EFFECTS OF SYNTHETIC FOOD COLORS ON [H-3] SEROTONIN RELEASE FROM RAT BASOPHILIC LEUKEMIA-CELLS (RBL-2H3)

The authors investigated the applicability of an assay method for immediate allergic reaction in vitro to determine radioactivity of pre-incorporated [SH]serotonin from rat basophilic leukemia cells (RBL-2H3) stimulated with biotinylated IgE-avidin complex. Using the newly improved assay method, the effects of synthetic food colors on immediate allergic reaction were determined. The optimum ratio and amount of stimulator for the cell stimulation was found to be 3 mu g/ml (0.015 mu M) of biotinylated IgE and 1 mu g/ml (0.015 mu M) of avidin. Seven kinds of food colors including food red No. 2 (amaranth) and food yellow No. 4 (tartrazine) inhibited about 50% of [H-3] serotonin release atl mM compared to that of the cells exposed to the stimulator alone. Food blue No. 2 (indigo carmine) inhibited 20% of the release at 1 mM, while food red No. 106 (acid red) had no effect. Food red No. 3 (erythrosine), food red No. 104 (phloxine) and food red No. 105 (rose bengale) promoted [H-3]serotonin release from nonstimulated cells at lower concentration and showed strong lethal effect to the cells at higher concentration. Thus, it was suggested that food colors might modify immediate allergic response, and show cytotoxic action when ingested orally with foods.