Antibody-mediated neuronal apoptosis: therapeutic implications for prion diseases

Neuronal cell death is considered to be a hallmark in prion diseases. These disorders are believed to result from the post-translational conversion of a normal cell membrane sialoglycoprotein PrPC, composed primarily of alpha-helical structure, into a disease specific isoform, PrPSc that is rich in beta-sheet and partially proteinase-resistant. Recent in vivo studies indicate that prion replication can be inhibited by anti-PrP monoclonal antibodies that led to the indefinite delay in the development of prion disease. The recent report by Solforosi and colleagues has increased the need to understand pathway(s) leading to prion-associated apoptosis and neuronal death thought to be the cause of death in transmissible spongiform encephalopathy (TSE) individuals. Furthermore, these reports increased momentum about the use of antibody-based therapy in prion diseases, although great caution should be exerted when using anti-prion antibodies directly into the central nervous system (CNS) with special emphasis on refined strategies such as specific targeting of regions of the prion protein thought not to be involved in signalling pathways.