CD28 triggering enhances integrin-mediated T-cell migration. (A-C) Percentage of T-cell blasts (5 × 105/well) migrated at the indicated time points through endothelium (A), DAP.3 (B), or DAP.3–ICAM-1 (C) monolayers, fibronectin (D), or to a gradient of CXCL-12 (E) following CD28 triggering. The average percentage (±SE) of migrated T cells at the specified time points in 3 experiments with similar design is shown. (F) LFA-1 and VLA-4 clustering on the T-cell surface following CD28 triggering (indicated by arrows). Scale bar: 20 μm. (G) Mean percentage of T cells displaying polarized LFA-1 and VLA-4 aggregates in 300 cells from each sample in 3 independent experiments ± SD. (A) *P < .05 at all time points except 5 hours; (C) *P < .006; (D) *P < .002; (G) *P < .001.
