Rapid mobilization of intracellularly stored RANTES in response to interferon-gamma in human eosinophils

The CC chemokine RANTES is synthesized, stored, and upregulated in response to interferon-gamma (IFN-gamma) in human peripheral blood eosinophils. In this report, we propose that RANTES is rapidly mobilized from eosinophil cr ystalloid granules during agonist-induced degranulation. We stimulated puri fied eosinophils (>99%) from atopic asthmatics with 500 U/mL IFN-gamma to a nalyze the kinetics of mobilization and release of RANTES (0 to 240 minutes ). We used subcellular fractionation, immunogold analysis, two-color confoc al laser scanning microscopy (CLSM), and enzyme-linked immunosorbent assay (ELISA) to trace the movement of eosinophil-derived RANTES from intracellul ar stores to release. RANTES was rapidly mobilized (10 minutes) and release d after 120 minutes of stimulation (80 +/- 15 pg/mL per 2 x 10(6) cells).