SIMS amino acid compositional and ion-specific surface mapping sensitivity for each "heads-up" versus "tails-up" patterned region. Characteristic Fab and Fc fragment immobilized patterns served as controls. This provides first demonstration of pattern-specific, antibody orientation-dependent surface maps based on antibody domain- and structure-specific compositional differences by TOF-SIMS analysis. Since antibody immobilization and orientation are critical to many technologies, orientation characterization using TOF-SIMS could be very useful and convenient for immobilization quality control and understanding methods for improving the performance of antibody-based surface capture assays.
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Affiliation(s)
- Fang Liu
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112-5820 USA
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Manish Dubey
- Department of Chemical Engineering, Box 351750, University of Washington, Seattle, WA 98195-1750 USA
- National ESCA and Surface Analysis Center for Biomedical Problems, University of Washington, Seattle, WA 98195-1750 USA
| | - Hironobu Takahashi
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112-5820 USA
| | - David G. Castner
- Department of Chemical Engineering, Box 351750, University of Washington, Seattle, WA 98195-1750 USA
- Department of Bioengineering, Box 351750, University of Washington, Seattle, WA 98195-1750 USA
- National ESCA and Surface Analysis Center for Biomedical Problems, University of Washington, Seattle, WA 98195-1750 USA
| | - David W. Grainger
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112-5820 USA
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112-5820 USA
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35
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Atmanene C, Wagner-Rousset E, Malissard M, Chol B, Robert A, Corvaïa N, Dorsselaer AV, Beck A, Sanglier-Cianférani S. Extending Mass Spectrometry Contribution to Therapeutic Monoclonal Antibody Lead Optimization: Characterization of Immune Complexes Using Noncovalent ESI-MS. Anal Chem 2009; 81:6364-73. [DOI: 10.1021/ac9007557] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Cédric Atmanene
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Elsa Wagner-Rousset
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Martine Malissard
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Bertrand Chol
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Alain Robert
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Nathalie Corvaïa
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Alain Van Dorsselaer
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Alain Beck
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
| | - Sarah- Sanglier-Cianférani
- Laboratoire de Spectrométrie de Masse BioOrganique
(LSMBO), IPHC-DSA, University of Strasbourg UDS,CNRS, UMR7178; 25
rue Becquerel, 67087 Strasbourg, France, and Centre d’Immunologie
Pierre-Fabre (CIPF), 5 Av. Napoléon III, BP 60497, 74164 Saint-Julien-En-Genevois,
France
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Perelberg A, Ilouze M, Kotler M, Steinitz M. Antibody response and resistance of Cyprinus carpio immunized with cyprinid herpes virus 3 (CyHV-3). Vaccine 2008; 26:3750-6. [DOI: 10.1016/j.vaccine.2008.04.057] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 04/08/2008] [Accepted: 04/15/2008] [Indexed: 10/22/2022]
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Kobayashi N, Ohtoyo M, Wada E, Kato Y, Mano N, Goto J. Generation of a single-chain Fv fragment for the monitoring of deoxycholic acid residues anchored on endogenous proteins. Steroids 2005; 70:285-94. [PMID: 15784283 DOI: 10.1016/j.steroids.2004.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Revised: 11/15/2004] [Accepted: 11/19/2004] [Indexed: 11/20/2022]
Abstract
A subset of lipophillic bile acids, including deoxycholic acid (DCA) and lithocholic acid (LCA), are thought to be biologically transformed into reactive intermediates forming covalently modified, "tissue-bound" bile acids that can exert several toxic effects. We have generated a single-chain Fv fragment (scFv) as a probe to monitor DCA residues anchored on proteins. DNA fragments encoding the variable heavy (V(H)) and light (V(L)) domains of a mouse antibody raised against a DCA hapten (Ab #88) were cloned by rapid amplification of cDNA 5'-ends. These sequences were combined via a common linker sequence coding (Gly(4)Ser)(3) to construct a single scFv gene with the gene segments in the following order: 5'-V(H)-linker-V(L)-3'. This construct was subcloned into an antibody-expression vector, pEXmide 5; soluble scFv protein was then expressed in the bacterial periplasm of the XLOLR Escherichia coli strain. In a competitive enzyme-linked immunosorbent assay using DCA-coated microtiter plates, the scFv provided a dose-response curve for free DCA ranging between 2 and 5000 pg/assay. The scFv reacts similarly with the l-lysine adduct of DCA (cross-reactivity, 72%), while bile acids having a modified DCA steroid skeleton were well-discriminated (cross-reactivity, <1%). This scFv could also monitor trace amounts of DCA residues anchored on a protein through DCA acyl adenylate reactions, the likely reactive intermediate. The present scFv may be a useful tool for trace characterization of tissue-bound bile acids; this usefulness may be significantly enhanced by fusion with signal-generating proteins, such as alkaline phosphatase or green fluorescent protein.
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Affiliation(s)
- Norihiro Kobayashi
- Kobe Pharmaceutical University, 4-19-1, Motoyama-Kitamachi, Higashinada-ku, Kobe 658-8558, Japan
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Lakio L, Paju S, Alfthan G, Tiirola T, Asikainen S, Pussinen PJ. Actinobacillus actinomycetemcomitans serotype d-specific antigen contains the O antigen of lipopolysaccharide. Infect Immun 2003; 71:5005-11. [PMID: 12933843 PMCID: PMC187330 DOI: 10.1128/iai.71.9.5005-5011.2003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2003] [Revised: 04/15/2003] [Accepted: 06/11/2003] [Indexed: 11/20/2022] Open
Abstract
Actinobacillus actinomycetemcomitans is a gram-negative, facultatively anaerobic bacterium which is associated especially with aggressive forms of periodontitis. Contradictory results on the localization of the A. actinomycetemcomitans serotype-specific antigen have been reported. The aim of the present study was to characterize the A. actinomycetemcomitans serotype d-specific antigen. The antigen was isolated by affinity chromatography. The affinity column was prepared from immunoglobulin G isolated from rabbit antiserum raised against A. actinomycetemcomitans serotype d. The isolated antigen was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and silver staining, all of which revealed a ladder-like structure typical for the O antigen of lipopolysaccharide (LPS). In a displacement enzyme-linked immunosorbent assay (ELISA), the isolated antigen displaced in a concentration-dependent manner the binding of the polyclonal rabbit antiserum raised against A. actinomycetemcomitans serotype d to the competing whole-cell serotype d antigen. The isolated antigen contained LPS, and an equal concentration of LPS isolated from A. actinomycetemcomitans serotype d gave a similar displacement curve in the ELISA. In order to test the immunogenic properties of the isolated antigen, it was used to immunize a rabbit. The antiserum raised against the isolated antigen displayed specificity in Western blotting and ELISA similar to that of antibody raised against LPS isolated from A. actinomycetemcomitans serotype d. In conclusion, our results show that the A. actinomycetemcomitans serotype d-specific antigen contains the O-antigenic structure of LPS.
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Affiliation(s)
- Laura Lakio
- Institute of Dentistry, University of Helsinki, and Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Finland.
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