Rap1 activation by stimulators of the respiratory burst in resting neutrophils. (A) Neutrophils were stimulated with 100 ng/mL TPA or IgG-coated latex beads. Samples were taken at indicated time points after stimulation. Rap1 activity was determined as described in the legend to Fig 1. (B) Respiratory burst induced in resting neutrophils by TPA (100 ng/mL) measured using a Clark oxygen electrode.