Hydrated autoclave pretreatment enhancement of prion protein immunoreactivity in formalin-fixed bovine spongiform encephalopathy-affected brain.

The efficacy of three pretreatment techniques for the detection of prion protein (PrP) in formalin-fixed, paraffin-embedded bovine spongiform encephalopathy (BSE)--affected brain tissue were compared using automated image analysis. The most abundant immunostaining was in the form of particulate expression observed in sections pretreated with hydrated autoclaving for 30 min. Considerably less immunostaining occurred in sections pretreated with formic acid and no specific particulate immunostaining was detected in sections pretreated with hydrolytic autoclaving. Hydrated autoclaving pretreatment of sections prior to PrP immunolabelling gives visualisation of widespread sites of abnormal PrP deposition in the brain, allowing detailed study of the form and distribution of the protein in routinely fixed bovine central nervous system affected with BSE.