Fig. 5.

Functional suppressor activity of CD4⁺ CD25^high Treg cells isolated from the spleen of untreated tumor-bearing (right middle panel) or long-term cured mice (right lower panel) on naïve responder T cells. Spleen Treg cells isolated by immunomagnetic cell sorting (dot plot analysis indicating purity of sorted cells is shown in the left) were tested at a 1:8 (Treg:responder T cell) ratio in an anti-CD3 mAb proliferation assay. CFSE-labeled spleen cells from naïve mice were used as responder cells. The right upper panel shows proliferation of naïve T cells in the absence of added Treg cells. Experiments are representative of three replicates with similar results. Inhibition of CSFE dilution was significant for both untreated NB-bearing and long-term cured mice Treg cells (p < 0.05)