In vivo progenitor activity of B220^lo

c-kit⁺CD19⁻ FL cells.Total 15-dpc FL cells and sorted B220^loc-kit⁺CD19⁻ cells (fraction e) were injected into irradiated C57BL/6-Rag2/γc^−/− mice at 7 × 10⁴ and 10⁴ cells per mouse, respectively, corresponding to an equivalent number of 500 TCPs. Four weeks after cell transfer, the blood (A), thymus (B), BM (C), and i-IELs (D) were analyzed by flow cytometry. The presence of donor-derived cells was assessed by gating on Ly5.1⁺ cells. Numbers indicate the relative percentage within the indicated gates. The results are representative of 4 experiments.