Epitope mapping of clone VK41.

(A) Competition for binding to the heavy chain of factor VIII of phages corresponding to VK34 (•) and VK41 (□) with mAb CLB–CAg 9. Binding is expressed as a percentage of maximal binding. (B) Reactivity of phages corresponding to VK34 and VK41 with plasma-derived factor VIII heavy chain (pdFVIII HCh), rFVIII (rFVIII), rFVIII-HCII (HCII), and rFVIII-Tyr^718,719,723→Phe (Y718, 719, 723F). Phage ELISAs were performed as described in “Materials and methods.” Binding of phage to rFVIII is expressed as a percentage relative to binding of VK41 to rFVIII.