Generating monoclonal antibodies to the opioid receptor.

BALB/c mice were immunized with an opioid receptor complex over the period of 1 year. Spleen cells from the mouse, whose serum inhibited opiate binding to rat neural membranes to the greatest extent, were fused with P3-X63-Ag8. 653.3 myeloma cells. By radioimmunoassay (RIA), 32 cell lines have been detected that secrete an antibody to a component of the isolated receptor complex. Antibodies from 2 of the cell lines have an effect on opiate binding to rat neural membranes. One antibody, OR-689.2.4 is an IgM cryoglobulin. This antibody partially inhibited the binding of 3H-dihydromorphine (3H-DHM), 3H-naloxone, 3H-ethylketocyclazocine (3H-EKC), and 3H-D-Ala2, D-Leu5 enkephalin (3H-DADLE) to rat neural membranes. The other antibody, OR-465.3, inhibited the binding of 3H-DHM and 3H-naloxone to rat neural membranes by a maximum of 70%. This antibody also inhibited the binding of 3H-DADLE to neural membranes but, did not affect the binding of this peptide to membranes from the neuroblastoma-glioma hybrid cell line, NG108-15. Work is ongoing to generate monoclonal antibodies specific for each subclass of opioid receptor.