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Mast Cell Line (mast + cell_line)

Distribution by Scientific Domains

Medical Sciences	88%

Selected Abstracts

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]

Proteasome-driven turnover of tryptophan hydroxylase is triggered by phosphorylation in RBL2H3 cells, a serotonin producing mast cell line

FEBS JOURNAL, Issue 19 2002
Yoshiko Iida
We previously demonstrated in mast cell lines RBL2H3 and FMA3 that tryptophan hydroxylase (TPH) undergoes very fast turnover driven by 26S-proteasomes [Kojima, M., Oguro, K., Sawabe, K., Iida, Y., Ikeda, R., Yamashita, A., Nakanishi, N. & Hasegawa, H. (2000) J. Biochem (Tokyo) 2000, 127, 121,127]. In the present study, we have examined an involvement of TPH phosphorylation in the rapid turnover, using non-neural TPH. The proteasome-driven degradation of TPH in living cells was accelerated by okadaic acid, a protein phosphatase inhibitor. Incorporation of 32P into a 53-kDa protein, which was judged to be TPH based on autoradiography and Western blot analysis using anti-TPH serum and purified TPH as the size marker, was observed in FMA3 cells only in the presence of both okadaic acid and MG132, inhibitors of protein phosphatase and proteasome, respectively. In a cell-free proteasome system constituted mainly of RBL2H3 cell extracts, degradation of exogenous TPH isolated from mastocytoma P-815 cells was inhibited by protein kinase inhibitors KN-62 and K252a but not by H89. Consistent with the inhibitor specificity, the same TPH was phosphorylated by exogenous Ca2+/calmodulin-dependent protein kinase II in the presence of Ca2+ and calmodulin but not by protein kinase A (catalytic subunit). TPH protein thus phosphorylated by Ca2+/calmodulin-dependent protein kinase II was digested more rapidly in the cell-free proteasome system than was the nonphosphorylated enzyme. These results indicated that the phosphorylation of TPH was a prerequisite for proteasome-driven TPH degradation. [source]

Phlomis umbrosa root inhibits mast cell-dependent allergic reactions and inflammatory cytokine secretion

PHYTOTHERAPY RESEARCH, Issue 2 2008
Tae-Yong Shin
Abstract The effect of an aqueous extract of Phlomis umbrosa Turcz. (Labiatae) root (PUAE) on mast cell-dependent allergic reactions and inflammatory cytokine secretion were investigated. PUAE (0.01,1 g/kg) inhibited compound 48/80-induced systemic allergic reaction. When PUAE was employed in a systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. PUAE (0.1 and 1 g/kg) also significantly inhibited the local allergic reaction activated by anti-dinitrophenyl (DNP) IgE. PUAE (0.001,1 mg/mL) dose-dependently inhibited the histamine release from rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE. PUAE (0.01,1 mg/mL) inhibited the secretion of interleukin (IL)-1, in phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated human mast cell line (HMC-1) cells. PUAE (1 mg/mL) inhibited the gene expression and production of the main inflammatory cytokine, TNF- ,, in HMC-1 cells. These results provide evidence that PUAE may be beneficial in the treatment of allergic diseases. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Nicotinic acetylcholine receptors on basophils and mast cells

ANAESTHESIA, Issue 12 2006
P. S. Sudheer
Summary Anaphylaxis in response to drugs administered during anaesthesia is a rare but potentially catastrophic event. The anaesthetic drugs most commonly associated with anaphylaxis are neuromuscular blocking agents. As these drugs act on the nicotinic acetylcholine receptor of the neuromuscular junction, potentiation of anaphylaxis by a nicotinic receptor on basophils and mast cells is plausible. The aim of this study was to investigate whether nicotinic acetylcholine receptors are present on a human basophil and mast cell lines as their presence may suggest a mechanism of associated anaphylaxis. Nicotinic receptors were demonstrated on a basophil and a mast cell line using an ,-bungarotoxin,fluorescein conjugate by flow cytometry and by both conventional and confocal microscopic techniques. The identity of this receptor was confirmed by reverse transcriptase PCR and quantitative PCR. [source]

Blockade of superoxide generation prevents high-affinity immunoglobulin E receptor-mediated release of allergic mediators by rat mast cell line and human basophils

CLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2002
T. Yoshimaru
Summary Background Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. Objective The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. Methods RBL-2H3 cells were directly stimulated with anti-rat Fc,RI ,-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human Fc,RI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). Results Cross-linking of Fc,RI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-Fc,RI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-Fc,RI mAb or by allergen in parallel. Conclusion These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon Fc,RI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders. [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]

Human mast cells express androgen receptors but treatment with testosterone exerts no influence on IgE-independent mast cell degranulation elicited by neuromuscular blocking agents

EXPERIMENTAL DERMATOLOGY, Issue 3 2010
WenChieh Chen
Please cite this paper as: Human mast cells express androgen receptors but treatment with testosterone exerts no influence on IgE-independent mast cell degranulation elicited by neuromuscular blocking agents. Experimental Dermatology 2010; 19: 302,304. Abstract:, Women predominate in the anaphylactic reactions to neuromuscular blocking agents (NMBA). The expression of oestrogen receptors has been demonstrated in mast cells and oestrogen treatment can enhance mast cell degranulation, but the influence of androgens remains largely unclear. Our immunocytochemical study showed the expression of androgen receptor (AR) in mast cells isolated from human foreskin as well as in two human mast cell lines, HMC-1 and LAD2. The amount of AR was most abundant in human skin mast cells as determined by real-time polymerase chain reaction analysis. Treatment of the HMC-1 mast cells with testosterone or 17,-oestradiol, alone or in combination with different NMBA, did not affect mast cell degranulation as measured by the release of ,-hexosaminidase. Our study shows for the first time the expression of AR in human skin mast cells. Further studies using primary human mast cell cultures are needed to understand whether and how sex hormones can influence mast cell activation. [source]