IFNG and bacterial infectious disease: Furthermore, our findings showed robust or more rapid significant up-regulation of NKEF and T-bet followed by IFN-γ expression/transcript, especially in the skin, highlighting the possibility, as discussed above, of group 1 ILC-like population including NK-like cells at the skin barrier in salmon, which may in turn have evolved to respond immediately to pathogenic signals and to aid the adaptive immune system in mounting a robust T-bet mediated type 1 immune response against bacterial infection.