title: Development of antibody fragments for immunotherapy of prion diseases.
abstract: Prions are infectious proteins responsible for a group of fatal neurodegenerative diseases called TSEs (transmissible spongiform encephalopathies) or prion diseases. In mammals, prions reproduce themselves by recruiting the normal cellular protein PrP(C) and inducing its conversion into the disease-causing isoform denominated PrP(Sc). Recently, anti-prion antibodies have been shown to permanently cure prion-infected cells. However, the inability of full-length antibodies and proteins to cross the BBB (blood-brain barrier) hampers their use in the therapy of TSEs in vivo. Alternatively, brain delivery of prion-specific scFv (single-chain variable fragment) by AAV (adeno-associated virus) transfer delays the onset of the disease in infected mice, although protection is not complete. We investigated the anti-prion effects of a recombinant anti-PrP (D18) scFv by direct addition to scrapie-infected cell cultures or by infection with both lentivirus and AAV-transducing vectors. We show that recombinant anti-PrP scFv is able to reduce proteinase K-resistant PrP content in infected cells. In addition, we demonstrate that lentiviruses are more efficient than AAV in gene transfer of the anti-PrP scFv gene and in reducing PrP(Sc) content in infected neuronal cell lines. Finally, we have used a bioinformatic approach to construct a structural model of the D18scFv-PrP(C) complex. Interestingly, according to the docking results, Arg(PrP)(151) (Arg(151) from prion protein) is the key residue for the interactions with D18scFv, anchoring the PrP(C) to the cavity of the antibody. Taken together, these results indicate that combined passive and active immunotherapy targeting PrP might be promising strategies for therapeutic intervention in prion diseases.
authors.affiliation: Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, 25 Rue du Docteur Roux, Paris Cedex 15, France.
authors.forename: Vincenza
authors.initials: V
authors.lastname: Campana
authors.forename: Lorena
authors.initials: L
authors.lastname: Zentilin
authors.forename: Ilaria
authors.initials: I
authors.lastname: Mirabile
authors.forename: Agata
authors.initials: A
authors.lastname: Kranjc
authors.forename: Philippe
authors.initials: P
authors.lastname: Casanova
authors.forename: Mauro
authors.initials: M
authors.lastname: Giacca
authors.forename: Stanley B
authors.initials: SB
authors.lastname: Prusiner
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Legname
authors.forename: Chiara
authors.initials: C
authors.lastname: Zurzolo
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D002478:Cells, Cultured; D000229:Dependovirus / Q000235:genetics; D005822:Genetic Vectors; D007135:Immunoglobulin Variable Region / Q000276:immunology* / Q000627:therapeutic use*; D007167:Immunotherapy / Q000379:methods*; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D018621:PrPC Proteins / Q000276:immunology; D018620:PrPSc Proteins / Q000276:immunology*; D017096:Prion Diseases / Q000628:therapy*; D011328:Prions; D012608:Scrapie / Q000628:therapy; D014760:Viral Fusion Proteins / Q000276:immunology
chemical_list: D000906:Antibodies; D007135:Immunoglobulin Variable Region; D018621:PrPC Proteins; D018620:PrPSc Proteins; D011328:Prions; D014760:Viral Fusion Proteins