The generation of M-DC is inhibited by a c-fms inhibitor. Replicate M-CSF and FL cultures were conducted in parallel in the presence or absence of a range of c-fms receptor tyrosine kinase inhibitor (A) or Flt3 inhibitor (B) concentrations. At the end of the culture period, all cells were counted. The number of cells harvested from cultures without inhibitor was set at 100%. Cells from cultures containing inhibitor were expressed as a percentage of cells obtained in the absence of inhibitor. The data shown in each panel are from one experiment each, representative of 2 experiments carried out for each of the inhibitors.