Cells were prepared and resuspended in serum-free DMEM (2.3×106/mL; A). Peptide-modified BSA probes, naïve BSA or control proteins were spotted on a petri dish as indicated (B). After blocking the plastic surface with BSA, cells were added and incubated for 15-20 min in a humidified incubator (37°C, 5% CO2; C). Floating cells were aspirated, the samples were washed with PBS, and attached cells were visualized by phase contrast microscopy. Technical details have been described recently [24].
