Figure 2.

Implication of the E-prostanoid 4 (EP4) receptor in prostaglandin (PG) E₂-mediated inhibition of innate lymphoid cell 2 (ILC2). (A) mRNA expression for each of the four PGE₂ receptor subtypes in purified ILC2 cells as determined by RT-PCR. Representative results from one out of three independent experiments are shown. (B–D) Purified ILC2 cells were stimulated with IL-33 (20 ng/ml) in the presence or absence of PGE₂ (10 nM), sulprostone (1 μM), butaprost (1 μM), PGE₁-alcohol (1 μM), AH6809 (10 μM), and/or ONO-AE3-208 (10 μM). The cultures were analyzed on day 6. Live cells were numerated by trypan blue exclusion (B). IL-5 and IL-13 levels in the supernatant were measured by ELISA (C). IL-5 and IL-13-secreting cells were detected by intracellular staining (D). Representative dot plots (left) and the percentage of IL-5⁺IL-13⁺ cells (right) are shown. Each experiment was repeated at least three times with duplicates for each group. Data are presented as mean ± SD unless indicated otherwise. *p < 0.05; **p < 0.01; and ***p < 0.001.