FIG. 4.
Kinetics of ERK1/2, SAPK/JNK, and p38 phosphorylation by B. anthracis Sterne strain spores (B.a. spores) in human lung slices. Human lung tissue slices were exposed to 1 × 106 Sterne spores for the times indicated in the presence of gentamicin. Lung lysates were prepared, and the levels of total and phosphorylated ERK1/2 (A, B, and C), p38 (D, E, and F), and SAPK/JNK (H, I, and J) were assessed by Western blot analysis. PMA (100 ng/ml) and LPS (1 μg/ml) were used as positive controls, and spore diluent was used as a negative control. Western blots were probed with an antibody specific for phosphorylated ERK1/2 (A), p38 (D), or SAPK/JNK (H). Identically prepared blots were also probed with pan-antikinase antibody against ERK1/2 (B), p38 (E), or SAPK/JNK (I). Activation as determined by the ratio of phosphorylated kinase to total kinase for ERK1/2 (C), p38 (F), and SAPK/JNK (J) is also shown.