Figure 5.

Effects of anti-OX40 ligand (OX40L) monoclonal antibody (mAb) on the proliferation of CD4⁺ T cells stimulated by purified OX40L⁻ mature DCs (mDCs). (a) OX40L⁻ mDCs were purified in a cell sorter and irradiated. CD4⁺ T cells and OX40L⁻ mDCs were mixed at a ratio of 1000 : 1 and co-cultured in a 96-well culture plate for 7 days in the presence of the indicated reagents. Cells were pulsed with [³H]thymidine ([³H]TdR) (0·5 µCi/well) for the last 7 hr of culture and the incorporated radioactivity was measured in a liquid scintillation counter. Results are expressed as mean counts ± standard deviation (SD) of triplicate samples. The asterisk indicates a P-value of < 0·05 for comparison with the suppressed reactivity. (b) CD4⁺ T cells and allogeneic OX40L⁻ mDCs were mixed at a ratio of 10 : 1 and co-cultured in a 96-well culture plate for 7 days. Cells were collected on days 3, 5 and 7, and the expression of OX40L was examined on mDCs.