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Background: We performed an in vitro elicitation test to determine the ability of different types of wheat-allergic patients' IgE to induce humanized mast cell activation after the addition of various time-treated acid-hydrolyzed wheat proteins (HWPs)., Methods: The reactivity of heat- and various time-treated acid-hydrolyzed glutens (acid-HGs) and commercial acid-HWP (HWP1), using serum IgE from wheat allergy accompanied by skin and rhinoconjunctival sensitization to HWP1 in the facial soap, pediatric subjects with food allergy to native wheat, adult wheat-dependent exercise-induced anaphylaxis subjects, and nonatopic healthy subjects, was elucidated by dot blot and a luciferase assay-based in vitro elicitation test (EXiLE test)., Results: Serum from subjects sensitized with HWP1 reacted only to acid-HGs (acid-HGs treated for 0.5-3 or 6 h), but not native gluten, in the results of the dot blot. In contrast, sera from pediatric subjects sensitized with native wheat reacted to native gluten more strongly and showed only slight reactions to 0.5- to 1-hour-treated acid-HGs. The results of the in vitro elicitation test showed that acid hydrolyzation of the gluten attenuated antigen-induced luciferase expression in a time-dependent manner for sera from native-wheat-sensitized pediatric subjects. On the other hand, in the sera from HWP1-sensitized subjects, acid hydrolyzation of the gluten for 0.5 h dramatically increased luciferase expression., Conclusions: Even after prolonged hydrolyzation, acid-HGs still retained the ability to activate mast cells in the case of HWP1-sensitized subjects., (Copyright © 2012 S. Karger AG, Basel.)

Propolis is considered to down-regulate type I allergy, but the effective components of propolis remain unknown. In addition, propolis components vary depending on the area from which they are collected due to variations among wild plants in an area. Therefore, we compared the effects of water and ethanol extracts of propolis from Brazil and China on mast cell degranulation and cytokine production, thereby identifying effective components in propolis. The amount of released beta-hexosaminidase via high-affinity IgE receptor I (Fc epsilon RI) from rat basophilic leukemia (RBL-2H3) cells was used as an index of degranulation. All propolis extracts inhibited degranulation from antigen-stimulated RBL-2H3 cells, but the effective doses differed according to collection areas. The ethanol extract of Chinese propolis, which was the strongest inhibitor of mast cell degranulation, was divided into compounds using normal- and reversed-phase liquid chromatography. The isolated anti-allergic components were identified as chrysin, kaempferol and its derivative, and chrysin was revealed to inhibit IL-4 and MCP-1 production from antigen-stimulated RBL-2H3 cells. HPLC quantification also revealed the Brazilian propolis extract to contain only small amounts of these flavonoids, which suggested that variation in propolis components could affect anti-allergic properties., ((c) 2010 Elsevier B.V. All rights reserved.)

The Ca(2+)-promoted Ras inactivator (CAPRI), a Ras GTPase-activating protein, is involved in the inactivation of mitogen-activated protein kinase pathway. However, a precise role of CAPRI in immune responses is still unknown. Here we showed that overexpression of CAPRI suppresses antigen-induced degranulation and cytokine production in mast cells (RBL cells). Antigen elicited the translocation of CAPRI to the plasma membrane from the cytoplasm, which was concomitant with the increase in the intracellular Ca(2+) concentration. The nuclear import of extracellular signal-regulated kinase 2 (ERK2) occurred after the re-localization of CAPRI to the cytoplasm in the mast cells, suggesting that the early phase of ERK2 activation is eliminated. A mutant of GAP-related domain, CAPRI(R472S), showed a feeble translocation to the plasma membrane but did not affect the degranulation, ERK2 activation, and cytokine production. The results suggested that the translocation of CAPRI to the plasma membranes regulates crucially cellular responses in mast cells.

Background: An in vitro elicitation test employing human high-affinity IgE receptor-expressing rat mast cell lines appears to be a useful method for measuring mast cell activation using a patient's IgE and an allergen; however, such cell lines are sensitive to human complements in the serum. We have recently developed a new luciferase-reporting mast cell line (RS-ATL8) to detect IgE crosslinking-induced luciferase expression (EXILE) with relatively low quantities of serum IgE. Methods: A total of 30 patients suspected of having egg white (EW) allergy were subjected to an oral food challenge (OFC) test; then, the performances of EW-specific serum IgE (CAP-FEIA), EW-induced degranulation, and EXILE responses in RS-ATL8 cells were compared using receiver-operating characteristic (ROC) curve analysis. The patients' sera were diluted to 1 : 100, which causes no cytotoxicity when sensitizing the RS-ATL8 cells for the degranulation and EXILE tests. Results: The area under the ROC curves was highest in the EXILE test (0.977), followed by CAP-FEIA (0.926) and degranulation (0.810). At an optimal cutoff range (1.648-1.876) calculated from the ROC curve of the EXiLE test, sensitivity and specificity were 0.944 and 0.917, respectively. A 95% positive predictive value was given at a cutoff level of 2.054 (fold increase in luciferase expression) by logistic regression analysis. Conclusions: In contrast to in vivo tests, the EXILE test appears to be a useful tool in diagnosing patients suspected of having IgE-dependent EW allergy without the risk of severe systemic reactions. [ABSTRACT FROM AUTHOR]