A synthetic peptide induces a new anti-dextran idiotype.

We have synthesized the JH1 peptide and coupled it to keyhole limpet haemocyanin for use as an immunogen. A serum from an animal hyperimmunized with this immunogen demonstrated binding to both peptide and native immunoglobulin. Furthermore, this serum seems to define an idiotypic determinant nearly unique to alpha (1 ---- 3) dextran-binding immunoglobulins. Synthetic peptide immunogens may be a useful tool in probing the molecular basis of idiotypy.