Multimerization of Peptide Mimotopes for Blocking of Factor VIII Neutralizing Antibodies |
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| Authors: | Christoph Kessel Dr Wolfhart Kreuz Dr Katharina Klich Karin Becker‐Peters Frank Vorpahl Ursula Dietrich Dr Thomas Klingebiel Dr Christoph Königs Dr |
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| Affiliation: | 1. J.?W. Goethe University, Department of Pediatrics III, Molecular Hemostasis and Immunodeficiency, Theodor‐Stern‐Kai 7, 60596 Frankfurt am Main (Germany), Fax: (+49)?69?6301?83991;2. current address: Karolinska Institute, Department of Medical Biochemistry and Biophysics, Stockholm (Sweden);3. Georg‐Speyer‐Haus, Institute of Biomedical Research, Paul‐Ehrlich‐Stra?e 42–44, 60595 Frankfurt am Main (Germany) |
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| Abstract: | About 30 % of patients with severe hemophilia A develop neutralizing antibodies (inhibitors) to coagulation factor VIII (FVIII) upon treatment with exogenous factor preparations. Two peptides, C6 (NPVENMMDRDSQ) and H10 (QSPWQTWFTRAL), that mimic putative inhibitor epitopes (mimotopes), were previously selected by phage display screening of plasma samples from patients with inhibitors. Synthetic peptide mimotopes inhibited IgG binding to FVIII (IC50: 30–50 μM ). This effect was increased by an equimolar combination of both mimotopes. Mimotopes were fused to the C‐terminal multimerization domain of the C4bp α‐chain and expressed as multimers in 293T cells. Multimerized mimotopes showed improved binding to anti‐FVIII IgG and prolonged in vitro half‐life relative to synthetic peptides. The two mimotopes were combined in heteromultimers by co‐transfection of 293T cells with respective vectors, resulting in bi‐specific molecules that almost completely blocked polyclonal antibody binding to FVIII (IC50: 2–3 μM ). This strategy is capable of functionally improving synthetic peptides by multimerization and could provide a basis for novel therapeutic approaches for patients with hemophilia A and inhibitors. |
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| Keywords: | drug design hemophilia A mimotopes oligomerization phage display |
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