IgE-dependent expression of interleukin-5 mRNA and protein in human lung: Modulation by dexamethasone

Abstract

mRNA and protein expression of the Th2 cytokines IL-4 and IL-5 from human lung were examined during the first 4 hr following IgE-mediated triggering, a time representative of the evolving late-phase reaction (LPR). Lung explants were incubated for 16 hr at 37°C in culture media alone or with added dexamethasone (10-6 M), washed, and then challenged with buffer or anti-IgE (3 μg/ml). Using RNase protection assays, in 16/16 individual lungs IL-5 mRNA expression was observed at 4 hr following anti-IgE and at no points following buffer challenge. Fragments released 1129 c 499 ng of IL-5/g wet wt over a 24-hr period (mean ± SEM, n = 5). Neither IL 4 transcripts nor protein were detected in any anti-IgE challenges. Both the IgE-mediated IL-5 mRNA and protein responses were below the limits of detection following dexamethasone preincubation, suggesting a mechanism for the potent inhibitory effects of these agents observed in the LPR. © 1995 Academic Press, Inc.