VWF protects FVIII from endocytosis by dendritic cells and subsequent presentation to immune effectors

Blood. 2007 Jan 15;109(2):610-2. doi: 10.1182/blood-2006-05-022756. Epub 2006 Sep 19.

Abstract

Von Willebrand factor (VWF) is a chaperone molecule for procoagulant factor VIII (FVIII). Its role in the reduction of the immunogenicity of therapeutic FVIII in patients with hemophilia A has been evoked but lacks clear cellular and molecular rationale. Here, we demonstrate that VWF protects FVIII from being endocytosed by human dendritic cells (DCs) and subsequently presented to FVIII-specific T cells. The immunoprotective effect of VWF requires a physical interaction with FVIII because the endocytosis of FVIII was significantly restored on hindering the formation of the VWF-FVIII complex. Interestingly, VWF had no direct inhibitory effect either on the ability of DCs to present antigenic peptides or on the activation potency of CD4+ T cells. We thus propose that VWF may reduce the immunogenicity of FVIII by preventing, upstream from the activation of immune effectors, the entry of FVIII in professional antigen-presenting cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen Presentation / immunology*
  • Cells, Cultured
  • Dendritic Cells / immunology*
  • Dendritic Cells / ultrastructure
  • Endocytosis / immunology*
  • Factor VIII / immunology*
  • Humans
  • T-Lymphocytes / immunology*
  • von Willebrand Factor / physiology*

Substances

  • von Willebrand Factor
  • Factor VIII