Expression of interleukin-16 by human epithelial cells. Inhibition by dexamethasone.

Production of chemoattractants by bronchial epithelial cells may contribute to the local accumulation of inflammatory cells in patients with bronchial asthma and other pulmonary diseases. Recently, interleukin (IL)-16 (lymphocyte chemoattractant factor) was reported to be a potent chemotactic stimulus for CD4+ T lymphocytes and eosinophils, the types of leukocyte found in the proximity of bronchial epithelium in asthmatic individuals. To test the possibility that bronchial epithelial cells produce IL-16, we analyzed RNA and culture supernatants from the human bronchial epithelial cell line BEAS-2B, using reverse transcription–polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. BEAS-2B constitutively expressed IL-16 messenger RNA (mRNA) and protein; IL-16 expression was significantly upregulated in a concentration-dependent manner within 24 h by stimulation with histamine, IL-1β, or tumor necrosis factor (TNF)-α whereas interferon-γ did not significantly increase IL-16. Findings ...