Fig. 2. Effect of TWEAK on survival of (A) HUVEC and (B) HDMEC. ECs were cultured for 48 hours in CS-C complete media (CM) or incomplete media (IM) with or without TWEAK or VEGF. Anti-TWEAK mAb AB.G11 and control Ig were added as specified on the bar graphs. Cells were stained with FITC-Annexin-V and PI, and the percentage of viable and apoptotic cells is indicated. The results with HUVEC and HDMEC are the mean percentages ±s.d. of n=4 and n=2 experiments, respectively. HUVEC cultures with TWEAK versus IM were significantly different with respect to the percentage of viable cells and the percentage of apoptotic cells (p<0.05 by Student’s t test for each comparison indicated by asterisks).