sq-23377 and Hypersensitivity

Topics: Allergens; Asthma; Bronchial Provocation Tests; Bronchoalveolar Lavage Fluid; Cells, Cultured; Chemotaxis, Leukocyte; Clone Cells; Flow Cytometry; Gene Expression Regulation; Gene Rearrangement, T-Lymphocyte; Humans; Hypersensitivity; Hypersensitivity, Immediate; Inflammation; Interferon-gamma; Interleukins; Ionomycin; Lymphocyte Activation; Phytohemagglutinins; Receptors, Antigen, T-Cell, alpha-beta; Staining and Labeling; T-Lymphocyte Subsets; Tetradecanoylphorbol Acetate

The mechanisms underlying the allergy-protective effects of raw cow's milk are poorly understood. The current focus is mainly on the modulation of T cell responses. In the present study, we investigated whether raw cow's milk can also directly inhibit mast cells, the key effector cells in IgE-mediated allergic responses. Primary murine bone marrow-derived mast cells (BMMC) and peritoneal mast cells (PMC), were incubated with raw milk, heated raw milk, or shop milk, prior to IgE-mediated activation. The effects on mast cell activation and underlying signaling events were assessed. Raw milk was furthermore fractionated based on molecular size and obtained fractions were tested for their capacity to reduce IgE-mediated mast cell activation. Coincubation of BMMC and PMC with raw milk prior to activation reduced β-hexosaminidase release and IL-6 and IL-13 production, while heated raw milk or shop milk had no effect. The reduced mast cell activation coincided with a reduced intracellular calcium influx. In addition, SYK and ERK phosphorylation levels, both downstream signaling events of the FcεRI, were lower in raw milk-treated BMMC compared to control BMMC, although differences did not reach full significance. Raw milk-treated BMMC furthermore retained membrane-bound IgE expression after allergen stimulation. Raw milk fractionation showed that the heat-sensitive raw milk components responsible for the reduced mast cell activation are likely to have a molecular weight of > 37 kDa. The present study demonstrates that raw cow's milk can also directly affect mast cell activation. These results extend the current knowledge on mechanisms via which raw cow's milk prevents allergic diseases, which is crucial for the development of new, microbiologically safe, nutritional strategies to reduce allergic diseases.

Topics: Allergens; Animals; Calcium; Cattle; Cell Membrane; Cell Survival; Cells, Cultured; Cytokines; Extracellular Signal-Regulated MAP Kinases; Female; Hypersensitivity; Immunoglobulin E; Ionomycin; Mast Cells; Mice; Milk; Phosphorylation; Protein Binding; Receptors, IgE; Syk Kinase

Scopoletin is an antioxidant found in certain weedy plants. It exerts anti-inflammatory, anti-allergic, and anti-diabetic activities. It remains unknown whether scopoletin regulates T helper (Th) cells, including Th 1 and Th 2 cells. We found that scopoletin significantly inhibited phorbol myristate acetate (PMA)/ionomycin-induced interleukin-4 (IL-4), IL-5, and IL-10 production in EL-4 T cells. In addition, scopoletin significantly enhanced the inhibitory action of PMA/ionomycin on interferon-γ (IFN-γ) expression. In EL-4 T cells, PMA/ionomycin treatment markedly increased the expression of nuclear factor of activated T cells (NFAT) and GATA-3; in contrast, scopoletin significantly down-regulated expressions of these transcription factors. Furthermore, this downregulation depended on protein kinase C (PKC) attenuation. This leads us to suggest that the anti-allergic properties of scopoletin might be mediated by the downregulation of cytokine expression in Th 2 cells.

Topics: Animals; Cell Line, Tumor; Cytokines; Hypersensitivity; Interferon-gamma; Interleukin-1; Interleukin-10; Interleukin-4; Ionomycin; Lymphoma, T-Cell; Mice; Phytotherapy; Protein Kinase C; Scopoletin; Tetradecanoylphorbol Acetate; Th2 Cells

The effect of butylated hydroxytoluene (BHT), which is used widely as an antioxidant, on IgE-dependent allergic responses in vivo and in vitro was investigated. For in vivo study, passive cutaneous anaphylaxis (PCA) was elicited in rats by i.d. injection of anti-DNP IgE and 48 h later by i.v. injection of DNP-HSA. BHT was i.p. given immediately after anti-DNP IgE injection. For in vitro studies, the rat mast cell line RBL2H3 sensitized with monoclonal anti-dinitrophenol (DNP) IgE was challenged with the multivalent antigen DNP-human serum albumin (DNP-HSA) in the presence or absence of BHT. beta-Hexosaminidase and histamine released from RBL2H3 cells, as indicators of degranulation of the cells, the concentration of intracellular Ca2+, the level of phosphorylated-Akt, and global tyrosine phosphorylation as indicators of mast cell activation, were measured. The results showed that BHT given to anti-DNP IgE-sensitized rats augmented DNP-specific PCA in a dose-dependent manner. In the presence of BHT, IgE-induced releases of beta-hexosaminidase and histamine from RBL2H3 cells were increased. BHT also further elevated IgE-mediated increased concentrations of intracellular Ca2+ and the levels of phosphorylated-Akt, but did not affect global tyrosine phosphorylation, in RBL2H3 cells. Moreover, the PI3K inhibitor LY294002 inhibited IgE-dependent degranulation and its enhancement by BHT. These findings indicate that BHT may upregulate PCA by enhancing mast cell degranulation associated with enhancements of intracellular Ca2+ concentration and PI3K activation, suggesting that BHT might affect allergic diseases such as allergic rhinitis and asthma.

Topics: Animals; Antioxidants; beta-N-Acetylhexosaminidases; Butylated Hydroxytoluene; Calcium; Cell Degranulation; Cell Line, Tumor; Dinitrophenols; Dose-Response Relationship, Drug; Histamine Release; Hypersensitivity; Intracellular Fluid; Ionomycin; Ionophores; Male; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, IgE; Time Factors; Tyrosine

C-C chemokines and adhesion molecules expressed on eosinophils play an important role in the pathology of allergic inflammatory disease. C-C chemokines such as eotaxin or RANTES are involved in beta(2) integrin expression on purified eosinophils; so far we have no data on unpurified eosinophils in the peripheral blood. We measured beta(1) and beta(2) integrin activation after stimulation with eotaxin or RANTES in vitro using whole-blood flow-cytometric analysis.. Heparinized whole blood obtained from allergic patients with eosinophilia or normal subjects was diluted with the same volume of RPMI 1640, and then cells were incubated in the presence or absence of PMA/ionomycin or chemokines for 45 min at 37 degrees C. After hemolyzation with lysing solution, expression of CD11b, CD11a, CD18 and CD49d on eosinophils was measured using flow cytometry.. The expression of CD11b, CD11a and CD18 in allergic patients was significantly higher than that in normal subjects. CD11b and CD18 expression showed a significant increase after stimulation with C-C chemokines, which was remarkable in allergic patients.. Eosinophils in the blood of allergic patients exhibited a higher expression of beta(2) integrins and were more sensitive to RANTES and eotaxin than those of normal subjects.

Topics: Adult; CD11a Antigen; CD11b Antigen; CD18 Antigens; Chemokine CCL11; Chemokine CCL5; Chemokines, CC; Eosinophilia; Eosinophils; Female; Flow Cytometry; Humans; Hypersensitivity; Integrin beta Chains; Ionomycin; Male; Middle Aged; Tetradecanoylphorbol Acetate

IL-4 plays a pivotal role in the development of allergic inflammation via induction of IgE isotype switching, increase of IgE receptor expression, promoting Th2 cell differentiation, and stimulating several genes involved in atopic disorders. Previous studies in human and mouse models have shown that high vitamin E intake correlates with low IgE concentration and reduced prevalence of allergic reactions. We, therefore, investigated the mechanism of the vitamin E effect on T cells. We show here that the natural free radical scavenger vitamin E suppresses IL-4 protein levels in human peripheral blood T cells in a dose-dependent manner. The effect of vitamin E on IL-4 expression occurs at the mRNA level. Vitamin E has been implicated in inhibition of DNA binding and function of the redox-regulated transcription factors NF-kappaB and AP-1. Investigation of the molecular mechanism by which vitamin E suppresses IL-4 transcription shows that it blocks binding of transcription factors to two important IL-4 promoter binding sites for NF-kappaB and AP-1 and interferes with promoter activity upon T cell activation. Our data provide molecular evidence supporting the beneficial effect of dietary vitamin E on atopic disorders.

Topics: Antibodies, Monoclonal; Binding Sites; Depression, Chemical; Gene Expression Regulation; Humans; Hypersensitivity; Interleukin-2; Interleukin-4; Ionomycin; Jurkat Cells; Lymphocyte Activation; NF-kappa B; Promoter Regions, Genetic; RNA, Messenger; T-Lymphocytes; Tetradecanoylphorbol Acetate; Transcription Factor AP-1; Vitamin E

Mast cells reside in tissues, where upon activation through the high-affinity-IgE-receptor (FcepsilonRI) they degranulate and orchestrate the allergic reaction. Mast cells survive this activation and can thus be reactivated. In this study we demonstrate that this process depends on the pro-survival gene A1. Activation of mast cells through FcepsilonRI resulted in degranulation, strong induction of A1 mRNA and protein, and cell survival. In contrast, A1-deficient mast cells released granule mediators similar to the wild-type control, but the cells did not survive an allergic activation. Furthermore, A1(-/-) mice that had been sensitized and provoked with allergen exhibited a lower number of mast cell compared with littermate controls. The induction of A1 was dependent on calcium, as EDTA prevented A1 expression. The calcium ionophore, ionomycin, induced A1 expression and mast cell survival, whereas compound 48/80, a well-known mast cell secretagogue, did not. This study uncovers the importance of A1 for mast cell survival in allergic reactions, and it proposes A1 as a potential target for the treatment of allergic diseases.

Topics: Animals; Apoptosis; Cell Line; Cell Survival; DNA-Binding Proteins; Granulocyte-Macrophage Colony-Stimulating Factor; Hypersensitivity; Interleukin-3; Interleukin-4; Ionomycin; Mast Cells; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Nerve Growth Factor; p-Methoxy-N-methylphenethylamine; Proto-Oncogene Proteins c-bcl-2; Receptors, IgE; Replication Protein C; Stem Cell Factor; Up-Regulation