Lethal model for respiratory syncytial virus infection using C57BL/6 mice

A mouse model of respiratory syncytial virus (RSV) infection is useful for fundamental research aimed at developing antiviral drugs. Previous mouse models of RSV infection were unable to adequately mimic the pathophysiology of human patients due to the low amplification efficiency of this virus in the mouse lung. Furthermore, mice other than BALB/C mice are difficult to use for the RSV infectious model. We established a new mouse-adapted RSV strain, MP11. The MP11 virus can cause severe pneumonia in C57BL/6 mice and efficiently replicate and induce inflammation in the lung. Therefore, C57BL/6 mice can be used for RSV infection experiments using MP11 virus. We established a reverse genetics system for the MP11 virus using our mouse model. This system enables detailed analyses of the MP11 virus, such as functional analysis of each viral protein. Our study provides techniques that can advance fundamental research in elucidating the pathogenesis of RSV infections.