title: A monoclonal antibody capable of modulating opioid binding to rat neural membranes.
abstract: A monoclonal antibody capable of inhibiting opioid binding to rat neural membranes has been produced. Spleen cells from a BALB/c mouse, immunized with a partially purified opioid receptor complex, were fused with P3-X63.Ag8.653.3 myeloma cells. The cell line OR-689.2.4 secreted an IgM that was capable of partially inhibiting opioid binding to rat neural membranes under equilibrium binding conditions, while not affecting the binding of nonopioid ligands. Control mouse immunoglobulins and heat-denatured OR-689.2.4 did not inhibit opioid binding to membranes. The purified immunoglobulin inhibited the binding of [3H]dihydromorphine in a titrable, saturable, and reversible manner, as well as the binding of the delta-ligand [3H][D-Ala2,D-Leu5]enkephalin, the kappa-ligand [3H] ethylketocyclazocine, and 3H-labeled antagonists. In addition to blocking the binding of opioids to membranes, the immunoglobulin could also displace bound [3H]dihydromorphine from neural membranes. The 125I-labeled immunoglobulin specifically bound to neural membranes with a Kd of 1.3 nM and a maximal number of binding sites of 41.8 fmol/0.25 mg of membrane protein. In a titrable manner, the immunoglobulin precipitated opioid binding sites from a solubilized preparation of neural membranes. When OR-689.2.4 conjugated to Sepharose was incubated with the partially purified opioid receptor complex, labeled with 125I, a 35,000-dalton protein was specifically bound by the immunoglobulin. This antibody provides a tool for probing the multiple opioid binding sites.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D003496:Cyclazocine / Q000031:analogs & derivatives / Q000378:metabolism; D004090:Dihydromorphine / Q000378:metabolism; D004174:Diprenorphine / Q000378:metabolism; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D016314:Ethylketocyclazocine; D005445:Flunitrazepam / Q000378:metabolism; D007075:Immunoglobulin M; D007700:Kinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D009270:Naloxone / Q000378:metabolism; D009294:Narcotics / Q000378:metabolism*; D009417:Nerve Tissue / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D007075:Immunoglobulin M; D009294:Narcotics; D011957:Receptors, Opioid; D004174:Diprenorphine; D009270:Naloxone; D016314:Ethylketocyclazocine; D004743:Enkephalin, Leucine; D005445:Flunitrazepam; D016308:Enkephalin, Leucine-2-Alanine; D011813:Quinuclidinyl Benzilate; D004090:Dihydromorphine; D003496:Cyclazocine