Molecular cloning of cDNAs for immunoglobulin variable regions of a monoclonal anti-idiotypic antibody specific for sigma receptors.

In previous work on sigma (sigma) receptors, we established a hybridoma cell line, 10G9, producing a monoclonal anti-idiotypic antibody (anti-Id mAb) to the monoclonal and anti-haloperidol antibody. The anti-Id mAb showed specific binding affinity to sigma receptors in immunoprecipitation and competition experiments. Here we isolated and sequenced cDNA clones for the variable regions of the anti-Id mAb. These combinations of segments and formation of the unique CDR3 were considered to be the structural basis for the diversity of the antigen-binding site of our anti-Id mAb and, therefore, for its binding activity to sigma receptors.