The preparation of plasma fibronectin antigen and antiserum

Affinity chromatography of human plasma, using either gelatin or fibrinogen coupled to Sepharose 4B, depletes the plasma of fibronectin. Other ‘contaminant’ proteins are also bound by this procedure on the column and elute with the fibronectin, as shown by using the bound and eluted fraction to immunise rabbits. Such antisera can be rendered specific for fibronectin by absorption with fibronectin depleted plasma. Alternatively, purified fibronectin can be obtained by a two-stage chromatographic procedure using a second separation on Sephacryl S300, and immunization with this as antigen produces monospecific antiserum. This reacts both with plasma and tissue fibronectin.