antigen-presenting cells through the high-affinity receptor for IgE (FcεRI) represents a key pathomechanism in type I allergy and many forms of asthma. Objective: We sought to establish an in vitro molecular model for the interaction of human FcεRI, IgE, and the corresponding allergen and to identify monoclonal anti-human IgE antibodies with a therapeutic profile different from previously estab...

FcεRI aggregation on the surface of mast cells results in degranulation, a response which is potentiated by binding of stem cell factor (SCF) to its receptor Kit. We observed that one of the major initial signaling events associated with FcεRI-mediated activation of human mast cells (HuMCs) is the rapid tyrosine phosphorylation of a protein of 25-30 kD. The phosphorylation of this protein was a...

Ag-mediated crosslinking of IgE-FcεRI complexes activates mast cells and basophils, initiating the allergic response. Of 34 donors recruited having self-reported shrimp allergy, only 35% had significant levels of shrimp-specific IgE in serum and measurable basophil secretory responses to rPen a 1 (shrimp tropomyosin). We report that degranulation is linked to the number of FcεRI occupied with a...

BACKGROUND The etiology of chronic idiopathic urticaria (CIU) is not completely clear. There are a few antibodies were reported to correlate with CIU. OBJECTIVE To investigate the correlation these antibodies and CIU. METHODS The autologous serum skin test (ASST) and allergens were performed. Serum levels of immunoglobulin E (IgE), anti-FcεRI and anti-IgE, anti-Helicobacter pylori (HP) anti...

We examined the spatial targeting of early and downstream signaling mediated by the IgE receptor (FcεRI) in RBL mast cells utilizing surface-patterned 2,4 dinitrophenyl (DNP) ligands. Micron-sized features of DNP are presented as densely immobilized conjugates of bovine serum albumin (DNP-BSA) or mobile in a supported lipid bilayer (DNP-SLB). Although soluble anti-DNP IgE binds uniformly across...

Rictor is a regulatory component of the mammalian target of rapamycin (mTOR) complex 2 (mTORC2). We have previously demonstrated that rictor expression is substantially downregulated in terminally differentiated mast cells as compared with their immature or transformed counterparts. However, it is not known whether rictor and mTORC2 regulate mast cell activation. In this article, we show that m...

The role of IgE in allergic disease mechanisms is performed principally through its interactions with two receptors, FcεRI on mast cells and basophils, and CD23 (FcεRII) on B cells. The former mediates allergic hypersensitivity, the latter regulates IgE levels, and both receptors, also expressed on antigen-presenting cells, contribute to allergen uptake and presentation to the immune system. We...

The high-affinity IgE receptor, FcεRI, which is composed of α-, β-, and γ-chains, plays an important role in IgE-mediated allergic responses. In the current study, involvement of the transcription factors, PU.1, GATA1, and GATA2, in the expression of FcεRI on human mast cells was investigated. Transfection of small interfering RNAs (siRNAs) against PU.1, GATA1, and GATA2 into the human mast cel...

ige-mediated cell signaling, induced by cross-linking of high affinity receptor for ige (fcεri) in the presence of antigen (ag), is a well known mechanism described for mast cell activation in allergy and hypersensitivity reactions, which induces a spectrum of cellular responses such as secretion and up-regulation of cell surface fcεri. although for several years  ige  binding  to  fcεri  was  ...

Engagement of high-affinity immunoglobulin E receptors (FcεRI) activates two signaling pathways in mast cells. The Lyn pathway leads to recruitment of Syk and to calcium mobilization whereas the Fyn pathway leads to phosphatidylinositol 3-kinase recruitment. Mapping the connections between both pathways remains an important task to be completed. We previously reported that Phospholipid Scrambla...