Figure 3.

ETX prevents the enhanced proliferation of CD8⁺ T cell by 4-1BB signals. (a) BoDipy FL C₁₆ uptake by the activated CD8⁺ T cells 24 h after rat IgG or anti-4-1BB treatment. (b and c) CFSE-labeled and anti-CD3-activated CD8⁺ T cells were pre-incubated with the indicated concentration of ETX for 1 h and further treated with 5 μg/ml anti-4-1BB mAb for 2 days. The CD8⁺ T cells were stained with anti-CD8-PE-Cy5 and CFSE dilution of CD8⁺ T cells was subsequently analyzed by FACSCalibur (b). Proliferation index was calculated using Modfit LT software from b (c). (d) Anti-CD3-activated CD8⁺ T cells were pre-incubated with 150 μM ETX for 1 h and treated with rat IgG or anti-4-1BB mAb. Live cells were counted 1 or 2 days after anti-4-1BB treatment using an Automated Mammalian Cell Counter. Data are representative of three independent experiments. Results in a, c and d are means±s.d. (**P<0.01; ***P<0.001). Abbreviation: ETX, etomoxir.