Figure 5. Intracellular Ca²⁺ concentrations and the effect of extracellular Ca²⁺ in migrating activated T cells.

A. Time-dependent intracellular Ca²⁺ levels in the uropod (U), mid-body (M) and leading-edge (L) in a representative migrating T cell. Cells were loaded with 1 µM Fura-2, and the Fura-2 340/380 ratio was quantified using the MetaMorph software. A scheme representing the different cell compartments of a polarized migrating cell is shown as inset. B. Effect of extracellular Ca²⁺ removal on T cell migration. The motility was determined by following the same cell in physiological [Ca²⁺]_e (2 mM) and in Ca²⁺-free medium (0 Ca²⁺/EGTA). Control motility is the average motility over 20 min, while the motility in Ca²⁺ -free medium corresponds to the average of the last 5 min of 25 min in Ca²⁺-free medium. The data are the average of n = 17 cells from 2 different donors.