Figure 2. Foxp3⁺ Treg depletion enhances immune cell infiltration in B16F10 tumors. (A–F) Groups of C57BL/6 DEREG mice (n = 4–7) were inoculated s.c. with 5 × 10⁴ B16F10 melanoma cells on day 0. On days -2, 5 and 12, mice were injected i.p. with either 500 ng diphtheria toxin A (DTA) or PBS. On day 18–20, tumors were excised and tumor-infiltrating leukocytes were analyzed by flow cytometry. Frequencies of CD45.2⁺ (A), NK cells (B), total T (C), CD4⁺ T (D), CD8⁺ T (E) and Treg cells (F), upon gating on CD45.2⁺ (B–E) or CD4⁺ T cells (F) from PBS- or DTA-treated mice are shown. Statistical differences in the frequency of the indicated cell subsets between mice treated with PBS or DTA were determined by unpaired Student’s t-tests (*p < 0.05; **p < 0.01; ***p < 0.001). Each symbol represents a single mouse. Data shown are pooled from three independent analyses.