Monoclonal antibodies to dalargin--a synthetic analog of enkephalins.

Monoclonal antibodies (MABs) to a new drug Dalargin (Tyr-D-Ala-Gly-Phe-Leu-Arg) enhancing ulcer healing have been produced. Dalargin is a synthetic analog of Leu-enkephalin. With about 40 compounds tested in competition radioimmunoassay it has been shown that specificity of the MABs is directed against the N-terminal tetrapeptide of the molecule. The MABs are sensitive to amino acid substitutions in any of the positions of the fragment and have no cross-reactivity with endogenous opioids. Their further application in pharmacokinetic studies in humans and for characterization of opioid receptors is discussed.