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High-affinity IgE Receptor (high-affinity + ige_receptor)

Distribution by Scientific Domains

Medical Sciences	87%

Selected Abstracts

Mast cell regulation of epithelial TSLP expression plays an important role in the development of allergic rhinitis

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2008
Masanori Miyata
Abstract Epithelial cell-derived thymic stromal lymphopoietin (TSLP) is a master switch for asthma or atopic dermatitis by inducing a dendritic cell-mediated Th2-type allergic inflammation. Allergic rhinitis is also pathologically characterized by Th2-type allergic inflammation. This study demonstrates that mast cells regulate the epithelial TSLP expression in allergic rhinitis. TSLP expression was found to be up-regulated predominantly in the nasal epithelium in the ovalbumin (OVA)-sensitized and -nasally challenged mouse model of allergic rhinitis, which was abolished in mast cell-deficient WBB6F1-W/Wv in comparison with control WBB6F1-+/+ mice. Similarly, the epithelial TSLP expression was reduced in Fc receptor , chain (Fc,R)-deficient mice, where the high-affinity IgE receptor (Fc,RI) is not expressed on mast cells, in comparison with control C57BL/6 mice. Furthermore, the administration of neutralizing TSLP antibody during the challenge phase of OVA inhibited the development of allergic rhinitis. These results suggest that the direct stimulation of epithelial cells by antigens alone may not be sufficient to induce TSLP expression in the nasal epithelium, and that mast cell regulation of epithelial TSLP expression, possibly via Fc,RI, plays an important role in the development of allergic rhinitis. [source]

Mast cell lines HMC-1 and LAD2 in comparison with mature human skin mast cells , drastically reduced levels of tryptase and chymase in mast cell lines

EXPERIMENTAL DERMATOLOGY, Issue 9 2010
Sven Guhl
Please cite this paper as: Mast cell lines HMC-1 and LAD2 in comparison with mature human skin mast cells , drastically reduced levels of tryptase and chymase in mast cell lines. Experimental Dermatology 2010; 19: 845,847. Abstract:, To circumvent the costly isolation procedure associated with tissue mast cells (MC), two human MC lines, i.e. HMC-1 and LAD2, are frequently employed, but their relation to mature MC is unknown. Here, we quantitatively assessed their expression of MC markers in direct comparison to skin MC (sMC). sMC expressed all lineage markers at highest and HMC-1 cells at lowest levels. LAD2 cells expressed comparable high-affinity IgE receptor , (Fc,RI,) and Fc,RI, but less Fc,RI, than sMC and displayed slightly reduced, but robust Fc,RI-mediated histamine release. Only minor differences were found for total histamine content and c-Kit expression. Huge, and to this level unexpected, differences were found for MC tryptase and chymase, with sMC >>> LAD2 > HMC-1. Taken together, HMC-1 cells represent very immature malignantly transformed MC, whereas LAD2 cells can be considered intermediately differentiated. Because of the minute levels of MC proteases, MC lines can serve as surrogates of tissue MC to a limited degree only. [source]

Semi-purification of the immunoglobulin E-sweat antigen acting on mast cells and basophils in atopic dermatitis

EXPERIMENTAL DERMATOLOGY, Issue 4 2006
A. Tanaka
Background:, Sweating aggravates the symptoms of atopic dermatitis (AD). We have recently reported positive skin reactions and histamine release from basophils in response to autologous sweat in patients with AD. Objective:, To characterize the biochemical and immunological properties of the substance in sweat that evokes histamine release and to study the usability of the basophil-histamine release test with the sweat antigen for AD. Methods:, Sweat collected from healthy volunteers was purified using chromatographies. Serum immunoglobulin (Ig)E of four patients with AD were purified using an affinity-chromatography column with anti-IgE antibodies. The amount of semi-purified sweat antigen (138 ng protein/ml) that induced a half-maximum reaction of basophils of a patient with AD was utilized for the basophil histamine release test. The involvement of specific IgE and high-affinity IgE receptor (Fc,RI) in the reactions was examined using basophils of healthy volunteers, a human mast cell line (LAD2), and a rat basophilic leukemia cell line transfected with human ,-subunit of Fc,RI (RBL-48). Results:, The semi-purified sweat antigen induced histamine release from the basophils of 47 of 61 (74.6%) patients with AD and four of 46 (8.7%) healthy controls. Both basophils and mast cells sensitized with the patient-derived IgE showed degranulation upon stimulation with the sweat antigen. However, no reaction was observed when cells were sensitized with myeloma IgE or the antigen was treated with proteases. Conclusion:, The semi-purified standardized sweat antigen consists of a protein that induces degranulation of basophils and mast cells via antigen-specific IgE and Fc,RI in patients with AD. [source]

Differential expression of mast cell characteristics in human myeloid cell lines

EXPERIMENTAL DERMATOLOGY, Issue 9 2004
Pia Welker
Abstract:, In order to better understand the mechanisms governing display of mast cell characteristics in human myeloid cells, we have studied the mast cell phenotype in human promyelocytic (HL-60) and myelocytic (U-937, TPH-1) vs. basophilic (KU-812) and mast cell (HMC-1) lines, in part also in skin mast cells and blood monocytes, at mRNA and protein level before and after stimulation with mast cell growth factors. In unstimulated cells, mRNA for the stem cell factor (SCF) receptor c-kit and the gamma chain of the high-affinity IgE receptor (Fc,RI) was noted in all cells studied. Like mast and basophilic cells, THP-1 cells expressed the Fc,RI, and , chains and weakly histidine decarboxylase (HDC), but they lacked mRNA for mast cell-specific proteases [tryptase, chymase, carboxypeptidase A (CPA)]. In contrast, HL-60 and U-937 cells lacked Fc,RI,, but expressed tryptase and chymase, HL-60 cells also CPA. KU-812 cells failed to express the basophil-specific marker 2D7. After a 10-day culture with SCF or fibroblast supernatants, baseline mRNA expression of most mast cell characteristics was upregulated, whereas c-kit mRNA expression decreased in all but THP-1 cells. Differential mRNA expression of Fc,RI vs. protease (tryptase) was confirmed at protein level by immunocytochemistry and enzymatic activity. KU-812 cells are thus closest to skin mast cells in that they express all molecules studied, except for chymase, followed by THP-1 cells that lack all mast cell proteases. In contrast, HL-60 and U-937 cells fail to express the Fc,RI, and , chains but express most mast cell proteases. The selective and differential expression of mast cell characteristics in human myeloid cell lines suggests that induction of the mast cell phenotype is regulated by several independent genes and that mast cells and basophils branch off at early and distinct points of myeloid development. [source]

Infiltrating cells and related cytokines in lesional skin of patients with chronic idiopathic urticaria and positive autologous serum skin test

EXPERIMENTAL DERMATOLOGY, Issue 5 2003
M. Caproni
Abstract:, In approximately one-third of patients with chronic idiopathic urticaria (CIU), autoantibodies against the high-affinity IgE receptor and/or against IgE can be detected and a wheal-and-flare response can be provoked by the intradermal injection of autologous serum (ASST). In this study we aimed to further characterize the inflammatory response observed in the subgroup of CIU patients with positive ASST and serum-evoked histamine-release in vitro from basophils in comparison with unaffected skin and healthy donors. An immunohistochemical analysis of infiltrating cells (CD4, MPO, EG1, EG2, tryptase), cytokines (IL-4, IL-5, IFN-,), chemokines and chemokine receptors (IL-8, CCR3, CXCR3), and adhesion molecules (ICAM-1, VCAM-1, ELAM-1) was performed on seven selected patients (four males and three females; median age: 45 years; range: 22,57) and five healthy donors. Cytokine evaluation was also performed in five psoriatic patients to obtain an additional control. In spontaneous wheals we observed an increased number of CD4+ T lymphocytes when compared with the controls, and an increased number of neutrophils and eosinophils, whereas mast cells did not show a significant variation. A significant expression for IL-4 and IL-5 could only be observed in lesional skin, while IFN-, showed a slight expression in the same site. Chemokine receptors CCR3 and CXCR3 did not show a defined polarized response in either lesional or unaffected skin. An increased expression of all cellular adhesion molecules (CAMs) studied was detected in spontaneous wheals. The lack of a significant difference in the expression of tryptase + mast cells, T lymphocytes, IL-8, CXCR3 and CCR3, a few CAMs between the lesional and unaffected skin of CIU patients suggests a wide immunological activation that involves not only lesional tissues, but possibly extends to the whole of the skin's immune system. [source]

Fc,RI, gene (FCER1A) promoter polymorphisms and total serum IgE levels in Japanese atopic dermatitis patients

INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2010
Y. Niwa
Summary Two promoter polymorphisms of the high-affinity IgE receptor ,-subunit (Fc,RI,) gene (FCER1A), ,66T>C (rs2251746) and ,315C>T (rs2427827), were analysed in Japanese atopic dermatitis subjects. Patients with the ,315CT/TT genotype tended to have higher total serum IgE levels, while the proportion of ,315CT/TT genotype or the ,315T allele was significantly higher in those with highly elevated total serum IgE concentrations. [source]

Eosinophils in bronchial mucosa of asthmatics after allergen challenge: effect of anti-IgE treatment

ALLERGY, Issue 1 2009
E. L. J. Van Rensen
Background:, Anti-IgE, omalizumab, inhibits the allergen response in patients with asthma. This has not been directly related to changes in inflammatory conditions. We hypothesized that anti-IgE exerts its effects by reducing airway inflammation. To that end, the effect of anti-IgE on allergen-induced inflammation in bronchial biopsies in 25 patients with asthma was investigated in a randomized, double-blind, placebo-controlled study. Methods:, Allergen challenge followed by a bronchoscopy at 24 h was performed at baseline and after 12 weeks of treatment with anti-IgE or placebo. Provocative concentration that causes a 20% fall in forced expiratory volume in 1 s (PC20) methacholine and induced sputum was performed at baseline, 8 and 12 weeks of treatment. Changes in the early and late responses to allergen, PC20, inflammatory cells in biopsies and sputum were assessed. Results:, Both the early and late asthmatic responses were suppressed to 15.3% and 4.7% following anti-IgE treatment as compared with placebo (P < 0.002). This was paralleled by a decrease in eosinophil counts in sputum (4,0.5%) and postallergen biopsies (15,2 cells/0.1 mm2) (P < 0.03). Furthermore, biopsy IgE+ cells were significantly reduced between both the groups, whereas high-affinity IgE receptor and CD4+ cells were decreased within the anti-IgE group. There were no significant differences for PC20 methacholine. Conclusion:, The response to inhaled allergen in asthma is diminished by anti-IgE, which in bronchial mucosa is paralleled by a reduction in eosinophils and a decline in IgE-bearing cells postallergen without changing PC20 methacholine. This suggests that the benefits of anti-IgE in asthma may be explained by a decrease in eosinophilic inflammation and IgE-bearing cells. [source]

Conformationally Constrained Mimics of the Membrane-Proximal Domain of Fc,RI,

CHEMBIOCHEM, Issue 15 2007
Carsten Peters Dr.
Spitting image. The peptide fragment KAPREKYWL is part of the high-affinity IgE receptor and is critical in mast cell signaling. By applying ring-closing metathesis (RCM), conformationally constraint cyclic peptides were prepared that mimicked the 3D structure of KAPREKYWL. Peptide 1 (illustrated in the scheme) showed strong binding to a monoclonal anti-KAPREKYWL antibody; this was predicted by molecular modeling. [source]