Figure 3.

Regulatory T cells (Tregs) were increased in skin tumors, draining lymph nodes, and lung metastasis of CCL17 transgenic (TG) mice. Skin tumors, draining lymph nodes, and spleen were harvested 14 days after subcutaneous injection of B16F1 melanoma cells, while metastatic lung tissues were harvested 21 days after intravenous injection of B16F1 melanoma cells. Expression levels of markers of Tregs were evaluated by quantitative reverse transcription-PCR in skin tumors, draining lymph nodes, and metastatic lung tissues from wild-type (WT) mice and CCL17 TG mice. The frequency of Tregs was analyzed by flowcytometric approach in lymph nodes and spleen from WT mice and CCL17 TG mice. (A) Foxp3 mRNA levels were significantly higher in skin tumors of CCL17 TG mice than those of WT mice. IL-10 mRNA levels were significantly upregulated in skin tumors, lymph nodes, and metastatic lung tissues of CCL17 TG mice compared with those of WT mice. (B) Representative flowcytometric images showing the frequency of Foxp3⁺ CD4⁺ cells in the draining lymph nodes from WT mice and CCL17 mice on days 0 and 14 after tumor injection. (C) The frequency of Foxp3⁺ CD4⁺ cells was significantly increased in lymph nodes and spleen on day 14. The frequency of Foxp3⁺ CD25⁺ cells was significantly upregulated in lymph nodes on day 14. Data are presented as mean ± SEM of three independent experiments (n = 6 for each group). * p < 0.05 WT versus CCL17 TG mice.