AbstractTwo polyclonal antibodies were raised by immunizing rabbits with two non carrier‐linked synthetic peptides whose amino acid sequences corresponded to codons 89–107 (peptide P1) and 219–233 (peptide P2) of the translated cDNA sequence of murine PrP protein. These free peptides, whose structural characteristics in solution were studied by circular dichroism, elicited a reasonable immunologic response in animals. Both antibodies still recognized the corresponding immunogens after affinity chromatography purification. However, only antibodies raised to the former sequence reacted by immunobolt with a purified preparation of murine scrapie amyloid protein. These findings are discussed together with their correlation to peptide structure and the effectiveness of this simplified immunization proc