Fig. 5 (A) Effect of wortmannin on anti-IgE-induced activation marker upregulation. Heparinized PB cells were incubated with 500nM wortmannin for 15 min at 37°C prior to stimulation with 1µg/ml anti-IgE antibody. After stopping the reaction, cells were stained and analyzed as described in Fig. 2. (B) Effect of prostaglandin D₂ (PGD₂) on activation marker upregulation. PB cells were stimulated with 10 µM PGD₂ for 10 min at 37°C. After stopping the reaction, cells were stained and analyzed as described in Fig. 2.