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Updated: Aug 8, 2026
Whole-Cell Recording of Calcium Release-Activated Calcium (CRAC) Currents in Human T Lymphocytes
Published on: December 21, 2010
An electrophysiological study of calcium entry during normal human T-lymphocyte activation
R Ricci1, M Buffelli, A P Riviera
1Istituto di Anatomia Patologica, Universita' Cattolica, Roma, Italy.
Insights
Normal human T-cells do not exhibit large inward currents upon mitogenic stimulation, unlike leukaemic Jurkat T-cells. Calcium influx in healthy T-cells relies on internal store depletion, not direct membrane currents.
Area of Science:
- Immunology
- Cell Biology
- Physiology
Background:
- Human leukaemic Jurkat T-cells and T-cell clones show large inward currents upon mitogenic stimulation.
- These currents occur even when intracellular calcium ([Ca2+]i) is normal or moderately low.
- The mechanism of calcium influx in normal T-cells remains a subject of investigation.
Purpose of the Study:
- To investigate whether normal human T-cells exhibit similar large inward currents as leukaemic T-cells.
- To determine the conditions under which calcium influx occurs in normal T-cells during mitogenic stimulation.
Main Methods:
- Whole-cell patch-clamp recordings were performed on normal human T-cells.
- Cells were subjected to mitogenic stimulation.
- Cellular responses to depolarization, including macroscopic IK currents, were monitored.
Main Results:
- Normal human T-cells did not display large whole-cell inward currents upon mitogenic stimulation.
- These cells, however, responded normally to depolarization with macroscopic IK currents, indicating viability.
- The findings align with the understanding that Ca2+ influx in normal T-cells is primarily dependent on internal store depletion.
Conclusions:
- Normal human T-cells do not generate large inward currents in response to mitogenic stimulation under the studied conditions.
- Calcium influx in normal T-cells is predominantly mediated by the depletion of intracellular calcium stores.
- This study differentiates calcium signaling pathways between normal and leukaemic T-cells.
Abstract:
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].
