Activation of macrophages and neutrophils by an endothelium growth suppressing factor

An endothelial cell growth-suppressing factor (EGSF) was purified from the serum-free conditioned medium of the mouse P388D1 culture in the presence of carboxymethylated curdlan. The purified EGSF showed two bands corresponding to the molecular masses of 55 and 63 kDa by silver staining on a SDS-polyacrylamide gel under reducing conditions. This factor strongly suppressed the proliferation of endothelial cells from bovine artery, human umbilical vein, and human dermal vas capillare and this suppression was observed to be reversible. We found that EGSF was a potent chemoattractant for macrophages and neutrophils. EGSF mediated the adhesion of neutrophils to BAEs and transendothelial migration of neutrophils. Macrophages stimulated by EGSF produced nitrite in a dose-dependent manner. EGSF did not affect the proliferation of T lymphocytes. These findings suggest that EGSF acts not only as a potent inhibitor for the growth of endothelial cells but also an activator for macrophages and neutrophils. Thus EGSF plays a role in an inflammatory response in the endothelium.