title: Binding of bovine T194A PrP(C) by PrP(Sc)-specific antibodies: potential implications for immunotherapy of familial prion diseases.
abstract: Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases that are based on the misfolding of a cellular prion protein (PrP(C)) into an infectious, pathological conformation (PrP(Sc)). There is proof-of-principle evidence that a prion vaccine is possible but this is tempered with concerns of the potential dangers associated with induction of immune responses to a widely-expressed self-protein. By targeting epitopes that are specifically exposed upon protein misfolding, our group developed a vaccine that induces PrP(Sc)-specific antibody responses. Here we consider the ability of this polyclonal antibody (SN6b) to bind to a mutant of PrP(C) associated with spontaneous prion disease. Polyclonal antibodies were selected to mimic the vaccination outcome and also explore all possible protein conformations of the recombinant bovine prion protein with mutation T194A [bPrP(T194A)]. This mutant is a homolog of the human T183A mutation of PrP(C) that is associated with early onset of familial dementia. With nanopore analysis, under non-denaturing conditions, we observed binding of the SN6b antibody to bPrP(T194A). This interaction was confirmed through ELISAs as well as immunoprecipitation of the recombinant and cellularly expressed forms of bPrP(T194A). This interaction did not promote formation of a protease resistant conformation of PrP in vitro. Collectively, these findings support the disease-specific approach for immunotherapy of prion diseases but also suggest that the concept of conformation-specific immunotherapy may be complicated in individuals who are genetically predisposed to PrP(C) misfolding.
authors.affiliation: Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada.
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Madampage
authors.forename: Pekka
authors.initials: P
authors.lastname: Määttänen
authors.forename: Kristen
authors.initials: K
authors.lastname: Marciniuk
authors.forename: Robert
authors.initials: R
authors.lastname: Brownlie
authors.forename: Olga
authors.initials: O
authors.lastname: Andrievskaia
authors.forename: Andrew
authors.initials: A
authors.lastname: Potter
authors.forename: Neil R
authors.initials: NR
authors.lastname: Cashman
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Lee
authors.forename: Scott
authors.initials: S
authors.lastname: Napper
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000906:Antibodies / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D000918:Antibody Specificity; D002417:Cattle; D003704:Dementia / Q000235:genetics / Q000276:immunology / Q000628:therapy; D057809:HEK293 Cells; D006801:Humans; D007167:Immunotherapy; D020125:Mutation, Missense; D018621:PrPC Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018620:PrPSc Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D017510:Protein Folding; D014612:Vaccines / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D000906:Antibodies; D018621:PrPC Proteins; D018620:PrPSc Proteins; D014612:Vaccines
keywords: antibodies; conformation-specific immunotherapy; nanopore; neurodegenerative diseases; prion diseases; protein conformation; protein denaturation; protein misfolding