The further purification and identification of connective tissue factor 2 (CTF-2) is being carried out. A large molecular weight substance in connective tissue that inhibits epithelial cell growth has also been identified and partially purified. A method to isolate and maintain rabbit skin endothelial cells in cell culture has been developed, and the growth characteristics and nutritional requirements of endothelial cells has been determined. Interaction of skin epithelial cells with endothelial cells in vitro is being studied.