Differential antiviral activities of respiratory syncytial virus (RSV) inhibitors in human airway epithelium

Abstract

Objectives: We report the use of reconstituted 3D human airway epithelium cells (HuAECs) of bronchial origin in an air-liquid interface to study respiratory syncytial virus (RSV) infection and to assess the efficacy of RSV inhibitors in (pre-)clinical development. Methods: HuAECs were infected with RSV-A Long strain (0.01 CCID 50 /cell, where CCID 50 represents 50% cell culture infectious dose in HEp2 cells) on the apical compartment of the culture. At the time of infection or at 1 or 3 days post-infection, selected inhibitors were added and refreshed daily on the basal compartment of the culture. Viral shedding was followed up by apical washes collected daily and quantifying viral RNA by RT-qPCR. Results: RSV-A replicates efficiently in HuAECs and viral RNA is shed forweeks after infection. RSV infection reduces the ciliary beat frequency of the ciliated cells as of 4 days post-infection, with complete ciliary dyskinesia observed by day 10. Treatmentwith RSV fusion inhibitors resulted in an antiviral effect onlywhen added at the time of infection. In contrast, the use of replication inhibitors (both nucleoside and non-nucleoside) elicited a marked antiviral effect evenwhen the start of treatmentwas delayed until 1 day or even 3 days after infection. Levels of the inflammation marker RANTES (mRNA) increased ~200-fold in infected, untreated cultures (at 3weeks post-infection), but levels were comparable to those of uninfected cultures in the presence of PC786, an RSV replication inhibitor, suggesting that an efficient antiviral treatment might inhibit virus-induced inflammation in thismodel. Conclusions: Overall, HuAECs offer a robust and physiologically relevant model to study RSV replication and to assess the efficacy of antiviral compounds.