Cloning and sequence analysis of cDNAs encoding the heavy and light chain variable regions of an Ab2beta anti-idiotypic monoclonal antibody possessing an internal image of cocaine.

We report here the cloning and sequence analysis of cDNAs encoding the variable regions of an Ab2beta anti-idiotypic monoclonal antibody (K1-4c, gamma1kappa) that mimics the configuration of cocaine. The Ab2beta specifically binds to the human dopamine transporter as shown by confocal immunofluorescence microscopy. The sequence of the heavy chain complementarity-determining region 3 of K1-4c is strikingly similar to that of a monoclonal antibody (F11.2.32) specific for HIV-1 protease. Three or four amino acids in the epitope recognized by the anti-HIV-1 protease antibody are also present in the third extracellular loop of the dopamine transporter. This epitope is within the conserved region of the known transporters for dopamine, norepinephrine and serotonin in Homo sapiens, Rattus norvegicus, Caenorhabditis elegans and Drosophila melanogaster.