Effect of apigenin and wortmannin on mast cell adhesion and HUTS-21 β1 expression.

(A) Cells precultured with SCF alone or with SCF and IL-4 were treated for 60 minutes with 20 μM apigenin (Ap), 2 μM Gö 6976 (Gö), 100 nM wortmannin (Wo), or buffer control. Adhesion rates of mast cells stimulated with 100 ng/mL (54 nM) SCF compared to buffer control (0) were determined on fibronectin (means ± SD, n = 4). (B) Cells precultured with SCF alone were treated for 60 minutes with 20 μM apigenin (Ap), 2 μM Gö6976 (Gö), 100 nM wortmannin (Wo), or buffer control and then were incubated with buffer control or stimulated with 100 ng/mL (54 nM) SCF for 30 minutes before the expression of the HUTS-21 epitope was analyzed. Isotype control staining is shown in gray. Dotted lines show the HUTS-21 β1 staining of unstimulated mast cells, full lines after stimulation with SCF. Results of 1 of 3 representative experiments are shown. Mast cell purity was 98% or greater.