Effect of PGE₂ on exocytosis of β-hex by hMCs. (A) hMCs were primed for 5 days with IL-4, sensitized with IgE overnight, and then stimulated with medium alone, anti-IgE, or staphylococcal PGN (50 μg/mL) for 30 minutes in the presence or absence of PGE₂ (10 μM). Values are expressed as percent of total cellular β-hex release and are the mean ± SEM from 5 experiments. (B) Primed and unprimed hMCs were stimulated for 30 minutes with PGE₂ (10 μM) and compared for exocytosis. Some of the primed cells were treated overnight with PTX before activation. Values are mean ± SEM from 3 experiments. ^*Significant relative to unprimed cells.