Figure 2.

Degranulation of RBL-2H3 (open bars) and B6A4C1 (filled bars) mast cells. Adherent cells were sensitized overnight with biotinylated anti-DNP IgE and stimulated for 60 min at 37°C with no trigger (unstimulated), 10 nM streptavidin, 100 ng/ml DNP-BSA (antigen), 700 nM A23187 plus 80 nM PMA, 700 nM A23187, or 200 nM thapsigargin, as indicated. Cellular supernatants were assayed for β-hexosaminidase released from the cells as described in Methods. Degranulation is expressed as a percent of the total β-hexosaminidase activity released by TX-100 lysis, which was similar for both cell lines.