(A) Inhibition of AS283 lymphoma cell adhesion to Tat-activated EC. EC were treated for 4 hours with medium alone (control) or Tat-MBP (20 ng/mL) and thereafter incubated with antibodies against the adhesion molecules E-selectin, VCAM-1, and ICAM-1. Adhesion of AS283 lymphoma cells was evaluated after 30 minutes. (B) AS283 lymphoma cell adhesion to VCAM-1. Wells were coated with 5 μg/mL VCAM-1 or buffer only (control). AS283 cells treated or not with antibodies against VLA-4 were incubated on soluble VCAM-1–coated plastic for 30 minutes. Results show the attached cells as a percentage of total cells added. Columns, mean of three replicates and representative of 1 of 3 experiments; bars, SD. *P< .05 compared with EC treated with Tat-MBP without MoAb (A) or to VCAM-1 (B).