Since it was recently shown that CD11b+CD11cintLy6C+ cells previously defined as Tip-DCs are the major IFN-β producers upon Listeria infection [29], we wanted to know whether Tip-DCs belong to LysM-expressing monocyte /macrophage population and whether we could confirm the production of IFN-β by such cells. This evidence concerns the gene IFNB1 and listeriosis.