Binding of bovine T194A PrPC by PrPSc-specific antibodies |
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Authors: | Claudia A Madampage Pekka M??tt?nen Kristen Marciniuk Robert Brownlie Olga Andrievskaia Andrew Potter Neil R Cashman Jeremy S Lee Scott Napper |
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Institution: | 1.Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada;2.Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada;3.Canadian Food Inspection Agency; Ottawa Laboratory Fallowfield; Ottawa, ON Canada;4.Vancouver Coastal Health Research Institute; University of British Columbia; Vancouver, BC Canada |
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Abstract: | Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases that are based on the misfolding of a cellular prion protein (PrPC) into an infectious, pathological conformation (PrPSc). 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 PrPSc-specific antibody responses. Here we consider the ability of this polyclonal antibody (SN6b) to bind to a mutant of PrPC 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 PrPC 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 PrPC misfolding. |
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Keywords: | nanopore prion diseases conformation-specific immunotherapy antibodies protein conformation protein misfolding protein denaturation neurodegenerative diseases |
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