PURPOSE The mast cell plays a pivotal role in the human immune response. Crosslinking of 2 IgE molecules bound to the high affinity IgE receptor (FcεRI) on the surface of the mast cell results in mast cell degranulation and the release of several proinflammatory mediators. Patients with type-I allergy have increased levels of IgE in the blood compared to healthy individuals. METHODS In a 6-we...

The mechanism of chronic mast cell activation in asthma is unclear. Monomeric immunoglobulin (Ig)E in the absence of allergen induces mediator release from rodent mast cells, indicating a possible role for IgE in the continued activation of mast cells within the asthmatic bronchial mucosa. In this study it was investigated whether monomeric IgE induces Ca2+ influx and mediator release from huma...

The Tec family tyrosine kinase, IL-2-inducible T cell kinase (Itk), is expressed in T cells and mast cells. Mice lacking Itk exhibit impaired Th2 cytokine secretion; however, they have increased circulating serum IgE, but exhibit few immunological symptoms of allergic airway responses. We have examined the role of Itk in mast cell function and FcepsilonRI signaling. We report in this study that...

The present study was conducted to examine the effects of two protein tyrosine kinase inhibitors, genistein and tyrphostin 47, on an in vitro model of allergic asthma. Guinea pigs were sensitized with purified IgG raised against ovalbumin (OA). Isolated sensitized bronchial rings contracted in response to OA in a concentration-dependent manner, maximum contraction being achieved at 1 microg/ml....

Upon various stimulations, mast cells (MCs) release a wide variety of chemical mediators stored in their cytoplasmic granules, which then initiates subsequent allergic reactions. Lysophosphatidylserine (LysoPS), a kind of lysophospholipid, potentiates the histamine release from MCs triggered by antigen stimulation. We previously showed through structure-activity studies of LysoPS analogs that L...

Mast cells are critical actors of hypersensitivity type I (allergic) reactions by the release of vasoactive and proinflammatory mediators following their activation by aggregation of the high-affinity receptor for immunoglobulin E (FcεRI). We have previously identified Phospholipid Scramblase 1 (PLSCR1) as a new molecular intermediate of FcεRI signaling that amplifies degranulation of the rat m...

The Vitamin-A-metabolite retinoic acid (RA) acts as a master regulator of cellular programs. Mast cells (MCs) are primary effector cells of type-I-allergic reactions. We recently uncovered that human cutaneous MCs are enriched with RA network components over other skin cells. Yet, direct experimental evidence on the significance of the RA-MC axis is limited. Here, skin-derived cultured MCs were...

Mast cells perform a significant role in the host defense against parasitic and some bacterial infections. Here we show that in the dog, degranulation of brain mast cells evokes hypothalamic-pituitary-adrenal responses via histamine release. A large number of mast cells were found in a circumscribed ventral region of the hypothalamus, including the pars tuberalis and median eminence. When these...

We used light and electron microscopy to analyze the eyelid inflammation that develops in transgenic mice that overexpress interleukin-4 (IL-4; Tepper et al, Cell 62:457, 1990). Analysis of alkaline Giemsa-stained plastic sections examined by light microscopy (Dvorak et al, J Exp Med 132:558, 1970), as well as by routine transmission electron microscopy, indicated that the mast cells in the inf...