Pig Tumor-secreted Vascular Permeability Factor -Terminal Amino Acid Sequence of Guinea

Rodent and human tumor cell lines secrete a potent vascular permea bility factor (VPF) which causes a rapid and substantial increase in microvascular permeability to plasma proteins without causing mast cell degranulation, or endothelial cell damage or without exciting an inflam matory cell infiltrate |D. R. Senger, S. J. Galli, A. M. Dvorak, C. A. Perruzzi, V. S. Harvey, and H. F. Dvorak. Science (Wash. DC), 219: 983-985,1983; D. R. Senger, C. A. Perruzzi, J. Feder, and H. F. Dvorak. Cancer Res., 46: 5629-5632, 1986|. VPF now has been purified to homogeneity from guinea pig tumor cell culture medium; it is a V/, 34,000-43,000 protein, and a NH2-terminal amino acid sequence has been derived. A synthetic peptide corresponding to amino acid residues 1-24 of the native protein was used to raise rabbit antibodies which bind all of the vessel permeability-increasing activity secreted by guinea pig tumor cells and which stain purified VPF on immunoblots. These findings establish that this NHz-terminal amino acid sequence was derived from the permeability factor. Homolog) searches found no identity or close similarity between VPF Nil .-terminal sequence and database sequences, indicating that VPF is distinct from other proteins for which sequence data are available. In particular, no sequence similarity was found between tumor-secreted VPF and other mediators of increased vessel permeability including plasma and glandular kallikreins.