FIGURE 2.

iPLA₂β plays no role in the effector functions of mast cells. A–C, IgE-sensitized BMMCs from Pla2g6^+/+ and Pla2g6^−/− mice were challenged with the indicated concentrations of Ag for 10 min, and the releases of β-HEX (A), PGD₂ (B), and LTC₄ (C) into the supernatants were evaluated (mean ± S.D., n = 5–6). D, LTC₄ generation by Pla2g6^+/+ and Pla2g6^−/− BMMCs treated for 10 min with 100 ng/ml SCF or 1 μm A23187 (mean ± S.D., n = 3). E, IgE/Ag-stimulated BMMCs from Pla2g6^+/+ and Pla2g6^−/− mice were cultured for 10 h in the presence of SCF and IL-1β (which amplify cytokine expression in BMMCs (63)) to assess IL-6 secretion (mean ± S.D., n = 3). F, IgE/Ag-triggered Ca²⁺ influx into BMMCs. A representative monitoring of intracellular Ca²⁺ levels in Pla2g6^+/+ (white circles) and Pla2g6^−/− (solid circles) BMMCs after Ag challenge (upper panel) and an average value at 3 min (mean ± S.E.; n = 3) (lower panel) are shown. G and H, IgE-sensitized Pla2g6^+/+ and Pla2g6^−/− CTMC-like cells, which had been cocultured for 1 week with Swiss 3T3 fibroblasts, were treated with or without Ag for 10 min, and the releases of β-HEX (G) and PGD₂ (H) into the supernatants were evaluated (mean ± S.D., n = 3). I, IgE-sensitized Pla2g6^+/+ and Pla2g6^−/− mice were challenged with or without Ag to assess PCA reaction (mean ± S.D., n = 5).