Induction of VCAM-1 on murine endothelial cells.

(A) Time-course. H-end73 (◍, ○) and H-end80 (□) cells were cocultured for different lengths of time with NQ22 (◍, ░) or NQ29 (○, □) cell suspensions obtained from frankly leukemic spleen (NQ22) or from a large SC tumor mass (NQ29), and the percentage of VCAM-1 positive cells was assessed by flow cytometry analysis using anti-VCAM-1 mAb 429. H-end80 stimulated with 100 ng/mL lipopolysaccharide (△) for 3 hours was used as positive control and similarly processed for flow cytometry analysis. (B) Induction of VCAM-1 by different cell types. H-end80 cells were cocultured for 7 hours with cell suspensions obtained from in vitro-grown NQ22 cells (NQ22 vitro), NQ22 cells isolated from an infiltrated spleen (NQ22 spleen), or a subcutaneous tumor mass (NQ22 SC mass) and from a subcutaneous mass of NQ29 cells (NQ29 SC mass). The expression of VCAM-1 was assessed with mAb 429. Control, isotype-matched unrelated primary antibody was added; basal, basal expression of VCAM-1 in H-end80 cells.