TF and infection: To assess these findings in an in vivo viral infection model, we employed intranasal infection with MHV-A59 (MHV) in mice (Supplementary information, Fig. S14a).42,43 The level of TF in bronchoalveolar lavage fluid (BALF) increased progressively, reaching a peak on the 5th day post-MHV infection (Supplementary information, Fig. S14b).