To investigate the dependence of individual immunological processes on DC, a transgenic mouse system (CD11c-DTR/GFP mice) has been developed that allows conditional depletion of CD11c⁺ DC in vivo through administration of diphtheria toxin. We have performed careful histological analysis of CD11c-DTR/GFP mice at different time points after diphtheria toxin injection and confirmed the transient depletion of CD11c⁺ cells from lymph nodes and spleen. Unexpectedly, the injection of diphtheria toxin completely depleted marginal zone and metallophilic MΦ from the spleen and their sinusoidal counterparts from the lymph nodes. This finding limits the use of CD11c-DTR/GFP mice for the analysis of the role of DC to models and read outs that are proven to be independent of marginal zone and sinusoidal MΦ.