Fig. 4

Differential activation of GEFs modulates CD40-induced counteractive effector functions. a-c Immunoblot analyses of total and phosphorylated (p-) p38MAPK and ERK-1/2 in the anti-CD40 antibody (3 μg/ml) stimulated P388D1 cells: un-transfected or transfected with Sos-1/2, Vav and Ras-GRP specific siRNA. siRNA treated P388D1 cells were stimulated with anti-CD40 antibody (3 μg/ml) for 15 min. Suppression of Sos-1/2 (a) reduced CD40 (3 μg/ml)-induced ERK-1/2 phosphorylation whereas silencing of Ras-GRP (b) and Vav (c) using respective siRNA reduced CD40 (3 μg/ml)-induced p38MAPK phosphorylation. d-f ELISA of IL-10 and IL-12p70 from the culture supernatants of the P388D1 cells transfected with the indicated GEF siRNA, followed by treatment with anti-CD40 antibody (3 μg/ml) for 48 h. respectively. p ≤ 0.05; ** p ≤ 0.005; *** p ≤ 0.0005 compared with control P388D1 cells.