Effect of TGF-β 1–triggered down-regulation of SDF-1 secretion inα 5β 1-dependent cell adhesion to fibronectin. BCECF-AM–labeled NCI-H929 cells were preincubated with T134 or anti-α 5 mAb and subsequently were exposed for 1 minute at 37°C to supernatants from MS-5 cells treated with or without TGF-β 1 (+ TGF-β 1 and –TGF-β 1, respectively). Cells were added to wells containing plasma fibronectin and were subjected to adhesion for 2 minutes after a short spin. Nonbound cells were washed, and the extent of adhesion was measured in a fluorescence analyzer. Also shown is the triggering of cell adhesion by recombinant SDF-1α (100 ng/mL) compared with samples incubated with adhesion medium alone (control). Data represent the means ± SDs of triplicate samples from a representative result of 3 experiments. Reduction in triggering of cell adhesion was significant (*P < .05), according to Student 2-tailed t test.