Prostaglandin E2 and the suppression of phagocyte innate immune responses in different organs.

The local and systemic production of prostaglandin E(2) (PGE(2)) and its actions in phagocytes lead to immunosuppressive conditions. PGE(2) is produced at high levels during inflammation, and its suppressive effects are caused by the ligation of the E prostanoid receptors EP(2) and EP(4), which results in the production of cyclic AMP. However, PGE(2) also exhibits immunostimulatory properties due to binding to EP(3), which results in decreased cAMP levels. The various guanine nucleotide-binding proteins (G proteins) that are coupled to the different EP receptors account for the pleiotropic roles of PGE(2) in different disease states. Here, we discuss the production of PGE(2) and the actions of this prostanoid in phagocytes from different tissues, the relative contribution of PGE(2) to the modulation of innate immune responses, and the novel therapeutic opportunities that can be used to control inflammatory responses.