An electrophysiological study of calcium entry during normal human T-lymphocyte activation.

Our aim was to observe whether normal human T-cells respond to mitogenic stimulation with large whole-cell inward currents (composed of identifiable single-channel contributions) when [Ca2+]i is not markedly lowered but instead kept normal or moderately low, as has been reported in human leukaemic Jurkat T-cell line and T-cell clones [Kuno et al. (1986) Nature 323, 269-73; Kuno and Gardner (1987) Nature 326, 301-304; Gardner (1990) Annu. Rev. Immunol. 8, 231-252]. Whole-cell patch recordings showed no such currents in cells otherwise normally responding to depolarisation with the macroscopic IK described in T-lymphocytes and thus deemed viable, in agreement with the notion that Ca2+ influx in normal T-cells enterily depends on depletion of internal stores [Putney (1986) Cell Calcium 7, 1-12; Putney (1990) Cell Calcium 11, 611-624].