Flow cytometric measurement of calcium influx in murine T cell hybrids using Fluo-3 and an organic-anion transport inhibitor.

A method is described to facilitate flow cytometric analysis of calcium mobilization upon stimulation of murine T cell hybrids. In these transformed cell lines, the accuracy of cytometric measurement of free cytoplasmic calcium with Fluo-3 is compromised by the rapid loss of the intracellular dye. We have found that the addition of sulfinpyrazone, a known organic-anion transporter inhibitor in epithelial cells and in macrophages, severely impairs the leakage of the Fluo-3 probe from the cytoplasmic matrix. Under appropriate conditions, sulfinpyrazone has little effect on the cell physiology and permits the detection of calcium influx in a variety of murine T cell hybrids.