PrPSc-specific antibodies do not induce prion disease or misfolding of PrPC in highly susceptible Tga20 mice

Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders caused by misfolding of a cellular protein PrP^C into an infectious conformation PrP^Sc. Previously our group demonstrated induction of PrP^Sc-specific antibodies with a SN6b vaccine that targets regions of the protein that are exposed upon misfolding. There are concerns that these antibodies could function as templates to promote misfolding and cause disease. To evaluate the consequences of prolonged exposure to PrP^Sc-specific antibodies in a prion sensitized animal, tga20 mice were vaccinated with the SN6b vaccine. No clinical signs of disease were detected up to 255 d post-vaccination, and postmortem assay of brains and spleens revealed no proteinase-K resistant PrP. These results suggest that vaccinating against TSEs with the SN6b antigen is safe from the standpoint of prion disease induction.