To investigate the influence of type I IFN on lymph node colonization, we compared wild type C57BL/6, IFN-b 2/2 and IFNAR 2/2 mice. Like in spleen, a defect in the type I IFN system resulted in lower bacterial numbers (Fig. 2) confirming a detrimental role of these cytokines also in lymph nodes. These differences were only detectable at 48 hours p.i., consistent with the peak of IFN-b production at this time point.