Fig. 4.

Intracellular calcium pools are altered at different stages of long-term CD4⁺ T cell culture. Release of calcium from intracellular pools was assessed in cells cultured as in Figs 2 and 3. Calcium responses were assessed in Ca²⁺-free medium by sequential addition of phytohaemagglutinin, thapsigargin and ionomycin as described previously [19]. Ionomycin responses did not change over time and so are omitted for clarity.