In 95% of T cells, this consists of an α and β chain, whereas in 5% of T cells this consists of γ and δ chains. This ratio changes during ontogeny and in diseased states. So the idiotype of each V region of a single immunoglobulin molecule may be comprised of as many as 15–20 idiotopes, which can be distinguished by monoclonal anti-idiotypic antibodies or defined by a specific and unique amino acid sequence. http://www.creative-biolabs.com/anti-idiotypic-antibodies-production-service-detecting-t-cell-receptors.html