Partial purification and characterization of a vascular permeability factor secreted by a human colon adenocarcinoma...

The established human colon adenocarcinoma cell line, HT-29, secretes a vascular permeability factor (VPF) in vitro. The factor has been purified from serum-free conditioned medium by acidification, cation-exchange, and reverse-phase and anion-exchange high-performance liquid chromatography. The VPF is a non-glycosylated acidic protein of apparent molecular weight 45,000, and is at least 4 orders of magnitude more potent than histamine as an inducer of vascular permeability. Its biological activity is unaffected by soybean trypsin inhibitor or by inhibitors of histamine, kinins, prostaglandins, or acid proteases. The VPF induces vascular permeability within minutes, which suggests a direct effect on the endothelial cell.