Immunoreactivity of a synthetic pentadecapeptide corresponding to the N-terminal region of the scrapie prion protein.

A pentadecapeptide with an amino acid sequence corresponding to the amino-terminal region of the scrapie prion protein was synthesized. Immunization of a rabbit with the peptide conjugated with ovalbumin induced specific antibodies. The antibodies reacted with all three of the major polypeptides in a proteinase K-treated fraction obtained from brains of mice infected with the Obihiro strain of scrapie agent. Some peptides in the proteinase-untreated fraction also shared antigenicity with the three major polypeptides. Specific polypeptides were also detected by the antiserum in a fraction prepared from spleens, but only two of the three major polypeptides were found and the amounts of the polypeptides were less than in brain.