Kinetics of ERK1/2, SAPK/JNK, and p38 phosphorylation by influenza virus in human lung slices. Human lung tissue slices were exposed to 6 × 106 PFU/ml of influenza virus PR8 and OK/06 for the times indicated. Lung lysates were prepared, and 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) was used as positive controls, and virus diluent was used as a negative control. Western blots were probed with antibody specific for phosphorylated ERK1/2 (A), p38 (D), or SAPK/JNK (H) are shown. Identically prepared blots were also probed with pan-anti-kinase antibody against ERK1/2 (B), p38 (E), or SAPK/JNK (I). Activation as determined by the ratio of phosphorylated kinase/total kinase for ERK1/2 (C), p38 (F), and SAPK/JNK (J) is graphed as shown.