Figure 6.

Rebalancing TGF-β/PGE₂ contributed to T cell activation. (A) Flowchart of the in vitro experiment. DCs of virous treatments incubated with OVA-I (1 µg/ml); CD8⁺ T cells were isolated from the spleen of OT-I mice using CD8⁺ T cell sorting magnetic beads. Then DC and T cells were co-cultured at a 1:5 ratio for three days. After that T cells were stained for FACS. (B) In vitro T-cell activation was measured by flow cytometry (P., positive percentage; M., mean fluorescence intensity). (C) Bar graphs of the results of FACS experiments; N = 3, *p < 0.05. (D) Flowchart of the in vivo experiment. C57BL/6J mice were inoculated with subcutaneous U14 tumors in the thigh on day 1. TGF-βi or PGE₂i was administered intragastrically on days 14 and 15. RT was conducted on day 14 and Fluc⁺ DCs were injected intra-tumorally on day 16. Migration dynamics of Fluc⁺ DCs were traced over the subsequent 2 d. Tumor-draining LNs (t-LNs) were dissected 7 d after injecting Fluc⁺ DCs. Cell proliferation and T-cell priming in t-LN suspensions were evaluated. (E) A photo of the tumor site. (F) The effects of TGF-β and PGE₂ on homing of DCs to t-LNs were investigated by bioluminescence imaging. (G) Cell number in the t-LN cell suspensions. (H-J) Results for T cell activation based on measurements of CD44 (H), CD69 (I), and TNF-α (J) expression in CD8⁺ T cells; N = 3; *p < 0.05. The above experiments were repeated twice.