OBJECTIVES: Interferon-beta (IFNbeta) induces strong antiviral effects and is therefore an attractive agent to prevent or reduce the incidence of virus-mediated exacerbations in asthmatic or chronic obstructive pulmonary disease (COPD) patients. We therefore investigated the effects of prophylactic IFNbeta on respiratory epithelial cells infected with rhinovirus (RV). METHODS: A549 cells and primary bronchial epithelial cells (PBECs) were exposed for 18 h to IFNbeta. Then, IFNbeta was either removed or maintained in the supernatant for the rest of the experiment and cells were infected with RV-1B at t = 0 or 72 h after the initial exposure to IFNbeta. RESULTS: Viral RNA levels were decreased in both cell types. Furthermore, both viral RNA and infectious virus levels in the supernatant of infected A549 cells were still significantly reduced at 72 h after removal of IFNbeta. This pronounced antiviral pre-treatment effect was associated with increased expression of the antiviral genes IFN-stimulated protein of MR15000 (ISG15) and Myxovirus resistance 1 (Mx1) and the effect was maintained even when IFNbeta levels in the supernatant of A549 cells were undetectable. CONCLUSIONS: These data show that IFNbeta has not only a strong, but also a long-lasting protective effect against RV infection of respiratory epithelium.