Figure 2.

SMase D does not alter internal store Ca²⁺ release in human T lymphocytes. (A) Fura-2 ratio signals from experiments shown in Fig. 1 D but with axes rescaled to better show the internal store release component for cells treated with SMase D (SMD, red) or catalytically inactive enzyme (CON, black). (B) Peak values (error bars represent mean ± SEM; n = 5) of Fura-2 ratio signals from Tg-stimulated cells in experiments as shown in A. (C) Fura-2 ratio signals of (38–84) T cells in a single 40× field, where the upper bar above the panel indicates these treatments: after 2-min rest, cells were treated with SMD (red) or CON (black) for 3 min, and then with 1 µg ionomycin (Iono) for 12 min; the lower bar shows the Ca²⁺-containing solution type. (D) Peak values (error bars represent mean ± SEM; n = 4) of Fura-2 ratio signals from ionomycin-stimulated cells in experiments as shown in C.