Figure 5.

Entamoeba histolytica trigger extracellular calcium mobilization in neutrophils. Human neutrophils were incubated with fura-2 for 30 min and then placed in PBS with EGTA. Neutrophils were stimulated (arrow) with (A) 10 nM formyl-methionyl-leucyl-phenylalanine (fMLF), or were stimulated with (B) E. histolytica trophozoites (amoeba). After about 250 s, an excess (4 mM) Ca²⁺ was added to the buffer. Changes in cytosolic calcium concentration were assessed by measuring the variations in fluorescence of fura-2-loaded cells. Tracings are representative of three experiments. (C) The increase of cytosolic calcium concentration (Δ [Ca²⁺]) is shown from intracellular or extracellular calcium pools. Data are mean ± SEM of three experiments.