ISG15 Is Upregulated in Respiratory Syncytial Virus Infection and Reduces Virus Growth through Protein ISGylation

ABSTRACT Human respiratory syncytial virus (RSV), for which neither a vaccine nor an effective therapeutic treatment is currently available, is the leading cause of severe lower respiratory tract infections in children. Interferon-stimulated gene 15 (ISG15) is a ubiquitin-like protein that is highly increased during viral infections and has been reported to have an antiviral or a proviral activity, depending on the virus. Previous studies from our laboratory demonstrated strong ISG15 upregulation during RSV infection in vitro . In this study, an in-depth analysis of the role of ISG15 in RSV infection is presented. ISG15 overexpression and small interfering RNA (siRNA)-silencing experiments,…