Monoclonal antibodies against the S2-serotonin receptor from rat brain that cross-react with dopamine and opiate receptors

Abstract

Balb/c mice were immunized with rat striatal integral membrane proteins. After hybridization of splenocytes with myeloma cells, hybridoma lines secreting antibodies against serotonin, dopamine and opiate receptors were detected by inhibition of ligand binding to brain membrane preparations. Antibodies from two positive lines, Mab/a9 and Mab/a18, were able to inhibit ligand binding to the S2-serotonin (Kd range: 10–100 nM), the μ-opiate (Kd range: 0.4–3 μM) and the δ-opiate receptors (Kd range: 0.7–1.1 μM), while Mab/a9 was also found to inhibit ligand binding to the D2/D4-dopamine receptor (Kd ∼ 50 nM). An apparent molecular mass of 60 kDa could be ascribed to the δ-opiate receptor and apparent molecular masses of 29 and 36 kDa to the μ-opiate receptor by ligand elution from immuno-precipitates.