Treg depletion after αCD25 and/or rhIL-7 in B16 tumor-bearing hosts. (A) Timing of tumor inoculation in relation to αCD25, rhIL-7, and adoptive transfer of pmel-1 LN cells. (B) Representative fluorescence-activated cell sorter plots on day 20 showing Treg frequencies in tumor-draining lymph nodes (TDLN) of treated mice. Results were consistent in 3 experiments. (C) Mean plus or minus SEM Treg frequencies in TDLNs of treated animals on day 16 (n = 6 or 7/group, results confirmed in 2 experiments). **P < .005. (D) Representative tissue sections on day 20 from TDLN and B16 tumors of animals from each treatment group showing FOXP3⁺ cells (red) versus nucleated cells (blue). Original magnification ×200.