Intratracheal instillation of RSV is superior to intranasal inoculation as a model method inducing critical immune cell infiltration.

Respiratory syncytial virus (RSV) causes a substantial global disease burden, particularly in children and older adults. Despite the availability of three vaccines and two prophylactic monoclonal antibodies, there remains an urgent unmet need for effective RSV treatments. Appropriate experimental animal models and modeling methods are essential for studying RSV pathogenesis and developing therapeutic and preventive agents. In this study, we introduced intratracheal instillation (ITS) method into mouse model of RSV infection and compared it with the conventional intranasal inoculation (INO) method; data showed that ITS method resulted in more efficient viral replication and more severe pathological changes than INO method. Then RNA-seq technology was used to sequence the lung tissues of RSV infected mice with ITS method, and further immunoinfiltration analysis based on transcriptomic profile demonstrated that the ITS approach can lead to the infiltration of multiple innate and adaptive immune cells. It is concluded that ITS of RSV is superior to INO as a model method in mice and can induce infiltration of key immune cells. Collectively, our study offers novel insights into the rational design of future in vivo infection methods with RSV, as well as providing a foundation for the investigation of the immune pathogenesis of RSV.