Figure 3.

Chronic-cytokine treatment with TNF-α and IL-1β prolongs transient VCAM-1 expression on fibroblast-like synoviocytes. Medium plus IL-1β (10 ng/ml) (closed circles), medium plus TNF-α (10 ng/ml), or medium alone (open circles) were added at day 0 and re-added at days 3, 6, and 9, over a 12-day period. Cell surface VCAM-1 expression was determined 48 hours after each cytokine addition using flow cytometry and mAb BBA-5 as primary antibody. Samples were analyzed using a FACScan and the results expressed as corrected MFI. Data are presented as the mean ± SE of six experiments. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (compared with medium-only control at the respective time point).