Lipopolysaccharide (LPS) induction of tristetraprolin (TTP) in resting THP-1 cells. Cells were incubated with and without LPS and then at specific times were permeabilized and stained with TTP antibody or a rabbit IgG control. (a) Induction was rapid, reaching a maximum at 1 hour. Results are expressed as the percentage change over baseline in MESF ± SE (n = 3). Significant increases are shown with respect to time 0 (*P < 0.05). (b) Confocal microscopy reveals the basal expression of TTP at time 0, and the upregulation at 2 hours after LPS treatment. The left panel shows the expression before LPS incubation, the right, after LPS stimulation. Nuclear staining was completed with propidium iodide. MESF = milliequivalents of soluble fluorescein; SE = standard error.