Figure 4. Calcium signal triggered by anti-CD3 particle binding.

T cells loaded with the 0.5 µM Fluo-3 calcium probe were placed in contact with anti-CD3 grafted particles (ρ_L = 1.9×10⁴/µm²). The intracellular calcium concentration [Ca²⁺ _i] was obtained from FL1 fluorescence intensity (see Materials and methods) for particle-bearing cells (▴) and free cells (•) identified by their respective FL3 intensity. This is a representative experiment out of more than four.