Induction of PI3K activity by cytokines and chemoattractants in human eosinophils. (A) Eosinophils (2 × 106) were left unstimulated for 5 minutes at 37°C (lane 1) or stimulated with the cytokines IL-5 (10−9 mol/L), IL-3 (10−9 mol/L), and GM-CSF (6 × 10−8mol/L) for 5 minutes at 37°C (lanes 2 to 4). Densitometric analysis showed that the fold induction compared with the unstimulated control (lane 1) was 61.7 (lane 2), 20.4 (lane 3), and 14.4 (lane 4). (B) Eosinophils (2 × 106) were stimulated with IL-4 (10−8 mol/L, lane 1) or with IL-4 (10−8mol/L) in combination with a MoAb directed against IL-4 (lane 2). The fold induction compared with the unstimulated control (lane 1) was 14.7 (lane 2) and 6.2 (lane 3). (C) In lanes 1 to 3, eosinophils (2 ×106) were stimulated for 1 minute at 37°C with PAF (10−6 mol/L), RANTES (10−6 mol/L), C5a (10−8 mol/L), respectively. Lane 4 represents an unstimulated control sample that was kept at 37°C for 1 minute. The fold induction compared with the unstimulated control (lane 4) was 15.3 (lane 1), 6.3 (lane 2), and 3.0 (lane 3). The experiment shown is representative of three other experiments.
