Rapamycin Inhibits Activator Protein-1 But Not Nuclear Factor-κB Activity of Mature Bone Marrow-Derived Dendritic Cells

Rapamycin (Rapa), a recently introduced immunosuppressive drug, appears to be effective in preventing acute allograft rejection episodes. Its effects on differentiation and maturation of dendritic cells (DCs) have been studied. In this report, we evaluated the effects of Rapa on the intracellular signal transduction pathways in mature DCs. The results showed that Rapa did not depress 1)65, p50, or I kappa B alpha expression. However, it dramatically reduced activator protein-1 activation. The fact that Rapa exerts a specific effect on activator protein-1 activity in mature DCs may contribute to its unique actions to prevent allograft rejection and induce immune tolerance.