Idiotypic determinants on human thyroglobulin autoantibodies derived from the serum of Hashimoto patients and EB virus transformed cell lines.

Rabbit anti-idiotypic reagents were prepared against three different human serum autoantibodies to thyroglobulin (Tg). Two of the rabbit antisera recognized private idiotypes (IdI) whilst a third antiserum recognized both an IdI and a cross-reactive idiotype (IdX) which was expressed in 50% of Hashimoto patients tested. A fourth anti-idiotype was produced against an IgM anti-Tg secreted by a patient's Epstein-Barr (EB) virus transformed lymphocytes. This antiserum only reacted with the immunizing IgM anti-Tg and therefore also recognized a private idiotype. Both the private and the public idiotypes appear to be restricted to the anti-Tg set of antibodies; this would favour the view that the IdX represents a collection of idotopes with the ability to bind Tg as their common feature, rather than a common structure based upon closely similar germ line derived amino acid sequences.