Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
1.
BMC Complement Altern Med ; 17(1): 521, 2017 Dec 04.
Article in English | MEDLINE | ID: mdl-29202738

ABSTRACT

BACKGROUND: European mistletoe (Viscum album) products used in cancer therapy are frequently combined with other anti-cancer-drugs. Hence, potential herb-drug interactions have become a major safety concern in mistletoe therapy. METHODS: Three European mistletoe products (Helixor® A, Helixor® M and Helixor® P from mistletoe grown on firs, apple trees and pines, respectively) were tested for inhibition of nine major cytochrome P450 (CYP) isoenzymes in a test system using pooled human liver microsomes and for induction of five CYP isoforms in human hepatocytes cultivated in vitro according to the relevant guideline. RESULTS: Major inhibition did not occur in any of the CYP marker reactions. For some CYP isoenzymes, a minor or intermediate inhibition could be observed, but without dose effect relationship. Induction activity (≥ 1.5-fold increase) was not found with any of the three mistletoe products. CONCLUSION: Since no induction capacity was found and major inhibition above 50% did not occur even with the highest concentration used, which is approximately 100,000-fold higher than the clinically relevant dose in plasma, a clinically relevant herb-drug interaction is not expected for Helixor® A, M, and P.


Subject(s)
Antineoplastic Agents/pharmacology , Cytochrome P-450 Enzyme Inhibitors/pharmacology , Cytochrome P-450 Enzyme System/drug effects , Mistletoe , Plant Extracts/pharmacology , Cytochrome P-450 Enzyme System/metabolism , Female , Hepatocytes/drug effects , Humans , Male , Microsomes, Liver/drug effects , Microsomes, Liver/metabolism
2.
Anal Bioanal Chem ; 407(6): 1673-83, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25572690

ABSTRACT

Birch (Betula) pollen is a major cause of allergy in northern and central Europe. The allergenic potency of products for diagnosis and therapy of birch pollen allergy is adjusted nearly exclusively to the major birch pollen allergen Bet v 1. Although every fifth patient is additionally sensitized to Bet v 4, both content and variability of this minor allergen in birch allergen products remain unclear due to a lack of simple and cost-effective quantitative methods. This study aimed to develop and in-house validate the first Bet v 4-specific sandwich enzyme-linked immunosorbent assay (ELISA). Based on a murine monoclonal antibody in combination with a polyclonal rabbit antiserum, the ELISA proved to be highly sensitive, with a lower limit of quantification of 30 pg/ml Bet v 4. After confirmation of satisfactory accuracy, reproducibility, and robustness, the ELISA was utilized to quantify Bet v 4 in 30 authorized birch allergen products. The allergen was detected in all samples tested, ranging from 0.2 to 4.4 µg/ml. No significant correlation of Bet v 4 was found with the respective amount of Bet v 1. In contrast to Bet v 1, also no correlation of Bet v 4 with total protein content or total allergenic activity could be observed. Thus, it seems presently unfeasible to base birch allergen product standardization additionally on Bet v 4. In light of these results, the continuous monitoring of Bet v 4 in birch allergen products with the presented ELISA will provide a basis for the understanding of the clinical relevance of minor allergens.


Subject(s)
Antigens, Plant/analysis , Calcium-Binding Proteins/analysis , Enzyme-Linked Immunosorbent Assay/methods , Plant Proteins/analysis , Pollen/chemistry , Animals , Blotting, Western , Humans , Limit of Detection , Reproducibility of Results
3.
J Clin Invest ; 116(12): 3160-70, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17111046

ABSTRACT

Control of pathogens by formation of abscesses and granulomas is a major strategy of the innate immune system, especially when effector mechanisms of adaptive immunity are insufficient. We show in human listeriosis that DCs expressing indoleamine 2,3-dioxygenase (IDO), together with macrophages, are major cellular components of suppurative granulomas in vivo. Induction of IDO by DCs is a cell-autonomous response to Listeria monocytogenes infection and was also observed in other granulomatous infections with intracellular bacteria, such as Bartonella henselae. Reporting on our use of the clinically applied anti-TNF-alpha antibody infliximab, we further demonstrate in vitro that IDO induction is TNF-alpha dependent. Repression of IDO therefore might result in exacerbation of granulomatous diseases observed during anti-TNF-alpha therapy. These findings place IDO(+) DCs not only at the intersection of innate and adaptive immunity but also at the forefront of bacterial containment in granulomatous infections.


Subject(s)
Dendritic Cells/metabolism , Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics , Listeria monocytogenes/growth & development , Antigens, CD/analysis , Antigens, Differentiation, Myelomonocytic/analysis , CD3 Complex/analysis , Cells, Cultured , Cyclooxygenase 2/genetics , Cyclooxygenase 2/metabolism , Dendritic Cells/cytology , Dendritic Cells/microbiology , Enzyme-Linked Immunosorbent Assay , Gene Expression/genetics , Granuloma/genetics , Granuloma/metabolism , Granuloma/microbiology , Humans , Immunoblotting , Immunohistochemistry , Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism , Interferon-gamma/genetics , Interferon-gamma/metabolism , Lewis X Antigen/analysis , Listeriosis/genetics , Listeriosis/metabolism , Listeriosis/microbiology , Macrophages/cytology , Macrophages/metabolism , Macrophages/microbiology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Oligonucleotide Array Sequence Analysis , S100 Proteins/analysis , Time Factors , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism
4.
Immunobiology ; 213(8): 621-7, 2008.
Article in English | MEDLINE | ID: mdl-18950592

ABSTRACT

The toll-like receptor 4 Asp(299)Gly polymorphism results in an inactive receptor. Heterozygosis is associated with reduced LPS-inducible IL-10 protein and IL-10 mRNA from blood leukocytes and isolated monocytes, while numerous other mediators are not affected. We could exclude that this effect is due to the differences in the kinetics of IL-10 release, in the expression of total surface TLR4 or in LPS-binding to monocytes between subjects heterozygous for the Asp(299)Gly polymorphism or homozygous carriers of the wild-type allele. Furthermore, we could show that IL-10 induction in general requires stronger LPS-triggering than TNF and is more sensitive to LPS inhibitors. The lower number of responsive wild-type TLR4 receptors on monocytes of heterozygotes may explain why only IL-10 release is affected.


Subject(s)
Interleukin-10/genetics , Leukocytes, Mononuclear/metabolism , Lipopolysaccharides/metabolism , Toll-Like Receptor 4/genetics , Tumor Necrosis Factor-alpha/metabolism , Alleles , Genotype , Heterozygote , Homozygote , Humans , Immunity, Innate , Interleukin-10/metabolism , Leukocytes, Mononuclear/cytology , Lipopolysaccharides/immunology , Polymorphism, Single Nucleotide , RNA, Messenger/analysis , Signal Transduction/immunology , Toll-Like Receptor 4/immunology , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/immunology
5.
J Endotoxin Res ; 12(3): 171-80, 2006.
Article in English | MEDLINE | ID: mdl-16719988

ABSTRACT

More than 90% of all publications on endotoxin were carried out with endotoxins (lipopolysaccharide, LPS) from enterobacteriaceae. We compared the immune stimulatory potency of 11 different LPSs using human whole blood incubations. While the majority of LPSs induced cytokine release equipotently, a 1,000-fold more LPS from Pseudomonas aeruginosa or Vibrio cholerae was still less potent in inducing TNF, IL-1 beta, IL-10 and IFN-gamma though it potently induced nanogram quantities IL-8. All LPSs tested, regardless of the micro-organism, showed Toll-like receptor (TLR)4-dependence, except for the LPSs from P. aeruginosa and V. cholerae, which were both TLR4- and TLR2-dependent. Interestingly, UV-inactivated P. aeruginosa bacteria, although Gram-negative, also showed TLR2- and TLR4-dependence. Re-purification of commercial LPS preparations by phenol re-extraction led to a complete loss of the TLR2 dependency, indicating contamination with lipoproteins. In the Limulus amebocyte lysate assay, often performed to exclude contamination in purified water likely to originate from P. aeruginosa, P. aeruginosa LPS was only 2-fold less potent than LPS from S. abortus equi or the assay standard LPS from E. coli. This results in an overestimation of pyrogenic burden by a factor of 500 in the sample when compared with the biological activity of highly purified P. aeruginosa LPS in human whole blood.


Subject(s)
Bacterial Toxins/toxicity , Leukocytes/drug effects , Limulus Test/methods , Lipopolysaccharides/toxicity , Animals , Blood/drug effects , Blood/metabolism , Bone Marrow Cells/drug effects , Bone Marrow Cells/immunology , Cytokines/metabolism , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay , Escherichia coli/immunology , Humans , Leukocytes/immunology , Leukocytes/metabolism , Lipopolysaccharides/classification , Lipopolysaccharides/immunology , Mice , Mice, Inbred C3H , Mice, Knockout , Pseudomonas aeruginosa/immunology , Toll-Like Receptors/genetics , Toll-Like Receptors/immunology , Toll-Like Receptors/metabolism
6.
J Interferon Cytokine Res ; 26(12): 887-92, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17238831

ABSTRACT

Immune defense capacity differs between men and women. Whereas men are more prone to infection and sepsis, women more commonly develop autoimmune diseases. We investigated the difference in cytokine secretion between males and females in response to different immune stimuli. Whole blood from 154 healthy volunteers (age 24 +/- 5.2; 82 females, 72 males) was collected within 2 h on 2 consecutive days. Blood from males produced significantly more tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, and IL-8 than blood from females in response to a high concentration of either lipopolysaccharide (LPS) or lipoteichoic acid (LTA), whereas IL-10 and interferon-gamma (IFN-gamma) secretion did not differ. Normalization of cytokine measurement to individual monocyte counts cancelled these differences for all parameters except TNF-alpha. Stimulation with a lower concentration of LPS (100 pg/mL) produced even stronger differences in cytokine release, which were not cancelled by normalization to the producing cells. The coefficients of variation (CV) of the LPS-induced and LTA-induced cytokine responses were higher in blood from women than men for all parameters and stimuli measured. Thus, the stronger innate immune response of males in comparison to females appears to stem not only from a difference in monocyte counts but also from the steepness of the response curve.


Subject(s)
Cytokines/blood , Immunity, Innate/drug effects , Lipopolysaccharides/pharmacology , Teichoic Acids/pharmacology , Adult , Blood Cells/drug effects , Blood Cells/immunology , Female , Humans , Immunity, Innate/immunology , Male , Monocytes/drug effects , Monocytes/immunology , Sex Factors
7.
Immunobiology ; 216(1-2): 24-31, 2011.
Article in English | MEDLINE | ID: mdl-20413180

ABSTRACT

Investigating the expression of lipoteichoic acid (LTA) from Listeria monocytogenes, we found two distinct structural variants of LTA (LTA1 and LTA2) using NMR and MS technology. While both LTA consisted of a poly-glycerophosphate backbone (differing in length) bound via a disaccharide to a diacyl-glycerol moiety, one LTA type (LTA2) possessed a second diacyl-glycerol moiety linked to the disaccharide via a phosphodiester. As examined in vitro, LTA2 in contrast to LTA1 failed to activate the L-ficolin dependent pathway of complement. Most interestingly, growth temperature had a strong influence on the expression levels of LTA1 and LTA2 in the cell wall: while the amount of LTA1 was comparable, the expression of LTA2 was low when Listeria had grown at room temperature (ratio of LTA1 to LTA2 was 1:0.06), but increased when Listeria had been cultivated at 37°C (ratio of LTA1 to LTA2 was 1:0.68). The observed shift in LTA expression, probably accompanying the switch from the saprophytic to the virulent entity, indicates an important adaptation to the different structural requirements inside the host cells.


Subject(s)
Lipopolysaccharides/chemistry , Lipopolysaccharides/metabolism , Listeria monocytogenes/physiology , Monocytes/metabolism , Teichoic Acids/chemistry , Teichoic Acids/metabolism , Temperature , Antigenic Variation/drug effects , Bacterial Adhesion/drug effects , Cell Growth Processes/drug effects , Cell Line , Complement Activation/drug effects , Complement Activation/immunology , Humans , Lectins/metabolism , Lipopolysaccharides/immunology , Listeriosis , Magnetic Resonance Spectroscopy , Molecular Structure , Monocytes/immunology , Monocytes/microbiology , Monocytes/pathology , Teichoic Acids/immunology , Ficolins
9.
Eur J Immunol ; 36(2): 371-9, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16453387

ABSTRACT

To investigate the circadian rhythm of inducible cytokine release and a potential pacemaker role of endogenous cortisol, cortisol levels as well as cytokine release from ex vivo LPS-stimulated blood were assessed at 4-h intervals over 24 h in 11 volunteers. We found a significant diurnal variation for IFN-gamma and IL-8, and a tendency for TNF, all inversely correlated to the serum cortisol levels, but no evidence for such a rhythm for IL-1beta and IL-6. In vitro IC(50) values for cytokine inhibition by hydrocortisone (HC) corresponded to the observed rank order for circadian rhythmicity. mRNA analyses revealed that this was due to a reduction of gene transcription. These effects of HC were significantly reversed by the glucocorticoid receptor antagonist RU486. Supplementation of HC in vivo to maintain morning cortisol levels throughout the day blunted the circadian rhythm of ex vivo LPS-induced cytokines. Surprisingly, no significant diurnal variation for any investigated cytokine was found in the same volunteer group upon stimulation with lipoteichoic acid (LTA), the gram-positive counterpart to LPS. Furthermore, 10-50-fold higher HC concentrations as compared to LPS were required to block LTA-induced cytokine release. LTA, in contrast to LPS, failed to activate Jun kinase, a reported target for HC action.


Subject(s)
Blood Cells/immunology , Circadian Rhythm/immunology , Hydrocortisone/immunology , Lipopolysaccharides/pharmacology , Teichoic Acids/pharmacology , Abortifacient Agents, Steroidal/pharmacology , Adult , Blood Cells/cytology , Blood Cells/metabolism , Cells, Cultured , Circadian Rhythm/drug effects , Cytokines/biosynthesis , Cytokines/immunology , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Enzyme Activation/immunology , Gene Expression Regulation/drug effects , Gene Expression Regulation/immunology , Humans , Hydrocortisone/blood , Lipopolysaccharides/immunology , Male , Mifepristone/pharmacology , Oncogene Protein p65(gag-jun)/immunology , Oncogene Protein p65(gag-jun)/metabolism , Receptors, Glucocorticoid/antagonists & inhibitors , Receptors, Glucocorticoid/immunology , Receptors, Glucocorticoid/metabolism , Teichoic Acids/immunology , Transcription, Genetic/drug effects , Transcription, Genetic/immunology
SELECTION OF CITATIONS
SEARCH DETAIL