Respiratory syncytial virus receptor expression in the mouse and viral tropism

Human respiratory syncytial virus (RSV) infects airway epithelium and can cause serious illnesses such as bronchiolitis and pneumonia. With the discovery of cell-surface nucleolin as a fusion receptor for RSV, the question arose as to whether nucleolin could explain RSV tropism in vivo. Here, we report the distribution of cell-surface nucleolin expression in tissues of normal mice and how this distribution of expression relates to what is known about RSV tropism and its clinical manifestations. Our results show evidence of cellsurface nucleolin expression in the respiratory tract. In addition, cell-surface nucleolin is expressed in tissues outside of the respiratory tract, many of which correspond to previous reports of tissue-specific RSV infection, and others that may allude to additional potential sites for RSV infection in vivo. Furthermore, our work provides a foundation for the investigation of nucleolin’s physiological function in various healthy mammalian tissues.