In contrast to the induction of AR by cAMP elevating agents, these mediators suppress inflammatory responses by inhibiting cytokine expression and T cell proliferation. Synthesis of several pro-inflammatory or Type 1 cytokines is inhibited by cAMP ( Figure 7E and [19, 20, 46, 47] , whereas cAMP can either inhibit or enhance production of Type 2 cytokines such as IL-4, IL-5 and IL-13 ( Figure 7E and [47] ) depending on the stimulation conditions [48, 49] .