Fig. 4. Ca²⁺ elevation enhances MAPK activation by parasite lysate or LPS. Macrophages were treated with medium (m) or stimulated with STAg (A; 50 µg/ml) or LPS (B; 100 ng/ml) either in the presence or absence of the Ca²⁺-mobilizing stimulus thapsigargin (1 µM) in normal Ca²⁺ media. Whole cell lysates were collected at the times indicated and immunoblotted for phospho-ERK1/2 and phospho-p38 then stripped and re-probed for total MAPK. Each experiment was repeated at least three times, and representative results are presented.