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Bongrand P. Is There a Need for a More Precise Description of Biomolecule Interactions to Understand Cell Function? Curr Issues Mol Biol 2022; 44:505-525. [PMID: 35723321 PMCID: PMC8929073 DOI: 10.3390/cimb44020035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 11/16/2022] Open
Abstract
An important goal of biological research is to explain and hopefully predict cell behavior from the molecular properties of cellular components. Accordingly, much work was done to build extensive “omic” datasets and develop theoretical methods, including computer simulation and network analysis to process as quantitatively as possible the parameters contained in these resources. Furthermore, substantial effort was made to standardize data presentation and make experimental results accessible to data scientists. However, the power and complexity of current experimental and theoretical tools make it more and more difficult to assess the capacity of gathered parameters to support optimal progress in our understanding of cell function. The purpose of this review is to focus on biomolecule interactions, the interactome, as a specific and important example, and examine the limitations of the explanatory and predictive power of parameters that are considered as suitable descriptors of molecular interactions. Recent experimental studies on important cell functions, such as adhesion and processing of environmental cues for decision-making, support the suggestion that it should be rewarding to complement standard binding properties such as affinity and kinetic constants, or even force dependence, with less frequently used parameters such as conformational flexibility or size of binding molecules.
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Puech PH, Bongrand P. Mechanotransduction as a major driver of cell behaviour: mechanisms, and relevance to cell organization and future research. Open Biol 2021; 11:210256. [PMID: 34753321 PMCID: PMC8586914 DOI: 10.1098/rsob.210256] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
How do cells process environmental cues to make decisions? This simple question is still generating much experimental and theoretical work, at the border of physics, chemistry and biology, with strong implications in medicine. The purpose of mechanobiology is to understand how biochemical and physical cues are turned into signals through mechanotransduction. Here, we review recent evidence showing that (i) mechanotransduction plays a major role in triggering signalling cascades following cell-neighbourhood interaction; (ii) the cell capacity to continually generate forces, and biomolecule properties to undergo conformational changes in response to piconewton forces, provide a molecular basis for understanding mechanotransduction; and (iii) mechanotransduction shapes the guidance cues retrieved by living cells and the information flow they generate. This includes the temporal and spatial properties of intracellular signalling cascades. In conclusion, it is suggested that the described concepts may provide guidelines to define experimentally accessible parameters to describe cell structure and dynamics, as a prerequisite to take advantage of recent progress in high-throughput data gathering, computer simulation and artificial intelligence, in order to build a workable, hopefully predictive, account of cell signalling networks.
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Bertin D, Mouhajir Y, Bongrand P, Bardin N. ICARE improves antinuclear antibody detection by overcoming the barriers preventing accreditation. Clin Chim Acta 2016; 454:57-61. [PMID: 26742604 DOI: 10.1016/j.cca.2015.12.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 12/28/2015] [Accepted: 12/28/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Antinuclear antibodies (ANA) are useful biomarkers for the diagnosis and the monitoring of rheumatic diseases. The American College of Rheumatology has stated that indirect immunofluorescence (IIF) analysis remains the gold standard for ANA screening. However, IIF is time consuming, subjective, not fully standardized and presents several issues for accreditation which is the process leading to ISO 15189 certification for medical laboratories. We propose an innovative tool for accreditation by using the quantitative evaluation of the automated image capture and analysis "ICARE" (Immunofluorescence for Computed Antinuclear antibody Rational Evaluation). METHODS We established the optimal screening dilution (1:160) and a fluorescence index (FI) cutoff for ICARE on a cohort of 91 healthy blood donors. Then, we evaluated performance of ICARE on a routine cohort of 236 patients. Precision parameters of ANA detection by IIF were evaluated according to ISO 15189. RESULTS ICARE showed an excellent concordance with visual evaluation (88%, Kappa=0.76) and significantly discriminated between weak to moderate (1:160-1:320 titers) and high (>1:320 titers) ANA levels. A significant correlation was found between FI and ANA titers (Spearman's ρ=0.67; P<0.0001). Using ICARE, we reported precision parameters such as repeatability (CV<13.8%) and reproducibility (CV<13.1%) as well as absence of inter-sample contamination for ANA detection by IIF according to ISO 15189 standards. CONCLUSIONS ICARE offers a precious help for the accreditation of IIF qualitative methods. This innovative quantitative approach is in adequacy with the process of continuous improvement of the quality of clinical laboratories.
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Preira P, Forel JM, Robert P, Nègre P, Biarnes-Pelicot M, Xeridat F, Bongrand P, Papazian L, Theodoly O. The leukocyte-stiffening property of plasma in early acute respiratory distress syndrome (ARDS) revealed by a microfluidic single-cell study: the role of cytokines and protection with antibodies. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2016; 20:8. [PMID: 26757701 PMCID: PMC4711060 DOI: 10.1186/s13054-015-1157-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 12/06/2015] [Indexed: 12/19/2022]
Abstract
Background Leukocyte-mediated pulmonary inflammation is a key pathophysiological mechanism involved in acute respiratory distress syndrome (ARDS). Massive sequestration of leukocytes in the pulmonary microvasculature is a major triggering event of the syndrome. We therefore investigated the potential role of leukocyte stiffness and adhesiveness in the sequestration of leukocytes in microvessels. Methods This study was based on in vitro microfluidic assays using patient sera. Cell stiffness was assessed by measuring the entry time (ET) of a single cell into a microchannel with a 6 × 9–μm cross-section under a constant pressure drop (ΔP = 160 Pa). Primary neutrophils and monocytes, as well as the monocytic THP-1 cell line, were used. Cellular adhesiveness to human umbilical vein endothelial cells was examined using the laminar flow chamber method. We compared the properties of cells incubated with the sera of healthy volunteers (n = 5), patients presenting with acute cardiogenic pulmonary edema (ACPE; n = 6), and patients with ARDS (n = 22), of whom 13 were classified as having moderate to severe disease and the remaining 9 as having mild disease. Results Rapid and strong stiffening of primary neutrophils and monocytes was induced within 30 minutes (mean ET >50 seconds) by sera from the ARDS group compared with both the healthy subjects and the ACPE groups (mean ET <1 second) (p < 0.05). Systematic measurements with the THP-1 cell line allowed for the establishment of a strong correlation between stiffening and the severity of respiratory status (mean ET 0.82 ± 0.08 seconds for healthy subjects, 1.6 ± 1.0 seconds for ACPE groups, 10.5 ± 6.1 seconds for mild ARDS, and 20.0 ± 8.1 seconds for moderate to severe ARDS; p < 0.05). Stiffening correlated with the cytokines interleukin IL-1β, IL-8, tumor necrosis factor TNF-α, and IL-10 but not with interferon-γ, transforming growth factor-β, IL-6, or IL-17. Strong stiffening was induced by IL-1β, IL-8, and TNF-α but not by IL-10, and incubations with sera and blocking antibodies against IL-1β, IL-8, or TNF-α significantly diminished the stiffening effect of serum. In contrast, the measurements of integrin expression (CD11b, CD11a, CD18, CD49d) and leukocyte–endothelium adhesion showed a weak and slow response after incubation with the sera of patients with ARDS (several hours), suggesting a lesser role of leukocyte adhesiveness compared with leukocyte stiffness in early ARDS. Conclusions The leukocyte stiffening induced by cytokines in the sera of patients might play a role in the sequestration of leukocytes in the lung capillary beds during early ARDS. The inhibition of leukocyte stiffening with blocking antibodies might inspire future therapeutic strategies. Electronic supplementary material The online version of this article (doi:10.1186/s13054-015-1157-5) contains supplementary material, which is available to authorized users.
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Malissen B, Bongrand P. Early T cell activation: integrating biochemical, structural, and biophysical cues. Annu Rev Immunol 2015; 33:539-61. [PMID: 25861978 DOI: 10.1146/annurev-immunol-032414-112158] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
T cells carry out the formidable task of identifying small numbers of foreign antigenic peptides rapidly and specifically against a very noisy environmental background of endogenous self-peptides. Early steps in T cell activation have thus fascinated biologists and are among the best-studied models of cell stimulation. This remarkable process, critical in adaptive immune responses, approaches and even seems to exceed the limitations set by the physical laws ruling molecular behavior. Despite the enormous amount of information concerning the nature of molecules involved in the T cell antigen receptor (TCR) signal transduction network, and the description of the nanoscale organization and real-time analysis of T cell responses, the general principles of information gathering and processing remain incompletely understood. Here we review currently accepted key data on TCR function, discuss the limitations of current research strategies, and suggest a novel model of TCR triggering and a few promising ways of going further into the integration of available data.
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Cazaux S, Sadoun A, Biarnes-Pelicot M, Martinez M, Obeid S, Bongrand P, Limozin L, Puech PH. Synchronizing atomic force microscopy force mode and fluorescence microscopy in real time for immune cell stimulation and activation studies. Ultramicroscopy 2015; 160:168-181. [PMID: 26521163 DOI: 10.1016/j.ultramic.2015.10.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 09/17/2015] [Accepted: 10/12/2015] [Indexed: 11/24/2022]
Abstract
A method is presented for combining atomic force microscopy (AFM) force mode and fluorescence microscopy in order to (a) mechanically stimulate immune cells while recording the subsequent activation under the form of calcium pulses, and (b) observe the mechanical response of a cell upon photoactivation of a small G protein, namely Rac. Using commercial set-ups and a robust signal coupling the fluorescence excitation light and the cantilever bending, the applied force and activation signals were very easily synchronized. This approach allows to control the entire mechanical history of a single cell up to its activation and response down to a few hundreds of milliseconds, and can be extended with very minimal adaptations to other cellular systems where mechanotransduction is studied, using either purely mechanical stimuli or via a surface bound specific ligand.
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Brodovitch A, Shenderov E, Cerundolo V, Bongrand P, Pierres A, van der Merwe PA. T lymphocytes need less than 3 min to discriminate between peptide MHCs with similar TCR-binding parameters. Eur J Immunol 2015; 45:1635-42. [PMID: 25782169 PMCID: PMC4657482 DOI: 10.1002/eji.201445214] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 02/17/2015] [Accepted: 03/13/2015] [Indexed: 11/10/2022]
Abstract
T lymphocytes need to detect rare cognate foreign peptides among numerous foreign and self-peptides. This discrimination seems to be based on the kinetics of TCRs binding to their peptide-MHC (pMHC) ligands, but there is little direct information on the minimum time required for processing elementary signaling events and deciding to initiate activation. Here, we used interference reflection microscopy to study the early interaction between transfected human Jurkat T cells expressing the 1G4 TCR and surfaces coated with five different pMHC ligands of 1G4. The pMHC concentration required for inducing 50% maximal IFN-γ production by T cells, and 1G4-pMHC dissociation rates measured in soluble phase or on surface-bound molecules, displayed six- to sevenfold variation among pMHCs. When T cells were dropped onto pMHC-coated surfaces, rapid spreading occurred after a 2-min lag. The initial spreading rate measured during the first 45 s, and the contact area, were strongly dependent on the encountered TCR ligand. However, the lag duration did not significantly depend on encountered ligand. In addition, spreading appeared to be an all-or-none process, and the fraction of spreading cells was tightly correlated to the spreading rate and spreading area. Thus, T cells can discriminate between fairly similar TCR ligands within 2 min.
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Agabriel C, Ghazouani O, Birnbaum J, Liabeuf V, Porri F, Gouitaa M, Cleach I, Grob JJ, Bongrand P, Sarles J, Vitte J. Ara h 2 and Ara h 6 sensitization predicts peanut allergy in Mediterranean pediatric patients. Pediatr Allergy Immunol 2014; 25:662-7. [PMID: 25376086 DOI: 10.1111/pai.12299] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/03/2014] [Indexed: 01/03/2023]
Abstract
BACKGROUND Peanut allergy (PA) management was improved by the introduction of molecular allergology, but guidelines for Mediterranean patients are lacking. We aimed at evaluating peanut component-resolved diagnosis as a diagnostic and prognostic tool in children from Southern France. METHODS In 181 pediatric patients, PA diagnosis was founded on medical history, skin prick testing, serum-specific IgE to Arachis hypogea extract and components, Pru p 4, and plant carbohydrates, and oral food challenge. Allergen microarray was also performed in 68 of these patients. RESULTS In peanut-allergic children (n = 117), IgE to Ara h 6 were most prevalent (64%), followed by Ara h 2 (63%), Ara h 1 (60%), and Ara h 9 (52%). Ara h 6 was the best predictor of PA. The second best predictor was the ratio of Ara h 2 IgE to peanut IgE (cutoff 0.113). Persistent childhood PA was associated with complex molecular profiles. Comparison of singleplex and microarray results showed poor concordance for Ara h 2 and Ara h 9. CONCLUSION Ara h 6 and Ara h 2 are the best predictors of PA at diagnosis in Mediterranean pediatric patients. Ara h 1, Ara h 8, and molecular complexity are associated with PA persistence.
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Brodovitch A, Limozin L, Bongrand P, Pierres A. Use of TIRF to Monitor T-Lymphocyte Membrane Dynamics with Submicrometer and Subsecond Resolution. Cell Mol Bioeng 2014; 8:178-186. [PMID: 25798205 PMCID: PMC4361759 DOI: 10.1007/s12195-014-0361-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 10/04/2014] [Indexed: 11/29/2022] Open
Abstract
A key step of adaptive immune responses is the T lymphocyte capacity to detect the presence of foreign antigens on specialized cells with high speed and specificity during contacts lasting a few minutes. Much evidence suggests that there is a deep link between the lifetime of molecular interactions between T cell receptors and ligands and T cell activation, but the precise mechanisms of bond formation and dissociation remain incompletely understood. Previous experiments done with interference reflection microscopy/reflection interference contrast microscopy disclosed transverse motions with several nanometer average amplitude of micrometer size membrane zones. More recently, total internal reflection fluorescence microscopy was used to show that the initial interaction between primary T lymphocytes and model surfaces involved the tip of microvilli (typically 0.2 µm2 area) generating apparent contacts of a few seconds that allowed cells to detect ligands of their membrane receptors. Here we show that these microvilli displayed minimal lateral displacements but quantitative fluorescence measurement suggested the occurrence of spontaneous transverse fluctuations of order of 67 nm amplitude during 1-s observation periods. This may play a major role in membrane receptor engagement and ensuing signal generation.
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Bégin P, Vitte J, Paradis L, Paradis J, Bongrand P, Chanez P, Des Roches A. Long-term prognostic value of component-resolved diagnosis in infants and toddlers with peanut allergy. Pediatr Allergy Immunol 2014; 25:506-8. [PMID: 24641729 DOI: 10.1111/pai.12216] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Vitte J, Agabriel C, Liabeuf V, Cleach I, Grob JJ, Sarles JJ, Bongrand P. Sequential allergen microarray testing during the follow-up of allergic patients. Clin Transl Allergy 2014. [PMCID: PMC4072171 DOI: 10.1186/2045-7022-4-s2-p48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Despierres L, Beziane A, Kaplanski G, Granel B, Serratrice J, Cohen W, Bretelle F, Rossi P, Morange PE, Weiller PJ, Robert Harlé J, Bongrand P, Bardin N. Contribution of anti-β2glycoprotein I IgA antibodies to the diagnosis of anti-phospholipid syndrome: potential interest of target domains to discriminate thrombotic and non-thrombotic patients. Rheumatology (Oxford) 2014; 53:1215-8. [DOI: 10.1093/rheumatology/keu003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Brodovitch A, Bongrand P, Pierres A. T lymphocytes sense antigens within seconds and make a decision within one minute. THE JOURNAL OF IMMUNOLOGY 2013; 191:2064-71. [PMID: 23898039 DOI: 10.4049/jimmunol.1300523] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Adaptive immune responses are triggered by the rapid and sensitive detection of MHC-bound peptides by TCRs. The kinetics of early TCR/APC contacts are incompletely known. In this study, we used total internal reflection fluorescence microscopy to image human T cell membranes near model surfaces: contact was mediated by mobile protrusions of <0.4 μm diameter. The mean lifetime of contacts with a neutral surface was 8.6 s. Adhesive interactions increased mean contact time to 27.6 s. Additional presence of TCR ligands dramatically decreased contact to 13.7 s, thus evidencing TCR-mediated triggering of a pulling motion within seconds after ligand encounter. After an interaction typically involving 30-40 contacts formed during a 1-min observation period, TCR stimulation triggered a rapid and active cell spreading. Pulling events and cell spreading were mimicked by pharmacological phospholipase Cγ1 activation, and they were prevented by phospholipase Cγ1 inhibition. These results provide a quantitative basis for elucidating the earliest cell response to the detection of foreign Ags.
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Vitte J, Bongrand P. Serum tryptase determination in patients with acute allergic reactions. J Allergy Clin Immunol 2013; 131:1714. [DOI: 10.1016/j.jaci.2013.03.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 03/13/2013] [Indexed: 10/26/2022]
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Robert P, Touchard D, Bongrand P, Pierres A. Biophysical description of multiple events contributing blood leukocyte arrest on endothelium. Front Immunol 2013; 4:108. [PMID: 23750158 PMCID: PMC3654224 DOI: 10.3389/fimmu.2013.00108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/26/2013] [Indexed: 12/16/2022] Open
Abstract
Blood leukocytes have a remarkable capacity to bind to and stop on specific blood vessel areas. Many studies have disclosed a key role of integrin structural changes following the interaction of rolling leukocytes with surface-bound chemoattractants. However, the functional significance of structural data and mechanisms of cell arrest are incompletely understood. Recent experiments revealed the unexpected complexity of several key steps of cell-surface interaction: (i) ligand-receptor binding requires a minimum amount of time to proceed and this is influenced by forces. (ii) Also, molecular interactions at interfaces are not fully accounted for by the interaction properties of soluble molecules. (iii) Cell arrest depends on nanoscale topography and mechanical properties of the cell membrane, and these properties are highly dynamic. Here, we summarize these results and we discuss their relevance to recent functional studies of integrin-receptor association in cells from a patient with type III leukocyte adhesion deficiency. It is concluded that an accurate understanding of all physical events listed in this review is needed to unravel the precise role of the multiple molecules and biochemical pathway involved in arrest triggering.
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Million M, Walter G, Bardin N, Camoin L, Giorgi R, Bongrand P, Gouriet F, Casalta JP, Thuny F, Habib G, Raoult D. Immunoglobulin G Anticardiolipin Antibodies and Progression to Q Fever Endocarditis. Clin Infect Dis 2013; 57:57-64. [DOI: 10.1093/cid/cit191] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Bronnert M, Mancini J, Birnbaum J, Agabriel C, Liabeuf V, Porri F, Cleach I, Fabre A, Deneux I, Grandné V, Grob JJ, Berbis P, Charpin D, Bongrand P, Vitte J. Component-resolved diagnosis with commercially available D. pteronyssinus Der p 1, Der p 2 and Der p 10: relevant markers for house dust mite allergy. Clin Exp Allergy 2013; 42:1406-15). [PMID: 22747483 DOI: 10.1111/j.1365-2222.2012.04035.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To establish the prevalence and serum levels of IgE to commercial Der p 1, Der p 2, Der p 10 and the carbohydrate MUXF3 in house dust-mite allergic patients. To compare individual vs. allergen microarray methods. METHODS Prevalence and serum levels of IgE to Dermatophagoides pteronyssinus extract and components Der p 1, Der p 2, Der p 10 and MUXF3, specific IgG4 to D. pteronyssinus, total serum IgE levels, and clinical features (age, asthma, rhinitis and atopic dermatitis) were determined in 123 patients (64 children) with the ImmunoCAP® method. ImmunoCAP ISAC® was performed in 24 patients. RESULTS All patients had serum IgE to D. pteronyssinus. Prevalences of serum IgE to commercial components were Der p 1 93%, Der p 2 77% (Der p 1 or Der p 2 94%), Der p 10 28% and MUXF3 25%. Levels of D. pteronyssinus IgE strongly correlated with Der p 1 and Der p 2 IgE (r = 0.89 and 0.85 respectively), but not Der p 10 and MUXF3. ImmunoCAP® and ImmunoCAP ISAC® were concordant, but the quantitative correlation was poor. No clinical implication for the prevalence, levels, or molecular IgE reactivity profile to house dust mite components was found. CONCLUSIONS AND CLINICAL RELEVANCE Commercially available Der p 1 and Der p 2 strongly correlate with IgE D. pteronyssinus. The lack of Der p 1 and Der p 2 IgE may help with differential diagnosis. Der p 10 serum IgE prevalence and levels suggest different patterns in food and mite-related tropomyosin sensitization. Serum IgE to carbohydrate MUXF3, although unexpectedly prevalent, were low and did not modify D. pteronyssinus IgE levels. Follow-up may be best carried out with individual rather than microarrayed components.
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Crétel⁎ E, Pierres A, Bongrand P, Robert P, Loundou A, Baumstarck-Barrau K, Villani P, Bonin-Guillaume S. Immunosenescence study in old polypathological patients. J Geriatr Oncol 2012. [DOI: 10.1016/j.jgo.2012.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Lo Schiavo V, Robert P, Limozin L, Bongrand P. Quantitative modeling assesses the contribution of bond strengthening, rebinding and force sharing to the avidity of biomolecule interactions. PLoS One 2012; 7:e44070. [PMID: 23024747 PMCID: PMC3443103 DOI: 10.1371/journal.pone.0044070] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 07/30/2012] [Indexed: 12/23/2022] Open
Abstract
Cell adhesion is mediated by numerous membrane receptors. It is desirable to derive the outcome of a cell-surface encounter from the molecular properties of interacting receptors and ligands. However, conventional parameters such as affinity or kinetic constants are often insufficient to account for receptor efficiency. Avidity is a qualitative concept frequently used to describe biomolecule interactions: this includes incompletely defined properties such as the capacity to form multivalent attachments. The aim of this study is to produce a working description of monovalent attachments formed by a model system, then to measure and interpret the behavior of divalent attachments under force. We investigated attachments between antibody-coated microspheres and surfaces coated with sparse monomeric or dimeric ligands. When bonds were subjected to a pulling force, they exhibited both a force-dependent dissociation consistent with Bell’s empirical formula and a force- and time-dependent strengthening well described by a single parameter. Divalent attachments were stronger and less dependent on forces than monovalent ones. The proportion of divalent attachments resisting a force of 30 piconewtons for at least 5 s was 3.7 fold higher than that of monovalent attachments. Quantitative modeling showed that this required rebinding, i.e. additional bond formation between surfaces linked by divalent receptors forming only one bond. Further, experimental data were compatible with but did not require stress sharing between bonds within divalent attachments. Thus many ligand-receptor interactions do not behave as single-step reactions in the millisecond to second timescale. Rather, they exhibit progressive stabilization. This explains the high efficiency of multimerized or clustered receptors even when bonds are only subjected to moderate forces. Our approach provides a quantitative way of relating binding avidity to measurable parameters including bond maturation, rebinding and force sharing, provided these parameters have been determined. Also, this provides a quantitative description of the phenomenon of bond strengthening.
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Thakur S, Massou S, Benoliel AM, Bongrand P, Hanbucken M, Sengupta K. Depth matters: cells grown on nano-porous anodic alumina respond to pore depth. NANOTECHNOLOGY 2012; 23:255101. [PMID: 22652407 DOI: 10.1088/0957-4484/23/25/255101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Recent experiments have shown unambiguously that living cells respond to the nano-topography of surfaces they grow on-specifically, the fate of stem cells grown on nano-porous titania or alumina have been shown to be decided by the pore size. However, most experiments have focused on pore size or pitch. Here we show that in addition to pore size and pitch, the depth of the pores has a profound effect on cell morphology and the arrangement of the actin cytoskeleton.
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Robert P, Aleksic M, Dushek O, Cerundolo V, Bongrand P, van der Merwe PA. Kinetics and mechanics of two-dimensional interactions between T cell receptors and different activating ligands. Biophys J 2012; 102:248-57. [PMID: 22339861 DOI: 10.1016/j.bpj.2011.11.4018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/14/2011] [Accepted: 11/17/2011] [Indexed: 12/22/2022] Open
Abstract
Adaptive immune responses are driven by interactions between T cell antigen receptors (TCRs) and complexes of peptide antigens (p) bound to Major Histocompatibility Complex proteins (MHC) on the surface of antigen-presenting cells. Many experiments support the hypothesis that T cell response is quantitatively and qualitatively dependent on the so-called strength of TCR/pMHC association. Most available data are correlations between binding parameters measured in solution (three-dimensional) and pMHC activation potency, suggesting that full lymphocyte activation required a minimal lifetime for TCR/pMHC interaction. However, recent reports suggest important discrepancies between the binding properties of ligand-receptor couples measured in solution (three-dimensional) and those measured using surface-bound molecules (two-dimensional). Other reports suggest that bond mechanical strength may be important in addition to kinetic parameters. Here, we used a laminar flow chamber to monitor at the single molecule level the two-dimensional interaction between a recombinant human TCR and eight pMHCs with variable potency. We found that 1), two-dimensional dissociation rates were comparable to three-dimensional parameters previously obtained with the same molecules; 2), no significant correlation was found between association rates and activating potency of pMHCs; 3), bond mechanical strength was partly independent of bond lifetime; and 4), a suitable combination of bond lifetime and bond strength displayed optimal correlation with activation efficiency. These results suggest possible refinements of contemporary models of signal generation by T cell receptors. In conclusion, we reported, for the first time to our knowledge, the two-dimensional binding properties of eight TCR/pMHC couples in a cell-free system with single bond resolution.
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He HT, Bongrand P. Membrane dynamics shape TCR-generated signaling. Front Immunol 2012; 3:90. [PMID: 22566969 PMCID: PMC3342369 DOI: 10.3389/fimmu.2012.00090] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 04/07/2012] [Indexed: 12/25/2022] Open
Abstract
Despite intensive investigation, the mechanisms of T cell receptor (TCR)-mediated signal generation remain poorly understood. Here we review various dynamic processes at the cell membrane that might critically control this signaling. Firstly, we summarize recent reports providing new information on the sensitivity of TCR/ligand interaction to the membrane environment and particularly to applied forces. Secondly, we review recent evidence that forces and displacements are continuously generated at cell surfaces. Thirdly, we summarize recent experimental evidence demonstrating the capacity of forces to generate signals. Lastly, we provide a quantitative model to exemplify the capacity of dynamic processes to modulate TCR properties such as specificity that were previously difficult to explain with conventional models. It is concluded that the described dynamic processes must be integrated into current models of TCR signaling.
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Robert P, Nicolas A, Aranda-Espinoza S, Bongrand P, Limozin L. Minimal encounter time and separation determine ligand-receptor binding in cell adhesion. Biophys J 2011; 100:2642-51. [PMID: 21641309 DOI: 10.1016/j.bpj.2011.04.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 03/31/2011] [Accepted: 04/04/2011] [Indexed: 10/18/2022] Open
Abstract
The binding properties of biomolecules play a crucial role in many biological phenomena, especially cell adhesion. Whereas the attachment kinetics of soluble proteins is considered well known, complex behavior arises when protein molecules are bound to the cell membrane. We probe the hidden kinetics of ligand-receptor bond formation using single-molecule flow chamber assays and Brownian dynamics simulations. We show that, consistent with our recently proposed hypothesis, association requires a minimum duration of contact between the reactive species. In our experiments, ICAM-1 anchored on a flat substrate binds to anti-ICAM-1 coated onto flowing microbeads. The interaction potential between bead and substrate is measured by microinterferometry and is used as an ingredient to simulate bead movement. Our simulation calculates the duration of ligand-receptor contacts imposed by the bead movement. We quantitatively predict the reduction of adhesion probability measured for shorter tether length of the ligand or if a repulsive hyaluronan layer is added onto the surface. To account for our results, we propose that bond formation may occur in our system by crossing of a diffusive plateau in the energy landscape, on the timescale of 5 ms and an energy barrier of 5 k(B)T, before reaching the first detectable bound state. Our results show how to relate cell-scale behavior to the combined information of molecular reactivity and biomolecule submicron-scale environment.
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Belhocine W, Ibrahim Z, Grandné V, Buffat C, Robert P, Gras D, Cleach I, Bongrand P, Carayon P, Vitte J. Total serum tryptase levels are higher in young infants. Pediatr Allergy Immunol 2011; 22:600-7. [PMID: 21736626 DOI: 10.1111/j.1399-3038.2011.01166.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mast cells participate in immune defense and allergic disease. At baseline, serum tryptase levels primarily reflect mast cell burden, while mast cell degranulation leads to granule tryptase release, which may be detectable as a transitory elevation of serum tryptase levels. Thus, mast cell burden and mast cell activity are reflected by serum tryptase levels, but reports are scarce in infants under 1 yr. We aimed at defining levels of total serum tryptase levels in this population. METHODS Total serum tryptase levels (ImmunoCAP; Phadia) were measured in 372 sera from infants younger than 1 yr. Two hundred and forty-two sera came from non-atopic, non-allergic infants in good condition, who had blood drawn for routine follow-up or diagnosis of illnesses that are not known to induce changes in serum tryptase levels. Seventy-two sera were from atopic and/or allergic infants, and 58 sera were from non-atopic, non-allergic infants requiring intensive care. RESULTS Median serum tryptase levels were highest in infant2s under 3 months (6.12 ± 3.47 μg/l) and gradually decreased before reaching levels similar to those described in adults and older children (3.85 ± 1.8 μg/l between 9 and 12 months). Atopic/allergic status was associated with even higher tryptase levels (14.20 ± 10.22 μg/l in infants younger than 3 months). Intensive care patients had lower levels of serum tryptase (4.12 ± 3.38 μg/l in infants younger than 3 months). Longitudinal follow-up was performed in 27 patients and showed tryptase levels decrease over time in individual patients. Infants'sex was not found to interfere with serum tryptase levels. CONCLUSION Total serum tryptase levels are significantly higher in younger infants compared with older ones. In infants of the same age, serum tryptase levels may vary according to the clinical condition and thus suggest mast cell involvement in the physiologic as well as in the allergic immune responses of young infants.
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Puech PH, Nevoltris D, Robert P, Limozin L, Boyer C, Bongrand P. Force measurements of TCR/pMHC recognition at T cell surface. PLoS One 2011; 6:e22344. [PMID: 21799834 PMCID: PMC3142151 DOI: 10.1371/journal.pone.0022344] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 06/25/2011] [Indexed: 01/07/2023] Open
Abstract
The rupture forces and adhesion frequencies of single recognition complexes between an affinity selected peptide/MHC complex and a TCR at a murine hybridoma surface were measured using Atomic Force Microscopy. When the CD8 coreceptor is absent, the adhesion frequency depends on the nature of the peptide but the rupture force does not. When CD8 is present, no effect of the nature of the peptide is observed. CD8 is proposed to act as a time and distance lock, enabling the shorter TCR molecule to bridge the pMHC and have time to finely read the peptide. Ultimately, such experiments could help the dissection of the sequential steps by which the TCR reads the peptide/MHC complex in order to control T cell activation.
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