Another study using 129SvEv mice showed that SARS-CoV infection resulted in self-limited bronchiolitis but progressed to severe pulmonary inflammation in Signal Transducer and Activator of Transcription 1 (STAT1) knockout mice, which are resistant to the effect of interferons, undermining the importance of the interferon response [174]. This evidence concerns the gene STAT1 and severe acute respiratory syndrome.