Visualizing Respiratory Syncytial Virus Replication in Live Mice

Modeling human respiratory syncytial virus (RSV) infection in vivo is an essential step in the search for novel vaccines, antiviral therapies, or preventive measures against RSV disease. The most commonly used experimental models of RSV infection are rodent models, in particular, inbred BALB/c mice and cotton rats (Bem et al., Am J Physiol Lung Cell Mol Physiol 301(2): L148-L156, 2011; Taylor, Vaccine 35(3): 469-480, 2017; Altamirano-Lagos, Front Microbiol 10: 873, 2019). However, depending on the RSV strain and viral titer, infection of mice with RSV can result in few or no symptoms, with viral load being estimated by RT-qPCR on lung tissue. By allowing the monitoring of the spread and intensity of the infection in the same animal over time, the use of recombinant RSV expressing the firefly luciferase represents a major advance in the study of RSV replication in the murine model.