XK and infection: In our study, insertion of the 16 aa LACK158-173 peptide into the viral NA led to a decrease in viral replication on d 3 after intranasal inoculation (Fig. S2) and mild symptoms of influenza infection (modest weight loss) when compared to mice infected with WT PR8 virus (50 pfu) which showed severe signs of infection (loss of body weight, ruffled fur, unresponsiveness).