The neuropathological diagnosis of Creutzfeldt-Jakob disease relies on the immunohistochemical demonstration of the proteinase-K resistant form of the prion protein (PrP(res)) in the brain tissue. The antigenicity of PrP(res) is strongly reduced by the formalin solution widely used to fix the tissue, thus the PrP(res) immunoreactivity is inconsistently detectable in formalin-fixed tissue. A better PrP(res) immunostaining can be obtained by using Carnoy's fixing solution, which is composed of ethanol, chloroform and acetic acid (6:3:1). PrP(res) can easily be extracted from Carnoy's-fixed, paraplast-embedded tissue. Accordingly, Carnoy's-fixed tissue can prior to immunolabeling be subjected to proteinase K and guanidine thiocyanate, which respectively eliminate the normal cellular form of prion protein and promote protein denaturation. In comparison with the best protocols for formalin- fixed tissue (i.e. - hydrolytic autoclaving or autoclaving in distilled water followed by formic acid and guanidine thiocyanate), PrP(res) immunostaining carried out on sections cut from Carnoy's-fixed, paraplast-embedded tissue blocks and subjected to proteinase K and guanidine thiocyanate, proved more successful to detect and map both diffuse and focal PrP(res) immunoreactivity, and to correlate the immunoreactivity pattern with MV polymorphism at PRNP codon 129 and PrP(res) banding and glycosylation pattern revealed by Western blot.
|Number of pages||7|
|Publication status||Published - Jan 2000|
ASJC Scopus subject areas
- Pathology and Forensic Medicine