The assay development of a molecular marker for transmissible spongiform encephalopathies

The transmissible spongiform encephalopathies are a group of neurodegenerative diseases which include Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep, and bovine spongiform encephalopathy (BSE) in cattle. Two-dimensional electrophoresis of proteins was previously used to identify two marker proteins, 130/131, which are selectively present in the cerebrospinal fluid (CSF) of patients with CJD and not in patients with other dementias. The recent characterization of these proteins by amino acid sequencing has identified them as members of the 14-3-3 family of proteins. Polyclonal antibodies against 14-3-3 (all isoforms), 14-3-3 gamma, 14-3-3 beta, and 14-3-3 theta are immunoreactive with a 30 kDa marker band from CJD CSF. Silver staining of two-dimensional electrophoresis separated BSE CSF proteins does not identify a similar marker. However, 14-3-3 immunoreactivity is found in cattle CSF when these proteins are blotted to polyvinylidene difluoride but not when blotted to nitrocellulose.