Migration of FLDCs to the thymus induces clonal deletion of antigen-specific SP thymocytes. (A) 2C-B6 BM chimeras were prepared by reconstituting heavily irradiated B6 mice with a mixture of 2C TCR Tg BM cells and B6 Ly5.1 BM cells. BM chimeras were then injected with B6 FLDCs or BALB/c FLDCs. The mice were analyzed for the frequency of wild-type and 2C thymocytes by flow cytometry (n = 5); 3 of 5 FLDC-injected mice exhibited an extensive deletion of 2C cells, as shown in the lower portion of the figure. (B) Mean percentage of 2C thymocytes of 5 individual mice. **P < .01. (C) DO11.10-BALB/c BM chimera mice were prepared by reconstituting irradiated BALB/c mice with a mixture of DO11.10 TCR Tg BM cells and BALB/c BM cells. BM chimeras were then injected with unloaded or OVAp-loaded FLDCs. The mice were analyzed for the frequency of wild-type and DO11.10 thymocytes by flow cytometry (n = 4); 2 of 4 mice showed the marked deletion of DO11.10 SP CD4 cells illustrated in the lower portion of the figure. (D) Data are means from 4 mice. *P < .05; **P < .01.