Effects of tumor necrosis factor-α, epidermal growth factor and transforming growth factor-α on interleukin-8 production by, and human rhinovirus replication in, bronchial epithelial cells

Abstract

Previous studies have shown that the epidermal growth factor (EGF) and transforming growth factor-α (TGF-α), members of the EGF growth factor family, regulate processes involved in airway repair after injury. Our studies were conducted to determine whether EGF and TGF-α directly control processes involved in the pathogenesis of airway inflammation and/or modulate the inflammatory effects of TNF-α in the airway mucosa. We have found that these cell growth factors directly induced interleukin-8 (IL-8) production by an immortalized human bronchial epithelial cell line (BEAS-2B cells). Furthermore, EGF and TGF-α enhanced tumor necrosis factor-α (TNF-α) induced IL-8 production by BEAS-2B cells. On the other hand, EGF but not TGF-α increased viral replication by BEAS-2B cells exposed to HRV-14. Moreover, TNF-α increased viral replication in the presence of EGF but not TGF-α. In conclusion, this study demonstrates that both EGF and TGF-α play an active role in the pathogenesis of airway inflammation.