iIn vitro/iStudies of Concanavalin-A-Induced Histamine Release from Human Basophils: Excess Bridging in the Inhibitory Region of the Dose-Response Curve

摘要

Concanavalin-A (Con A)-induced histamine release from human basophils was studied in vitro. The quantity of histamine released was accurately measured by a spectrofluorometric assay. It was determined that release induced by lower doses of Con A (suboptimum) is inhibited by monomer-Fc-specific anti-IgE whereas release induced by high doses of Con A (supraoptimum) is enhanced by the monomer: In addition, release induced by a near optimum concentration of antigen E can be inhibited by increasing concentrations of Con A. The data indicate that high concentrations of Con A render the basophil unresponsive by excess bridging and it appears that this cell turn-off is mediated by the membrane-bound IgE.