FIGURE 2.

pH_i and Na⁺/H⁺ exchanger activity in Th cell subsets and iTregs. A, alterations of cytosolic pH (pH_i) following an ammonium pulse in Th cell subsets and iTregs. Cells were loaded with H⁺ by treating with 20 mm NH₄Cl. Na⁺ was then removed by replacement with NMDG. NH₄Cl was then removed in a second step and Na⁺ was added with nigericin (pH_o 7.0) to calibrate each individual experiment. Original tracings of typical experiments are shown for pH_i measurement and Na⁺/H⁺ exchanger activity in Th cell subsets. B, arithmetic means ± S.E. (n = 3–5 independent experiments) of cytosolic pH prior to the ammonium pulse (pH_i) in Th cell subsets and iTregs. Asterisk (*) indicates a statistically significant difference (*, p < 0.05). C, arithmetic means ± S.E. (n = 3–5 independent experiments) of Na⁺-dependent recovery of cytosolic pH (ΔpH/min) in Th cell subsets. Asterisk (*) indicates a statistically significant difference (*, p < 0.05).