Fig. 3.

CD8⁺ T cells and DCs mediate the suppressive effects of 4-1BB triggering. SEA-injected C57BL/6 mice were injected i.p. with rat IgG or anti-4-1BB mAb on PI Days 0 and 2. Cells were isolated from ILN on PI Day 10, and then populations, including CD11c⁺CD8⁺ T cells, CD11c^–CD8⁺ T cells, and CD11c^high DCs, were purified. Responder CD4⁺ T cells were purified from rat IgG-treated mice. (A) CD11c⁺CD8⁺ T or CD11c^–CD8⁺ T cells were cultured with CD4⁺ T cells in the presence or absence of 0.1 μg/ml SEA for 3 days, and CD11c⁺ DCs from naïve mice were added to each well at 10% of cultured whole cells. (B) CD11c^high DCs from the rat IgG- or anti-4-1BB-treated group were cultured with CD4⁺ T cells in the presence of 0.1 μg/ml SEA for 3 days. The incubated cells were stained with PE-conjugated anti-CD4 and intracellularly stained with FITC-conjugated anti-BrdU according to the manufacturer’s instructions (BD Biosciences). All samples were analyzed on FACScan. The data are representative of three independent experiments.