PGE2 has been known to suppress Th1 responses. We studied the role of PGE2 in two representative chemokines, macrophage-derived chemokine (MDC) and IFN-inducible protein-10, production by LPS- or CD40-stimulated spleen cells. The production of MDC, one of the ligands for CCR4 preferentially expressed on Th2, was enhanced in nonstimulated, LPS-, CD40-, or CD3-stimulated spleen cells by the pretreatment with PGE2, while the production of IFN-inducible protein-10, a representative ligand for CXC chemokine receptor 3 expressed on Th1, was suppressed. MDC production was also enhanced by IL-4, IL-5, and intracellular cAMP-elevating agents such as dibutyryl cAMP and 3-isobutyl-1-methylxanthine, and the effect of IL-4, IL-5, and PGE2 was additive. However, the pretreatment with IL-6, IL-10, or TGF-β, or the neutralization of IFN-γ or IL-12 had no effect on MDC production. B cells, macrophages, and dendritic cells were main producers of MDC, while T cells produced only a small amount of MDC. MDC production by B cells was equally stimulated by LPS and anti-CD40 Ab, while that by macrophages and dendritic cells was more markedly stimulated by anti-CD40 Ab, and PGE2 further enhanced MDC production by these stimulated cells. These results indicate that PGE2 regulates Th1/Th2-related chemokine production by B cells, macrophages, and dendritic cells, and that this is a new function of PGE2 for the regulation of Th2 immune responses at the induction and activation stages.
