Patients with severe hemophilia A, after therapeutic exposure to factor VIII (fVIII), may develop inhibitory antibodies (Ab) to fVIII, that make their treatment difficult and costly. Antigen (Ag)-specific tolerance can be induced by administering the Ag through routes [e.g. nasal subcutaneous (s.c.)] that stimulate an immune response, than to abrogate an established response. In hemophilia patients with inhibitors, prevention of their further inhibitory response to forms of fVIII antigenically different from human fVIII may be easier to obtain that abrogation of their existing response to human fVIII. Porcine fVIII (pfVIII) is a possible such alternative to human fVIII. Mice genetically deficient in fVIII are a good model of hemophilia A, including appearance of inhibitors after intravenous (i.v.) Exposure to fVIII. To determine whether tolerization procedures using synthetic epitopes recognized by pfVIII-specific CD4+ cells prevent an immune response to pfVIII, in hemophilia A mice which already had inhibitors to human fVIII, will help development of similar treatments for hemophilia patients.
The specific aims will be: 1) To determine the epitopes recognized and the cytokines secreted by anti- fVIII CD4+ cells in hemophilia A mice immunized with pfVIII, using overlapping peptides spanning the pfVIII sequence. To know the epitope repertoire of anti-pfVIII CD4+ cells, and whether they are of the Th1, Th2 or other subsets will help selecting the best tolerization procedures. 2) To determine whether prior i.v. exposure of hemophilia A mice to human fVIII affects the epitopes recognized by anti-pfVIII CD4+ cells after i.v. administrations of pfVIII. 3) To use synthetic pfVIII peptides forming CD4+ epitope sequences, for tolerization procedures in hemophilia A mice. Nasal tolerization procedures will be attempted first, using synthetic pfVIII CD4+ epitopes. If nasal tolerization will not prevent development of CD4+ and Ab responses to pfVIII, s.c. OR I.V. tolerization procedures will be attempted, using the same pfVIII epitope peptides. 4) To investigate the epitope repertoire of anti-pfVIII CD4+ cells in hemophilia patients treated sequentially with human and porcine fVIII to assess whether the characteristics of the anti-fVIII CD4+ cells in the mice are representative of those of CD4+ cells in hemophilia patients treated with human and porcine fVIII.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
1P01HL065578-01
Application #
6357766
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
2000-09-05
Project End
2005-07-31
Budget Start
Budget End
Support Year
1
Fiscal Year
2000
Total Cost
$267,360
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Type
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Gharagozlou, Soheila; Sharifian, Ramazan A; Khoshnoodi, Jalal et al. (2009) Epitope specificity of anti-factor VIII antibodies from inhibitor positive acquired and congenital haemophilia A patients using synthetic peptides spanning A and C domains. Thromb Haemost 101:834-9
Hu, Genlin; Guo, Delan; Key, Nigel S et al. (2007) Cytokine production by CD4+ T cells specific for coagulation factor VIII in healthy subjects and haemophilia A patients. Thromb Haemost 97:788-94
Kren, Betsy T; Yin, Wenxan; Key, Nigel S et al. (2007) Blood outgrowth endothelial cells as a vehicle for transgene expression of hepatocyte-secreted proteins via Sleeping Beauty. Endothelium 14:97-104
Perez-Pujol, Silvia; Marker, Paul H; Key, Nigel S (2007) Platelet microparticles are heterogeneous and highly dependent on the activation mechanism: studies using a new digital flow cytometer. Cytometry A 71:38-45
Zhang, Yan; Wroblewski, Matthew; Hertz, Marshall I et al. (2006) Analysis of chronic lung transplant rejection by MALDI-TOF profiles of bronchoalveolar lavage fluid. Proteomics 6:1001-10
Wang, Jian-Guo; Mahmud, Shawn A; Thompson, Jacob A et al. (2006) The principal eosinophil peroxidase product, HOSCN, is a uniquely potent phagocyte oxidant inducer of endothelial cell tissue factor activity: a potential mechanism for thrombosis in eosinophilic inflammatory states. Blood 107:558-65
Bach, Ronald R (2006) Tissue factor encryption. Arterioscler Thromb Vasc Biol 26:456-61
Marsik, C; Endler, G; Halama, T et al. (2006) Polymorphism in the tissue factor region is associated with basal but not endotoxin-induced tissue factor-mRNA levels in leukocytes. J Thromb Haemost 4:745-9
Ohlfest, John R; Frandsen, Joel L; Fritz, Sabine et al. (2005) Phenotypic correction and long-term expression of factor VIII in hemophilic mice by immunotolerization and nonviral gene transfer using the Sleeping Beauty transposon system. Blood 105:2691-8
Park, Chang Won; Kren, Betsy T; Largaespada, David A et al. (2005) DNA methylation of Sleeping Beauty with transposition into the mouse genome. Genes Cells 10:763-76

Showing the most recent 10 out of 30 publications