PECAM-1–induced survival of CD34⁺ cells is dependent on PI-3K activation.

CD14⁺CD34⁺ cells were allowed to adhere to PECAM-1⁺–transfected fibroblats (D12P; A) or to mock-transfected cells (B), in the absence or presence of the F(ab′)₂ of the anti–PECAM-1 antibody (M89D3) or of LY294002 (20 μM), wortmannin (100 nm), herbimycin (100 nM) or PD98059 (10 μM) for 30 minutes, collected after 48 hours of culture, stained with PI as described in the legend to Figure 2, and run on a FACSort. We analyzed 10⁴ cells/sample; results are plotted as percentages of apoptotic (DNA content < 2n-diploid) cells (B-C). Murine Ig was used as control. Mean values ± SDs from 6 different experiments are shown.