Figure 1.

Intracellular Ca²⁺ increases in ESAT-6 treated neutrophils and precedes necrosis. (a) Sequential fluorescence micrographs showing accumulation of calcium (green, Fluo4) in Annexin V positive (purple)/PS externalised aged neutrophils after exposure to exogenous ESAT-6 (20 μg/ml). Uptake of propidium iodide (PI) (red) indicates necrosis of the cell. Arrow tracks an individual cell. White bar=10 μm. Panel (b) shows a representative quantitation of intracellular Ca²⁺ levels of a PS externalised (Annexin V+ve) cell exposed to ESAT-6 (16 responses in N=3 experiments). Panel (c) shows representative intracellular Ca²⁺ in a non-PS externalised neutrophil exposed to ESAT-6. (21 responses in N=4)