Rolipram suppresses MLR directly by inhibiting T cell prolifation and indirectly by modulating DC/T_reg interaction.

(A) BALB/c BMDC were cultured in absence or presence of C57BL/6 T_reg cells (1∶1 ratio) and rolipram (300 nM) for 4 h. Anti-CD3 (3 µg/ml) was added to every well. After fixation cells were cocultured with C57BL/6 Thy1.2⁺ T cells in a 10∶1 ratio for 3 days. Proliferation was determined by ³H-thymidine incorporation. (B) BALB/c BMDC were stimulated with LPS (100 ng/ml) for 4 h or left untreated and subsequently fixed with glutaraldehyde. C57BL/6 Thy1.2⁺ CD25⁻ T cells were cocultured with LPS stimulated or unstimulated fixed BMDC (1×10⁴ per well) for 3 days in a 10∶1 ratio. All depicted results were assayed in triplicate wells and are representative of three independent experiments. (*) indicates significant differences by Mann-Whitney U-test; n.s. – no significant differences.