Modulation of Th1- and Th2-like cytokine production from mitogen-stimulated human peripheral blood mononuclear cells by phosphodiesterase inhibitors.

1. Effects of phosphodiesterase (PDE) inhibitors on the production of IFN-gamma, IL-2, IL-4 and IL-5 by phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells (PBMC) were investigated. In addition, we investigated the effects of dibutyrylcyclic AMP (dbcAMP) and a beta-adrenoceptor agonist on production of these cytokines. 2. Type IV, type III and nonselective PDE inhibitors were effective at inhibiting the production of IFN-gamma and IL-2 production in a dose-dependent manner. In contrast, IL-4 and IL-5 production was inhibited by only the highest concentration of type IV inhibitor, and other agents had no effect on the production. 3. Similarly, dbcAMP inhibited the production of IFN-gamma and IL-2 more potently than IL-4 and IL-5. 4. The addition of a beta-adrenoceptor agonist increased the inhibitory effect of PDE inhibitors tested on the production of IFN-gamma and IL-2. 5. These results indicate that PDE inhibitors or cAMP-elevating agents modulate Th1 cytokine more effectively than Th2 cytokine production.