Abstract
The majority of asthma exacerbations are caused by rhinovirus. Currently the treatment of asthma exacerbations is inadequate. Previous evidence suggests that macrolide antibiotics have anti-inflammatory and antiviral effects; however, the mechanism is unknown. We investigated the anti-rhinoviral potential of macrolides through the induction of antiviral gene mRNA and protein. Primary human bronchial epithelial cells were pre-treated with the macrolides azithromycin, erythromycin and telithromycin, and infected with minor-group rhinovirus 1B and major-group rhinovirus 16. The mRNA expression of the antiviral genes, type I interferon-β and type III interferon-λ1, interferon-λ2/3, and interferon-stimulated genes (retinoic acid inducible gene I, melanoma differentiation associated gene 5, oligoadenylate synthase, MxA and viperin) and pro-inflammatory cytokines (interleukin (IL)-6 and IL-8), and rhinovirus replication and release were measured. Azithromycin, but not erythromycin or telithromycin, significantly increased rhinovirus 1B- and rhinovirus 16-induced interferons and interferon-stimulated gene mRNA expression and protein production. Furthermore, azithromycin significantly reduced rhinovirus replication and release. Rhinovirus induced IL-6 and IL-8 protein and mRNA expression were not significantly reduced by azithromycin pre-treatment. In conclusion, the results demonstrate that azithromycin has anti-rhinoviral activity in bronchial epithelial cells and, during rhinovirus infection, increases the production of interferon-stimulated genes.