Amelioration of murine listeriosis in the absence of NK cells and NKT cells and the analysis of the influence of double-stranded RNA on anti-bacterial resistance

NK1.1^+cells have been considered to play a protective role in various bacterial infections by secreting IFN-·upon infection。Yet，we have obtained the first evidence that NK cells play a detrimental role in protection against intracellular bacteria，Listeria monocytogenes.In contrast，we also found that anti-listerial resistance was markedly enhanced by PolyI：C and that NK cells participate in this mechanism.Thus，because our findings clearly demonstrated the new role of NK cells in intracellular bacterial infection，we consider it likely that our study contributes to the development not only of bacteriology，but also of immunology。

NK1.1^+ cells have been considered to play a protective role in various bacterial infections by secreting IFN-・upon infection. Yet, we have obtained the first evidence that NK cells play a detrimental role in protection against intracellular bacteria, Listeria monocytogenes. In contrast, we also found that anti-listerial resistance was markedly enhanced by PolyI:C and that NK cells participate in this mechanism. Thus, because our findings clearly demonstrated the new role of NK cells in intracellular bacterial infection, we consider it likely that our study contributes to the development not only of bacteriology, but also of immunology.