Adhesion of α_Dβ₂- and α_Mβ₂-expressing HEK 293 cells to different ligands. HEK 293 cells expressing wild-type α_Dβ₂ (□) and α_Mβ₂ (), and mock-transfected cells (▪), were labeled with calcein and their adhesion to different ligands was tested. Aliquots (50 μL) of 5 × 10⁵/mL cells in DMEM/F-12 were added to the wells coated with increasing concentrations of different ligands. After incubation for 30 minutes at 37°C, the nonadherent cells were removed by 2 washes with PBS and fluorescence was measured. The number of adherent cells was calculated by using the fluorescence of aliquots with a known number of labeled cells. Maximal adhesion to each substrate is shown as was determined from the dose-dependent curves of adhesion. Maximal adhesion to fibronectin (Fn), fibrinogen (Fg), plasminogen (Pg), Cyr61, vitronectin (Vn), P2-C, and VCAM-1 was observed at coating concentrations of 10 μg/mL, 2 μg/mL, 10 μg/mL, 2.5 μg/mL, 5 μg/mL, 50 μg/mL, and 5 μg/mL, respectively. Data are expressed as a percentage of added cells and are the mean ± SE of 3 to 6 individual experiments.