Grethe Bergseth - Academia.edu (original) (raw)
Papers by Grethe Bergseth
Journal of Biomedical Materials Research Part a, Aug 1, 2005
In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the ... more In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the contribution of leukocyte populations in the synthesis of inflammatory mediators. This was done by depleting the blood of specific cell types using magnetic beads coated with monoclonal antibodies against leukocyte surface antigens. Synthesis of interleukin 8 (IL-8) was highly dependent on CD15ϩ cells and was reduced by 80% when these cells were removed from the blood. Correspondingly, IL-8 production showed a high correlation with the concentration of granulocytes (r ϭ 0.77, p Ͻ 0.0001). Synthesis of monocyte chemoattractant protein 1 (MCP-1) was dependent on CD14ϩ cells and was reduced by 35% when these cells were removed from the blood. Correspondingly, MCP-1 production correlated with the concentration of monocytes (r ϭ 0.39, p Ͻ 0.0001). Synthesis of leukotriene B4 (LTB4) was highly dependent on CD15ϩ cells and was reduced by 75% when these cells were removed from the blood. Correspondingly, LTB4 production correlated strongly with the granulocyte concentration (r ϭ 0.54, p Ͻ 0.0001). As expected, complement activation was not affected by cell depletion and did not correlate with the concentration of any of the cell types. Thus, artificial surface-induced IL-8 and LTB4 synthesis was almost exclusively granulocyte dependent. However, MCP-1 synthesis was mainly a product of monocytes, although granulocytes and other subpopulations may partly contribute.
Clinical Immunology, 2015
Complement C5 inhibitor eculizumab treatment in atypical hemolytic uremic syndrome is effective, ... more Complement C5 inhibitor eculizumab treatment in atypical hemolytic uremic syndrome is effective, but associated with high costs. Complement inhibition monitoring in these patients has not been standardized. In this study we evaluated novel functional assays for application in routine follow-up. We documented that the Wieslab® complement screen assay showed a sensitivity of 1-2% of C5 activity by adding purified C5 or normal human serum to a C5 deficient serum. All the patient samples obtained during the treatment course, were completely blocked for terminal complement pathway activity for up to four weeks after the eculizumab infusion. Levels of complexes between eculizumab and C5 were inversely correlated to the complement activity (p=0.01). Moreover, titrating serum from eculizumab-treated patients into normal serum revealed that eculizumab was present in excess up to four weeks after infusion. Thus, we demonstrate sensitive, reliable and easy-performed assays which can be used to design individual eculizumab dosage regimens.
Blood, 2002
Complement plays an essential role in inflammation and tissue damage. However, it is largely unkn... more Complement plays an essential role in inflammation and tissue damage. However, it is largely unknown to what extent the system acts as a primary inducer of secondary mediator systems in the inflammatory network of human whole blood. Here we describe a novel in vitro model using the thrombin-specific hirudin analog lepirudin as anticoagulant, which, in contrast to heparin, did not interfere with complement activation. The model was used to study the role of complement in Escherichia coli-induced inflammatory responses. Granulocyte and monocyte oxidative burst was complement dependent as it was reduced by 85% and 70%, respectively, by the C3 [corrected] binding peptide compstatin. A similar reduction was found by inhibition of C5, C5a, and C5a receptor (C5aR). Furthermore, anti-CR3 antibodies were as efficient as the C5aR antagonist in reducing granulocyte oxidative burst, whereas blocking CD14 or C3aR had no effect. Up-regulation of granulocyte CR3 was virtually abolished by a C5aR a...
A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monocl... more A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monoclonal antibodies was established. The following conditions for correct collection and preservation of blood samples were required: venipuncture directly into a vacutainer containing citrate, theophylline, adenosine and dipyridamole, storage on ice, and separation of plasma within 30 minutes. Thereafter, the plasma TSP concentration remained constant at room temperature
Molecular Immunology, 2008
Thrombosis Research, 2000
A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monocl... more A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monoclonal antibodies was established. The following conditions for correct collection and preservation of blood samples were required: venipuncture directly into a vacutainer containing citrate, theophylline, adenosine and dipyridamole, storage on ice, and separation of plasma within 30 minutes. Thereafter, the plasma TSP concentration remained constant at room temperature
Molecular Immunology, 2008
Proceedings of the National Academy of Sciences, 2009
Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, i... more Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to Gram-negative bacteria were
Molecular Immunology, 2014
Molecular Immunology, 2011
The initial interaction of Gram-negative bacteria with erythrocytes and its implications on leuko... more The initial interaction of Gram-negative bacteria with erythrocytes and its implications on leukocyte phagocytosis and oxidative burst in human whole blood were examined. Alexa-labeled Escherichia coli, wild-type H44/76 Neisseria meningitidis (N. meningitidis) and the H44/76lpxA lipopolysaccharide (LPS)-deficient mutant were incubated with whole blood using lepirudin as anticoagulant which has no adverse effects on complement. Bacteria free in plasma, bound to erythrocytes or phagocytized by granulocytes and monocytes were quantified using flow cytometry. The effects of the C3 inhibitor compstatin, a C5a receptor antagonist (C5aRa) and a complement receptor 1 (CR1)-blocking antibody (3D9) were examined. Most bacteria (80%) immediately bound to erythrocytes. The binding gradually declined over time, with a parallel increase in phagocytosis. Complement inhibition with compstatin reduced erythrocyte binding and bacterial C3 opsonization. In contrast, the C5aRa efficiently reduced phagocytosis, but did not affect the binding of bacteria to erythrocytes. The anti-CR1 blocking mAb dose-dependently reduced bacterial binding to erythrocytes to nil, with subsequent increased phagocytosis and oxidative burst. LPS had no effect on these processes since similar results were obtained using an LPS-deficient N. meningitidis mutant. In vivo experiments in a pig model of sepsis showed limited binding of bacteria to erythrocytes, consistent with the facts that erythrocyte CR1 receptors are absent in non-primates and that the bacteria were mainly found in the lungs. In conclusion, complement-dependent binding of Gram-negative bacteria to erythrocyte CR1 decreases phagocytosis and oxidative burst by leukocytes in human whole blood.
Molecular Immunology, 2009
Study the role of complement in the initial binding of the Gramnegative E. coli and N. meningitid... more Study the role of complement in the initial binding of the Gramnegative E. coli and N. meningitidis bacteria to erythrocytes and leukocytes in fresh human whole blood and in piglets in vivo.
Molecular Immunology, 2007
Journal of Immunological Methods, 2014
Electroluminescent assays for epitopes on the complement components C3dg, terminal complement com... more Electroluminescent assays for epitopes on the complement components C3dg, terminal complement complex (TCC) and factor B/Bb (fB/Bb) have been developed with capture and detection antibodies to produce detection limits C3dg=91±9ng/mL, TCC=3±0.1ng/mL and fB=55.7±0.1ng/mL. The assay performance was assessed against a series of zymosan and heat aggregated IgG (HAIgG) in vitro activations of complement using a calibrated activated complement serum (ACS) as calibration standard. The ACS standard was stable within 20% accuracy over a 6-month period with freeze-thaw cycles as required. Differential activation of the complement cascade was observed for TCC showing a pseudo-first order formation half-life of 3.5h after activation with zymosan. The C3dg activation fragment indicates a 10% total activation for both activation agents. The kinetic-epitope analysis for fB indicates that the capture epitope is on the fB/Bb protein fragment which can then become covered by the formation of C3bBb or C3bBbP complexes during the time course of the cascade.
Journal of Biomedical Materials Research Part A, 2005
In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the ... more In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the contribution of leukocyte populations in the synthesis of inflammatory mediators. This was done by depleting the blood of specific cell types using magnetic beads coated with monoclonal antibodies against leukocyte surface antigens. Synthesis of interleukin 8 (IL-8) was highly dependent on CD15ϩ cells and was reduced by 80% when these cells were removed from the blood. Correspondingly, IL-8 production showed a high correlation with the concentration of granulocytes (r ϭ 0.77, p Ͻ 0.0001). Synthesis of monocyte chemoattractant protein 1 (MCP-1) was dependent on CD14ϩ cells and was reduced by 35% when these cells were removed from the blood. Correspondingly, MCP-1 production correlated with the concentration of monocytes (r ϭ 0.39, p Ͻ 0.0001). Synthesis of leukotriene B4 (LTB4) was highly dependent on CD15ϩ cells and was reduced by 75% when these cells were removed from the blood. Correspondingly, LTB4 production correlated strongly with the granulocyte concentration (r ϭ 0.54, p Ͻ 0.0001). As expected, complement activation was not affected by cell depletion and did not correlate with the concentration of any of the cell types. Thus, artificial surface-induced IL-8 and LTB4 synthesis was almost exclusively granulocyte dependent. However, MCP-1 synthesis was mainly a product of monocytes, although granulocytes and other subpopulations may partly contribute.
Journal of Biomedical Materials Research Part A, 2008
Exposing blood to an artificial surface results in a systemic inflammatory response, including cy... more Exposing blood to an artificial surface results in a systemic inflammatory response, including cytokine release and complement activation. We studied the artificial surface-induced inflammation in human whole blood using an extensive panel of inflammatory mediators including proinflammatory cytokines, chemokines and growth-factors and investigated the role of the complement system in the induction of this response. Using multiplex technology, 27 different inflammatory mediators were measured after circulating blood for 4 hours in polyvinyl chloride tubing. The C3 inhibitor compstatin was used to block complement activation. A significant (p < 0.05) increase in 14 of the 27 mediators was induced by the surface, of which 7 were chemokines (IL-8, MCP-1, MIP-1α, MIP-1β, RANTES, eotaxin and IP-10) and 5 were growth-factors (G-CSF, GM-CSF, VEGF, PDGF and FGF). The traditional proinflammatory cytokines like IL-1β, TNFα and IL-6 were not induced, although IL-6, as well as IL-15 and IL-17 increased if the surface was coated with highly bioincompatible laminaran. Inhibition of complement activation with compstatin significantly (p < 0.05) reduced the formation of 12 of the 14 mediators. For 10 of the 12 mediators, the inhibition was by 2/3 or more, for the remaining two the inhibition was more moderate. A highly biocompatible heparin-coated PVC surface was used as negative control and completely abolished the whole inflammatory response. The artificial surface PVC markedly induced a broad spectrum of chemokines and growth-factors, which was largely dependent on activation of complement.
Immunobiology, 2012
Complement has long been recognized as an essential part of the innate immune response that contr... more Complement has long been recognized as an essential part of the innate immune response that contributes to the maintenance of homeostasis, the modulation of adaptive immunity, and the development of various pathologies. The potential usefulness, in both research and clinical settings, of compounds that detect or
Journal of Biomedical Materials Research Part a, Aug 1, 2005
In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the ... more In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the contribution of leukocyte populations in the synthesis of inflammatory mediators. This was done by depleting the blood of specific cell types using magnetic beads coated with monoclonal antibodies against leukocyte surface antigens. Synthesis of interleukin 8 (IL-8) was highly dependent on CD15ϩ cells and was reduced by 80% when these cells were removed from the blood. Correspondingly, IL-8 production showed a high correlation with the concentration of granulocytes (r ϭ 0.77, p Ͻ 0.0001). Synthesis of monocyte chemoattractant protein 1 (MCP-1) was dependent on CD14ϩ cells and was reduced by 35% when these cells were removed from the blood. Correspondingly, MCP-1 production correlated with the concentration of monocytes (r ϭ 0.39, p Ͻ 0.0001). Synthesis of leukotriene B4 (LTB4) was highly dependent on CD15ϩ cells and was reduced by 75% when these cells were removed from the blood. Correspondingly, LTB4 production correlated strongly with the granulocyte concentration (r ϭ 0.54, p Ͻ 0.0001). As expected, complement activation was not affected by cell depletion and did not correlate with the concentration of any of the cell types. Thus, artificial surface-induced IL-8 and LTB4 synthesis was almost exclusively granulocyte dependent. However, MCP-1 synthesis was mainly a product of monocytes, although granulocytes and other subpopulations may partly contribute.
Clinical Immunology, 2015
Complement C5 inhibitor eculizumab treatment in atypical hemolytic uremic syndrome is effective, ... more Complement C5 inhibitor eculizumab treatment in atypical hemolytic uremic syndrome is effective, but associated with high costs. Complement inhibition monitoring in these patients has not been standardized. In this study we evaluated novel functional assays for application in routine follow-up. We documented that the Wieslab® complement screen assay showed a sensitivity of 1-2% of C5 activity by adding purified C5 or normal human serum to a C5 deficient serum. All the patient samples obtained during the treatment course, were completely blocked for terminal complement pathway activity for up to four weeks after the eculizumab infusion. Levels of complexes between eculizumab and C5 were inversely correlated to the complement activity (p=0.01). Moreover, titrating serum from eculizumab-treated patients into normal serum revealed that eculizumab was present in excess up to four weeks after infusion. Thus, we demonstrate sensitive, reliable and easy-performed assays which can be used to design individual eculizumab dosage regimens.
Blood, 2002
Complement plays an essential role in inflammation and tissue damage. However, it is largely unkn... more Complement plays an essential role in inflammation and tissue damage. However, it is largely unknown to what extent the system acts as a primary inducer of secondary mediator systems in the inflammatory network of human whole blood. Here we describe a novel in vitro model using the thrombin-specific hirudin analog lepirudin as anticoagulant, which, in contrast to heparin, did not interfere with complement activation. The model was used to study the role of complement in Escherichia coli-induced inflammatory responses. Granulocyte and monocyte oxidative burst was complement dependent as it was reduced by 85% and 70%, respectively, by the C3 [corrected] binding peptide compstatin. A similar reduction was found by inhibition of C5, C5a, and C5a receptor (C5aR). Furthermore, anti-CR3 antibodies were as efficient as the C5aR antagonist in reducing granulocyte oxidative burst, whereas blocking CD14 or C3aR had no effect. Up-regulation of granulocyte CR3 was virtually abolished by a C5aR a...
A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monocl... more A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monoclonal antibodies was established. The following conditions for correct collection and preservation of blood samples were required: venipuncture directly into a vacutainer containing citrate, theophylline, adenosine and dipyridamole, storage on ice, and separation of plasma within 30 minutes. Thereafter, the plasma TSP concentration remained constant at room temperature
Molecular Immunology, 2008
Thrombosis Research, 2000
A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monocl... more A novel enzyme immunoassay for plasma thrombospondin (TSP) based on commercially available monoclonal antibodies was established. The following conditions for correct collection and preservation of blood samples were required: venipuncture directly into a vacutainer containing citrate, theophylline, adenosine and dipyridamole, storage on ice, and separation of plasma within 30 minutes. Thereafter, the plasma TSP concentration remained constant at room temperature
Molecular Immunology, 2008
Proceedings of the National Academy of Sciences, 2009
Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, i... more Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to Gram-negative bacteria were
Molecular Immunology, 2014
Molecular Immunology, 2011
The initial interaction of Gram-negative bacteria with erythrocytes and its implications on leuko... more The initial interaction of Gram-negative bacteria with erythrocytes and its implications on leukocyte phagocytosis and oxidative burst in human whole blood were examined. Alexa-labeled Escherichia coli, wild-type H44/76 Neisseria meningitidis (N. meningitidis) and the H44/76lpxA lipopolysaccharide (LPS)-deficient mutant were incubated with whole blood using lepirudin as anticoagulant which has no adverse effects on complement. Bacteria free in plasma, bound to erythrocytes or phagocytized by granulocytes and monocytes were quantified using flow cytometry. The effects of the C3 inhibitor compstatin, a C5a receptor antagonist (C5aRa) and a complement receptor 1 (CR1)-blocking antibody (3D9) were examined. Most bacteria (80%) immediately bound to erythrocytes. The binding gradually declined over time, with a parallel increase in phagocytosis. Complement inhibition with compstatin reduced erythrocyte binding and bacterial C3 opsonization. In contrast, the C5aRa efficiently reduced phagocytosis, but did not affect the binding of bacteria to erythrocytes. The anti-CR1 blocking mAb dose-dependently reduced bacterial binding to erythrocytes to nil, with subsequent increased phagocytosis and oxidative burst. LPS had no effect on these processes since similar results were obtained using an LPS-deficient N. meningitidis mutant. In vivo experiments in a pig model of sepsis showed limited binding of bacteria to erythrocytes, consistent with the facts that erythrocyte CR1 receptors are absent in non-primates and that the bacteria were mainly found in the lungs. In conclusion, complement-dependent binding of Gram-negative bacteria to erythrocyte CR1 decreases phagocytosis and oxidative burst by leukocytes in human whole blood.
Molecular Immunology, 2009
Study the role of complement in the initial binding of the Gramnegative E. coli and N. meningitid... more Study the role of complement in the initial binding of the Gramnegative E. coli and N. meningitidis bacteria to erythrocytes and leukocytes in fresh human whole blood and in piglets in vivo.
Molecular Immunology, 2007
Journal of Immunological Methods, 2014
Electroluminescent assays for epitopes on the complement components C3dg, terminal complement com... more Electroluminescent assays for epitopes on the complement components C3dg, terminal complement complex (TCC) and factor B/Bb (fB/Bb) have been developed with capture and detection antibodies to produce detection limits C3dg=91±9ng/mL, TCC=3±0.1ng/mL and fB=55.7±0.1ng/mL. The assay performance was assessed against a series of zymosan and heat aggregated IgG (HAIgG) in vitro activations of complement using a calibrated activated complement serum (ACS) as calibration standard. The ACS standard was stable within 20% accuracy over a 6-month period with freeze-thaw cycles as required. Differential activation of the complement cascade was observed for TCC showing a pseudo-first order formation half-life of 3.5h after activation with zymosan. The C3dg activation fragment indicates a 10% total activation for both activation agents. The kinetic-epitope analysis for fB indicates that the capture epitope is on the fB/Bb protein fragment which can then become covered by the formation of C3bBb or C3bBbP complexes during the time course of the cascade.
Journal of Biomedical Materials Research Part A, 2005
In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the ... more In an in vitro whole blood model of artificial surface-induced inflammation, we have studied the contribution of leukocyte populations in the synthesis of inflammatory mediators. This was done by depleting the blood of specific cell types using magnetic beads coated with monoclonal antibodies against leukocyte surface antigens. Synthesis of interleukin 8 (IL-8) was highly dependent on CD15ϩ cells and was reduced by 80% when these cells were removed from the blood. Correspondingly, IL-8 production showed a high correlation with the concentration of granulocytes (r ϭ 0.77, p Ͻ 0.0001). Synthesis of monocyte chemoattractant protein 1 (MCP-1) was dependent on CD14ϩ cells and was reduced by 35% when these cells were removed from the blood. Correspondingly, MCP-1 production correlated with the concentration of monocytes (r ϭ 0.39, p Ͻ 0.0001). Synthesis of leukotriene B4 (LTB4) was highly dependent on CD15ϩ cells and was reduced by 75% when these cells were removed from the blood. Correspondingly, LTB4 production correlated strongly with the granulocyte concentration (r ϭ 0.54, p Ͻ 0.0001). As expected, complement activation was not affected by cell depletion and did not correlate with the concentration of any of the cell types. Thus, artificial surface-induced IL-8 and LTB4 synthesis was almost exclusively granulocyte dependent. However, MCP-1 synthesis was mainly a product of monocytes, although granulocytes and other subpopulations may partly contribute.
Journal of Biomedical Materials Research Part A, 2008
Exposing blood to an artificial surface results in a systemic inflammatory response, including cy... more Exposing blood to an artificial surface results in a systemic inflammatory response, including cytokine release and complement activation. We studied the artificial surface-induced inflammation in human whole blood using an extensive panel of inflammatory mediators including proinflammatory cytokines, chemokines and growth-factors and investigated the role of the complement system in the induction of this response. Using multiplex technology, 27 different inflammatory mediators were measured after circulating blood for 4 hours in polyvinyl chloride tubing. The C3 inhibitor compstatin was used to block complement activation. A significant (p < 0.05) increase in 14 of the 27 mediators was induced by the surface, of which 7 were chemokines (IL-8, MCP-1, MIP-1α, MIP-1β, RANTES, eotaxin and IP-10) and 5 were growth-factors (G-CSF, GM-CSF, VEGF, PDGF and FGF). The traditional proinflammatory cytokines like IL-1β, TNFα and IL-6 were not induced, although IL-6, as well as IL-15 and IL-17 increased if the surface was coated with highly bioincompatible laminaran. Inhibition of complement activation with compstatin significantly (p < 0.05) reduced the formation of 12 of the 14 mediators. For 10 of the 12 mediators, the inhibition was by 2/3 or more, for the remaining two the inhibition was more moderate. A highly biocompatible heparin-coated PVC surface was used as negative control and completely abolished the whole inflammatory response. The artificial surface PVC markedly induced a broad spectrum of chemokines and growth-factors, which was largely dependent on activation of complement.
Immunobiology, 2012
Complement has long been recognized as an essential part of the innate immune response that contr... more Complement has long been recognized as an essential part of the innate immune response that contributes to the maintenance of homeostasis, the modulation of adaptive immunity, and the development of various pathologies. The potential usefulness, in both research and clinical settings, of compounds that detect or