Effect of PGE₂ and receptor-selective analogs on cytokine generation by hMCs. (A) Effect of various doses of PGE₂ on the generation of TNF-α by IL-4-primed, sensitized hMCs stimulated for 6 hours with anti-IgE or PGN (10 μg/mL). Values are the means of triplicate samples from a single experiment. Similar data were obtained with the cells of a second donor. (B) Effect of PGE₂ (10 μM) on the production of TNF-α and IL-5 by IL-4-primed, sensitized hMCs stimulated with anti-IgE or PGN for 6 hours. Values are expressed as percentage of control and are the means ± SEM from 3 separate experiments. (C) Effect of receptor-selective agonists on TNF-α generation by hMCs stimulated with anti-IgE. Primed, sensitized hMCs were stimulated for 6 hours in the presence of PGE₂ (10 μM) or the indicated concentrations of the EP receptor-selective agonists. Values are expressed as percentage of the DMSO control and are means ± SEM from 3 experiments. (D) Real-time PCR showing effect of PGE₂ and receptor-selective agonists on the FcϵRI-induced steady-state expression of TNF-α mRNA. Data are from a single experiment, and are similar to that obtained in a second experiment. ^*Significantly different from control.