Applications of immunoperoxidase techniques in specificity testing of monoclonal antibodies (Mabs) against von Willebrand factor (vWf).

The present communication describes the production of a new series of murine Mabs against von Willebrand factor (vWf) in which specificity was tested using immunoperoxidase techniques. Seven Mabs showed specific reactivity with native and disaggregated vWf, whereas no binding was found to material from patients with severe homozygous (or doubly heterozygous) von Willebrand's disease (vWd) or factor VIII coagulant antigen (VIII:Ag). These Mabs are thought to carry separate specificities as only slight or no competitive activity was detected. Four Mabs partially inhibited the ristocetin-induced platelet agglutination and three interacted with vWf-binding to type I collagen. All antibodies bound to the complete range of vWf multimers of normal plasma. Excellent binding and detection properties of Mabs were found in asymmetrical two-site enzyme linked immunosorbent assays (ELISA) for quantitation of vWf antigen (vWf:Ag). One particular antibody (Mab vWf-33) discriminated vWf material from a number of subtype II vWd plasmas tested.