Figure 4. Reduced FcεRI-dependent Ca²⁺ influx following BMMC-T_reg engagement, but not intracellular Ca²⁺ mobilization.

(A) BMMCs loaded with FURA-2AM were stimulated via FcεRI in the absence (BMMC, black line) or presence of CD4⁺CD25⁻ T cells (T resting, green line), WT CD4⁺CD25⁺ T_regs (red line) or OX40^−/− CD4⁺CD25⁺ T_regs (blue line) and fluorescence emission was monitored. (B) FURA-2AM-loaded BMMCs were stimulated via FcεRI and co-cultured with WT CD4⁺CD25⁺ T_regs (red line) in the absence of extracellular Ca²⁺. 400 sec after Ag stimulation, 2μM Ca²⁺ was added to the medium and fluorescence emission was monitored. (C and D) At the end of each experiment, 14 minutes after Ag addition, percentage of β-hexosaminidase release from individual sample, was measured. Results shown are representative of three independent experiments.