PRION PROTEIN IMMUNOCYTOCHEMISTRY - UK 5 CENTER CONSENSUS REPORT

Creutzfeldt-Jakob disease (CJD) and other prion diseases are associate d with the deposition of insoluble prion protein (PrPCJD) in the centr al nervous system (CNS). Antibodies raised against PrPCJD also react w ith its precursor protein, a soluble form of PrP (PrPC), which is wide ly distributed in the normal CNS. This cross-reactivity has in the pas t raised doubts as to the specificity and diagnostic reliability of Pr P immunolocalization, especially in familiar cases which are atypical clinically and which lack characteristic pathology findings. Following an MRC-funded workshop which focused on this problem, a multicentre p rospective study was set up to identify a reliable protocol for PrPCJD immunocytochemistry. Five UK centres took part in this study and demo nstrated consistent staining of plaques, vacuolar deposits in severe s pongiform change, and perineuronal deposits using a variety of antibod ies and enhancement procedures. A protocol using formic acid, guanidin e thiocyanate, and hydrated autoclaving pre-treatment in conjunction w ith a monoclonal PrPCJD antibody produced the clearest immunochemical results and is presented as the consensus UK recommendation for PrPCJD immunocytochemical procedures.