Characteristics of a monoclonal beta-endorphin antibody recognizing the N-terminus of opioid peptides.

The properties of a mouse monoclonal antibody to beta-endorphin secreted by a clone of hybrid myelomas (3-E7) are described. The antibody displays virtually complete cross-reactivity to met-enkephalin and leu-enkephalin, but no cross-reactivity to beta-lipotropin, alpha-N-acetyl-beta-endorphin and des-Tyr1-beta-endorphin. Substantial cross-reactivity is seen with some other naturally occurring opioid peptides bearing the enkephalin sequence, such as dynorphin, alpha-neo-endorphin and BAM 22, but cross-reactivity is lacking in the case of certain synthetic enkephalin derivatives possessing a D-amino acid in position 2. The data indicate that for the binding of an antigen to the antibody the N-terminal tyrosine moiety is essential. The antibody recognizes, thus, a site which is of functional significance for the interaction of many naturally occurring opioid peptides with the opiate receptor.