Morphine-mimetic anti-paratypic antibodies: cross-reactive properties.

Polyclonal, anti-idiotypic, rabbit antibodies have been raised against four murine monoclonal anti-morphine Fab fragments. The antibody preparations, after affinity purification, have been shown to contain an anti-paratypic fraction which reversibly inhibits morphine binding to the anti-morphine antibodies and to cellular opiate receptors. Using some of the unique properties of this system, for the first time cross-reactivities of anti-paratypic antibodies with the monoclonal anti-morphine IgGs have been examined including competition for the same binding sites by a classical opiate agonist/antagonist pair.