Transendothelial migration of antileukemia T-cell lines in response to recombinant chemokines or supernatants containing chemoattractants. Migration was assayed through Transwell inserts covered with the HUVEC cells (upper panel) or the bone marrow endothelial cell line BMEC (lower panel). The bars represent the percentage of input T cells migrated over the 6-hour chemotaxis assay. RANTES and MIP-1 were used at 100 ng/mL. The supernatant is from the culture of autologous T-cell lines (day 30) restimulated for 48 hours by irradiated CD40-stimulated leukemia cells (2:1 ratio). The combination of anti–LFA-1 (5 μg/mL), anti–ICAM-1 (5 μg/mL), and anti-CD18 (5 μg/mL) was used as blocking antibodies. Peripheral blood and/or bone marrow T cells purified by negative selection were used as negative controls; no significant transendothelial migration was observed through either HUVEC (<3%) or BMEC (<2%). The results shown are from 1 experiment (2 patients) and are representative of 3 different patients studied using the HUVEC and the BMEC layers.