Studies on the mechanisms involved in antigen-evoked pleural inflammation in rats: contribution of IgE and complement.

Immunoglobulin E (IgE) has been shown to play a critical role in the allergic late-phase reaction, which is marked by intense leukocyte infiltration and edema. In this study we assessed the allergic pleural inflammation triggered by intrapleural (i.pl.

Histamine-potentiating activity in rat anaphylactic pleural fluid: role of serotonin.

The identity of the histamine-potentiating activity detected in the rat anaphylactic pleural washing was investigated. Wistar rats of both sexes, weighing 150-200 g, were sensitized by injecting subcutaneously (sc) a mixture of ovalbumin and Al(OH)3 14 days before allergen challenge. In sensitized rats, intrapleural (ipl) injection of ovalbumin (12 micrograms/cavity) caused an intense protein exudation.

In vivo assessment of mast cell functional alteration induced by L-leucine methyl ester, using the passive cutaneous anaphylaxis technique.

We have recently reported that in vitro, mast cells were sensitive to the action of L-leucine methyl ester (Leu-OMe), a lysosomotropic compound. We now report the in vivo effect of Leu-OMe on mast cells, qualitatively assessed by using the passive cutaneous anaphylaxis (PCA) reaction. The L- but not the D-stereoisomer of Leu-OMe (25 mM) injected together with Dactylis glomerata, pollen-specific, IgE-containing serum inhibited the PCA reaction in rat skin triggered by a subsequent challenge with the corresponding allergen.

Ultrastructural changes in mouse peritoneal mast cells in response to L-leucine methyl ester or anti-IgE.

We studied the ultrastructural features of mouse peritoneal mast cells in response to a non-immunologic lysosomotropic agent, L-leucine methyl ester (Leu-OMe), as compared to well-known immunologic stimulation mediated by anti-IgE antibodies. Total peritoneal exudate cells were collected from CBA/J mice, with mast cells representing 3 to 8% of total cells. The secretory granules in unstimulated mast cells were heterogeneous in size and shape, but intragranular material displayed a homogeneous electron-dense appearance.

Effects of L-leucine methyl ester (Leu-OMe) on mouse peritoneal mast cells: characterization of histamine release versus cytotoxicity.

L-Leucine methyl ester (Leu-OMe), a lysosomotropic compound, has been found to eliminate several lysosome-rich cellular subtypes and all natural killer cell function from peripheral blood mononuclear cells. In this report, the effect of Leu-OMe on mouse peritoneal mast cells is described. The L-Leu-OMe induced the release of histamine from mouse peritoneal mast cells in a dose-dependent manner (0.