Figure 1.

PGD₂, PGE₂, and PGI₂ direct the functions of eosinophils. Eosinophils express receptors for PGD₂ (DP1, DP2), PGE₂ (EP2, EP4), and PGI₂ (IP). Via DP2, PGD₂ attracts eosinophils to the site of inflammation, enhances eosinophil mobilization from the bone marrow, and upregulates CD11b expression. In line with the chemotactic response, PGD₂-mediated activation of eosinophils results in increased size and altered cell shape. DP1 and DP2 cooperatively regulate the synthesis of LTC₄. DP1 has been shown to enhance the DP2-mediated Ca²⁺ response and to prolong the survival of eosinophils in vitro. Counteracting pro-inflammatory mechanisms PGE₂ and PGI₂ suppress the activation of eosinophils and hence dampen pro-inflammatory signals. Despite the negative regulation of eosinophil effector and chemotactic functions by PGE₂ and PGI₂, PGE₂ was shown to decrease eosinophil apoptosis in vitro.