Immunoreactivity of specific epitopes of PrPSc is enhanced by pretreatment in a hydrated autoclave

Antigenic profile of human recombinant PrP: generation and characterization of a versatile polyclonal antiserum

We describe the quality of a rabbit polyclonal antiserum (Sal1) that was raised against mature human recombinant prion protein (rhuPrP). Epitope mapping demonstrated that the Sal1 antiserum recognized six to eight linear antigenic sites, depending on the animal species. The versatility of the antiserum was evident from the range of animal species and immunochemical techniques where it could be applied successfully. Antigen absorption studies revealed differences in the location and number of epitopes remaining after incubation with soluble or aggregated antigen.Our knowledge concerning immunoprophylaxis against prion diseases and the important role played by conformational changes of PrP is increasing rapidly. The findings reported here should add to this body of knowledge.

Detection of PrP in extraneural tissues

Transmissible spongiform encephalopathies (TSEs) or "prion diseases" are a group of unconventional fatal diseases. TSEs are characterised by the accumulation of a modified form of the normal host glycoprotein, PrP (PrP(c)). In the course of infection PrP(c) is converted to an abnormally protease resistant form, PrP(Sc). The exact nature of the infectious agent responsible for these diseases remains controversial. While there is compelling evidence that TSE agents contain an informational molecule, possibly a nucleic acid, some believe that the infectious agent or "prion" is solely composed of PrP(Sc). Nevertheless, PrP is required for TSE pathogenesis, as mice devoid of the PrP gene (PrP(-/-)) remain healthy when challenged with TSE isolates and are unable to replicate infectivity within the central nervous system (CNS) or in other tissues. In recent years immunocytochemistry has been used to pinpoint which cells are associated with abnormal accumulations of PrP, providing important information on the cellular targeting of TSE infection. In uninfected and scrapie-infected mice, PrP protein is found in the CNS and in extraneural tissues such as spleen and lymph nodes. In the peripheral lymphoid system, PrP is associated with follicular dendritic cells that are known to be important for replication of infectivity for at least one TSE strain. This review will focus on current methods for the immunocytochemical detection of PrP in murine extraneural tissues, mainly lymphoid tissues, and will discuss recent findings on the role of the peripheral lymphoid system in TSE pathogenesis.

The immunodetection of the abnormal isoform of prion protein

Transmissible spongiform encephalopathies such as scrapie in sheep and goats, Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cattle, are neurodegenerative disorders. A proposed causative agent for these diseases is an infectious protein, the so called 'prion'. An abnormal isoform of prion protein (PrPSc) can be detected according to the prion propagation method used. As PrPSc appears to constitute the main, if not the only, infectious entity its detection for the diagnosis of prion diseases is important. Immunodetection methods for PrPSc analysis are popular tools for diagnosis and research studies. In this paper, a review of the present knowledge concerning immunodetection is presented and the enhancement of the immunoreactivity of antisera to mouse and hamster prion protein peptides using the techniques of Western blotting and immunohistochemistry is summarized.