Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2007
Publication Date: 9/1/2007
Citation: Nicholson, E.M., Kunkle, R.A., Hamir, A.N., Lebepe Mazur, S., Orcutt, D. 2007. Detection of the disease-associated isoform of the prion protein in formalin-fixed tissues by Western blot. Journal of Veterinary Diagnostic Investigation. 19:548-552. Interpretive Summary: This work presents a method for the detection of the disease associated form of the prion protein in formalin fixed tissues by Western blot. An accurate diagnosis of a transmissible spongiform encephalopathy is typically confirmed by of the disease associated form of the prion protein by at least 2 distinct methods. Previously it was assumed that the formalin fixation required for analysis by one common diagnostic method, immunohistochemistry, rendered the material unsuitable for analysis by Western blot, another common diagnostic method. We describe a method for tissue treatment that allows the use of formalin fixed tissues for Western blot detection of the disease associated form of the prion protein. The approach can be readily incorporated into any existing Western blot diagnostic regimen enabling the use of formalin fixed tissue in this commonly used laboratory diagnostic technique.
Technical Abstract: Clinical signs of prion disease are not pathognomonic and include a variety of differential diagnoses. Specific immune responses have not been detected in affected organisms, serological tests to obtain evidence for the presence of the infectious agent are not available, and nucleic acid-based detection methods are not applicable due to the unusual nature of the infectious agent. Prion disease diagnosis is primarily conducted by means of immunodetection of the infectious agent, typically by at least 2 distinct procedures with immunohistochemistry and Western blot being the most informative. These approaches differ in the need for formalin fixed and frozen/fresh tissue respectively. Here we present a method for the detection of the disease associated isoform of the prion protein by Western blot using formalin fixed tissues. The approach requires only minimal modification of existing Western blot procedures and could readily be incorporated into existing detection regimines for confirmatory purposes when fresh or frozen tissues are unavailable.