CD9-LEL-GST inhibits leukocyte transendothelial migration and promotes cell detachment under flow. (A) CD9-LEL-GST peptide inhibits transendothelial lymphoid migration in Transwells. HUVEC monolayers were activated with TNF-α alone or in combination with the different LEL-GST peptides. Then, human PBLs were added to the upper compartment and allowed to migrate for 5 to 7 hours. Cell migration was analyzed by flow cytometry and represented as the mean ±SEM with respect to control untreated monolayers, of 4 independent experiments performed in duplicate. ^**P < .005 in a Student t test. (B) Preincubation with CD9 LEL-GST fusion protein augments detachment under flow conditions. The percentage of detachment of PBLs was analyzed in 8 to 10 fields under increasing flow rates and represented as the mean ±SEM. indicates untreated cells; ×, C152A; ▪, CD9-GST; and ▴, C153A. ^**P < .005 in a Student t test.