Stockinger et al. [28] defined cells with surface antigens characteristic of macrophages as major producers of type I IFN during Listeria infection. According to the recent publication of Dresing et al. [29] , TNF-a and iNOS producing Tip-DCs, that share markers with macrophages, were the main cellular source of IFN-b in the course of Listeria infection. Our data showed that a LysM-expressing cell population is responsible for IFN-b production in murine listeriosis. Testing sorted macrophages, DCs and Tip-DCs for type I IFN and LysM expression revealed that the LysM promoter was active in all three cell populations. However, only Tip-DCs were able to express vast amounts of IFN-b in agreement with Dresing et al. [29] . Interestingly, such Tip-DCs showed strong expression of LysM. This sheds some doubts on the DC nature of Tip-DCs, which was originally defined by their T cell priming capacity in mixed lymphocyte reaction [29] . Thus, Tip-DCs might as well be defined as inflammatory monocytes.