DCs might be involved only at the very early time points after infection and IFN-b production might be below our detection limit. We think this is unlikely given the extreme sensitivity of our reporter system. Alternatively, infected DCs might undergo apoptosis before they are able to significantly contribute to IFN production or IFN production in DCs might be inhibited by L. monocytogenes. The latter notion would be in agreement with the fact that pDCs also do not produce IFN-b.