Fig. 4.

Fibroblast conditioned medium does not induce endothelial cell (EC) activation. A minimal volume (2 ml per 25-cm² culture flask) of medium (Dulbecco's modified Eagle's medium (DMEM)) was conditioned for 24 h by scleroderma (S1–S5) or control (N1–N4) dermal fibroblasts and then added to confluent cultures of the human EC line IE-7. Neither E-selectin nor vascular cell adhesion molecule-1 (VCAM-1) were up-regulated. Some media induced modest up-regulation of intercellular adhesion molecule-1 (ICAM-1) but in no wells was ICAM-1 reduced below its constitutive level of expression. Quantification was by cell-bound ELISA using absorbance at 450 nm in triplicate wells (mean ± s.d.). Control wells had no cytokine added and reflect constitutive expression of the adhesion molecules. Adhesion molecules were readily up-regulated by tumour necrosis factor-alpha (TNF-α) at 100 U/ml final concentration. Similar data were obtained in two further experiments.