Binding of FVIII to recombinant vWF. The ability of WT or mutated rvWF to bind FVIII was determined as described in Fig 1A. Conditioned media samples: (•), WT rvWF; (▪) Asn116rvWF; (▴) hybrid Asp/Asn116rvWF. Each dilution sample was analyzed in duplicate and the results were averaged. Similar results were consistently observed when three independent tansfection media were tested in three separate experiments.