DEVELOPMENT AND CHARACTERIZATION OF ANTIMORPHINE ANTI-IDIOTYPIC ANTIBODIES

DAVID SHEUNG SHUN NG, Purdue University

Abstract

The objective of this research was to develop and characterize anti-idiotypic antibodies that would recognize and bind the opiate receptors. The anti-idiotypic antibodies were developed against antimorphine antibodies which were produced in rabbits by immunization with 3-O-carboxymethylmorphine-bovine serum albumin. In vitro studies demonstrated that binding of opiate ligands to antimorphine antibodies was saturable, stereospecific, and selective among agonists of different opiate receptor subtypes. In isolated mouse vas deferens, antimorphine antibodies (90 (mu)g/ml) antagonized the inhibitory action of morphine but not that of ketocyclazocine. In the tail flick analgesic test, antimorphine antibodies (3 (mu)g, icv) produced a transient attenuation of the analgesic effect of morphine in mice. Ketocyclazocine analgesia was not antagonized by the same treatment. These results indicated that antimorphine antibodies behaved as 'receptor-like' molecules with recognition properties similar to the opiate receptors. Anti-idiotypic antibodies which cross reacted with the opiate receptors were generated by immunizing guinea pigs with purified antimorphine antibodies. Antiserum from immunized guinea pigs reacted positively to antimorphine antibodies in the interfacial (ring) test and decreased the amount of antimorphine antibodies able to react with morphine in binding assay. Antimorphine anti-idiotypic antibodies were also detected in guinea pig antisera by their inhibition of ('3)H-naloxone binding to mouse brain opiate binding sites. The inhibition in ligand binding was concentration dependent and was due to a decrease in the number of binding sites without altering the affinity of the remaining binding sites. In bioassays for opiates, guinea pig antiserum inhibited the contraction of electrically stimulated guinea pig ileal longitudinal muscle and mouse vas deferens. However, the inhibition was not reversed by naloxone. In the tail flick test, guinea pig antiserum (5 (mu)l, icv) alone did not induce an antinociceptive response in mice but attenuated the analgesic effect of morphine (2.5 mg/kg, sc). It is concluded that antimorphine anti-idiotypic antibodies, which react with the opiate receptors, were developed without isolating the receptors. These anti-idiotypic antibodies would be important tools to study the structure and function of the opiate receptors.

Degree

Ph.D.

Subject Area

Pharmacology

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