The CD99-expressing antigen-specific memory/effector T_H1cell line SJL.PLP7 does not bind via CD99 to mouse bEnd.5 endothelioma cells. (A) Binding of anti-CD99 antibodies (solid line) and control IgG (thin line) to SJL.PLP7 cells as analyzed by flow cytometry. (B) SJL.PLP7 cells were allowed to adhere to bEnd.5 cells in the absence of antibodies (w/o Ab), or in the presence of 30 μg/mL antibodies against ESAM (anti-ESAM), against CD99 (anti-CD99), or against ICAM-1 (anti–ICAM-1). P < .005, anti–ICAM-1 versus w/o Ab. The results are presented as the mean ± SEM, and are representative of at least 3 separate experiments.