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Zetterström, A., Hämäläinen, M. D., Karlberg, E., Winkvist, M., Söderquist, M., Öhagen, P., . . . Nyberg, F. (2019). Maximum Time Between Tests: A Digital Biomarker to Detect Therapy Compliance and Assess Schedule Quality in Measurement-Based eHealth Systems for Alcohol Use Disorder. Alcohol and Alcoholism, 54(1), 70-72
Open this publication in new window or tab >>Maximum Time Between Tests: A Digital Biomarker to Detect Therapy Compliance and Assess Schedule Quality in Measurement-Based eHealth Systems for Alcohol Use Disorder
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2019 (English)In: Alcohol and Alcoholism, ISSN 0735-0414, E-ISSN 1464-3502, Vol. 54, no 1, p. 70-72Article in journal (Refereed) Published
Abstract [en]

Aim: To evaluate, in a breathalyzer-based eHealth system, whether the time-based digital biomarker maximum time between tests' (MTBT) brings valuable information on alcohol consumption patterns as confirmed by correlation with blood phosphatidyl ethanol (PEth), serum carbohydrate deficient transferrin (CDT) and timeline follow-back data.

Method: Data on 54 patients in follow-up for treatment of alcohol use disorder were analysed.

Results: The model of weekly averages of 24-log transformed MTBT adequately described timeline follow-back data (P < 0.0001, R = 0.27-0.38, n = 650). Significant correlations were noted between MTBT and PEth (P < 0.0001, R = 0.41, n = 148) and between MTBT and CDT (P < 0.0079, R = 0.22, n = 120).

Conclusions: The time-based digital biomarker maximum time between tests' described here has the potential to become a generally useful metric for all scheduled measurement-based eHealth systems to monitor test behaviour and compliance, factors important for dosing' of eHealth systems and for early prediction and interventions of lapse/relapse.

Place, publisher, year, edition, pages
OXFORD UNIV PRESS, 2019
National Category
Substance Abuse
Identifiers
urn:nbn:se:uu:diva-381927 (URN)10.1093/alcalc/agy086 (DOI)000462547100012 ()30541059 (PubMedID)
Funder
Vinnova, 2014-03659
Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-04-18Bibliographically approved
Encarnacao, J. C., Schulte, T., Achour, A., Bjorkelund, H. & Andersson, K. (2018). Detecting ligand interactions in real time on living bacterial cells. Applied Microbiology and Biotechnology, 102(9), 4193-4201
Open this publication in new window or tab >>Detecting ligand interactions in real time on living bacterial cells
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2018 (English)In: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 102, no 9, p. 4193-4201Article in journal (Refereed) Published
Abstract [en]

Time-resolved analysis assays of receptor-ligand interactions are fundamental in basic research and drug discovery. Adequate methods are well developed for the analysis of recombinant proteins such as antibody-antigen interactions. However, assays for time-resolved ligand-binding processes on living cells are still rare, in particular within microbiology. In this report, the real-time cell-binding assay (RT-CBA) technology LigandTracerA (R), originally designed for mammalian cell culture, was extended to cover Gram-positive and Gram-negative bacteria. This required the development of new immobilization methods for bacteria, since LigandTracer depends on cells being firmly attached to a Petri dish. The evaluated Escherichia coli CJ236 and BL21 as well as Staphylococcus carnosus TM300 strains were immobilized to plastic Petri dishes using antibody capture, allowing us to depict kinetic binding traces of fluorescently labeled antibodies directed against surface-displayed bacterial proteins for as long as 10-15 h. Interaction parameters, such as the affinity and kinetic constants, could be estimated with high precision (coefficient of variation 9-44%) and the bacteria stayed viable for at least 16 h. The other tested attachment protocols were inferior to the antibody capture approach. Our attachment protocol is generic and could potentially also be applied to other assays and purposes.

Place, publisher, year, edition, pages
SPRINGER, 2018
Keywords
Real-time interactions, Drug kinetics, Living bacteria, Antibodies
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-352571 (URN)10.1007/s00253-018-8919-3 (DOI)000429800600027 ()29550990 (PubMedID)
Funder
Swedish Research CouncilEU, European Research Council, 675555
Available from: 2018-08-07 Created: 2018-08-07 Last updated: 2019-11-22Bibliographically approved
Hamalainen, M. D., Zetterstrom, A., Winkvist, M., Soderquist, M., Karlberg, E., Ohagen, P., . . . Nyberg, F. (2018). Real-time Monitoring Using a Breathalyzer-Based eHealth System Can Identify Lapse/Relapse Patterns in Alcohol Use Disorder Patients. Alcohol and Alcoholism, 53(4), 368-375
Open this publication in new window or tab >>Real-time Monitoring Using a Breathalyzer-Based eHealth System Can Identify Lapse/Relapse Patterns in Alcohol Use Disorder Patients
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2018 (English)In: Alcohol and Alcoholism, ISSN 0735-0414, E-ISSN 1464-3502, Vol. 53, no 4, p. 368-375Article in journal (Refereed) Published
Abstract [en]

Aim: We introduce a new remote real-time breathalyzer-based method for monitoring and early identification of lapse/relapse patterns for alcohol use disorder (AUD) patients using a composite measure of sobriety, the Addiction Monitoring Index (AMI). Methods: We constructed AMI from (a) obtained test results and (b) the pattern of ignored tests using data from the first 30 patients starting in the treatment arms of two on-going clinical trials. The patients performed 2-4 scheduled breath alcohol content (BrAC)-tests per day presented as blood alcohol content (BAC) data. In total, 10,973 tests were scheduled, 7743 were performed and 3230 were ignored during 3982 patient days. Results: AMI-time profiles could be used to monitor the daily trends of alcohol consumption and detect early signs of lapse and relapses. The pattern of ignored tests correlates with the onset of drinking. AMI correlated with phosphatidyl ethanol (n = 61, F-ratio = 34.6, P < 0.0001, R = -0.61). The recognition of secret drinking could further be improved using a low alcohol detection threshold (BrAC = 0.025 mg/l, BAC(Swe) = 0.05% or US = 0.0053 g/dl), in addition to the legal Swedish traffic limit (BrAC = 0.1 mg/l, BAC(Swe) = 0.2% or US = 0.021 g/dl). Nine out of 10 patients who dropped out from the study showed early risk signs as reflected in the level and pattern in AMI before the actual dropout. Conclusions: AMI-time profiles from an eHealth system are useful for monitoring the recovery process and for early identification of lapse/relapse patterns. High-resolution monitoring of sobriety enables new measurement-based treatment methods for proactive personalized long-term relapse prevention and treatment of AUD patients. Clinical Trial Registration: The data used for construction of AMI was from two clinical trials approved by the Regional Ethics Committee of Uppsala, Sweden and performed in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participating subjects. The study was registered at ClinicalTrials.gov (NCT03195894).

Place, publisher, year, edition, pages
OXFORD UNIV PRESS, 2018
National Category
Substance Abuse
Identifiers
urn:nbn:se:uu:diva-362169 (URN)10.1093/alcalc/agy011 (DOI)000439653000004 ()29590325 (PubMedID)
Funder
VINNOVA, 2014-03659
Note

Correction: A correction has been published: Alcohol and Alcoholism, Volume 53, Issue 4, 1 July 2018, Pages 499, https://doi.org/10.1093/alcalc/agy028

Available from: 2018-10-05 Created: 2018-10-05 Last updated: 2018-10-05Bibliographically approved
Encarnacao, J. C., Barta, P., Fornstedt, T. & Andersson, K. (2017). Impact of assay temperature on antibody binding characteristics in living cells: A case study. BIOMEDICAL REPORTS, 7(5), 400-406
Open this publication in new window or tab >>Impact of assay temperature on antibody binding characteristics in living cells: A case study
2017 (English)In: BIOMEDICAL REPORTS, ISSN 2049-9434, Vol. 7, no 5, p. 400-406Article in journal (Refereed) Published
Abstract [en]

Kinetic and thermodynamic studies of ligand-receptor interactions are essential for increasing the understanding of receptor activation mechanisms and drug behavior. The characterization of molecular interactions on living cells in real-time goes beyond most current binding assays, and provides valuable information about the dynamics and underlying mechanism of the molecules in a living system. The effect of temperature on interactions in cell-based assays is, however, rarely discussed. In the present study, the effect of temperature on binding of monoclonal antibodies, cetuximab and pertuzumab to specific receptors on living cancer cells was evaluated, and the affinity and kinetics of the interactions were estimated at selected key temperatures. Changes in the behavior of the interactions, particularly in the on- and off-rates were observed, leading to greatly extended time to reach the equilibrium at 21 degrees C compared with at 37 degrees C. However, the observed changes in kinetic characteristics were less than a factor of 10. It was concluded that it is possible to conduct real-time measurements with living cells at different temperatures, and demonstrated that influences of the ambient temperature on the interaction behavior are likely to be less than one order of magnitude.

Keywords
drug kinetics, thermodynamics, real-time interactions, clinical monoclonal antibodies, growth factor receptors
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:uu:diva-345264 (URN)10.3892/br.2017.982 (DOI)000417416000002 ()29181152 (PubMedID)
Funder
EU, Horizon 2020, 2014-2020
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2019-11-22Bibliographically approved
Bondza, S., Björkelund, H., Nestor, M., Andersson, K. & Buijs, J. (2017). Novel Real-Time Proximity Assay for Characterizing Multiple Receptor Interactions on Living Cells. Analytical Chemistry, 89(24), 13212-13218
Open this publication in new window or tab >>Novel Real-Time Proximity Assay for Characterizing Multiple Receptor Interactions on Living Cells
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2017 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 89, no 24, p. 13212-13218Article in journal (Refereed) Published
Abstract [en]

Cellular receptor activity is often controlled through complex mechanisms involving interactions with multiple molecules, which can be soluble ligands and/or other cell surface molecules. In this study, we combine a fluorescence-based technology for real-time interaction analysis with fluorescence quenching to create a novel time-resolved proximity assay to study protein-receptor interactions on living cells. This assay extracts the binding kinetics and affinity for two proteins if they bind in proximity on the cell surface. One application of real-time proximity interaction analysis is to study relative levels of receptor dimerization. The method was primarily evaluated using the HER2 binding antibodies Trastuzumab and Pertuzumab and two EGFR binding antibodies including Cetuximab. Using Cetuximab and Trastuzumab, proximity of EGFR and HER2 was investigated before and after treatment of cells with the tyrosine-kinase inhibitor Gefitinib. Treated cells displayed 50% increased proximity signal, whereas the binding characteristics of the two antibodies were not significantly affected, implying an increase in the EGFR-HER2 dimer level. These results demonstrate that real-time proximity interaction analysis enables determination of the interaction rate constants and affinity of two ligands while simultaneously quantifying their relative colocalization on living cells.

National Category
Analytical Chemistry Immunology in the medical area
Identifiers
urn:nbn:se:uu:diva-339775 (URN)10.1021/acs.analchem.7b02983 (DOI)000418626300025 ()29160688 (PubMedID)
Available from: 2018-02-09 Created: 2018-02-09 Last updated: 2018-02-09Bibliographically approved
Bondza, S., Foy, E., Brooks, J., Andersson, K., Robinson, J., Richalet, P. & Buijs, J. (2017). Real-time Characterization of Antibody Binding to Receptors on Living Immune Cells. Frontiers in Immunology, 8, Article ID 455.
Open this publication in new window or tab >>Real-time Characterization of Antibody Binding to Receptors on Living Immune Cells
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2017 (English)In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 8, article id 455Article in journal (Refereed) Published
Abstract [en]

Understanding molecular interactions on immune cells is crucial for drug development to treat cancer and autoimmune diseases. When characterizing molecular interactions, the use of a relevant living model system is important, as processes such as receptor oligomerization and clustering can influence binding patterns. We developed a protocol to enable time-resolved analysis of ligand binding to receptors on living suspension cells. Different suspension cell lines and weakly adhering cells were tethered to Petri dishes with the help of a biomolecular anchor molecule, and antibody binding was analyzed using LigandTracer. The protocol and assay described in this report were used to characterize interactions involving eight cell lines. Experiments were successfully conducted in three different laboratories, demonstrating the robustness of the protocol. For various antibodies, affinities and kinetic rate constants were obtained for binding to CD20 on both Daudi and Ramos B-cells, the T-cell co-receptor CD3 on Jurkat cells, and the Fc gamma receptor CD32 on transfected HEK293 cells, respectively. Analyzing the binding of Rituximab to B-cells resulted in an affinity of 0.7-0.9 nM, which is similar to values reported previously for living B-cells. However, we observed a heterogeneous behavior for Rituximab interacting with B-cells, which to our knowledge has not been described previously. The understanding of complex interactions will be facilitated with the possibility to characterize binding processes in real-time on living immune cells. This provides the chance to broaden the understanding of how binding kinetics relate to biological function.

Keywords
affinity, kinetics, therapeutic antibody, B-cells, T-cells, CD20, Fc gamma receptor
National Category
Medical Biotechnology
Identifiers
urn:nbn:se:uu:diva-322794 (URN)10.3389/fimmu.2017.00455 (DOI)000399836900001 ()28484455 (PubMedID)
Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2017-11-29Bibliographically approved
Multia, E., Sirén, H., Andersson, K., Samuelsson, J., Forssén, P., Fornstedt, T., . . . Riekkola, M.-L. (2017). Thermodynamic and kinetic approaches for evaluation of monoclonal antibody - Lipoprotein interactions. Analytical Biochemistry, 518, 25-34
Open this publication in new window or tab >>Thermodynamic and kinetic approaches for evaluation of monoclonal antibody - Lipoprotein interactions
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2017 (English)In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 518, p. 25-34Article in journal (Refereed) Published
Abstract [en]

Two complementary instrumental techniques were used, and the data generated was processed with advanced numerical tools to investigate the interactions between anti-human apoB-100 monoclonal antibody (anti-apoB-100 Mab) and apoB-100 containing lipoproteins. Partial Filling Affinity Capillary Electrophoresis (PF-ACE) combined with Adsorption Energy Distribution (AED) calculations provided information on the heterogeneity of the interactions without any a priori model assumptions. The AED calculations evidenced a homogenous binding site distribution for the interactions. Quartz Crystal Microbalance (QCM) studies were used to evaluate thermodynamics and kinetics of the Low-Density Lipoprotein (LDL) and anti-apoB-100 Mab interactions. High affinity and selectivity were observed, and the emerging data sets were analysed with so called Interaction Maps. In thermodynamic studies, the interaction between LDL and anti-apoB-100 Mab was found to be predominantly enthalpy driven. Both techniques were also used to study antibody interactions with Intermediate-Density (IDL) and Very Low Density (VLDL) Lipoproteins. By screening affinity constants for IDL-VLDL sample in a single injection we were able to distinguish affinity constants for both subpopulations using the numerical Interaction Map tool.

Keywords
Monoclonal anti-apoB-100 antibody, Lipoproteins, Thermodynamics, Kinetics, Interaction map
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-316011 (URN)10.1016/j.ab.2016.10.024 (DOI)000392461000004 ()27984014 (PubMedID)
Funder
Swedish Research Council, 2015-04627
Available from: 2017-02-24 Created: 2017-02-24 Last updated: 2018-01-13Bibliographically approved
Hillerdal, V., Boura, V. F., Björkelund, H., Andersson, K. & Essand, M. (2016). Avidity characterization of genetically engineered T-cells with novel and established approaches. BMC Immunology, 17, Article ID 23.
Open this publication in new window or tab >>Avidity characterization of genetically engineered T-cells with novel and established approaches
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2016 (English)In: BMC Immunology, ISSN 1471-2172, E-ISSN 1471-2172, Vol. 17, article id 23Article in journal (Refereed) Published
Abstract [en]

Background: Adoptive transfer of genetically engineered autologous T-cells is becoming a successful therapy for cancer. The avidity of the engineered T-cells is of crucial importance for therapy success. We have in the past cloned a T-cell receptor (TCR) that recognizes an HLA-A2 (MHC class I)-restricted peptide from the prostate and breast cancer- associated antigen TARP. Herein we perform a side-by-side comparison of the TARP-specific TCR (TARP-TCR) with a newly cloned TCR specific for an HLA-A2-restricted peptide from the cytomegalovirus (CMV) pp65 antigen. Results: Both CD8(+) T-cells and CD4(+) T-cells transduced with the HLA-A2-restricted TARP-TCR could readily be detected by multimer analysis, indicating that the binding is rather strong, since binding occured also without the CD8 co-receptor of HLA-A2. Not surprisingly, the TARP-TCR, which is directed against a self-antigen, had weaker binding to the HLA-A2/peptide complex than the CMV pp65-specific TCR (pp65-TCR), which is directed against a viral epitope. Higher peptide concentrations were needed to achieve efficient cytokine release and killing of target cells when the TARP- TCR was used. We further introduce the LigandTracer technology to study cell-cell interactions in real time by evaluating the interaction between TCR-engineered T-cells and peptide-pulsed cancer cells. We were able to successfully detect TCR-engineered T-cell binding kinetics to the target cells. We also used the xCELLigence technology to analyzed cell growth of target cells to assess the killing potency of the TCR-engineered T-cells. T-cells transduced with the pp65 - TCR exhibited more pronounced cytotoxicity, being able to kill their targets at both lower effector to target ratios and lower peptide concentrations. Conclusion: The combination of binding assay with functional assays yields data suggesting that TARP- TCR-engineered T-cells bind to their target, but need more antigen stimulation compared to the pp65-TCR to achieve full effector response. Nonetheless, we believe that the TARP- TCR is an attractive candidate for immunotherapy development for prostate and/or breast cancer.

Keywords
T-cell receptor, Affinity, Avidity, LigandTracer, xCELLigence, HLA binding, TARP, CMV pp65
National Category
Immunology in the medical area
Identifiers
urn:nbn:se:uu:diva-300454 (URN)10.1186/s12865-016-0162-z (DOI)000379892000001 ()27411667 (PubMedID)
Funder
Swedish Cancer SocietySwedish Research Council
Available from: 2016-08-09 Created: 2016-08-09 Last updated: 2018-01-10Bibliographically approved
Reijmar, K., Edwards, K., Andersson, K. & Agmo Hernández, V. (2016). Characterizing and controlling the loading and release of cationic amphiphilic peptides onto and from PEG-stabilized lipodisks. Langmuir, 32(46), 12091-12099
Open this publication in new window or tab >>Characterizing and controlling the loading and release of cationic amphiphilic peptides onto and from PEG-stabilized lipodisks
2016 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 46, p. 12091-12099Article in journal (Refereed) Published
Abstract [en]

Recent studies have identified PEG-stabilized lipid nanodisks (lipodisks) as promising carriers for cationic amphiphilic peptides with antimicrobial and anticancer activity. Using fluorimetric and nanogravimetric methods, we have in this work characterized the parameters describing and controlling the binding of three selected peptides (melittin, LL37, and magainin 2) onto lipodisks. It was found that the affinity of melittin for lipodisks is independent of the disk size and rim charge. On the other hand, the number of binding sites is strongly dependent on both parameters, with the highest loading being obtained for small disks with a negatively charged rim. An optimized composition of the lipodisks was utilized to study the loading of antimicrobial peptides magainin 2 and human LL37. It was observed that although magainin 2 can be loaded in large amounts, it is released very fast upon dilution, which limits future therapeutic applications. In contrast, LL37 can be loaded at relevant concentrations and the formulation is stable. This opens up for applications of LL37-loaded lipodisks as antibiotics and in anticancer treatments.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-305377 (URN)10.1021/acs.langmuir.6b03012 (DOI)000388914400012 ()
Funder
Swedish Cancer Society
Available from: 2016-10-17 Created: 2016-10-17 Last updated: 2017-11-29Bibliographically approved
Wang, E., Björkelund, H., Mihaylova, D., Hagemann, U. B., Karlsson, J., Malmqvist, M., . . . Andersson, K. (2014). Automated functional characterization of radiolabeled antibodies: a time-resolved approach. Nuclear medicine communications, 35(7), 767-776
Open this publication in new window or tab >>Automated functional characterization of radiolabeled antibodies: a time-resolved approach
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2014 (English)In: Nuclear medicine communications, ISSN 0143-3636, E-ISSN 1473-5628, Vol. 35, no 7, p. 767-776Article in journal (Refereed) Published
Abstract [en]

Background The number of radiolabeled monoclonal antibodies (mAbs) used for medical imaging and cancer therapy is increasing. The required chemical modification for attaching a radioactive label and all associated treatment may lead to a damaged mAb subpopulation. This paper describes a novel method, concentration through kinetics (CTK), for rapid assessment of the concentration of immunoreactive mAb and the specific radioactivity, based on monitoring binding kinetics. Methods The interaction of radiolabeled mAb with either the antigen or a general mAb binder such as Protein A was monitored in real time using the instrument LigandTracer. As the curvature of the binding trace has a distinct shape based on the interaction kinetics and concentration of the functional mAb, the immunoreactive mAb concentration could be calculated through reverse kinetic fitting of the binding curves, using software developed for this project. The specific activity, describing the degree of radioactive labeling, was determined through the use of calibrated signal intensities. Results The performance of the CTK assay was evaluated on the basis of various mAb-based interaction systems and assay formats, and it was shown that the assay can provide accurate and repeatable results for immunoreactive concentration and specific activity, with both accuracy and relative SD values below 15%. Conclusion By applying reverse kinetics on real-time binding traces it is possible to estimate the functional concentration and specific activity of radiolabeled mAb. The CTK assay may in the future be included as a complement to current quality assessment methods of radiolabeled mAbs.

Keywords
antibodies, concentration, kinetics, LigandTracer, quality control, specific activity
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-228695 (URN)10.1097/MNM.0000000000000117 (DOI)000337698200011 ()
Available from: 2014-07-22 Created: 2014-07-21 Last updated: 2017-12-05Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9141-9242

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