The idiotype may be used as either protein or DNA in therapeutic vaccines. In the traditional rescue hybridization technique, the idiotype protein is produced by fusing the lymphoma cells with mouse myeloma cells to generate Id-secreting hybridomas. For recombinant idiotype protein production, the variable regions of the heavy (IGHV) and light (IGLV) chains of the tumor immunoglobulin (Ig) are cloned by polymerase chain reaction and inserted into plasmid or viral vectors for expression of idiotype proteins in cell lines, tobacco plants, or Escherichia coli. For idiotype DNA vaccination, the IGHV and IGLV of the tumor immunoglobulin are cloned and inserted into a plasmid vector for naked DNA injection.