SUBUNIT SELECTIVITY AND EPITOPE CHARACTERIZATION OF MABS DIRECTED AGAINST THE GABA-A BENZODIAZEPINE RECEPTOR

mAbs bd 17, bd 24, and bd 28 raised against bovine cerebral γ-aminobutyric acid (GABA(A))/benzodiazepine receptors were analyzed for their ability to detect each of 12 (GABA(A)) receptor subunits expressed in cultured mammalian cells. Results showed that mAb bd 17 recognizes epitopes on both β2 and β3 subunits while mAb bd 24 is selective for the α1 subunit of human and bovine, but not of rat origin. The latter antibody reacts with the rat α1 subunit carrying an engineered Leu at position four, documenting the first epitope mapping of a GABA(A) receptor subunit-specific mAb. In contrast to mAbs bd 17 and bd 24, mAb bd 28 reacts with all GABA(A) receptor subunits tested but not with a glycine receptor subunit, suggesting the presence of shared epitopes on subunits of GABA-gated chloride channels.