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Pretreatment of rat peritoneal mast cells, human basophils, bone marrow-derived mouse mast cells (BMMC) and mouse mast cell line PT-18 cells with 1 microgram/ml pertussis toxin (PT) failed to inhibit immunoglobulin E (IgE)-dependent histamine release from the cells. In BMMC and PT-18 cells, even 20-hr incubation of the cells with 1 microgram/ml PT, which(More)
The addition of the chemotactic peptide formylmethionylleucylphenylalanine (fMet-Leu-Phe) to human neutrophils pretreated with the cytokine granulocyte/macrophage colony-stimulating factor (GM-CSF) results in a 10-fold enhanced activity of phospholipase A2, measured as the release of arachidonic acid. It is found that GM-CSF increases the tyrosine(More)
The functional and biochemical responses evoked by the addition of platelet-activating factor (PAF) to a suspension of rabbit neutrophils have been characterized in an effort to define the mode of action of this lipid mediator. PAF was found to elicit a secretory response and to stimulate a rapid breakdown of the polyphosphoinositides, an increase in the(More)
An increase in the level of intracellular free calcium concentration in rabbit and human neutrophils stimulated by chemotactic factors has been demonstrated directly using the calcium-sensitive fluorescent probe quin-2. Addition of f-Met-Leu-Phe (10(-9) M), C5a (3 x 10(-9) M) or leukotriene B4 (6 x 10(-8) M) to the neutrophils induces a rapid increase in(More)
Kinases mediating phosphorylation and activation of cytosolic phospholipase A2 (cPLA2) in intact cells remain to be fully characterized. Platelet-activating factor stimulation of human neutrophils increases cPLA2 phosphorylation. This increase is inhibited by PD 98059, a mitogen-activated protein (MAP)/extracellular signal-regulating kinase (erk) 1(More)
Treatment of rabbit neutrophils with pertussis toxin, but not cholera toxin, inhibits the increases produced by formylmethionyl-leucyl-phenylalanine, leukotriene B4 and the calcium ionophore A23187 in the amounts of actin associated with the cytoskeletons. The increase in the cytoskeletal actin produced by phorbol 12-myristate, 13-acetate on the other hand(More)
The tumor co-promoter phorbol 12, myristate 13, acetate (PMA) has previously been shown to stimulate several of the characteristic functions (aggregation, degranulation, and the oxidative burst) of polymorphonuclear leukocytes (neutrophils). We describe here a novel feature of the action of PMA on neutrophils, namely its ability to inhibit the chemotactic(More)
The addition of low concentrations of phorbol 12-myristate 13-acetate to rabbit neutrophils induces cell aggregation, degranulation, increased oxygen consumption and an increase in the amount of actin associated with the cytoskeleton without a rise in the level of intracellular free calcium as measured using the fluorescent probe quin-2. The ability of(More)