Isolation and insolubilisation of human F VIII by affinity chromatography. 
A simple procedure has been developed for the isolation of coagulation factor VIII (F VIII) from plasma in a form which induces a monospecific antibody in rabbits.  Amino acid precipitation from plasma was followed by gel filtration on Sepharose 4B and further purification was achieved by affinity chromatography on heparin-Sepharose.  The material so isolated was identified by immunoelectrophoresis and lacked coagulant activity.  The antiserum produced in rabbits inhibited F VIII coagulant activity and von Willebrand factor activity as measured by ristocetin platelet agglutination.  The isolated IgG fraction insolubilised with CNBr-Sepharose 4B retained the ability to complex with F VIII.  This complex possessed F VIII coagulant activity which could be removed in 0.6 M NaCl and dissociated in 8 M urea.