Imidacloprid inhibits IgE-mediated RBL-2H3 cell degranulation and passive cutaneous anaphylaxis

BACKGROUND: Imidacloprid has been commonly used as a pesticide for crop protection and acts as nicotinic acetylcholine receptor agonists. Little information about the relationship between imidacloprid and allergy is available. OBJECTIVE: This study aims to examine the effects of imidacoprid on IgE-mediated mast cell activation. METHODS: The rat basophilic leukemia cell line RBL-2H3 (RBL-2H3 cells) were treated with 10(-3) – 10(-12) mol/L imidacloprid, followed by measuring the mediator production, influx of Ca(2+) in IgE-activated RBL-2H3 cells, and the possible effects of imidacoprid on anti-dinitrophenyl IgE-induced passive cutaneous anaphylaxis (PCA). RESULTS: It was shown that imidacoprid suppressed the production of histamine, β-hexosaminidase, leukotriene C4, interleukin-6, tumor necrosis factor-α, and Ca(2+) mobilization in IgE-activated RBL-2H3 cells and decreased vascular extravasation in IgE-induced PCA. CONCLUSION: It is the first time to show that imidacloprid suppressed the activation of RBL-2H3 cells.