[Purification of human fibronectin by precipitation and immunoadsorption]

Two types of human plasma fibronectin concentrate were obtained by simple, large scale, precipitation methods. Concentrate 1 contains 90% pure fibronectin in a mainly dimeric form. This easy, high yield method provides a functional fibronectin suitable for intravenous therapeutic purposes in deficient patients. Concentrate 2 contains 95-98% pure fibronectin with minimal amounts of fibronectin monomer and degradation products. It seems well adapted to serum free cultures of human cells. A third preparation of an apparently pure fibronectin has also been obtained by immuno-adsorption with a Sepharose 4B column to which has been coupled an anti-fibronectin monoclonal antibody. The capture of dimer, monomers and degradation products by this antibody and their release at pH 2.4 has been demonstrated by gel transfer on nitrocellulose sheet revealed by another monoclonal anti-fibronectin antibody labelled with peroxidase.