The cerebrospinal fluid (CSF) of patients suffering from Creutzfeldt-Jakob disease (CJD) display two unique polypeptide chains by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). In the absence of a well-defined ante-mortem diagnostic test for bovine spongiform encephalopathy (BSE), spinal fluid samples of eight normal cows and eight cows known to carry BSE by post-mortem histological analysis were investigated to verify if equivalent polypeptides were present. Proteins with similar migration to human CJD polypeptides were not detected. But surprisingly, a cluster of polypeptide spots that was faint or not detected in normal bovine CSF samples was found to be elevated or massively increased in BSE CSF samples (more than 10-fold increase). These elevated polypeptide chains were identified as apolipoprotein E.
Hochstrasser, D. F., Frutiger, S., Wilkins, M. R., Hughes, G., & Sanchez, J. C. (1997). Elevation of apolipoprotein E in the CSF of cattle affected by BSE. FEBS Letters, 416(2), 161–163. https://doi.org/10.1016/S0014-5793(97)01191-5