Figure 2.

CD4⁺CD25^hi T cells from the draining LNs of chronically infected mice originate from naturally occurring T reg cells and express Foxp3. (A) RAG2^−/− were reconstituted on the day of L. major infection with 3 × 10⁴ CD4⁺CD25^hi CD45.1⁺ T cells (Ly5.1) and 3 × 10⁵ CD4⁺CD25⁻CD45.2⁺ T cells (Ly5.2) from naive B6.SJL and B/6 mice, respectively. Values indicate the percentage of CD45.1⁺ cells within the CD25^hi and CD25^lo T cell subsets (12 wk after infection). (B) The expression of Foxp3 was evaluated by flow cytometry. Events were gated on CD4 and CD25 expression as indicated. Values indicate the percentage of events in the indicated quadrant. (C) WT B/6 mice were inoculated in the ear dermis with 10³ L. major metacyclic promastigotes. At 12 wk after infection, the draining LNs were collected and cells were analyzed by flow cytometry. Results are shown for CD4⁺TCR-β⁺ cells. Values indicate the percentage of Foxp3⁺ cells (filled histograms) for each CD25 subset, as defined on the left panel, when compared with isotype control–stained cells (open histograms). Results are representative of three independent experiments.