title: An antigen-activated DFP-inhibitable enzyme controls basophil desensitization.
abstract: Diisopropyl fluorophosphate (DFP), an inhibitor of serine esterases, enhances IgE-mediated histamine release from human basophils and blocks the desensitization process (i.e., the antigen-induced hyporesponsiveness) in these cells. Both activities occur at relatively low concentrations of DFP (0.1 to 0.5 mM) and are dependent on an antigen-activated intracellular event: if DFP is removed before antigen addition, it has neither effect. Neither hydrolyzed DFP nor the non-phosphorylating diisopropyl methyl phosphate enhanced histamine release or blocked desensitization. In addition to providing a demonstrable biochemical correlate of desensitization, our data suggest that the desensitization process controls the release of mediators of allergic reactions.
mesh_terms: D000941:Antigens / Q000276:immunology; D001491:Basophils / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D001667:Binding, Competitive; D002469:Cell Separation; D003888:Desensitization, Immunologic; D004306:Dose-Response Relationship, Immunologic; D004789:Enzyme Activation; D004950:Esterases / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006636:Histamine Release / Q000187:drug effects; D006801:Humans; D007531:Isoflurophate / Q000494:pharmacology*; D007700:Kinetics
chemical_list: D000941:Antigens; D007531:Isoflurophate; D004950:Esterases; C022635:serine esterase