Transgenic mice with an Ig locus recombination substrate are used to detect redirection of lymphoid progenitors to dendritic fates. (A) CLPs with a history of Ig recombination were sorted on the basis of VEX fluorescence and placed in culture with or without CpG. Flow cytometry performed 8 days later revealed normal lymphopoiesis and continued VEX labeling for control cells (left 2 panels), whereas CpG-treated cells generated several classes of DCs and NK-like IKDCs (right 4 panels). (B) Transgenics were also injected with CpG, and BM cells were evaluated by flow cytometry 1 week later. Percentages of cells with a history of recombination (VEX⁺) are given for each of the indicated cell types. Data are representative of 2 independent experiments (*significant difference, P < .05). Error bars represent SEM.