Detection of dermorphin-like immunoreactivity in immune tissues

Site-directed antibodies against synthetic relateddermorphin peptides have previously been produced andcharacterized. One of them, specifically recognizingthe crucial opioid message (the N-terminal part ofthe molecule Tyr-D-Ala-Phe-Gly), was used in the presentstudy in order to detect and localize endogenousdermorphin-like molecules in immune tissues.Dermorphin-like peptides were found to be present inspleen and thymus of rat and mouse. The HPLCprofile of the immunoreactive material showeda major peak at a retention time of 32±1 min.Purification of immune cells by panning proceduresshowed that both B and T cells contained thisimmunoreactive material. Biochemical characterizationof the dermorphin-like immunoreactivity indicated thatthis material is a peptide resistant toaminopeptidase hydrolysis, suggesting the presence ofa putative D-amino acid residue or a residueconferring resistance to a proteolytic process.