Inhibition of TEC-thymocyte binding by MoAbs anti-β1 and anti-β4 integrins. Binding assays were performed between TEC monolayers plated and grown to tight confluence and PKH26-GL dye-labeled thymocytes (1:5 TEC/thymocyte ratio) for 1 hour at 37°C in humidified atmosphere of 5% CO₂. Purified antibodies were separately incubated with TEC and thymocytes for 30 minutes before binding at 5 μg/mL and maintained during the test. PBS⁻indicates assays performed in PBS Ca²⁺Mg²⁺-free. Nonadherent thymocytes were removed by gentle washings. TEC and bound thymocytes were detached by trypsin-EDTA, washed, vortexed to disrupt aggregates, and counted by flow cytometry. Results were expressed as the ratio of TEC:thymocytes recovered and as a percentage of the ratio of the untreated controls. Shown are the mean values ± SD of four independent experiments performed with TEC and thymocytes obtained from different donors.